Article Title

The Bilateral Deficit and the Acute Effects of Heavy Bilateral and Unilateral Squats on Sprinting


Tholis, M., Moir, G.L., East Stroudsburg University, East Stroudsburg, PA

Purpose: To evaluate differences in the bilateral deficit in the lower body of resistance-trained (RT) and sprint-trained (SP) athletes and to investigate the acute effects of heavy bilateral and unilateral back squats on straight-line sprint running performance. Methods: In a randomized cross-over design a group of RT men (n=5; age: 19.8 ± 1.5 years; height: 1.83 ± 0.03 m; mass: 100 ± 9.5 kg) and a group of SP men (n=7; age: 18.9 ± 1.1 years; height: 1.77 ± 0.08 m; mass: 74.4 ± 5.5 kg) attended four testing sessions during a two week period. Each subject had their 1-repetition maximum (1-RM) back squat assessed both bilaterally and unilaterally during the first two sessions. The bilateral deficit (BD) was calculated as the difference between the bilateral and unilateral 1-RM loads. During the final two sessions each subject performed three baseline 55 m sprints separated by two minutes of recovery. Following a further five minutes of recovery, each subject completed a series of heavy back squats performed with loads equivalent to 55, 75, and 90% of their bilateral (HBS) and unilateral (HUS) 1-RM. A further three 55 m sprints were completed four minutes after the heavy squat protocols. The order of the final two testing sessions was randomized. Differences in 1-RM values, BD, and the change in the fastest sprint times between the groups were assessed using an ANOVA model with p ≤ 0.05. Results: The RT group produced greater 1-RM values compared to the SP group (mean difference: 28 kg; p = 0.012) while the bilateral 1-RM loads were greater than the unilateral 1-RM loads (mean difference: 53.4 kg, p < 0.001). The BD in the SP was less than in the RT (SP mean difference: 41.9 kg; RT mean difference: 65.0 kg; p = 0.12). The SP group were significantly faster than the RT group (mean difference: -0.64 s; p = 0.006). The HBS protocol resulted in an increase in 55 m sprint time (mean difference: 0.09 s; p = 0.038) as did the HUS (mean difference: 0.12 s; p = 0.008), with no statistical differences between the protocols or the groups. Conclusion: Neither HBS nor HUS protocols were useful in eliciting acute improvements in short sprint performance in RT or SP men.

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