Biomechanics Final Paper

WESTERN OREGON UNIVERSITY

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The Biomechanical Analysis of the Olympic Snatch Lift

PE 483

JR Jones & John Taylor

3/19/2010

Procedure:

The purpose of this project was to determine the biomechanical advantages

that are taking place during the Olympic snatch lift. Not only are we trying to

determine the correct bar path, amount of time spent in each phase of the

exercise, and/or the specific joint angles during those phases. How does the

increase in weight change the amount of velocity generated throughout the lift?

What is the most efficient method of hoisting that bar overhead in order to

avoid injury and maximize force production? How will the acceleration be

effected during an increase in the weight of the bar in comparison to the lower

weights? What type of variations of this exercise could be used in order to

improve different phases of this lift? These questions were some of the major

reasons JR Jones and I decided to choose this activity. JR had not had much

previous experience with the activity and since he is interested in bodybuilding

and has even competed before, we thought it to be a good idea to divulge into

this topic even further. I am a fan of the snatch exercise as I am also a fan of

plyometric training. I am the type of person that believes that training

explosive type of movements and muscles will improve athletic performance. JR

and I both share the interest of training individuals and would both like to one

day pursue a graduate degree in the field of exercise science, maybe even

biomechanics. We both were interested in the fundamentals of the movement,

especially JR because it was an opportunity to completely absorb the information

since he had no prior bad habits to deal with. I often would worry about not

making mistakes when I would perform the exercise, and therefore, I would assume

that most of my analysis would be spent on fixing the potential mistakes within

each identified phase of my lift and also fix any mechanical flaws. Those types

of flaws have yet to be fully recognized, however, we can assume the having an

arched back is going to inhibit performance and may even result in an injury. We

can assume that if the individual does not have their feet about shoulder width

apart and adjacent with each other, they might also suffer and injury and/or

have trouble completing the lift. The Olympic snatch lift is designed to be

performed with certain movement principles, and through this analysis, we will

attempt to identify each one of those and how that movement principle relates to

the biomechanical conceptual methods such as inertia, impulse, work, and power.

Those principles will be well-known by the end of this analysis, and we as a

group intend on figuring out why and how such events are possible. The velocity

of the bar in motion, the acceleration of the bar, and how the joint actions

begin to change throughout different points in the movement, are all concepts

that were intriguing to both me and JR. Wanting to choose something that would

lead us into brand new territory, unlike a baseball player choosing a baseball

swing or pitch, or field goal kicking using an extra point, I chose not to do

something football related and JR chose something he had never performed prior

to this analysis. I was never a big fan of the Olympic snatch lift growing up

albeit I was a big fan of the power clean, and power clean and jerk. Snatch was

an exercise that you couldnt load up the weight as much and required many more

technical aspects than getting underneath a large amount of weight. I saw an

incredible athlete perform the snatch a couple years after that and realized how

great of an athletic tool that it can be. It offers a sound technical learning

experience; the whole body is working in unison, and offers the explosive type

of movement associated with a number of sports. I did a paper in the winter of

2010 about plyometric training (PT) and came to the conclusion that PT helps

athletes in variety of sports, such as volleyball, tennis, and wrestling. I

imagine that after completed a similar study, and/or even completing this

project will lead me to the same conclusion about the Olympic snatch lift.

Mechanical Principles:

The objective of the snatch is to lift the barbell from a resting position

on the ground, to stable a position with overhead with the arms locked out.

Inertia is an objects resistance to change. As described by Newtons Law of

Inertia, an object in motion will remain in motion unless acted on by and

outside force. Mass is directly related to inertia. The greater mass an object

has, the greater its inertia, or resistance to change. In order for an athlete

to complete a snatch, they have to apply enough force on the bar to overcome its

resting inertia. Once the bar is moving it will not accelerate past its initial

velocity unless the athlete continues to apply a force on the bar great enough

to overcome its moving inertia. An Impulse is the amount of force applied over

time. Inertia of the bar requires a continual force to be applied to it. The

greater the amount of time relative to the absolute time that force can be

applied to the bar, the greater the vertical displacement will be. This is

closely related to work. Mechanical work describes the amount of force applied

over a distance. Similar to an impulse, the greater work, or magnitude of the

force and the distance through which it is applied, the greater the final

vertical displacement of the bar will be. The success of the snatch depends on

the maximum height of the bar to be great enough to allow for the athlete to get

into the catch position under the bar the force of gravity is working on the bar

in the opposite direction of the pull. To overcome the force of gravity and

benefit from inertia to achieve maximal vertical displacement above the point at

which force can effectively be applied the athlete must generate momentum.

Momentum is the quantity of an objects movement, and describes the velocity of

the mass of an object. The greater the momentum achieved, the better it will

resist the change of direction imposed by gravity. This is inertia working in

favor of the athlete, resulting in a vertical distance greater than that of the

impulse and work. To generate this momentum the bar must be accelerated to its

maximum velocity.

The total work done on the bar describes the force that is being applied

to the bar, and the distance through which it is applied. To do work no change

acceleration past the initial velocity it is necessary. To successfully perform

the snatch it is necessary to reach maximum velocity. Power is the rate of work

done on the bar. It describes the change in work over time. The greater the

amount of work on the bar over the shortest amount of time, greater the power.

The more power generated means that a greater force is applied to the bar. That

force pulls the bar through a greater distance in a shorter amount of time.

This acceleration results in a greater max velocity of the bar at the end of the

pull. A greater momentum at this point when the athlete can no longer apply

force the bar resists the opposing pull of gravity. The resulting vertical

displacement allows time to achieve optimal position to catch the bar overhead.

The Muscle Snatch

(Dawes, J. 2007)

The snatch exercise is as an exercise that is commonly used to improve

explosiveness and develop overall athleticism (Daws, 2007). The power and full

snatches are a great way to incorporate a dynamic warm-up that will involve

total body movement training. The muscle snatch is an exercise that is performed

much slower than some of its more explosive counterparts such as the clean.

Muscle snatch is a great exercise to incorporate into a training program because

it does provide some explosion and the lift is so technical and dynamic, that

several body parts have to be working in-synch, otherwise there could be a

breakdown that might even result in an injury. Sports that will likely

incorporate snatch into the training regiment include but are by no means

limited to, football players, wrestlers, volleyball players, track and field

sprinters/jumpers, power lifters, and rugby players. The snatch is an exercise

that takes time and effort in order to be performed correctly and efficiently so

the athlete isnt at an increased risk of injury. Many athletic events require

the athlete to use one-side of their body at one time, which has led to the

incorporation of more single-arm snatch activities. For example, and NFL

linebacker will benefit from these type of exercises because of situations where

they are asked to shed blocks coming from the opposing team in or to make a

play. Being able to have the hips and single-arm explode in unison during the

single-arm snatch exercise has the ability to translate onto the football field

in that given situation. There are other reasons why the snatch is a great

exercise that becomes incorporated in several strength and conditioning circles,

whether its for a great warm-up or improved performance on the playing field.

Biomechanical comparison of unilateral and bilateral power snatch lifts.

