Speed, Agility, and Speed-Endurance

Development

NSCA Chapter 20 Page 471

Speed, Stride Frequency, and Stride Length• Speed

– The ability to move the body in one intended direction as fast as possible

– Product of stride length and stride frequency (rate)• Stride Frequency (rate)

– Number of strides taken in a given amount of time (or distance)

– It may be improved with core strength, plyometric training, and technique

• Stride Length– The distance covered in one stride, during running– High correlation to leg length (2.1 to 2.5 times leg

length)

Agility

• The ability to start (accelerate), stop (decelerate and stabilize), and change direction quickly, while maintaining proper posture

• Requires high levels of neuromuscular efficiency

• Individual is constantly regaining a center of gravity over his or her base of support, while changing directions, at various speeds

Quickness• Reaction time

• The ability to react and change body position with maximum rate of force production, in all planes of motion, from all body positions, during functional activities

• Ability to react to visual, auditory, and kinesthetic feedback

Physiological Factors of Speed and Agility

• Genetic Factors– Muscle fiber type

• Body Fat

• Height

• Age

• Gender

• Anaerobic or Speed Endurance (ability to use fuel)

Muscle Fiber Type• There are three types of

muscle fibers found in various parts of every athletes body:

– Slow-Twitch Red (type I)

– Fast-Twitch Red (type IIa)

– Fast-Twitch White (type IIb)

Slow-Twitch Red (Type I) Muscle Fibers

• Relies on oxygen to produce energy (aerobic)

• Develops force slowly

• Fatigue resistant (high endurance)

• Low power output

• High aerobic capacity for energy supply

• Endurance athletes have 70-80% Type I fibers

Fast-Twitch Red (Type IIa) Muscle Fibers• This intermediate fiber type

can contribute to both anaerobic and aerobic activity

• Develops force relatively quickly

• Elite sprinters have 70-80% Type II fibers

• Moderate:

– Fatigability

– Power output

– Aerobic and anaerobic power

Fast-Twitch White (Type IIb) Muscle Fibers

• This fiber type does not rely on oxygen to produce energy (anaerobic)

• Develops force rapidly

• High fatigability (low endurance)

• Low aerobic power• High anaerobic power

• The two fiber types generally produce the same amount of force per contraction, but fast twitch fibers produce that force at a higher rate (they fire more rapidly).

• Muscles with a high percentage of fast-twitch fibers exert quicker, more powerful contractions

• Individuals born with a high percentage of fast-twitch fiber have a higher speed potential than those born with slow-twitch fibers

Muscle Fibers

Muscle Fibers• People who are not athletes have

50% Type I and II• The right kind of high-intensity training

(heavy load) will recruit and train fast-twitch fibers and aid in the improvement of acceleration and speed–Olympic lifts–Heavy medicine ball

Muscle Fibers• Postural muscles such as the soleus are

composed mostly of slow-twitch fibers whereas the quadriceps contain a mixture of both fibers, which permit jogging and sprinting

• The theory that slow-twitch fibers can be changed into fast-twitch fibers is controversial–New evidence suggests that prolonged

high-intensity training may produce that effect and improve the ratio of fast-twitch to slow-twitch fibers

Body Fat

• Body fat <6% for men

• Body fat of <15% for women

• The lower ranges may by unhealthy, depending on the individual

• On the other hand, excess fat negatively affects both acceleration and speed

Age• No physiological reason exists for speed to diminish significantly from age 25-35 unless the athlete ceases training, loses strength and power, or adds body fat

Gender• World records by men in the 100 meters

are .75 seconds faster than those by women

• The faster stride rates and longer strides of males appear to account for the time differences

• Hormonal and anatomical differences have implications for acceleration and speed

Proper Running Mechanics• Foot/Ankle Complex:

– Pointing straight ahead in a dorsiflexed position when it hits ground

– Excessive flattening or external rotation of foot creates stress and decreases overall performance

• Knee Complex:– Knees straight ahead– Excessive adduction or internal rotation of the

femur leads to overuse injuries

Proper Running Mechanics• Lumbo-Pelvic-Hip Complex (core)

–The body should have a slight lean during accleration

–The spine should be fairly neutral without excessive extension or flexion

• Head–In line with the lumbo-pelvic-hip-

complex

Proper Sprint Mechanics• Triple Flexion on the Front of the Leg

– Ankle dorsiflexion– Knee flexion– Hip flexion– Keeping the lumbar spine neutral

• Triple Extension on the Back of the Leg– Ankle plantarflexion– Knee extension– Hip extension– Keeping the lumbar spine neutral

Training Stride Length• Resisted Sprinting

• Examples– Running uphill or upstairs– Running with a parachute, harness, or sled

Training Stride Frequency (Rate)

• Stride Frequency:–Over-speed training

•Running at speeds higher than the individual is used to

• Examples: –Running down hill –High speed treadmills–Tubing

Mechanics of Speed

• Other factors in determining speed:

–Strength–Explosive

Power (Plyometrics)

–Flexibility–Muscle

Imbalance

Mechanics of Speed• Muscle Balance:

– Prime movers in sprinting are the knee extensors, hip extensors, and ankle plantar flexors

– An imbalance usually exists between the knee extensors/flexors

– The strength of the hamstring muscle group is a sprinter’s weakest link

– It should be improved to 70 to 90 percent of the strength of the quadriceps group

– A minimum ratio of 70 percent is recommended for the prevention of injury

Speed Training Program Design• Frequency:

– number of speed training sessions per week, depends on individuals goals

• Recovery: – 1:5 to 1:10 between repetitions

• Volume: – distance covered during a training session

(50 meters to 100 meters)

• Progression: principles of progression

Speed Training Program Design

• Stabilization–4-6 speed ladder drills–1-2 cone drills

• Strength–6-9 speed ladder drills–1-2 cone drills

• Power–6-9 speed ladder drills–2-4 cone drills

Speed and Cone Drills

Speed Endurance• The metabolic conditioning needed to support

speed/agility movements over an extended period of time (six or more seconds)

• Athletes with poor speed endurance are unable to accelerate and sprint repeatedly because of fatigue–Offensive lineman vs. receiver

• Slowing occurs because of lactic-acid buildup• Improved lactic-acid tolerance, increased

quick energy stores, and improvement in the rate that quick energy is available are related to anaerobic fitness, age and nutrition.