Effect of back squat depth on lower-body postactivation potentiation

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• Postactivation potentiation (PAP) describes the increase in muscular force production following prior activity.
• Squat variations, differing in depth and mechanical demands, may influence PAP levels and subsequent athletic performance.

Purpose of the Study:

• To compare the effects of parallel squats (PS) and quarter squats (QS) as stimuli for postactivation potentiation.
• To determine which squat variation yields superior improvements in countermovement jump (CMJ) performance.

Main Methods:

• Twenty-seven male semiprofessional rugby union players participated.
• Participants performed a baseline countermovement jump (BL-CMJ), followed by either PS or QS at their 3-repetition maximum load, then rested before a post-intervention CMJ (POST-CMJ).
• Jump height, peak power, impulse, and flight time were measured using a contact mat.

Main Results:

• Both PS and QS induced significant PAP for all measured variables (p < 0.05).
• The parallel squat (PS) stimulus resulted in significantly greater improvements in CMJ performance compared to the quarter squat (QS) stimulus.
• Specific improvements for PS vs. QS included: jump height (4.6 ± 2 vs. 3.5 ± 2 cm), impulse (15 ± 6 vs. 12 ± 5 N·s), peak power (285 ± 109 vs. 215 ± 96 W), and flight time (34 ± 23 vs. 26 ± 11 ms).

Conclusions:

• This study demonstrates that different squat variations can elicit PAP.
• Parallel squats are more effective than quarter squats in enhancing subsequent countermovement jump performance.
• The greater gluteal activation and work produced during the deeper parallel squat are suggested to be responsible for the superior PAP effect.