Effect of Imposing a Delay During Benchpress

Document Type

Article

Publication Date

5-2015

Publication Title

Medicine & Science in Sports & Exercise Supplemental

DOI

10.1249/01.mss.0000479347.32341.10

ISSN

1530-0315

Abstract

The benchpress (BP) is one of the most commonly used upper-body resistance training exercises. Numerous methods of performing the BP lift have been employed by strength and conditioning professionals seeking to develop explosive power. Performing the benchpress in a rapid manner would be expected to help develop explosive power and strength in the upper-body of athletes. Using 95% maximal load, the delay between the eccentric and concentric movements was shown to potently influence the velocity, force and power generated during the subsequent concentric phase. Whether similar effects exist for lighter loads remains unknown.

PURPOSE: To quantify the decline in peak velocity and power production by imposing delays of 1.5s, 3s, and 4.5s between the eccentric and concentric phases of BP at 75% maximal load.

METHODS: Ten physically active men (24.8 ± 1.9yrs, 1.79 ± .06m, 84.4 ± 7.5kg) with 6≥ months BP experience completed a 1 repetition-maximum (1RM) assessment. Following a rest period of 3-7 days, subjects performed three BP repetitions each of regular BP (RBP), 1.5s short-pause BP (SPBP), 3.0s medium-pause BP (MPBP), 4.5s long-pause BP (LPBP), and pure-concentric BP (PCBP). Subjects performed a total of 15 lifts at 75% 1RM with 2-3min of rest between repetitions. During each lift, a 12 camera motion analysis system recorded bar displacement. Using the bar mass along with displacement, peak velocity and peak power were computed and averaged across the three trials.

RESULTS: Results demonstrated RBP peak velocity (PV) as significantly greater to SPBP (34.13%, p=.008), MPBP (51.0% diff, p=.001), LPBP (49.5% diff, p=.009), and PCBP (50.5% diff, p=.012). SPBP PV was significantly greater than LPBP (11.4 % diff, p=.007). RBP peak power (PP) was greater than SPBP (32.7 % diff, p=.008), MPBP (49.2%, p=.009), LPBP (49.0% diff, p=.001), and PCBP (52.3 % diff, p=.012). SPBP PP was greater (12.3% diff, p=.014) than LPBP PP.

CONCLUSION: These results confirm a significant decline in peak velocity and power development with increasing pauses between the BP phases at 75% 1RM. The benefit of a pre-stretch appears to dissipate with delays greater than 1.5s. Future research should examine the mechanisms by which the pauses affect subsequent force and power production.

Comments

© 2015 American College of Sports Medicine

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