Biomechanics of the Squat and Deadlift

7/26/2019 Biomechanics of the Squat and Deadlift

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Table of ContentsIntroduction ................................................................................................................... 4

Advanced Models .............................................................................................................................................. 4

Assumptions/Limitations ............................................................................................................................. 4

Moment Arms ................................................................................................................ 5

Support Moment ........................................................................................................... 6

Force Sharing ................................................................................................................. 8

Barbell Squat Torques ................................................................................................ 9

Knee Dominant Squat .................................................................................................................................. 10

Hip Dominant Squat ..................................................................................................................................... 11

Barbell Deadlift Torques ......................................................................................... 12

Knee Dominant Deadlift .............................................................................................................................. 12

ROM and Torque ......................................................................................................... 13

Passive-Elastic and Active Muscle Force ............................................................ 14

Sticking Regions .......................................................................................................... 15

Long Femurs in the Squat ........................................................................................................................... 16

The Effect of Femur Length on Maximum Squat Strength ......... ........... ........... .......... ........... ......... 17

Long Arms in the Deadlift ........................................................................................................................... 18

Gluteus Maximus EMG and Hip Extension Torque-Angle Curves .............. 20

Effect of Gluteus Maximus Hypertrophy on Maximum Hip Extension

Torque ............................................................................................................................ 21

Spinal Rounding .......................................................................................................... 23

Spinal Rounding Torques ........................................................................................................................... 23

Spinal Rounding in the Deadlift ............................................................................................................... 23

Spinal Rounding and Spinal Loading ..................................................................................................... 24

Spinal Rounding and Deadlift Muscle Activation .............................................................................. 24

Biomechanics of the Lumbopelvic Hip Complex.............................................. 25

Counterbalance Squat and Torques ..................................................................... 26

Trunk Position in the Squat .................................................................................... 27

High Bar vs Low Bar Squats .................................................................................... 28

Squat Variations ......................................................................................................... 29

Front Squat ....................................................................................................................................................... 29

2 x 4: Maximum Strength Page 2


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Back Squat ........................................................................................................................................................ 29

Box Squat .......................................................................................................................................................... 29

Zercher Squat .................................................................................................................................................. 29

Deadlift Variations ..................................................................................................... 31

Conventional Deadlift .................................................................................................................................. 31

Sumo Deadlift .................................................................................................................................................. 31

Trap Bar Deadlift ........................................................................................................................................... 31Hack Lift ............................................................................................................................................................ 31

Common Dysfunctions .......................................................................................... 33

Knee Valgus ...................................................................................................................................................... 33

Butt Wink .......................................................................................................................................................... 33

Poor Ankle Mobility ...................................................................................................................................... 33

Poor Core Stability ........................................................................................................................................ 34

Dorsiflexion Aids in the Squat ............................................................................... 35

Belts and Intra-Abdominal Pressure ................................................................... 36

Knee Wraps, Suits, Briefs, and Torque ................................................................ 37

Theoretical Effects of Support Gear........................................................................................................ 38

Bands, Chains, and Torque ......................................................................................................................... 39

Assistance Lifts ............................................................................................................................................... 40

Hip Thrust ......................................................................................................................................................... 41

Back Extension on GHD ............................................................................................................................... 41

45 Hyper .......................................................................................................................................................... 41

Good Morning.................................................................................................................................................. 42

Reverse Hyper................................................................................................................................................. 42

Glute Ham Raise ............................................................................................................................................. 43



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Introduction

The word biomechanics stems from the Greek language for life mechanics, but this

doesnt really tell us much; Oxford tells us a bit more, the study of the mechanical laws

relating to the movement or structure of living organisms. Biomechanics can refer to a

number of subconcentrations, such as fluid dynamics or tissue modeling, but perhaps the

most relevant to strength & conditioning is musculoskeletal biomechanics.

Musculoskeletal biomechanics is a subconcentration of biomechanics in which the

mechanical laws of physics are applied to the human musculoskeletal system. When one

performs a closed chain kinetic movement, their body can be viewed as a system of levers

so that the torque on each joint can be calculated. The torque on a joint is indicative of how

much turning force is being placed on that joint, which can enable us to estimate how hard

a muscle (or group of muscles) has to work to overcome that torque in order to move or

prevent the movement of a joint about its axis. Another term for torque is moment.

Throughout this text, the biomechanics of the squat, deadlift, and their variations will be

discussed, paying particular attention to the effects of technique and form on joint torques.

Advanced ModelsIn an ideal world, we would use techniques such as muscle modeling, which requires three-

dimensional motion capture, electromyography, force plates, and specialized software to

help us calculate precise and individualized biomechanical evaluations. Unfortunately, this

equipment costs hundreds of thousands of dollars and is only used in extensive

biomechanics laboratories. However, this does not mean that biomechanical principles

cannot be applied using the naked eye.

Assumptions/LimitationsThroughout this text, certain assumptions are made, as we do not have access to the

advanced modalities previously described. Assumptions and limitations within this text

are as follows:

Assuming that the lifter pushes through the center of the foot

Assuming that the center of gravity is positioned near the load itself in the barbell

squat and through the scapula for the barbell deadlift

Ignoring muscle co-contractions

Ignoring electromyography (EMG)

Focusing on external load, not system mass (ignoring superincumbent bodyweight)

Not using video capture and force plates

Not using inverse dynamics or 3D modeling Focusing only on vertical forces during the squat and deadlift

Ignoring momentum, looking at instantaneous torques using quasi-static models

Assuming that the plate radius is 22.5cm

Omitting hand length with regards to grip in the deadlift

Assuming a high bar squat position

Assuming that the spine stays rigid and no pelvic tilt exists



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Moment Arms

In physics, a moment arm is simply the perpendicular distance from the axis of rotation to

the line of action of the force. In biomechanics, there are two types of moment arms that

you should be familiar with. Theres the muscle moment arm, which is internal and

represents the leverage of a muscle (perpendicular distance between the joint center and

muscle line of pull), and theres the resistance moment arm, which is external and

represents the perpendicular distance between the load and the joint center. This text willfocus on resistance moment arms.

With squats, the moment arm (sometimes called lever arm) can be estimated by examining

the horizontal distance between the joint center and the ground reaction force vector.

With heavy loads, we can assume that the horizontal component of the ground reaction

force vector is negligible. Therefore, the ground reaction force vector is perpendicular to

the ground and is formed by drawing a line that connects the center of gravity and center of

pressure through the feet, as depicted to the left.

