Speed, Agility, and Speed-Endurance Development NSCA Chapter 20 Page 471

Speed, Stride Frequency, and Stride Length 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

Muscle Fibers 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 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

Training Stride Length Resisted Sprinting Examples Running uphill or upstairs Running with a parachute, harness, or sled

Training Stride Frequency (Rate) Over-speed training Running at speeds higher than the individual is used to Examples: Running down hill High speed treadmills Tubing

Explosive Power (Plyometrics) 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 Power 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.