Assessing Reliability in Flywheel Squat Performance: The Role of Sex and Inertial Load.

Area of Science:

• Sports Science
• Biomechanics
• Human Performance

Background:

• Within-session reliability is crucial for accurate performance assessment in strength and conditioning.
• Understanding how sex and inertial load affect reliability is vital for individualized training programs.

Purpose of the Study:

• To investigate the impact of sex and inertial load on the reliability of flywheel half-squat performance metrics.
• To determine the sensitivity of various performance outcomes to changes in inertia and sex.

Main Methods:

• 21 males and 25 females completed two sets of six repetitions at four different inertial loads.
• Measured outcomes included mean force, mean and peak power, impulse, and work during concentric and eccentric phases.
• Calculated reliability using intraclass correlation coefficient (ICC), coefficient of variation (CV), and typical error (TE) versus smallest worthwhile change (SWC).

Main Results:

• Excellent between-set reliability (ICC > 0.803 for males, > 0.946 for females) was observed across all variables, loads, and contraction phases.
• Coefficient of variation (CV) values were consistently good (≤9%) for all variables.
• Significant interactions between inertia and sex were found for power-related variables, indicating sex-specific responses to different inertial loads.

Conclusions:

• Flywheel half-squat performance exhibits excellent within-session reliability for both sexes across all tested inertial loads and contraction phases.
• Inertial load configuration and sex differences are important considerations when interpreting performance data and profiling athletes.