(Lauder & Lake, 2008)

I mentioned before how certain sports might include the unilateral power

snatch because they may encounter situations on the playing surface that would

require a unilateral movement as opposed to a bilateral movement. I saw a

magnificent catch in the 2009 College Bowl series when a North Carolina player

made an acrobatic catch and had to use a couple of one-footed hops to keep in

the end zone. This was a situation where unilateral leg squats might have played

a role in this excellent example of body control. The same situation goes for

this exercise, I used to the example of a linebacker in football benefitting

from unilateral snatch lifts, especially an outside linebacker who encounters

most blocks with one side. Biomechanical characteristics of the one-handed

dumbbell power snatch were examined to determine whether significant differences

existed between unilateral and bilateral weightlifting movements. Kinetic and

kinematic movement data were recorded from 10 power weightlifters during one

handed dumbbell and traditional barbell power snatch performance with loads of

approximately 80% of respective lift one repetition maximums with the use of 2

synchronized Kistler force plates and high-speed 3 dimensional video. The

results highlighted asymmetry in the ground reaction force and kinematic profile

of the one-armed dumbbell power snatch, which was a deviation from the bilateral

movement. In addition, the non-lifting side of the one-armed dumbbell catching

phase was double that of the lifting side loading rate. These results measure

balanced deviations in the movement patterns of the unilateral power snatch

movement both during the concentric muscular tightening of load vertical

displacement, and the loading implications of unilateral landing. That supports

the debate that unilateral variations of weightlifting movements may provide a

different training stimulus. Which would support my theory that certain athletes

will benefit from this unilateral type of training, some more than others.

Triple Extension: The Key to Athletic Power. (Frounfelter, 2009)

This article focuses on the benefits of training triple extension ability

for weightlifters, suggesting that the explosive action of ankle, knee, and hip

during weightlifting is a critical factor in increasing athletic success. It

describes weightlifting movements such as the power clean and power snatch that

can help in improving the triple extension of lifters. Triple extension is a

position of the hips, knees, and ankles that power lifters are trying to achieve

in order to improve performance. I thought this would be a good article to get

off the library reserve system because it has to deal with explosion and since

the abstract isnt very long, I am curious to see what the NSCAs Performance

Training Journal has to offer. I did find this article in Sport Discus and

therefore it might not be beneficial for me to use once the article arrives and

I have read it over. The topic of triple extension and how the power snatch can

improve that position is why I included this article into my lit review

assignment. This article is only a year old and so that was also another factor

that made me want to get this from the library reserve, new information about

the snatch and how it may improve athletic performance is going to be useful

information. The author has affiliations as a staff physical therapist at the

Baldwin Area Medical Center in Baldwin, Wisconsin. There were enough positives

about this article that allowed me to choose it as one of my 5 sources for this

review, and although I dont have too much information on the article, I have

enough reasons for why I should order it off reserve, and for now, that is good

enough for me.

Unsuccessful vs. successful performance in snatch lifts: a kinematic approach.

(Gourgoulis, Aggeloussis, Garas, & Mavromatis, 2009)

The rationale of this study was to determine the kinematic characteristics

of snatch movements that result in an unsuccessful performance, involving the

barbells drop in front of the weightlifter. There were 7 high-level men

weightlifters competing at the international level. The successful and

unsuccessful snatch lifts of each one with the same load were recorded with 2 S-

VHS camcorders, and selected points onto the body and the barbell were digitized

manually using the Ariel Performance Analysis System. The statistical treatment

of the data showed no significant differences between successful and

unsuccessful lifts in the angular displacement and velocity data of the lower

limb joints. No significant differences were also found in the trajectory and

vertical linear velocity of the barbell or the generated work and power output

during the first and second pulls of the lift. However, significant differences

were found in the direction of the barbells resultant acceleration vector,

suggesting that proper force application onto the barbell is a crucial factor

for a successful performance in snatch lifts. Coaches should then pay particular

attention to the applied force onto the barbell from the first pull. The last

two sentences of that abstract were the reasons why I chose this one as one of

my five. It was a good example of how vectors play a crucial role in the snatch

lift, the book shows an example of this, and Dr. Caster used an example from his

Biomechanics course at WOU describing a country where the weightlifters

understood this principle. Its not necessarily straight up, but up and

backwards, the difference in your vector may be the difference in successful and

unsuccessful performance.

Coaching of the Snatch/Clean Pulls With the High Pull Variation.

(Waller, Piper, & Miller, 2009)

The information in this article presents the technique of snatch/clean

pulls for strength and conditioning professionals to be used in a strength

program that will enhance an athletes ability to produce speed and power. Pulls

by definition, are explosive lifts of a bar that rests on a platform or pulling

blocks. The focus is given on two pull styles, the clean grip and the snatch

grip, which can reportedly be further broken down into pull and high-pull.

Instructions on the technique of full pull and coaching the pulls are included.

This would be a credible article to get off of the library reserve because it

discusses the differences in techniques between the snatch and the clean and

gives coaching points on both. My topic is the snatch and this could be a good

resource to use in order to emphasize coaching points of the lift and ways those

same coaching points may translate somewhere on the sports playing surface. I do

not have all the information about this article but from what the abstract has

given me and the concept that these are sport science professionals, this seems

like a good article to use. It will be interesting to see if the coaching points

of this article match up and/or relate to the vector concept from article #4.

Technical aspects of this lift should include some understanding of vector

concepts, I hope it doesnt just say, lift the bar straight up and get under

it. The language used needs to be critical have some correlation to the other

articles otherwise I might have to throw it out. From what I can tell though, it

seems like a credible article from a well know journal.

Power lifting Versus Weightlifting for Athletic Performance (Chiu, 2007)

It is explained in the article Power lifting Versus Weightlifting for

Athletic Performance (Chiu, 2007) that specificity of training is key to

successfully improving performance. If an athlete is required to compete

explosively, then that athlete must train explosively. Explosiveness, or power,

can be defined as Power= force x velocity. To improve power, training should

focus on developing rate of force production, as well as maximal force

production. Maximal strength training improves an athletes ability to produce

force. Standard exercises used in maximal strength training such as the bench

press, dead lift, and squat, improve max force production, but do not elicit max

power outputs. This is due to the speed the exercises are traditionally

performed at. These exercises can be modified to allow for greater power

outputs, but only at the expense of intensity. Performance of these exercises

at lower intensities negates the maximal strength adaptations they are

originally designed to produce.

Weight lifting movements are ground-based exercises that incorporate

multiple joints and muscle groups. The power snatch, and power clean and jerk,

are weight lifting exercises that will improve explosive strength. They require

max, or near maximal power outputs as well as optimal balance and coordination

for successful performance. The characteristics of these exercises are very

similar to the actions executed in most all athletic competition.

Implementation of these into strength and conditioning program will facilitate

the enhancement of such qualities in a safe and controlled environment.

When designing a strength and conditioning program, both max force and

velocity should be considered. To accomplish this, the parameters of the

program should include a variation of loads and subsequent velocities.

Incorporating Weight lifting/explosive power training and maximal strength

training into your program will elicit the best results.

Biomechanical Comparison of Unilateral and Bilateral Power Snatch Exercises

(Lauder & Lake, 2008)

As discussed in the article Biomechanical Comparison of Unilateral and

Bilateral Power Snatch Exercises (Lauder & Lake, 2008), the implementation of

unilateral weight lifting exercises into training programs has become

increasingly popular. Using dumbbells in place of barbells allows for a less

technical, yet effective method of implementing variety to strength and

conditioning programs. The rational for the use of unilateral movements stems

from the asymmetry observed in the performance of such an exercise. The idea is

that these may result in beneficial adaptations different from those of

traditional bilateral versions. The power snatch requires a loaded bar to be

lifted overhead in one movement. The performance of this movement is dependent

upon the sequence and the magnitude of the forces applied and the subsequent

lower limb angular displacements. Lauder and Lake conducted a biomechanical

comparison of unilateral and bilateral power snatch lifts. The purpose for this

comparison was to improve upon the current understanding of biomechanical

characteristics involved with these lifts. With this understanding coaches can

better use the snatch exercise and its variations, as a tool to enhance

performance while avoiding injury.