A compound movement consists of moving multiple levers about

multiple joints in order to complete a movement. For example,

during the deadlift, knee extension and hip extension occur

simultaneously. This is drastically different from isolation

movements such as the preacher curl whereby elbow flexion is

the only joint action occurring. During the preacher curl, the

humerus (upper arm) is in a fixed position such that the forearm

must rotate about a fixed axis, and thus not leaving much room to

modify the movement. Compound movements have more

degrees of freedom, or more ways to complete the movement,

consequently making compound movements more complicated,

harder to analyze, and more unique from person-to-person.

Movement variation between individuals is not necessarily a bad

thing, but it can help identify strengths and weaknesses during

movement by calculating joint torques and seeing how different

lifters favor different joints.

This manual uses computer-aided design (CAD) drawings drawn

to scale in order to depict the changing moment arms and

subsequent changing joint torques associated with lower body

exercise, paying particular attention to the barbell squat and

deadlift.

Moment arms of the knee

and hip during a squat.



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Support Moment

Using the moment arm and load being used (along with the superincumbent bodyweight,

or mass of the bodyweight above the joint being examined in standing exercises), torques

can be calculated. Torque () is the product of the force and moment arm, as described in

the equation below where ris the length of the moment arm in meters and Fis the force in

Newtons.

=

In biomechanics, torque is calculated using Newton meters (Nm). Newtons are the SI unit

of force. Because gravity on Earth is constant, we can use 9.8 m/s2for a(well round up to

10 for the sake of simplicity in this manual),and simply substitute the mass of the load in

kilograms for m(well use 100 kg throughout this text). The equation below will calculate

the force in Newtons using the units described.

=

When calculating torque, the force will be constant and the length of the moment arm will

determine differences in torque. With explosive lifts, youd need to deal with momentum,

but with heavy lifts, this momentum can be ignored, as quasi-static models with lifts taking

more than 2-seconds have been shown to be 99% as accurate as dynamic models (Lander

et al., 1990). Variations in form and lever length will show that a movement can be

completed using an infinite number of torque and moment variations.

In many activities, it is surprising to find that the body tends to distribute a fairly consistent

total amount of joint torque independent of the movement style between the three primary

lower body joints. For example, lets say that 200 Nm of lower body extensor torque is

required to lift a box. The body could move mostly at the hips and utilize 150 Nm of hipextension torque and 25 Nm of ankle plantar flexion and knee extension torque to achieve

the task. It could also produce 120 Nm of knee extension torque, 50 Nm of hip extension

torque, and 30 Nm of plantar flexion torque. The take-away point here is that there are

many movement patterns that can lead to successful lifting outcomes, and the various

lifting styles tend to require similar total extensor torques but with different distributions

across the various joints.

See the three pictures below representing a lifter picking up a 20-kg box with a knee-

dominant style, a blended style, and a hip-dominant style; the combined hip and knee

moments of the three variations is 84.36 Nm, 84.54 Nm, and 82.56 Nm, respectively.

In this manual, will stand for hip extension torque, while will stand for kneeextension torque.



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Examples

= = 20 10 2

= 200

Lander, J. E., Simonton, R. L., & Giacobbe, J. K. (1990). The effectiveness of weight-belts

during the squat exercise. Medicine and science in sports and exercise,22(1), 117-126.

= 200 0.1535 = 30.7

= 200 0.2683 = 53.66

= 30.7 + 53.66 = 84.36

= 200 0.3097 = 61.94

= 200 0.1129 = 22.58

= 61.94 + 22.58 = 84.54

= 200 0.4571 = 91.42

= 200 0.0389 = 7.78

= 91.42 7.78 = 82.56



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Force Sharing

It is not uncommon for more than one muscle to be able to control for the same joint action,

illustrated by the actions of the gluteus maximus and hamstrings on hip extension. How

much each muscle contributes to a joint action depends on a number of factors, including

the joint angle and the strength of each muscle, but these factors are not universal. For

example, the prime mover of the hip thrust is the gluteus maximus, but the hamstrings

contribute to hip extension as well, so hip extension forces are not mutually exclusive to

one muscle. The contribution of a muscle to a movement on a joint is not the same in every

person, thus exercises must be chosen in accordance to how that individual can activate the

intended target musculature.

Studies show that with cueing and focus of attention, one can change the amount of EMG

activity in the various synergists during a movement involving multiple muscles (Lewis &

Sahrman, 2009). For example, using more glutes during hip extension will cause a

decrease in hamstring activation. Whats more, this force sharing has been shown to be

easier to do with lighter loads compared to maximal loads (Snyder & Fry, 2012). Although

we can assume that if a movement produces a large magnitude of hip extension torque, itwill be a good movement for the gluteus muscles, we must be careful with our assumptions

as the movement could be carried out largely by the hamstring and adductor muscles.

Lewis, C. L., & Sahrmann, S. A. (2009). Muscle activation and movement patterns during

prone hip extension exercise in women.Journal of athletic training, 44(3), 238.

Snyder, B. J., & Fry, W. R. (2012). Effect of Verbal Instruction on Muscle Activity During the

Bench Press Exercise. The Journal of Strength & Conditioning Research,26(9), 2394-2400.



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Barbell Squat Torques

During the torque calculation of a squat, as seen in the drawing below, we can assume that

the center of the barbell falls in line with the gravitational force vector (the lifter does not

shift the barbell too far forward or backward relative to the midfoot). A line representing

the gravitational force vector should be drawn through the bar and center of pressure of

the feet (assumed to be midfoot), as shown below. This line should be perpendicular to theground (we can assume that most of the force is vertical during a squat).

In order to calculate hip and knee torques, lines representing the moment arms should be

drawn perpendicularly from the ground reaction force vector to each of the said joint

centers, as depicted below. Remember, we are ignoring body mass and focusing on barbell

mass. If we wanted to be more accurate, we would look at system mass, which includes

both, however, this allows for simpler calculations.

= = 100 10

2

= 1000 Because the measurements given are in centimeters,

we will convert them to meters:

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100 = 0.2122 =

= = 1000 0.2122 = 212.2

The torque at both the hips and knees is 212.2 Nm.

To the left is the ideal squat, that is, the momentarms are equal to one another to balance out the

torques on the joints. However, this is not a perfect

world and people often do not squat with equal

moments. Powerlifters tend to squat with greater hip

moments while Olympic weightlifters tend to squat

with more equal hip and knee moments. There are

two variations to any squat: a knee dominant and hip

dominant version (actually theres a continuum with

every possible combination in between).

Learning how to adjust the torques depending on thetask at hand will enable the lifter or coach to make

better decisions in programming and training.



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Knee Dominant SquatBelow is a free body diagram representing a lifter that has a knee dominant squat. The

individuals trunk is more upright which decreases the hip moment and increases the knee

moment. Because the knee moment is now greater, the individual must overcome a greater

knee torque in order to move the weight.

