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.
Tholis, M. and Moir, G.L.
"The Bilateral Deficit and the Acute Effects of Heavy Bilateral and Unilateral Squats on Sprinting,"
International Journal of Exercise Science: Conference Proceedings:
2, Article 80.
Available at: http://digitalcommons.wku.edu/ijesab/vol9/iss2/80
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