Ten male weight lifters average age (30.210.2) years volunteered for the

study. The average height and mass of the subjects was (1744.4cm) and

(81.514.6kg) respectively. Each had at least one year of experience with both

movements having been used consistently as a part of their training programs.

Each individual performed three trials at 80% of both the unilateral dumbbell

snatch and the bilateral barbell snatch. The joint and bar kinematics were

recorded with a 3 dimensional video camera as well as two synchronized force

platforms. This configuration allowed for simultaneous recording of joint

kinematics and vertical ground reaction forces for each leg concurrently. For

better comparison, both the dumbbell and barbell snatch movements were broken

down into comparable phases. These lift-phases were determined by changes in

knee angular displacement and are described in order as: First Pull, Knee

Flexion, Second Pull, unweighting, and catch loading phase.

Analysis of the barbell snatch data supported observations that both sides

work in symmetrical fashion with Joint kinematics and vertical force ground

reaction forces demonstrated negligible dissimilarity. In comparison, the

dumbbell snatch results reflected asymmetry between legs in joint kinematics and

vertical ground reaction forces. The leg same to the arm holding the weight,

though the magnitude was lesser, the vertical ground reaction force patterns

were similar to that seen in the barbell snatch. These patterns present greater

amplitude between the end of the knee flexion phase and the second pull phase.

This, depicting the decrease in ground reaction force just before increased

force production initiating the second pull phase. The non- lifting side leg

pattern shows consistent, and greater vertical ground reaction force being

generated through the pull phase at a significantly faster rate compared to the

lifting side leg. The non-lifting side leg also showed a vertical ground force

generation rate almost twice that of the lifting side leg during the catch

loading phase. This supports the rationale behind the method of incorporating

unilateral exercises into strength and conditioning programs as a way to add

variance.

Patterns illustrating the kinetics of the bar through each snatch variation

were derived from the data as well. The barbell snatch demonstrated greater

horizontal displacement, less vertical displacement, and lower vertical velocity

compared to the dumbbell snatch. These results show the influence the bar has

on the kinematics of the snatch. In the barbell variation the bar must be

pulled up to, and around the knees. As a result, vertical displacement and

velocity are decreased due to the horizontal compensations for the bar necessary

to perform the exercise. The dumbbell starting position between the feet allows

for uninterrupted extension. This encourages vertical displacement.

The results of this study validate the use of unilateral exercises in

strength and conditioning programs. The deviation seen compared to the

traditional barbell snatch supports the use of these exercises as a method for

adding variance to a program. Moreover, the idea that the specificity of such

variations may be especially beneficial athletes competing in unilateral type

events is derived. The placement and the path allowed by using a dumbbell

results in a more direct route overhead and less horizontal displacement. To a

strength and conditioning coach this means that less time can be spent on

technique without increasing the risk of injury. The combination of these

factors have a positive influence on the risk to benefit ratio of a training

program making the single arm dumbbell snatch a great training tool.

Application of the Power Snatch for Athletic Conditioning

(Waller, Piper, & Miller, 2009)

As explained in the article Application of the Power Snatch for Athletic

Conditioning" (Waller, Townsend, & Gattone, 2007). Power is generated from the

lower extremities rapidly exerting force into the ground. The snatch is a

ground based, full body exercise that emphasizes explosive triple extension.

Triple extension is the act of extending at the hip, knee, and ankle joints.

Triple extension is a fundamental action that most athletic movements are

derived form. When used correctly as a part of a conditioning program, the

snatch can facilitate significant speed and strength adaptations in the legs and

trunk, resulting in improved power production.

Understanding if and when a snatch should be used in a training program

depends on the individual. If the athletes performance is dependent on the

rate of force production then enhancing power output should be the priority of

the training program. This refers to any sport involving jumping, pushing,

lifting, or hitting. Because it shares fundamental mechanics with these

actions, the snatch or a variation of, can be a very affective training tool.

There are many variations of the snatch. Each characterized by its starting

position. The traditional snatch is used in competitive weight lifting and

starts from the ground and finishes in a deep squat position with the bar

overhead. There are four main bordering positions used as a progression for

teaching the snatch. These positions are also the starting positions for common

snatch variations and are listed in order from top to bottom.

1. Power position

2. Bar above the knees

3. Bar below the knees

4. From the floor

The starting position used is dependent on the athletes goals and

capabilities. The power snatch, which begins at the power position at the hips

or mid thigh, is most commonly used. At this position the athlete is at about a

to squat position, most similar to an athletic position. Most variations

starting above the floor end in an extended hip position, adding an overhead

squat component to the movement.

When teaching a snatch the strength and conditioning professional should

use a top to bottom approach. Starting with and overhead squat, progression

takes the athlete down through each position to the floor. It is up to the

strength and conditioning professional to decide when or if progression from the

power position is necessary. Progressing from the overhead squat to the power

position is only appropriate once the exercise is mastered. This meaning that

the athlete can perform the exercise through the full range of motion without

compensation of spinal alignment. Progression from the power position is

dependent upon mastery, as well as need. If a full snatch is not specific to

the movements the athlete performs in competition, then further progression to

that position may not be necessary.

Placement and progression of a snatch exercise variation in an athletes

program can greatly influence its effectiveness. Within the workout session,

the snatch should be the first working exercise. This will insure performance

is not affected by fatigue. Loads should allow for 3-5 repetitions per set

without decline in technique. Sufficient rest periods between reps and sets are

necessary to promote technique as well.

The use of the snatch will vary between training phases related to

competition. In initial preparatory phases the focus is on learning proper

technique.

Any flexibility/stability issues should be addressed at this time to ensure

mastery of initial positions. Assuming the athlete is read, position and load

will be progressed as necessary.

In season training the snatch is still a part of the training program.

During competition the snatch will be used in order to maintain the power

developed from previous training phases. Loads will be high and volume will be

low.

In post season phases when recovery is the priority, snatch variations are

still used, but no progressions in position or intensity are made. Coming full

cycle, back in the preparatory phases, other Olympic type lifts can be taught

because the snatch technique has already been mastered.

The snatch and its variations can significantly improve sports performance

if used correctly. It should be an integral part of the athletes entire

training cycle. The variation should best simulate the actions the athlete

performs in competition. The exercise used should be implemented and progressed

appropriately to the needs and capabilities of the athlete.

Triple Extension: The Key to Athletic Power (Frounfelter, 2009)

Power can be described as the ability to move an object as quickly as

possible over a given distance. This is also a basic description of the

physical aspect of sports. Athletic power can then be thought of as the ability

of an athlete to move them self, or an external object, i.e. ball, bat, bar, or

an opponent. Because power is fundamental to athletic performance, it should be

the basis of program design.

To maximize the results from a strength and conditioning program, it must

be designed to improve the mechanism responsible for power output (Frounfelter,

2009). This mechanism is known as triple extension and describes the explosive

extension of the hip, knee, and ankle joints. Weight lifting exercises such as

the snatch and the clean and jerk are the two lifts performed in competitive

weight lifting. Movements like the snatch, utilize the power generated by

triple extension to move heavy loads from the ground explosively overhead.

