Effect of Weightlifting Shoes on Stability During Barbell Squat in High Intensity Cross Training Athletes

The use of weightlifting shoes with the aim of improving stability during high-intensity barbell squats is common. The shoes have a heel lift that favors ankle dorsiflexion range of motion while potentially reducing trunk range of motion. Assuming they increase stability, we aimed to test the hypothesis that wearing weightlifting shoes, compared to conventional shoes, would reduce the amplitude and velocity of the center of pressure displacement during the squat movement. An experimental, laboratory-based study with 3-dimensional movement analysis was conducted. Sixteen competitive athletes (8 females and 8 males; 27 ± 3 years; 72 ± 11kg) performed barbell squats with three different loads (50%, 70%, and 90% of 3-repetition maximum) and two types of footwear (conventional shoes and weightlifting shoes). Kinematic and kinetic data were collected using eight infrared cameras (Vicon Motion Systems) and two force plates (AMTI). The amplitude of center of pressure displacement (CoP) was calculated and expressed as a percentage of foot size. Peak trunk flexion angle, center of pressure peak velocity (Vel-CoP) and CoP in the mediolateral and anteroposterior directions were verified for the concentric and eccentric phases. Comparisons between shoes were drawn using Wilcoxon tests. We found a reduction in the amplitude of anteroposterior CoP displacement for the weightlifting shoes compared to conventional shoes during the concentric phase of the 90% of 3-repetition maximum squat (mean difference = 1.75^% p=0.025). Additionally, we observed a reduction in the velocity of CoP displacement in the mediolateral direction for weightlifting shoes compared to conventional shoes during the concentric phase at 90% of 3RM (mean difference = 4.15 mm/s, p = 0.018). Furthermore, weightlifting shoes significantly decreased the peak trunk flexion angle compared to conventional shoes at 70% of 3RM (mean difference = 1.47°, p = 0.009). All other comparisons did not yield significant effects. The results suggest that weightlifting shoes enhance stability in high load barbell squats, which may contribute to better control, body alignment, and to a more efficient transfer of force in the squats.