Sprint athletes: testing and training Flashcards
sprint velocity is equal to what?
•Stride length(m) x stride rate (stride/s or Hz)
defining sprint phases?
Acceleration phase: defined as continual rise in velocity
Maximal velocity phase: defined as when the athlete reaches peak velocity
Speed maintenance phase: defined as the involuntary deceleration phase of a maximal sprint
ground length and its effect
Usain Bolt has a ground contact length approx. 5 to 10 cm longer than competitors:
Velocity ~ stance contact length (m) / contact time (s) (assume 0.08 s is minimal CT)
- 1.05 m / 0.08 s = 13.1 m/
- 1.0 m / 0.08 s = 12.5 m/s
Even with same contact time, UB potential max is higher
why aren’t all tall people faster?
depends on the force they generate
training for speed: considerations before training?
Can the athlete produce high levels of force, in short periods of time, in relevant movement patterns (sport specific)?
Can the athlete produce high levels of force, in small periods of time?
Can the athlete produce high levels of force?
Does the athlete have the ability to move efficiently, possess the appropriate body composition and ability to tolerate the work loads required to become stronger?
training for speed: Training considerations for speed: Acceleration
- Maximal strength relative to body mass to overcome inertia (Young et al., 2001)
- Concentric explosive strength of hip, knee and ankle extensors (Young et al., 1995)
- Longer GCT = greater application of slow SSC characteristics (relatively)
- Greater emphasis on horizontal force development (body orientation!)
what to see when sprinting: acceleration?
Big split of arms and legs
forward lean
neutral postural alignment pushing through long axis of body
complete pushes and triple extension
low heel recovery
gradual progression of body angles
Training considerations for speed: Maximal velocity sprinting
- Ability to develop high levels of force in a extremely short periods of time (<100 ms)
- Concentric power production of hip extensors to create high levels of force (Goodwin, 2011)
- Leg stiffness (knee and ankle) to reduce GCT (Goodwin, 2011)
- Shorter GCT = greater application of fast SSC characteristics
- Greater emphasis on vertical force development
what to see when sprinting: maximal velocity sprinting
upright posture
powerful and dynamic arm swings
high knee recovery
front side dominance
relaxation in face, shoulder and hands
foot contact under the hips
vertical shin angle at GCT
Pre-activation prior to contact
what types of strengths increase force production (in order)
- Maximal strength
* Explosive strength •Reactive strength
Strength training and its effect on sprint ability?
Strong Correlation
Squat Strength change vs. Sprint change
(r= -0.77, p= 0.0001)
Suggests there is transfer between increases in lower-body strength and sprint performance
14-weeks strength training = ↑ rate of force development
Stretch-shortening cycle (SSC)
eccentric—>concentric
Pre-activation (active state) before eccentric phase
Short and quick Eccentric-quasi isometric phase
Coupling time (couple con with ecc)
(<200 ms= Fast SSC;
> 200 ms= Slow SSC)
Structures involved in SSC: Contractile component:
muscle model—> contractile component (cc)—>overlap of the actin and myosin—>active tension
Structures involved in SSC: Series elastic component:
muscle model—>series of elastic component (SEC)—>connective tissues within the tendon—>1. smoothen out the rapid changed in the muscle tension. 2. passive tension
Structures involved in SSC: Parallel elastic component:
muscle model—>parallel elastic component (PEC)—>parallel connective tissues: sarcolemma, epimysium, perimysium, endomysium—>passive tension