The torques can be calculated as follows:

= = 1000 0.1414 = 141.4 = 1000 0.2829 = 282.9



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Hip Dominant Squat

A hip-dominant squat is just the opposite of a knee dominant squat, that is, the individual

leans forward and sits back more, which in turn increases the hip moment and decreases

the knee moment. The hips now have more torque to overcome and the knees have less.

Hip-dominant squat torques can be calculated like so:

=

= 1000

0.2829

= 282.9

= 1000 0.1414 = 141.4



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Barbell Deadlift Torques

The torque of a deadlift is calculated similarly to that of the squat, and again, it is safe to

assume that the center of the barbell is the center of gravity, thus, it is where we draw the

gravitational force vector. As one would probably think, the deadlift is a very hip dominant

movement when compared to the squat, as seen below.

= = 100 10 2

= 1000 Because the measurements given are in

centimeters, we will convert them to meters:

45.71 1

100 = 0.4571 =

= = 1000 0.4571 = 457.1 = 1000 0.0389 =38.9

Knee Dominant Deadlift =

= 1000 0.3879 = 387.9 = 1000 0.0290 = 29.0

As you can see, the hip and knee dominant deadlifts are

quite different than those of the squat. The top image

actually involves a knee-flexion net moment where the

hamstrings dominate the quadriceps, whereas the

bottom image shows a knee-extension net moment

where the quadriceps dominate the hamstrings.However, the net torques are only around 70Nm apart.

Any way you slice it, the deadlift is a hip dominant

movement.



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ROM and Torque

Once one has basic knowledge of the workings of torque, it is easy to see how range of

motion affects the torque placed on joints. In the picture below, youll see a parallel squat

and a quarter squat. Assume a 100kg load for the parallel squat and 115kg load for the

quarter squat.

= 1000 0.2121 = 212.1

= 1150.02 0.1844 = 212.1

As you can probably imagine, similar torques are created with partial movements

compared to full range movements because more load can be utilized. In the above

example, one would need 15% more load to make up for less ROM (right) in order to match

the torques placed on his joints in the deeper squat (left). The full range movements

possess greater moment arms with lower forces, while the partial movements possess

smaller moment arms with greater forces. Since torque equals perpendicular force times

the length of the moment arm, you end up with similar torques. It should be noted,however, that full range movements tend to produce greater hypertrophic adaptations in

the literature (Bloomquist et al., 2013).

Bloomquist, K., Langberg, H., Karlsen, S., Madsgaard, S., Boesen, M., & Raastad, T. (2013).

Effect of range of motion in heavy load squatting on muscle and tendon

adaptations. European journal of applied physiology, 1-10.



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Passive-Elastic and Active Muscle Force

There are two forces that make up total muscle forces: passive-elastic and active. As one

would probably guess, active forces originate from the contracting muscles, but passive-

elastic forces are less heard of. A passive-elastic force is simply the force generated from

the elasticity in passive tissue structures, such as tendons and the elastic properties of

muscle. Theyre called into play when the structure is stretched and are for the most part

independent of active contraction. However, titin, a large molecule in the sarcomere, elicitsmuch more passive force when activated and stretched.



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Sticking Regions

Everybody has a weak point, or sticking region, in the squat and deadlift. These become

especially apparent at near-maximal loads and tend to be different for everyone, but why

do these sticking points occur?

Various theories have been presented, but here, we are going to concentrate on two ofthose theories. The first being that sticking regions are caused by the lifter running out of

passive forces, for example from titin and other passive tissues, and having to switch over

to purely active, contractile forces. This seems to be the case in the bench press (Elliot et al.,

1989). This is most likely the cause of most sticking regions.

Another theory is that the body acts like a spring, especially in large individuals. Lets take

the squat, for example. As one descends, their hamstrings will make contact with their

calves and their belly will make contact with their thigh. These tissues pressing against one

another will create contributory passive forces in the bottom of a lift. This is not the case

for every individual and varies greatly between lifters depending on their form, depth, and

size.

Where sticking regions occur seems to differ greatly from individual to individual, but they

are similar between lifts in the same individual. For example, person A will have a similar

sticking region in both the sumo and conventional deadlift, but those sticking regions will

differ from person Bs sticking regions in the sumo and conventional deadlift (McGuigan &

Wilson, 1996).

It should be noted that often the sticking regions in the squat

and the deadlift occur at different joint angles. For the hips,

the sticking points are at 82 and 96 for the squat and

deadlift, respectively. For the knees, the sticking points areat 101 and 155 for the squat and deadlift, respectively.

These data indicate that one lift does not necessarily carry

over to the other lift, as sticking points are significantly

different from one another (Hales et al., 2009).

Elliott, B. C., Wilson, G. J., & Kerr, G. K. (1989). A biomechanical analysis of the sticking

region in the bench press. Medicine and Science in Sports and Exercise,21(4), 450.

McGuigan, M. R., & Wilson, B. D. (1996). Biomechanical analysis of the deadlift. The Journalof Strength & Conditioning Research, 10(4), 250-255.

Hales, M. E., Johnson, B. F., & Johnson, J. T. (2009). Kinematic analysis of the powerlifting

style squat and the conventional deadlift during competition: is there a cross-over effect

between lifts?. The Journal of Strength & Conditioning Research,23(9), 2574-2580.



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Anthropometry and Torque (Lightning Bolt)

The length of ones limbs and trunk have a large effect on the torques their bodies must

produce in order to move a load. Every individual possesses an inherent lightning bolt

when you consider the anatomical lengths of their torsos, femurs, and tibias. These limb

length proportions determine much of what form looks like in a squat. Technique, muscle

strengthening, and motor control can certainly alter form, but theres only so much one can

do, especially with extreme proportions.

Long Femurs in the Squat

The Crural Index is the ratio of the length of the lower leg to that of the upper leg. If one

has a low Crural Index, that is, longer femurs, it puts the lifter in a disadvantageous position

during the squat. The next page shows a comparison of a squatter with normal femurlength with a squatter with short femurs and a squatter with long femurs. Taken to an

extreme level, if most of the total lightning bolt is taken up by the spine and tibias, the

lifter will stay upright and be much stronger in the squat as a result. Conversely, if most of

the total lightning bolt is taken up by the femur, the lifter will fold like an accordion and

be weaker in the squat as a result.

