Comparing the kinematics of back squats performed with different heel elevations

Purpose
Back squat (BS) is a popular exercise owing to its capacity to develop lower limb strength. During BS, trunk inclination and knee range of motion (RoM) are relevant aspects of a proper technique, and these movement kinematics parameters can be positively altered with official weightlifting shoes lifting the heel 13 mm above the ground. Wedges are a low-cost alternative to lifting the heel to different heights, but movement kinematics adaptations with higher elevations, above 25 mm, are not well described in the literature. Thus, we compared the effect of different heights of heel wedges on BS kinematics.

Methods
Fifteen experienced recreational weightlifters (22 ± 5.4 years; 83 ± 11 kg; 179 ± 6 cm; 5 ± 2.1 years of BS experience) were conveniently selected. Three randomized conditions were applied: barefoot (B), 25-mm (W25), and 50-mm wedges (W50). BS movement was assessed by kinematic analysis with an optoelectronic camera system.

Results
After ANOVA, the post-hoc indicated significant RoM differences in reducing trunk (F = 27.27; p < 0.01) and increasing knee (F = 16.87; p < 0.01) flexions between conditions. Post-hoc analysis verified decreasing trunk inclination (B > W25 > W50; p < 0.05) and increasing knee (B < W25 < W50; p < 0.05) RoM with increasing wedge height.

Conclusions
Higher wedges allowed positive adaptations by promoting a more upright trunk position and greater BS depth. Using a heel wedge can be a low-cost and viable strategy to optimize BS technique in a variety of training settings and contexts.