Peak lifting velocities of men and women for the reduced inertia squat exercise using force control

Abstract

The purpose of the research was to determine peak velocities for the reduced inertia squat exercise at various resistance levels based on an isometric strength assessment for both men and women. On a Smith machine modified for pneumatic resistance, 12 males and 12 females previously trained college-age participants performed a maximal isometric strength assessment with knee angles of 90 degrees , 110 degrees , 130 degrees , 150 degrees and 170 degrees (180 degrees = full extension) followed by dynamic maximal effort squats with resistance maintained at 40, 50, 60, 70, and 80% of their lowest maximum isometric strength. No interaction existed between the men and women during isometric strength tests with the men stronger in every joint position (P < 0.05). The lowest isometric strength occurred at 90 degrees without variation. There was an interaction between men and women for peak lifting velocity during the dynamic lifts (P = 0.021) with the men producing higher velocities at all levels of resistance (P < 0.05). The difference in peak velocity between the sexes was greatest at the lowest resistance level and that difference was less significant at the higher resistance levels. The relationship between resistance force and peak lifting velocity is applicable to increasing the efficiency of the squat by maximizing force output per repetition by varying the resistance as the lifter approaches peak velocity similar to isokinetics with preloading and active instead of reactive resistance.