These types of lifts are essentially an explosive series of flexion and

extensions that result in maximal power generation. If utilized appropriately,

these exercises are unparalleled in their ability to train and develop athletic

power.

Introduction:

Performance objectives of the first phase begin with the flexion of the

knees, hips, and ankles. The toes are to be pointed slightly outwards, the body

is relaxed at the arms and a lordotic back position is maintained. This is the

starting position of the snatch lift, the butt is down and the head is up, ready

to explode through the movement.

The second phase of the snatch lift is bringing the bar up to about the

chest area and being able to raise the hips and shoulders simultaneously. When

the bar reaches chest-height, the goal is to then drop underneath the bar and

catch it while being in a squat position with the elbows in complete extension.

The third phase of the snatch lift is the stand-up phase in which the

individual goes from the squatted position from phase two, into the standing

position. The elbows are still fully extended and from this position, the

athlete is able to move into the final phase, which is the return back to the

first phase.

The final phase of the snatch lift is the return phase, where the athlete

is avoiding the act of dropping the bar straight down, and rather returning to

the first phase in control of the bar. Athletes can get lazy when doing these

types of lifts, the clean, is another lift that doesnt always produce the type

of results its capable of, because the individual performing the exercise is

not completing the lift by performing the return phase.

Key elements of each phase-

1st- Knees, ankles, hips are in flexion. Tight locked back, relaxed shoulders,

feet pointed out wards, bar at the shins, make sure the shoulders are over the

bar and not behind.

2nd- Powerful extension of the hip, knee, and ankle, pulling under the bar is a

process of eccentric muscle action and receiving the bar requires core and

shoulder stability.

3rd- This action should be performed slowly, with coordination and core stability

so that the athlete doesnt loose footing or become injured due to a jerky

movement.

4th- Again, it is important the athlete keep this phase as smooth as possible in

order to avoid injury. If the athlete is unable to control the bar on the way

back down, they should consider changing the amount of weight.

The main concept of the snatch lift is the explosive aspect of hip, knee,

and ankle extension that takes place, that extension is critical in most sports

movements. The smooth, coordinated approach to the other phases of the lift is

also crucial in core stability and body control. All of these concepts are key

elements to most sporting activities and therefore makes it a popular choice

among strength and conditioning coaches.

The Olympic snatch is a ground based compound movement. The objective of

the snatch is to lift the bar from the ground to a stable position over head.

The successful performance of the snatch is the result of a complex series of

joint actions. These actions can be broken down into phases based on their

contribution to the entire movements. The Olympic snatch is a full-body

movement that can be broken down into 7 separate phases. The analyses of the

phases can help us to gain a better understanding of the motion as a whole.

Preparatory Phase

The preparatory phase is the static starting position for the snatch.

Proper starting position puts the body in a position that will facilitate

optimal force production. Poor starting position will result in minimal force

production. This will have a negative effect performance, and may result in

compensations possibly leading to injury.

First Pull

The first pull starts the movement. It describes the movement of the bar

from the ground to above the knees. This movement should be accomplished

primarily through knee extension.

Scoop

The scoop is a transition phase between the first and second pull. The

objective of the scoop phase is to reposition the body in relation to the bar.

This will relocate the center of gravity to the position necessary to enable the

athlete to utilize the power generated by the hips in the second pull. Failure

to do so will negatively affect performance due to altered range of motion,

particularly at the hips, and increased strain on the back and shoulders as a

compensatory mechanism.

Second Pull

The second pull phase begins with the bar at the mid to top thigh.

Explosive hip extension, accentuated by knee and ankle extension, is the main

source of power for the movement. Athletes using the snatch as a training tool

for other sports often begin their movement from this position (power snatch).

Third Pull

The third pull begins after triple extension reached in the second pull.

Essentially the athlete is pulling himself under the bar as is travels

vertically. Shoulder abduction, external rotation, and simultaneous concentric

hip and knee flexion characterize this phase.

Catch

In the catch phase, the athlete controls and stabilizes the bar overhead.

In the Olympic snatch this is done in the deep squat position. Catching the bar

in the deep squat position facilitates the movement of heavier loads due to the

fact that the athlete does not have to pull the bar as high. This places more

importance on the previous third pull phase. To control and stabilize the bar

in this position requires optimal stabilization strength, especially in the

hips, trunk, and shoulders.

Overhead Squat

The Overhead Squat describes the final phase of the snatch when the athlete

must stand from the deep squat position maintaining control and stabilization of

the bar overhead. Not only is strength of the hip and knee extensors key in

performing this phase, but trunk and shoulder flexibility, and stabilization

strength are crucial.

This analysis is to take two snatch lifts performed by one individual (JR Jones),

and determine the total time that each lift took, as well as the time it took to

perform each phase described in the checklist. The two sets of data will be compared

using a data table and column graph to illustrate relationships between absolute

timing and relative timing. The return phase is expected to take the longest of the

four phases because it is performed with more control in order to avoid injury.

Relative timing will be measured as a percentage, as in the percentage of time it

takes to complete one phase relative to the total time it takes to complete the

entire lift. The purpose of this analysis is to determine areas that could be

improved in order to make the lift more efficient and more successful. There should

be similarities in the amount of time it takes to perform each of the lifts because

they are being performed by the same individual. The objective is to isolate the

movement from beginning to end. An accurate recording can then be used to determine

how much time is spent in for example the return phase, and then how the complete

benefits of this exercise may not be sufficiently attained if the return phase isnt

performed by the individual.

The video kinematics measurements were conducted in order to track the

bodys major joint movements in motion, over the time involved in performing a

standard Olympic snatch lift. From that measurement, the joint angles at the

various phases of movement were calculated for the knee and elbow joints using a

pro-tractor. The knee, ankle, hip, and elbow joints all play a pivotal role in

the snatch lift exercise, and by studying the joints together in relationship to

one another, observations could be completed made regarding the effects of

losing the use of one or more joints or angles. For example, it would be

virtually impossible to do a high amount of weight if the knee joint wasnt

allowed to bend because it would cause too much strain on the lower back. The

knowledge of correct joint angles, especially during the transitional phases of

the movement, will help prevent future injury and may offer areas of improvement

that may affect the consistency of the movement and the ability to generate

velocity and conserve energy through the process. The track of the bar was also

recorded to show the path the bar takes while in motion to complete the lift.

Tracking the path of the bar demonstrates the points in which the bar is moving

vertically and horizontally.

This analysis was performed in order to determine the velocity of the bar

as it is moving in the air during the hang-snatch exercise. There will be an

accelerometer attached to the end of the bar that will give a recording through

a computer screen showing the changing points in velocity, acceleration, and

position. The purpose of doing an analysis like this is to compare them to the

other variations of the lift such as adding more weight and/or changing the

style of the lift. Comparing the velocity and acceleration profiles, as well as

how it relates to position would be a good way to observe how the two will

change. I would expect an Olympic style snatch lift to have a higher

acceleration and velocity early on in the lift because of the increased joint

angle. However, there is an increased resistance to gravity the object (bar)

needs to go through so that might also have an effect. The following will be a

description on how exactly the results were obtained. There wasnt a lot of

allotted time to use the physics lab on one period of time, and the experiment

that used different weights wasnt registering at that day, so there are only

two trial Runs available, acceleration will include the second run, and velocity

and position will include the first trial run.

