Changes in the force-time curve during a repeat power ability assessment using loaded countermovement jumps

Area of Science:

• Sports Science
• Biomechanics
• Human Movement Analysis

Background:

• Traditional repeat power ability (RPA) assessments rely on discrete variables like peak power output.
• Analyzing the entire force-time curve offers deeper insights into RPA performance changes.

Purpose of the Study:

• To analyze changes in the force-time curve during RPA assessments using statistical parametric mapping (SPM).
• To compare force-time curve differences between participants with low and high RPA scores.

Main Methods:

• Eleven field hockey players performed 20 loaded countermovement jumps (LCMJ20).
• Force-time data was analyzed using SPM, with peak power and RPA percent decrement (RPA_%dec) calculated.
• SPM one-way ANOVA and independent t-tests identified significant changes and group differences (α=0.05, p<0.001).

Main Results:

• Propulsive forces significantly decreased from 74-98% of the movement as the LCMJ20 progressed (p<0.001).
• Greatest differences in force occurred between jump series 1 and 2 (70-98%) and series 1 and 3 (86-99%).
• Participants with lower RPA_%dec scores exhibited greater braking and propulsive forces (p<0.001).

Conclusions:

• Force reduction in the late propulsive phase is evident during LCMJ20.
• SPM analysis refines understanding of force-time curve changes during RPA assessments.
• Lower RPA_%dec scores indicate superior maintenance of peak power, reflected in greater braking and propulsive forces.