Take world-class 114-pound Polish powerlifter Andrzej Stanaszek, for example. Stanaszek

is a dwarf, meaning he has disproportionately short limbs and is less than 410 (he actually

stands under 4). These proportions give him a mechanical advantage to lift huge loads,

including a 662.5 lb squat and 402.3 lb bench press. Both the bench and squat favor

shorter limbs. ClickHEREto see his squat. Ironically, these same proportions dont appearto help him in the deadlift -HEREAndrzej fails with 319 lbs.

http://www.youtube.com/watch?v=X57aLTTEX_whttp://www.youtube.com/watch?v=X57aLTTEX_whttp://www.youtube.com/watch?v=X57aLTTEX_whttp://www.youtube.com/watch?v=7BOl7ThV2vEhttp://www.youtube.com/watch?v=7BOl7ThV2vEhttp://www.youtube.com/watch?v=7BOl7ThV2vEhttp://www.youtube.com/watch?v=7BOl7ThV2vEhttp://www.youtube.com/watch?v=X57aLTTEX_w


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Below are squats and their moment arms for a normal sized femur, disproportionately long

femur (+20%), and disproportionately short femur (-20%), respectively.

Medium Femurs

= 1000 0.2122 = 212.2

Long Femurs

= 1000 0.2546 = 254.6

Short Femurs

= 1000 0.1697 = 169.7

The resulting knee and hip torques are directly proportional to the increase or decrease in

femur length (20%). As you can imagine, having shorter femurs confers a distinctadvantage in the squat!

The Effect of Femur Length on Maximum Squat StrengthNow, lets say we have two individuals: one with short femurs and one with long femurs (as

seen above). How does femur length and its effects on torque requirements affect how

much one can lift? Well, lets find out. Lets assume each lifter possesses 500Nm of hip

extension torque and 400Nm of knee extension torque at the bottom of the squat, which

would make them highly advanced powerlifters.



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Long Femurs

=400

0.2546

= 1571.09

=500

0.2546

= 1963.86

= + = 1571.09 + 1963.86 = 3534.95 =796.35 lbs

Short Femurs

=400

0.1697

= 2357.10

=500

0.1697

= 2946.38

= + = 2357.10 + 2946.38 = 5393.48 =1,215.04 lbs

According to these estimations, a squatter with 20% shorter femurs with the same amount

of knee and hip extension torques can squat 41.6% more than a squatter with 20% longer

femurs. In fact, reducing femur length transformed the powerlifter from strong to world

record holder!

Long Arms in the DeadliftBecause the starting position of the deadlift is determined by an individuals arm length, an

individual with longer arms is at a much greater mechanical advantage than an individual

with shorter arms. This is due to the peak torque of a deadlift being at the bottom of the

movement. A more vertical trunk angle can be seen in the diagrams below just adding

length to the arms of the lifter without altering leg and torso lengths.

Lamar Gant is a great example of a phenomenal deadlifter with long arms. At a bodyweight

of 132, Gant was able to pull 683.4 lbs. ClickHEREto watch Lamars deadlift notice thathe locks out with the bar resting just above the kneecaps. The free body diagram on the

following page shows why and is drawn similarly to the squats in that the arms were either

shortened or elongated by 20%. The first image is normal length, second is shortened, and

third is elongated.

http://www.youtube.com/watch?v=klXVGdlLx-Ihttp://www.youtube.com/watch?v=klXVGdlLx-Ihttp://www.youtube.com/watch?v=klXVGdlLx-Ihttp://www.youtube.com/watch?v=klXVGdlLx-I


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Medium Arms = 1000 0.4571 = 457.1

Short Arms = 1000 0.4610 = 461.0

Long Arms = 1000 0.4326 = 432.6

The resulting hip torques are directly proportional to the increase or decrease in arm

length (20%). In addition the joints have to move through a much larger range of motion,

which will lead to greater fatigue throughout the lift. As you can imagine, having longer

arms confers a distinct advantage in the deadlift!



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Gluteus Maximus EMG and Hip Extension

Torque-Angle Curves

Worrell et al. (2001) investigated gluteus maximus EMG and its relation to hip extension

torque, and the findings are puzzling to say the least. Below is a rendition of Figure 6 from

the study.

Subjects performed maximal hip extension torque at four different angles of hip flexion. As

you can see, hamstring EMG does not change very much throughout the hip range of

motion, however, gluteus maximus EMG rises from a flexed to an extended hip position.

Interestingly, hip extension torque is greater in a hip flexed position compared to a hip

extended position. Why this occurs is not fully understood. We are probably stronger in

hip flexion due to the increased involvement of the adductors in hip extension. The glutes

probably fire harder at end range hip extension to compensate for their shorter lengths or

because they have better leverages at that range of motion.

These findings are highly applicable to training as they explain how the muscle works and

provide some insight as to the best way to train the gluteus maximus. If one wants to

optimize the gluteus maximus hypertrophic response, he or she needs to incorporate

multiple hip extension movements such as hip thrusts, squats, and deadlifts.

Worrell, T. W., Karst, G., Adamczyk, D., Moore, R., Stanley, C., Steimel, B., & Steimel, S.

(2001). Influence of joint position on electromyographic and torque generation during

maximal voluntary isometric contractions of the hamstrings and gluteus maximus

muscles. The Journal of orthopaedic and sports physical therapy, 31(12), 730.



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Effect of Gluteus Maximus Hypertrophy on

Maximum Hip Extension Torque

It is well known that when a muscle is hypertrophied, it is also stronger. This is due to the

increase in physiological cross sectional (PCSA). Lets quickly familiarize ourselves with a

few formulas pertaining to muscle PCSA and its relationship to torque.

(2) =(3)

()

() =(2) ( 2 )

Specific tension refers to the force exerted by the fibers per unit of PCSA. This would be

measured in N/cm2. Muscle force denotes how much force the muscle pulls with, but as

we know from previous sections in this text, we care about torque.

In order to calculate the muscle moment (torque), we must multiply the muscle force bythe perpendicular distance from the muscles line of pull to the joint center. The following

image shows how hypertrophy can affect the muscles moment arm and therefore, moment.



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As you can see, as a muscle hypertrophies, it not only gets larger and farther from the joint

center, but the angle of the fibers also change, thus giving it a larger capacity for torque

development. Below is an example of how someones hip extension torque would change

as a result of a 31.85% increase in gluteus maximus size.

= 28.92 2 = 28.92 2 61

2

= 1,764.12

Muscle force corrected for angle of insertion

1764.12 sin 73 = 1,687.04

Muscle Moment1,687.04 0.0469 = 79.12

= 38.13 2 = 38.13 2 61

2

= 2,325.93

Muscle force corrected for angle of insertion

2325.93 sin 90 = 2,325.93

Muscle Moment2,325.93 0.0567 = 131.88

Thus, a gluteus maximus that is 31.85% larger can produce 50% more hip extension torque.