Methods:

In order to evaluate overall performance of the snatch, each phase will be

analyzed. A checklist outlining the key elements affecting performance in each

phase will be used. The basis for proper technique is taken from the analysis

of technique demonstrated by world class weightlifting competitors. Each phase

can be graded based on comparison to a previous analysis, another athlete, or to

the standards set by world class weightlifting competitors. A high score on a

proceeding phase should facilitate a higher score on the phase of focus. This

analysis will be a beneficial tool to the strength and conditioning coach,

useful for revealing specific weaknesses in technique, allowing for easy

formulation of an effective, individualized plan to improve performance.

Because the snatch is a power movement, video observation will be the most

effective method for analysis.

There is a line of motion so to speak, that looks like a backwards candy

cane. That line is the path the bar travels in order to successfully complete

the lift. When viewing the videos by the Velocity Sports performance institute,

Athletes Performance institute, and others, I was able to compare a variety of

different lifts from both male and female. The grading of their performance will

be constituted solely from the phase checklist above, meaning personal

limitations will only be noted and the individual will not be graded down

because of it. For example, a shorter individual will have an easier time

achieving the portion of the 2nd phase that requires the individual to reach the

position of deep squat. The taller athlete naturally will have a longer set of

arms and although the same visual picture may not exist, it is possible both

athletes are both achieving the necessary postures. I plan to make most of my

future observations form video as opposed to real time, however, I will take

notes during the filming of this exercise and compare what was seen at real time

with what takes place on film.

The experiment was completed using the University of Linfields weight facility, a

ZR 850 Camcorder, JR Jones, a 45 lbs weight bar, two five lbs training plates, and a

tri-pod. The video information was uploading into the imovie application at the ITC

Center at Western Oregon University. The videos were cut-up into individual

repetitions so that each snatch lift could be isolated, broken down, and compared

with other cut-ups. The cut-ups were then transferred into a Quicktime.doc so that

they could be viewed at a framerate of 30 frames per second. Two videos were chosen

from the list and then broken down by each of the four phases determined through the

checklist. A data table was created in order to build a chart that will compare the

two snatch lifts side by side to determine how closely related each phase is to each

other and how the overall timing differs from one lift to the next, keeping in mind

that the weight isnt being changed. The weight of the bar and the two training

plates is constant in each of the two lifts performed by JR Jones.

In order to track the movement for the kinematic measurements, a Mac computer was

used in order to convert the iMovie into a quicktime.mov. Once the playback footage

was available, similar to the Phase-Timing analyses, the major joints were pinpointed

using a 17 Dell Monitor in Western Oregons Hammersly Library. Tracing paper was

attached to the front of the monitor screen and a pencil was utilized to mark the

major joints, (i.e., ankle, knee, hip, and elbow) in a linear pattern at designated

frames. There will be two different videos used for this example to compare the

differences in phases and the degree of angle found in the knee and hip joints. Once

the marks are completed, they are connected to give a two dimensional representation

of body position throughout the action of the snatch. The representation was then

arranged in a sequence from the start of the preparatory phase to the end of the

Third phase of the movement. The return phase of the movement was ignored during this

portion of analyses. As mentioned previously, the end result was measured using a

pro-tractor to record the changes in hip and knee joint action. Ankle or elbow joint

angles can be used as well, however, for this particular analysis, we chose to

measure the hip and knee because of bigger hypothetic changes we expected to observe

in each phase

A 45lbs barbell was taken into the physics lab and set onto the floor in

the middle of the room. An accelerometer was set-up above the bar and a censor

was attached on the end of the bar. The censor was tested several times to

ensure that it was directly, or as close to being under the accelerometer as

possible. Once and accurate reading was determined to be available, JR did a

couple of hang-snatch lifts in order to get a reading on the computer.

Unfortunately, we were only able to get one reading for each variable and ran

out of time because the professor needed his classroom. JR and I came back to

the lab on several occasions to try the test again and it was to no avail, we

did end up getting some results, but they were on Mr. Armstrongs personal

computer, which wasnt something we had recurrent access too. The results from

the initial experiment ended up giving us our best results and that will be the

data utilized for our results. Keep in mind that using this method, while

changing the style of the lift and/or the weight of the bar will provide

differences in peak velocity and acceleration. Once the data was available, it

was entered into three different spreadsheets and labeled velocity,

acceleration, and position. Getting the information off of the Datastudio.pgf,

and onto the spreadsheet via a notepad application, the 300 plus points in each

needed to be split into intervals for accuracy purposes. I used position as my

starting point and observed that Cell #133 was the point in which there started

to be a change in position. Velocity and acceleration were then broken down into

the same type of intervals. 27 cells were included in each interval, and then

the difference between the cells was determined and then recalculated onto a

data table. That data table was converted into a chart to determine where

velocity and acceleration were in terms of time. The starting points for each

interval were zeroed out in order to get a relative number that would be a

better representation for the chart.

Another approach that we took was graphing all the points in a line chart

using all the number from Cell #133 until Cell 322#, this time just for position

and velocity, since we can determine what acceleration is doing based on the

line of velocity. We chose the Cell #133 again because that was the cell that

began to show a change in position. Before charting the line graphs, we decided

to multiply all the Cells (133-322) by -1 in order to flip the chart around and

make it easier to read since the censor for the accelerometer was hanging over

head and not below the bar. Once those numbers were obtained, the line chart was

created for both position and velocity, and is included in the following

results.

Results:

Presented below is a checklist comprised of a workable set of key elements

relative to aforementioned phases. This checklist can be used as a tool to

evaluate the success of subjects in performing Olympic snatch. The checklist

was used to analyze the video footage of two athletes performing the Olympic

snatch.

Athlete #1 is a baseball player who has been involved in strength and conditioning programs for the past 12 years. Despite his

training experience the, has minimal experience with weightlifting exercises. The repetitions performed for this analysis were

his first eve r performed. Detailed explanation and demonstration of the movement were provided before the athlete

performed the recorded repetitions.

Name: Athlete #1 Date: 2010

Starting Position 23 /27

3rd Pull 15 /21

DOB: 1984 1st Pull 23 /27 Catch 25 /28

Experience: 1month Scoop

18 /27 Overhead

Squat 27 /27

Sport: Baseball

2nd Pull 19 /24

Training Phase: Pre-season

Scale: 1-poor 2-fair 3-ideal

Total: 143

79.0 %

Possible: 181

Preparatory Phase: Starting position

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Heels Shoulder width, under knees

Note: Hips up

Note: Hands approx body width outside

shoulders

Note: 3/4 width

Neutral Cervical

Spine

Note: slight Extension at neck

1 2 3 1 2 3 1 2 3 1 2 3

Weight in heels Note:

Back extended Note: posterior

Shoulders over bar Note:

Note:

1 2 3 1 2 3

pelvic tilt, slight rounding of back

1 2 3 1 2 3

Bar under knees Note:

Note: Shoulders

depressed & retracted

Note: shoulder protraction

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___9___/___9___

Total ___5___/___6___

Total ___7___/__9____

Total ___2_/__3_

1st Pull: Ground to knee clearance

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Movement initiated by knee extension

Note: Torso maintains starting angle with

horizontal

Note: Arms extended

Note: Neutral cervical

spine

Note: slight ext.

