Lower body power can be assessed via Jump Testing. GymAware users should select “Squat Jump (Counter Movement)” from the exercise list and instruct the athlete to make a preliminary dip by flexing the knees and hips, then immediately extend upwards to jump vertically off the ground. Such a movement utilises the ‘stretch shorten cycle’, which maximises performance through the momentary storage of elastic energy within the joint complex (Fig a).
An alternate type of jump is the ‘squat jump’ concentric, where the jumper starts from a stationary semi-squatted position (Fig b). The jumper does not employ a preliminary downward phase (i.e., a countermovement) and so the jump does not involve pre-stretching of muscles. Most athletes can jump 3 - 6 cm higher in a countermovement jump than in a squat jump concentric.
The PowerTool should be placed next to the athlete clear of their feet; a test protocol should be agreed on to ensure reliable data collection. To avoid errors with bar tilt you may wish to mount the PowerTool on the ceiling with a mount available in the Kinetic online shop.
A broom stick held across the shoulders minimises arm swing and also provides an attachment point for the tether. A few test jumps may be needed to ensure athlete familiarity and subsequent accuracy in data collection.
KEY PERFORMANCE VARIABLES
Many practitioners use GymAware to measure power, velocity and height of a vertical jump.
Jumps are popular because they are a quick, noninvasive, and a good method for monitoring the performance of the athlete.
BENEFITS TO THE COACH
Jump testing provides objective data to evaluate lower body athletic performance. Lower body explosive power is a valuable component of an athletes total athletic profile. Regular measurement (weekly) has proven to be a valuable indicator of fatigue.
Sheppard JM, Doyle TL (2008) Increasing compliance to instructions in the squat jump.
Riggs M, Sheppard JM (2009) The relative importance of strength and power qualities.
Taylor, K; Cronin, J (2011) Sources of variability in iso-inertial jump assessments.
Taylor, K; Hopkins, W (In review) Error of measurement in jump performance is influenced by training phase.