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Spinal Rounding

Some amount of spinal rounding, specifically in the thoracic region, is acceptable when

approaching maximal loads in the deadlift. Some lifters are strongest when maintaining a

good arch, while others are strongest when they round their spines. You want to make sure

the rounding is in the upper back and that lower back (lumbar) rounding is kept to a

minimum when pulling heavy loads. Here is why you may be stronger when rounding the

upper back.

Spinal Rounding TorquesDepicted below is a conventional deadlift for a lifter with a neutral spine, and the same

lifter pulling with a rounded spine. By rounding the spine, the individual is able to decrease

the hip moment, which decreases hip torque and in turn makes the load easier to lift.

Straight Back

= 1000 0.4571 = 457.1

Rounded Back

= 1000 0.4337 = 433.7

With a 45 arch, the moment arm on this individual shortens by around 5%. A 5% decrease in

torque could mean the difference between finishing a pull and not, especially in competition.Rounding also places the places the muscles at different starting lengths, especially if the pelvis

changes position. The pelvis modulates hip extensor length, with anterior tilting placing the hipextensors at longer lengths and posterior tilting placing the hip extensors at shorter lengths. How

this impacts strength is not very clear, but it may depend on the individual.

Spinal Rounding in the DeadliftThere are several other strength benefits to spinal rounding in addition to its effects on

joint torques, including:



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Increased Intra-Abdominal Pressure Provides additional spinal stabilization.

Passive Erector Support Titin filaments within the thoracic erectors and tendons

will provide resistance to stretch, similar to the way a spring works.

Spinal ligaments, fascia, joints, and discs When one approaches full flexion, these

are more or less the bodys last chance to support itself. One should not rely on

these structures, but they do provide support if need be.

Support from the rib cage and sternum According to Watkins IV et al. (2005), the

sternocostal complex has been shown to increase thoracic spine stability during

flexion/extension by 40%.

For more information on the benefits of spinal rounding in the deadlift, check out Bret

Conteras article on T-Nation,A Strong Case For The Rounded Back Deadlift.

Watkins IV, R., Watkins III, R., Williams, L., Ahlbrand, S., Garcia, R., Karamanian, A., ... &

Hedman, T. (2005). Stability provided by the sternum and rib cage in the thoracic

spine. Spine, 30(11), 1283-1286.

Spinal Rounding and Spinal Loading

Shearing forces occur when two parts of the body are not aligned which pushes one part ofthe body in one direction, and another part of the body in the other direction. This is vastly

different from compression forces, for which intervertebral discs are designed to handle

efficiently. When performing a lift, whether in the gym or in daily life, one should consider

the ramifications of shearing forces on spine health. While the dangers of shear loading

may be grossly exaggerated, spinal rounding undoubtedly places the discs and ligaments

under much greater load. Therefore, spinal rounding should be utilized sparingly, if ever.

Information from: McGill, S. (2007). Low back disorders: evidenced-based prevention and

rehabilitation. Human Kinetics.

Spinal Rounding and Deadlift Muscle Activation

When one rounds his or her spine, the ratio of active to passive forces acting on trunkextension decreases for the reasons described in the previous sections. In full stretch, the

erectors actually shut off, which is deemed myoelectric silence. This means that spinal

erector activation would decrease and, instead, passive tissues would support the spine.

http://www.t-nation.com/free_online_article/most_recent/a_strong_case_for_the_rounded_back_deadlifthttp://www.t-nation.com/free_online_article/most_recent/a_strong_case_for_the_rounded_back_deadlifthttp://www.t-nation.com/free_online_article/most_recent/a_strong_case_for_the_rounded_back_deadlifthttp://www.t-nation.com/free_online_article/most_recent/a_strong_case_for_the_rounded_back_deadlift


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Biomechanics of the Lumbopelvic Hip

Complex

The lumbar spine, pelvis, and hips make up the lumbopelvic hip complex. Learning how to

properly control and move through this complex can be difficult and daunting, but doing so

will result in a safer, more efficient lift.

One must keep in mind that these structures affect how ones lumbar spine moves as well,

hence the lumbo in lumbopelvic. For example, if one cannot flex at the hip joint any further,

they will compensate via posterior pelvic tilt and lumbar flexion. During periods of deep

hip flexion, such as the bottom of the squat, it may be beneficial to maintain anterior pelvic

tilt because 1) it will put more tension on the adductors and hamstrings and 2) the glutes

are already inhibited due to deep hip flexion. As for near lockout, such as the top of a

deadlift, the opposite is true: increased posterior pelvic tilt will be a more advantageous

position to produce hip extension torque because the gluteus maximus can better activate

in this position.

Intimately involved in the lumbopelvic hip complex are four different muscles groups: hip

abductors, hip adductors, hip flexors, and hip extensors; ones structure/anatomy greatly

affects how these function by either increasing or decreasing the moment arm of each

muscle. For example, a 2cm superior displacement of the hip joint center decreases the

moment generating capacity of the hip abductors by 49% and hip flexors by 22%. A hip

center displaced 2cm superiorly, 2cm laterally, and 2cm anteriorly was shown to maximize

hip extension torque (Delp & Maloney, 1993).

Bret does a phenomenal job introducing and further explaining the lumbopelvic hip

complex and these concepts inthis video.

Delp, S. L., & Maloney, W. (1993). Effects of hip center location on the moment-generating

capacity of the muscles.Journal of biomechanics,26(4), 485-499.

http://www.youtube.com/watch?v=h5WhWu1g080http://www.youtube.com/watch?v=h5WhWu1g080http://www.youtube.com/watch?v=h5WhWu1g080http://www.youtube.com/watch?v=h5WhWu1g080


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Counterbalance Squat and Torques

The counterbalance squat is a variation of the squat in which weight is held out in front of

ones body. This will shift the center of mass forward, which will allow a person to sit back

more in order to counteract this shift. The counterbalance is commonly done to help

someone learn the squat or learn pistol squats. The change in moment arms resulting from

this shift in center of gravity increases hip torque and decrease knee torque.

Lynn et al. (2012) looked at the effects of a counterbalance squat vs. regular squats. This

shows the effects of shifting the system center of mass forward on forward trunk lean,

which decreases knee extension torque while increasing hip extension torque.

Goblet Squat Counterbalance Squat = 1000 0.1982 = 198.2

= 1000 0.2261 = 226.1

= 1000 0.3183 = 318.3

= 1000 0.1060 = 106.0

Lynn, S. K., & Noffal, G. J. (2012). Lower Extremity Biomechanics During a Regular and

Counterbalanced Squat. The Journal of Strength & Conditioning Research,26(9), 2417-2425.