1 2 3 1 2 3 1 2 3 1 2 3

Weight in heels Note: weight shifts to front half of feet

Back extended Note: posterior pelvic tilt, slight rounding of back

Shoulders depressed &

retracted

Note: slight elevation at end of phase shoulder Protraction

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Bar clears knees close to body

Note: bar never Hips stay flexed

Note:

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___8___/___9_

Total__8__/___9

Total _5__/_6_

Total _2_/_3_

Scoop: Bar moves from just above knee to upper thigh

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Knees move forward under bar remaining

at shoulder width

Note: knees remain behind bar

Torso angle: + with horizontal unchanged at hip

Note: angle increases at hip

Arms extended

Note: elbow flexion shoulder abduction

Neutral cervical

spine

Note: Extension at neck

1 2 3 1 2 3 1 2 3 1 2 3

Weight in heels Note: mid to front of foot

Back extended Note: Shoulders


Note: elevation

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Bar close to body Note:

Hips stay flexed Note:

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___5___/___9___

Total ___7___/___9___

Total ____4__/__6__

Total _2_/_3_

2nd Pull: Triple Ext

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Triple extension Note: Minimal Plantar flexion and hip ext

Aggressive hip extension

Note: does not reach full extension

Arms extended Note: Neutral

cervical spine

Note: Result of change in torso angle

1 2 3 1 2 3 1 2 3 1 2 3

Feet leave the floor

Note:

Back extended

Note: Shoulders depressed and

retracted

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Note: Bar stays close to

body

Note: away early in phase & close in late phase

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ____4__/__6____

Total ____6__/____9__

Total __6___/___6__

Total _3__/_3_

3rd Pull: Downward movement under the bar

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Feet return to ground

Note:

Back extended

Note: Shoulders elevation

Note: shoulders protract

Late phase Neck

extension

Note: retraction

y-1 n-0 1 2 3 1 2 3 1 2 3

Aggressive Knee & hip flexion

Note: Slow flexion= poor ROM

Slight decrease in angle from horizontal

Note: Aggressive high pull and external rotation

Note: Poor speed & ROM in high pull and premature ext rot

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Note:

Note: Bar stays close

to body

Note: Bar travels away from upper body

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___3___/___3__

Total ___6___/___6___

Total ___5___/___9_

Total __1_/_3_

Catch: Downward motion after bar is overhead

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Feet just outside shoulders

Note: Torso parallel to

shins

Note: Arms fully extended over

head

Note: Neutral cervical

spine

Note: protracted & extended

1 2 3 1 2 3 1 2 3 1 2 3

Full squat depth Note: Only half squat


stable

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Weight in heels Note: weight mid to front foot

Note: Bar over Center

of Mass

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___8___/___9___

Total ___6___/___6___

Total ___9___/___9_

Total _2_/_3_

Overhead Squat: Upward movement from lowest catch position to full stand

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Full hip and knee extension

Note:

Back extended

Note:

Arms extended

Note: Protracted and

extended

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Feet just outside shoulder width

Note:

Upright

Note: Shoulders stable,

elevated, and retracted

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Weight balanced Note:

Note: Bar over Center

of Mass

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___9___/___9___

Total ____6__/___6___

Total ___9___/___9_

Total __3_/_3_

Athlete #2 is a college football player, who at the time of analysis was entering into spring season. He was successful

competing at the high school level. Though he is no longer weightlifting competitively, variations of these exercises are a

consistent part of his strength and conditioning programs for football.

Name: Athlete #2

Starting 25 /27 3rd Pull 18 /21

Date: 2010 Position

DOB: 1988 1st Pull 25 /27 Catch 23 /28

Experience: 5years competing Scoop

26 /27 Overhead

Squat 27 /27

Sport: Weightlifting/Football

2nd Pull 21 /24

Training Phase: Pre-season

Scale: 1-poor 2- fair 3-ideal

Total: 165

90.7 %

Possible: 182

Preparatory Phase: Starting position

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Heels Shoulder width, under knees

Note:

Hips up

Note: Hands approx body width

outside shoulders

Note: Neutral Cervical

Spine


1 2 3 1 2 3 1 2 3 1 2 3


Back extended Note: Shoulders over

bar

Note: Note:

1 2 3 1 2 3 1 2 3 1 2 3

Bar under knees Note:

Note: Shoulders


Note: shoulder protraction

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___9___/___9___

Total ___6___/___6___

Total ___8___/__9___

Total ___2___/__3___

1st Pull: Ground to knee clearance

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Movement initiated by knee extension

Note: Torso maintains starting angle with

horizontal

Note: Arms

extended

Note: Neutral

cervical spine


1 2 3 1 2 3 1 2 3 1 2 3




Note: shoulder Protraction

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Bar clears knees close to body

Note:

Hips stay flexed

Note:

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___9___/___9_

Total ___9___/___9_

Total __5__/__6__

Total __2_/_3_

Scoop: Bar moves from just above knee to upper thigh

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Knees move forward under

bar remaining at shoulder width

Note:

Torso angle with horizontal Increases

Note:

Arms extended

Note:

Neutral cervical spine


1 2 3 1 2 3 1 2 3 1 2 3




Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Bar close to body Note:

Hips stay flexed Note:

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___9___/___9___

Total ___9___/___9___

Total ___6__/__6_

Total __2__/__3_

2nd Pull: Triple Ext

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Triple extension Note: Minimal Plantar flexion

Aggressive hip extension

Note: good ROM motion, speed fair

Arms extended

Note: Neutral cervical spine

Note: Result of change in torso angle

1 2 3 1 2 3 1 2 3 1 2 3

Feet leave the floor

Note:

Back extended

Note: Shoulders depressed

and retracted

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Note: Bar stays close to

body

Note:

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ____5__/__6____

Total ___8__/____9__

Total __6__/__6__

Total __3__/___3__

3rd Pull: Downward movement under the bar

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Feet return to ground

Note: Back extended

Note: Shoulders elevation

Note: Neck extension

Note:

y-1 n-0 1 2 3 1 2 3 1 2 3

Aggressive Knee & hip flexion

Note: Slow flexion= poor ROM

Slight decrease in angle from horizontal

Note: Aggressive high pull and

external rotation

Note: Poor speed & ROM in high pull and premature ext rot

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Note:

Note: Bar stays

close to body

Note: Bar travels away from upper body

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___3___/___4__

Total ___6___/___6_

Total ___6___/_9_

Total ___3___/___3

Catch: Downward motion after bar is overhead

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Feet just outside shoulders

Note: Torso parallel to

shins

Note: approx 15 degrees forward

Arms fully extended over head

Note: Neutral

cervical spine

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Full squat depth Note: Only half squat


stable

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Weight in heels Note: weight mid to front foot

Note: Bar over

Center of Mass

Note: initial catch bar forward of C.O.M.

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___7___/___9__

Total ___5___/___6___

Total _8__/___9_

Total __3__/__3__

Overhead Squat: Upward movement from lowest catch position to full stand

Lower Extremity

Trunk

Upper Extremity

Head & Neck

Full hip and knee extension

Note:

Back extended

Note: Arms

extended

Note: Protracted

and extended

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Feet just outside shoulder width

Note:

Upright

Note: Shoulders stable,

elevated, and retracted

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Weight balanced Note:

Note: Bar over

Center of Mass

Note:

Note:

1 2 3 1 2 3 1 2 3 1 2 3

Total ___9___/___9___

Total ____6__/___6___

Total ___9___/__9

Total __3__/__3_

Snatch Anatomical Analysis

Preparatory Phase

The preparatory phase for the snatch is a static starting position. Ankles

are dorsi flexed aligning the toes under the knees and shoulders. The knees and

hips are flexed, and the trunk is hyperextended. The cervical spine is neutral.

The scapula is depressed, retracted, and rotated downward to support shoulder

flexion and horizontal abduction. This shoulder position joined with extended

elbows facilitates a wide grip on the bar. Pronation at the radiolulnar joint

and adduction of the wrist allows for an overhand grip on the bar. Early phase

movement begins when the athlete shifts his weight is back; maintaining a hyper

extended spine and a grip on the bar. The tension force generated through the

arms on the bar acts as a counter balance, allowing the athlete to maintain a

center of gravity as well as increasing tension force (potential energy) in the

athletes posterior side . This potential energy will be converted to kinetic

energy in the form of hip extension after the bar clears the knees.

Pull Phase

The pull phase is a series of full body concentric contractions that result

in the application of maximal vertical force on the bar. The goal of the phase

is maximal vertical displacement of the bar. Early phase movement begins when

the athlete shifts his weight is back; maintaining a hyper extended spine and a

grip on the bar. This is started with knee extension and accompanied with

simultaneous extension at the ankles, shoulders, and hips. Once the bar has

cleared the knees, hip extension becomes the primary joint action. The trunk

remains hyper extended, and the cervical spine neutral. Mid phase, as the hip,

knees, and ankles reach full extension (triple extension), the shoulders abduct,

and the elbows and writs flex. The Scapula elevates and rotates upward

supporting this movement. This adds to the vertical forces on the bar, as well

as decelerates/accelerates the vertical displacement of the athlete. Late phase

the shoulders externally rotate allowing for the passage of the bar overhead.

At this time the hips, knees, and ankle flex concentrically in preparation for

the catch.

Catch Phase

The catch phase describes the athlete accepting, and stabilizing the bar

overhead. The hips, knees, and ankles flex eccentrically slowing decelerating

the athlete as he returns to the ground and into a squat position under the bar.

The trunk remains hyper extended and the cervical spine still neutral. Early

phase concentric muscle contraction causes the elbows to extend, the shoulders

to further abduct and externally rotated concentrically, and then remain in such

position stabilizing the overhead weight via isometric muscle contraction. The

scapula remains retracted, elevated, and upwardly rotated, to support these

positions. The wrist extends from its previous flexion through a neutral

position to an extended position to catch the bar. After catching and

stabilizing under the bar, the athlete stands with the weight overhead. This

late phase of lower extremity joint action involves hip, and knee extension.

The torso, scapula, shoulders, elbows, and wrists continue to be stabilized by

isometric muscle contraction through this portion of the catch phase.

Prepatory Phase

Joint Action Muscles Contractio

n

Ankles Stabilization

Peroneus tertius Extensor

digitorum Extensor hallucis

longus Tibialis anterior

Isometric

Knees Stabilization

Vastus lateralis Vastus

Intermedius Vastus Medialis Gastrocnemius

Isometric

Hips Stabilization

Gluteus maximus Gluteus medius

(post fibers) Adductor magnus

Isometric

Trunk Stabilization Erector spinae

Quadratus lumborum

Isometric

Head/Neck Neutral Stabilization Isometric

Scapula Stablization Trapezius

(mid/lower fibers) Rhomboids

Isometric

Shoulders Stabilization Anterior Deltoid Upper pectoralis

major Isometric

Elbows Stabilization Isometric

Radiolulner Pronation Pronator teres

Pronator quadratus

isometric

Wrist Stabilization

Flexor carpi radialis

Flexor pollicis longus

Extensor carpi radialis brevis Extensor carpi radialis longus

Extensor pollicis longus Extensor

pollicis brevis Abductor pollicis

longus

Isometric

Pull Phase


n

Ankles Plantar flexion Pronation

Gastricnemius Soleus Tibialis

Posterior Flexor Digitorum

Longus Flexor hallucis longus

perouneus longus peroneus brevis

Concentric

Knees Extension

Vastus Lataralis Vastus

Intermedius Vastus medialis Rectus femoris

Concentric

Hips

Early Phase: Extension


(post fibers) Biceps femoris

Semimembrinosus Semitendinosus

Concentric

Late Phase: Flexion

Iliacus Psoas

Rectus femoris Sartorius

Pectineus Gracilis Tensor fascia

latae

Concentric

Trunk Hyperextension Erector spinae

Quadratus lumborum

Isometric

Head/Neck Neutral Stabilization Concentric

Scapulae Early Phase: Downward Rotation Depression Pectoralis minor

rhomboids Lower Trapezius

Concentric

Late Phase: Elevation Upward Rotation

Levator scapulae Rhomboids

Serratus Atnerior Trapezius

Levator scapulae rhomboids

Concentric

Shoulders

Early Phase: Extension

Latissimus dorsi Teres major

subscapularis Infraspinatus

Posterior Deltoid Pectoralis major

(lower fibers)

Concntric

Mid Phase: Abduction

Pectoralis major upper fibers

Deltoid Ant, mid, post, fibers

Supraspinatus

Concentric

Late Phase: External rotaion Infraspinatus Teres minor

Concentric

Elbows

Early Phase: stabilization Triceps brachii

Anconeus

Isometric

concentric

Late Phase: Flexion Biceps brachii

Brachialis Brachioradialis

Concentric

Radiolulnar Pronation Pronator teres

Pronator quadratus

Isometric

Wrist Early Phase: Stabilization






longus

Isometric

Late Phase: Pamlar flexion Abduction

Flexor Carpi radialis

Palmaris longus Flexor carpi

ulnaris Flexor digitorum sperficialis Flexor

digitorum profundus Flexor pollicisExtensor

carpi radialis brevis Extensor

carpi radialis longus Extensor pollicis longus

Extensor pollicis brevis Abductor pollicis longus

Concentric

Catch Phase


n

Ankles

Early Phase: Dorsi flexion Supination

Peroneus tertius Extensor

digitorum Extensor hallucis

longus Tibialis anterior

Concentric

Late Phase: Dorsi flexion supination

Gastricnemius Soleus Tibialis

Posterior Flexor Digitorum

Longus Flexor hallucis longus

perouneus longus peroneus brevis

Eccentric

Knees

Early Phase: flexion Semitendinosus

Semimembrinosus Biceps femoris

Concentric

Late Phase: Flexion

Vastus Lataralis Vastus

Intermedius Vastus medialis Rectus femoris

Eccentric

Hips Early Phase: Flexion




Eccentric

Late phase: Gluteus maximus Concentric

Gluteus medius



Trunk Stabilization Erector spinae

Quadratus lumborum

Isometric

Head/Neck Neutral Stabilization Eccentric

Scapula

Early Phase: Elevation Retraction Upward Rotation




Concentric

Stabilization




Isometric

Shoulder

Abduction External Rotation



Supraspinatus Infraspinatus Teres minor

Concentric

Late Phase: Abduction External Rotation



Supraspinatus Infraspinatus Teres minor

Isometric

Elbows

Early Phase: Pronation Extension Triceps brachii

Anconeus Concentric

Late Phase: Stabilization Triceps brachii

Anconeus Eccentric

Radiolulnar Pronation Pronator teres

Pronator quadratus

Isometric

Wrist

Early Phase: Extension Abduction

Extensor carpi ulnaris Extensor

carpi radialis brevis Extensor

carpi radialis longus Extensor

digitorum Extensor pollicis longus Flexor

carpi radialis

Concentric

Late Phase: Stabilization






longus

Isometric

The results of each phase will be graded in five categories:

Excellent, Above Average, Average, Below Average, and Needs Significant Improvement (NSI).