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Trunk Position in the Squat

One can change the torques of a squat simply by changing trunk position. When one leans

forward, as seen below, he or she is shifting the torques by decreasing the knee moment

and increasing the hip moment. This is simply another way of sparing the knees, which

may be an individuals weak link. The opposite is true for someone staying upright, in that

they are sparing their hips (and also lower back) and transferring torque to their knees by

shifting position to increase the knee moment and decrease the hip moment.

Some variables that may also affect trunk position are:

Dorsiflexion ROM If one cannot adequately dorsiflex, the knee cannot go forward,

therefore he or she must compensate at the hips by leaning forward more or by

rounding the spine. Otherwise, the lifter would fall backwards.

Tibia Length A short tibia means, at the same angle of dorsiflexion, ones hipmoment arm is greater than that of a person with a longer tibia.

Femur Length At the same angle of dorsiflexion, a person with a long femur will

have a greater hip moment arm than a person with a short femur, meaning he or she

will need to lean forward more to keep the center of gravity over the feet.

Strength Compensation As noted above, if one has weak knee extensors and

strong hip extensors, it may be beneficial to keep the knee moment small and

compensate by more forward lean. This is often seen mid-lift, i.e., the lifter runs out

of knee extension strength/torque, shifts the hips back to increase the hip moment

and decrease the knee moment (which also increases the spinal moment). This shift

in hips also increases hamstring length and allows for greater force output so the

lifter can finish the lift.

Moderate Lean = 1000 0.2122 = 212.2

= 1000 0.2122 = 212.2

Upright Torso = 1000 0.1733 = 173.3

= 1000 0.2510 = 251.0

Marked Forward Lean = 1000 0.2510 = 251.0

= 1000 0.1733 = 173.3



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High Bar vs Low Bar Squats

When one places the bar lower on the back, he or she must compensate by leaning forward

more. This makes low bar squats more hip dominant when compared to high bar, as

shown below. Notice the greater hip extension moments and lesser knee extension

moments in the low bar squat compared to the high bar squat.

High Bar Squat = 1000 0.21215 = 212.15

= 1000 0.21215 = 212.15

Low Bar Squat = 1000 0.3012 = 311.2

= 1000 0.1231 = 123.1



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Squat Variations

There are four primary variations of the squat: the front squat, back squat, box squat, and

Zercher squat. Each one of these variations distributes torques differently and those

torque distribution differentiations should be taken advantage of, especially to work on

weak points and during times of injury.

Front SquatDuring the front squat, the bar is placed across ones shoulders and is supported by the

hands. Shifting the bar forward shifts the center of gravity forward, which in turn allows

the lifter to stay more upright. This upright position spares the hips and low back by

placing more torque on the knees, making the front squat a knee dominant movement.

Back SquatThe most popular of the squat variations is the back squat. During the back squat, the bar

is placed on the upper trapezius and the bar is stabilized with the lifters hands. This

allows the lifter to go through a more natural range of motion.

Box SquatBox squats are very similar to back squats, but at the bottom portion, the lifter must sit on a

box. Typically, this movement allows the lifter to keep their shins more vertical as the lifter

leans forward to keep the center of mass over their feet. This alleviates stress on the knees

and makes the movement much more hip dominant than the typical back squat.

Zercher SquatThe Zercher squat is the most unique of the bunch in that instead of the weight resting on

the trunk, it is being held in the lifters elbows. This variation is somewhere between the

front squat and back squat in terms of hip and knee joint torques.

Below is a comparison of all four variations.



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Front Squat = 1000 0.1766 = 176.6

= 1000 0.2477 = 247.7

Back Squat = 1000 0.2122 = 212.2

= 1000 0.2122 = 212.2

Box Squat = 1000 0.4240 = 424.0

=/

Zercher Squat = 1000 0.3627 = 372.7

= 1000 0.0516 = 51.6



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Deadlift Variations

Similar to the squat, there are variations of the deadlift that make use of different

combinations of torque in order to complete the lift.

Conventional Deadlift

Obviously the most popular variation of the deadlift, the conventional deadlift, isperformed with the legs in between the arms. This variation is the most hip dominant.

Sumo DeadliftPowerlifters often utilize the sumo deadlift. By abducting and externally rotating the legs,

they can decrease the hip moment arm and perform the lift in a more upright position since

hip abduction brings their body closer to the bar.

Trap Bar DeadliftThe trap bar deadlift utilizes a trap bar rather than a barbell. This allows the load to be

shifted more posteriorly when compared to the conventional deadlift, and has similar

torque values to that of a squat. Some people refer to this as a squat/deadlift hybrid, or asquat-lift. This variation is much more knee dominant compared to all other common

variations of the deadlift.

Hack LiftA hack lift is very similar to a conventional deadlift, except that the bar is behind your legs

instead of in front. This makes the variation much more knee dominant.

Below is a comparison of all four variations.



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Conventional Deadlift = 1000 0.4571 = 457.1 =/

Sumo Deadlift = 1000 0.3307 = 330.7 =/

Hex Bar Deadlift = 1000 0.3017 = 301.7

= 1000 0.1191 = 119.1

Hack Lift = 1000 0.2108 = 210.8

= 1000 0.2096 = 209.6



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Common Dysfunctions

Knee ValgusKnee valgus occurs when someones knees collapse inwards toward one another. This

condition can exist out of movement, and is referred to asgenu valgum in those cases, but

during movement, it can often be seen in the concentric portion of a squat or landing from a

jump. Knee valgus is associated with ACL injuries and patellofemoral pain syndrome.

The gluteus medius is a small muscle on the side of your hip that attaches to your illiotibial

(IT) band, which attaches to the lateral aspect of your tibia. This muscle acts to abduct the

hip and, when strengthened, may help prevent knee valgus.

For more on knee valgus, check out Bretsblog article on it.

Butt WinkButt wink occurs when ones femur runs out of room during hip flexion and makes contact

with the acetabulum. This contact induces posterior pelvic tilt and lumbar flexion, and is

commonly seen in the bottom of a squat.

For more on butt wink, check out Bretsvideo on it.