Phase Snatch Lift # 1 SL # 2 Comparison

Starting (1st) Above Average Above Average Push (# 2)

2nd Phase Average Excellent #2

3rd Phase Average Above Average #2

Return (4th) Above Average N/A N/A

#1 can be viewed through YouTube.com

http://www.youtube.com/watch?v=yqP8xtlOIXY

# 2 can be also viewed through YouTube.com

http://www.youtube.com/watch?v=9nc4DpIzns8

Snatch

#1

Snatch

#2

Phase Frames

Beginning 17 13

Second 32 28

Stand-up 30 22

Return 108 80

Absolute Timing

Snatch #1 Snatch #2

Time(sec) Time(sec)

0.57 0.43

1.07 0.93

1 0.73

3.6 2.67

Relative Timing

Snatch #1 Snatch #2

100% 100%

9 9

17 19

16 15

58 57

0.57

1.07 1

3.6

0.43

0.930.73

2.67

0

0.5

1

1.5

2

2.5

3

3.5

4

Beginning Second Stand-up Return

T

i

m

e

(

s

e

c)Phase

Absolute Timing

Snatch #1

Snatch #2

Snatch Lift #1 (Training Plates): Phase Preparatory Pull Transition Catch

Hip Joint In Degrees 52 111 150 85

Knee Joint In Degrees

80 34 133 72

Inclination 27 82 80 77

9

17 16

58

9

1915

57

0

10

20

30

40

50

60

70

80

90

100

Beginning Second Stand-up Return

%

t

o

t

a

l

m

o

v

e

m

e

n

t

t

i

m

e

Phase

Relative Timing

Snatch #1

Snatch #2

Preparatory Pull Transition Catch

-1

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

1 7

13

19

25

31

37

43

49

55

61

67

73

79

85

91

97

10

3

10

9

11

5

12

1

12

7

13

3

13

9

14

5

15

1

15

7

16

3

16

9

17

5

18

1

18

7

19

3

Series1

Position:

Notice the change in position, how the bar is going up and then leveling

off at a certain point. Note: there are fuzzy areas of this chart that need to

be filtered, we assume there was some noise going on that caused the position

points to move up and down so frequently.

Velocity:

The velocity is going up at a rapid rate signifying the bar reaching the

top of the snatch lift and then returning to normal as the performer comes to a

pause at the top of the lift. We also assume an unknown amount of noise

taking place in this activity, and when the individual gets to the third phase

-0.2

0

0.2

0.4

0.6

0.8

1

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99106113120127134141148155162169176183190

S

of this lift, there is a rolling of the wrist joint action taking place, that

might have affected this chart as well.

Acceleration:

The acceleration numbers that we obtained through this activity were not as

accurate and clean as the position and velocity charts were, so we decided to

explain them using the velocity chart as well. The acceleration is the

velocity/time, so when we view the velocity curve, we notice an increase in

acceleration, then a point of no acceleration, followed by a period of negative

acceleration or deceleration. The velocity chart then shows a somewhat flat line

which would also represent a point of no acceleration.

Discussion:

A checklist is a valuable tool that can be used to accurately evaluate the

performance of any movement. Such tools are especially useful when analyzing

complex, explosive, movements such as the Olympic snatch. Using the information

gathered from video analysis, each phase is evaluated based on a qualitative

rating of its key elements. From this, a comprehensive grade is derived,

representative of the subjects overall strength of performance.

Comparing the video footage in real time, no major differences stand out.

Understanding the complexity of the snatch, this does not make sense giving the

fact that athlete #1 was performing the snatch for the first time, and athlete

#2 had at over six years of experience performing the lift.

Slowing the movement down using computer software, differences in technique

become evident. The results from checklist analysis provide a detailed

evaluation of their strengths and weaknesses. Athlete#2 had an overall strength

of performance score approximately 10% higher than Athlete #1. This is score is

valuable when comparing overall performance between athletes, as well as for

tracking progress. Comparing performance at each stage we begin to see the

individual strengths and weaknesses that set the athletes apart. On average,

Athlete #2 scored 2% higher on a given phase compared to Athlete#1. This

average does not have much value because the maximum point value of each phase

is not equal. When analyzing the scores of each phase, the outliers will be the

best indicators of strengths and weaknesses. Doing so, we see that Athlete#2

scored 8 points higher than Athlete#1 in the scoop phase. This suggests that

the scoop phase is the origin of Athlete #1s weakness and may be the

predominant factor affecting his overall strength of performance.

Say these same two athletes plan to reassess and compare their performance

using this checklist again the following month. Each athlete can use the

information on their checklist to design an effective strength and conditioning

program tailored to meet their specific needs. Looking at Athlete #1s

evaluation we see that he has a room for improvement in all phases. Noticing

that deviations seem to be greater in the phases following the scoop compared to

the phases leading it, we can deduce that the scoop phase is his greatest area

of weakness and may be the cause of deviation in the later phases. Improvement

in the key elements involved in the scoop phase should be the priority of the

next months strength and conditioning program.

This checklist is a valuable tool, but, each phase describes one, in a

sequence of 7 interconnected movements that combine to produce one fluid

movement.

What may seem like insignificant deviations in technique can alter the next

in sequence, compounding with each subsequent phase. Looking at the scores

following the scoop phase, the difference between scores increases compared to

the phase scores proceeding the scoop phase. These findings agree with our

understanding that each phase is interconnected, and is essentially a

description of one fluid movement.

Evaluated two separate videos, the first one was a video that looked like

it was a user uploaded video, and the second video was a training film on the

snatch lift from Velocity Sports Performance institute in Redondo Beach,

California. For the analysis of the first lift, I gave the athlete an above

average starting position because he demonstrated proper foot and bar placement.

During the latter stages of the lift, i.e. after a couple of reps, the athlete

looks to become off balanced in their foot position, a coach should keep an eye

on that. The second phase was given an average grade. It was borderline below

average too because it looks like the bar is unbalanced when the athletes elbows

reach full extension. I would like to see more body control and coordination

during this part of the movement. The third phase is the also considered average

and could also be considered below average depending on the repetition being

observed at the time. There are points when the athlete loses balance on the way

back to standing position, those sliding feet are a sign of improper balance and

body control. The fourth phase is viewable in the first lift and I gave the

grade of above average based on the fact the athlete finished this portion of

the lift. The athlete was only using the bar, which could be part of the

equation as to why the athlete is doing the return phase of the lift. This

portion of the lift should be an important coaching point for this athlete

because he has a lot of room to improve performance and its easier to develop

this habit during the beginning stages of this lift.

I viewed the second lift from the side angle and therefore I didnt give it

an automatic excellent grade. I assumed, because of the results of the other

phases of this lift, that the female athlete was going to be spot-on during the

starting phase of the snatch lift. The second portion of this lift got the

highest rating possible because of the coordination, explosion, and body control

that is on display during this phase. There is a build up, where the athlete is

beginning to rise up, the build up is slower than the explosive movement that

takes place once the bar reaches about hip level. When the bar reaches hip

level, the athlete pops their hips, receives the bar and hits a perfect deep

squat position. When I watch this portion of the snatch lift performed by this

athlete, I feel this would be a perfect example to demonstrate pace, explosion,

and body position. The athlete has a minor amount of trouble around the knee

region when trying to stand back up to the standing position of the lift. This

aspect is still considered to be above average by my standards, the fluidity of

the motion is not perfect and so I didnt give it an excellent grade. Not that

the movement or lift in general will ever be exactly perfect, but I cant

consider it to be close to it when there are noticeable flaws to be corrected. I

would like to see the same athlete from a front camera perspective in order to

view the athletes knee movement and facial expres

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