Poor Ankle MobilityThe ability for someone to dorsiflex may affect how they squat, that is, not allowing that

persons knees to go forward enough which puts an immense amount of torque on their

low back and may cause the person to go into butt wink sooner or have valgus collapse in

order to compensate. Proper ankle dorsiflexion will allow for a more balanced distribution

of torques, and these concepts are also discussed in Brets video on butt wink and article on

knee valgus.

http://bretcontreras.com/knee-valgus-valgus-collapse-glute-medius-strengthening-band-hip-abduction-exercises-and-ankle-dorsiflexion-drills/http://bretcontreras.com/knee-valgus-valgus-collapse-glute-medius-strengthening-band-hip-abduction-exercises-and-ankle-dorsiflexion-drills/http://bretcontreras.com/knee-valgus-valgus-collapse-glute-medius-strengthening-band-hip-abduction-exercises-and-ankle-dorsiflexion-drills/http://bretcontreras.com/squat-biomechanics-butt-wink-what-is-it-what-causes-it-how-can-it-be-improved/http://bretcontreras.com/squat-biomechanics-butt-wink-what-is-it-what-causes-it-how-can-it-be-improved/http://bretcontreras.com/squat-biomechanics-butt-wink-what-is-it-what-causes-it-how-can-it-be-improved/http://bretcontreras.com/squat-biomechanics-butt-wink-what-is-it-what-causes-it-how-can-it-be-improved/http://bretcontreras.com/knee-valgus-valgus-collapse-glute-medius-strengthening-band-hip-abduction-exercises-and-ankle-dorsiflexion-drills/


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Poor Core Stability

As mentioned earlier, spinal rounding is not just affected by a weak core, its affected by hip

and knee strength and is used as a compensatory mechanism. Blaming spinal rounding on

a weak core is a common misconception. Below, one can see how just 15 of spinal

rounding can shift torques in a front squat. If a lifter has weak quads, he or she will be

tempted to round the upper back in the front squat in order to shift more torque to the hips.

However, if one does need to increase their core stability, they can do so by bracing the

abdominals/obliques. This will increase intra-abdominal pressure, which will increasespinal stability. The downside of this is that it increases spinal compression and your

spinal erectors must produce more torque in order to counteract the spinal flexion

moments provided by your abdominals, and this may lead to greater fatigue.

Front Squat = 1000 0.1414 = 141.4

= 1000 0.2829 = 282.9

Roundback Front Squat = 1000 0.21215 = 212.15

= 1000 0.21215 = 212.15



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Dorsiflexion Aids in the Squat

Because dorsiflexion mobility is an issue for many lifters, there are external methods to

help compensate for a small ankle range of motion. These include everything from placing

a plate under someones heels to wearing Olympic lifting shoes. These methods, as seen

below, make someones starting position in slight plantar flexion, which in turn gives them

a greater range of motion before they reach their true dorsiflexion limit. This concept is

better understood by looking at the free diagrams below, assuming the dorsiflexion aidputs the lifter in 10 plantar flexion, this dorsiflexion aid can change the moment arms from

a 2:1 to nearly 1:1 ratio, thus balancing out hip and knee torques.

Back Squat = 1000 0.2829 = 282.9

= 1000 0.1414 = 141.4

Back Squat with Oly Shoes = 1000 0.2131 = 213.1

= 1000 0.2112 = 211.2



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Belts and Intra-Abdominal Pressure

As discussed earlier, IAP helps maintain a stable spine, but the addition of a belt will

enhance that effect by creating more intra-abdominal pressure. This is most likely due to

the rigidity of a belt (a bottle) compared to the rigidity of your muscles and connective

tissue (a balloon). Because of the elastic qualities of connective tissue, it will expand like a

balloon with some resistance. A belt, on the other hand, will not give way, thus limiting the

amount of volume in your abdominal cavity. Boyles law states that there is an inverserelationship between volume and pressure, and this explains why a tight belt will increase

IAP.



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Knee Wraps, Suits, Briefs, and Torque

By wearing what is often referred to as gear in powerlifting, one can shift their strength

curves, and therefore torque curves to become more even. This works by giving the lifter

assistance where they are weakest but, after that tension from the gear is gone, the lifter

must use their own strength to finish the lift. For example, with knee wraps, elastic tension

is added to the knee to help the lifter spring out of the hole in a squat. Once the lifter has

taken advantage of this elasticity, he or she must finish the lift with his or her own strength.

In the graph below, the black line represents the standard torque curve and the red line

represents the torque curve with gear.

Hip

Exte

nsion

Torq

ue

(Nm)

Hip Angle ()



38/43

Theoretical Effects of Support GearOlympic Shoes Knee Wraps Briefs/Squat Suit Belt

Mainly used for front

squats or Olympic

squats.

Mainly used in

geared powerlifting

during squats.

Mainly used in

geared powerlifting

during squats.

Mainly used for

squats and deadlifts.

Allows lifter to stay

more upright which

decreases spinal

torques and shifts

the demand more to

the knee joint.

Provides passive

knee extension

torque, especially

during deep knee

flexion.

Provides passive hip

extension torque,

especially during

deep hip flexion.

Enables the lifter to

produce greater

intra-abdominal

pressure during the

squat exercise.

A lifter with strong

knees but poor ankle

dorsiflexion rounds

his low back when

he squats. Using

Olympic shoes

enables him to squat

deeper whilekeeping his back

upright, leading to

greater forward

knee migration and

knee extension

torque.

A lifter can produce

300 Nm of active

knee extension

torque at the bottom

of a squat. With

knee wraps, he may

be able to produce

350 Nm of totaltorque.


400 Nm of active hip

extension torque at

the bottom of a

squat. With a briefs

and a squat suit, he

may be able to

produce 500 Nm oftotal torque.


200 mmHg of IAP

during the squat

exercise. Wearing a

belt, the lifter can

produce 230 mmHg,

which further

stabilizes the spine.

These seemingly minor aids combine to produce large increases in the total poundages that a lifter

can hoist.



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Dynamic Effort and Muscle Activation

Dynamic effort is a method of training popularized by Louie Simmons from Westside

Barbell. Many lifters swear by the dynamic effort method and have noticed marked

strength gains once implementing it. One major benefit of dynamic effort training is that it

is not as taxing on the CNS and can be performed more frequently compared to heavier

lifting. However, one pitfall with dynamic effort is that at the bottom range of motion, youwill accelerate the load, but one must slow down as he approaches the end range of motion

to prevent jarring forces from occurring associated with ballistics. Therefore, muscle

activation decreases to decelerate the bar at end range of motion. To counter this decrease

in muscle activation and increase the acceleration phase of the lift, bands and chains can be

used as accommodating resistance. Even a small amount of accommodating resistance

goes a long way in this regard.

Bands, Chains, and TorqueBands and chains work similarly to the way powerlifting gear works in that they alter the

strength and torque-angle curves, but the way in which they do it works a little bit

differently. Bands and chains are often used to add resistance towards the top of a lift, or

when a lifter is strongest. So, instead of decreasing the resistance in the beginning of a lift

like gear, bands and chains increase the resistance toward the end of the lift to help even

out the torque curve. A graph of this can be seen below, where the black line represents a

standard torque curve, and the red line represents the torque with accommodating

resistance.

Hip

Extension

Torque

(Nm)

Hip Angle ()



40/43

Assistance Lifts

Numerous, non-conventional lifts exist that may help one achieve more success with more

traditional compound lifts. Some important ones will be discussed, along with their

applicability to training and how they are carried over to other lifts.

Muscle Length Compared to Anatomical Position at Peak Hip Extension Torque

Glutes Hamstrings Vastis

Squat Lengthened Unchanged Lengthened

Deadlift/Good Morning Lengthened Lengthened Slightly Lengthened

Hip Thrust Unchanged Shortened Lengthened

Back Extension Unchanged Unchanged Unchanged

45 Hyper Slightly Lengthened Slightly Lengthened Unchanged



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Hip ThrustThe hip thrust, popularized by Bret Contreras, is an exercise in which the lifter places their

feet on the ground, upper back on a bench, and bar over their hips, and thrusts the bar

forward. EMG data shows this to be the most constructive exercise for gluteus maximus

activation, which would not only help hypertrophy the glutes, but also strengthen them.

Implications of stronger glutes include a stronger squat if hip extension is a bottleneck and

the lockout in the deadlift. The gluteus maximus has also been shown to be the strongest

stabilizer of the sacroiliac joint (SIJ) (Barker et al., 2013).

The activation patterns of the hip thrust jive very well with the findings of Worrell et al.

(2001), i.e., the gluteus maximus has the highest EMG activity at end range. Because the

force from the load is always perpendicular to the hips, resisting extension, one is able to

maximize hip extension torque and gluteal EMG activity. Below is a graph of the hip

extension torque in a hip thrust of a 64, 100kg male using a 220kg load.

Back Extension on GHDSomewhat of a misnomer, the back extension is really a hip extension exercise. Because the

legs are straight during the back extension, this exercise would elicit more hamstrings and,

because the back is held in a neutral position, the spinal erectors are working isometrically

to stabilize the spine. The gluteus maximus and hamstrings share the hip extension torque.

The movement can be performed on a glute ham developer. The most challenging position

in the back extension is at full lockout where the torso is fully extended.

45 HyperThe 45 Hyper is a piece of equipment on which the back extension is often performed.

The torques when performing a back extension on the 45 Hyper are on the graph and

show an inverted u-shaped curve, with the most challenging portion in the middle of the lift.



42/43

Good MorningA good morning is performed similarly to a stiff leg deadlift, but instead of the bar being

held in ones hands, it is placed on the back similarly to a back squat. This movement

elicits similar EMG activity as the stiff leg deadlift, that is, hamstrings and glutes

contributing to hip extension and the spinal erectors acting isometrically to maintain a

neutral spine. The torques necessary to complete a good morning are shown on the graph

and show that the most challenging portion is a the bottom of the movement when the hips

are fully flexed.

More information on these concepts, horizontal back extension, 45 hyper, and good mornings are

discussed further byContreras et al. (2013). Bret was also nice enough to record avideosummarizing the article and these concepts.

Contreras, B. M., Cronin, J. B., Schoenfeld, B. J., Nates, R. J., & Sonmez, G. T. (2013). Are All

Hip Extension Exercises Created Equal?. Strength & Conditioning Journal, 35(2), 17-22.

Reverse HyperThe reverse hyper was popularized by Louie Simmons at Westside Barbell and is a great

movement for learning how to control ones pelvis and lumbar spine during a hip hingewhile properly utilizing the glutes. The reverse hyper is performed by laying ones upper

body face down on a surface with the legs hanging off, secured to a pendulum via a strap.

The lifter will simply move in and out of hip flexion while controlling the movement with

their hip extensors. It should be noted that on the graph below, we are assuming a quasi-

static model, i.e., there is no momentum and that the lifter is not actively preventing the

weight from swinging past 90 of hip flexion.

Below is a graph showing the torque-angle curves of the previous four exercises if a 6, 200

lb subject were to hold a 100 lb weight at the top of his or her chest.

0

100

200

300

400

500

600

90 135 180

HipExtensionTorque(Nm)

Hip Angle

Hip Extension Exercise Torque-Angle Curves

Good Morning

45 Back extension

Horizontal Back

Extension

Reverse Hyper

http://bretcontreras.com/wp-content/uploads/Are-All-Hip-Extension-Exercises-Created-Equal.pdfhttp://bretcontreras.com/wp-content/uploads/Are-All-Hip-Extension-Exercises-Created-Equal.pdfhttp://bretcontreras.com/wp-content/uploads/Are-All-Hip-Extension-Exercises-Created-Equal.pdfhttp://www.youtube.com/watch?v=ks1FwB_RXn8http://www.youtube.com/watch?v=ks1FwB_RXn8http://www.youtube.com/watch?v=ks1FwB_RXn8http://www.youtube.com/watch?v=ks1FwB_RXn8http://www.youtube.com/watch?v=ks1FwB_RXn8http://www.youtube.com/watch?v=ks1FwB_RXn8http://bretcontreras.com/wp-content/uploads/Are-All-Hip-Extension-Exercises-Created-Equal.pdf


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Glute Ham RaiseJust like the name says, the GHR is an excellent movement for the development of ones

hamstrings, but as far as the glutes go, it is a bit of a misnomer. This is due to the fact that

knee flexion is the bottleneck: one has a much higher capacity for hip extension torque than

knee flexion torque, but the GHR puts a lot more torque on the knees than it does the hips.

It is performed on a glute ham developer (GHD) by extending at the knees and flexing at the

hips until the body forms an L shape. Once at the bottom, the lifter simply extends at the

hips and flexes at the knees.

As you can see, the GHR is a knee dominant (knee flexion) exercise and not a hip dominant

exercise. For more information on the Glute Ham Raise, check out Brets article on T-Nation,

Gutting the GHR.

Barker, P. J., Hapuarachchi, K. S., Ross, J. A., Sambaiew, E., Ranger, T. A., & Briggs, C. A.

(2013). Anatomy and biomechanics of gluteus maximus and the thoracolumbar fascia at

the sacroiliac joint. Clinical Anatomy.

0

100

200

300

400

500

600

Knee: 180

Hip: 90

Knee: 180

Hip: 135

Knee: 180

Hip: 180

Knee: 135

Hip: 180

Knee: 90

Hip: 180

Torque(Nm)

Glute Ham Raise Torque-Angle Curves

Hip Extension Torque Knee Flexion Torque
http://www.t-nation.com/free_online_article/most_recent/gutting_the_gluteham_raisehttp://www.t-nation.com/free_online_article/most_recent/gutting_the_gluteham_raisehttp://www.t-nation.com/free_online_article/most_recent/gutting_the_gluteham_raise

Biomechanics of the Squat and Deadlift

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