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North American Congress on Biomechanics Canadian Society for Biomechanics - American Society of Biomechanics University of Waterloo Waterloo, Ontario, Canada August 14-18, 1998 |
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A popular dynamic lifting mode for developing the upper body musculature is the bench press. It is recognized by the National Strength and Conditioning Association in the U.S. as the most widely used of any weight training exercises (Wilson, Elliot, & Kerr, 1989). The flat bench press is seen as an essential exercise for developing both heads of the pectoralis major (Barnett, Kippers, & Turner, 1995) and is one of the most popular techniques for measuring dynamic strength (Mayhew, Ball, Ward, & Arnold,1991).
Many variations of grip width are used by athletes and recreational lifters. Is there a grip width that is more advantageous than the others for the development of strength and power? Many research studies disagree with each other on which grip width is the best? McLaughlin (as cited in Wagner, Evans, Weir, Housh, & Johnson, 1992) suggested that a wide grip on the bar is most advantageous because it allows for maximal involvement of the pectoralis major muscle. Lander, et al. (1985) suggested that a moderate grip (90° arm angle) is more effective for maximal bench press performance. Theoretically, the moderate grip width allows for explosive force production off the chest at the beginning of the ascent, due to the small arm to trunk angle, while still allowing substantial contribution from the pectoralis major muscle throughout the movement due to the increasing arm to trunk angle up to 90 degrees (Lander et al.,1985). These studies report a moderate grip as being most effective, but used experienced male lifters who preferred the moderate grip. The use of novice lifters may be a better way to determine the most appropriate grip width. The novice lifter would have no bias as to which grip width they preferred and would thereby reduce the practice effect.
Therefore the purpose of the study was to investigate how grip width affected a 3-5 repetition bench press max performance on both female and male novice weight lifters.
The subjects in this research were a convenience group of 18-24 year-old male and female students enrolled at a moderately sized state university. All were screened to exclude those with previous experience in the bench press in the past year or for injuries that could be aggravated by the lift. A total of 33 participants signed informed consents and IRB approval was obtained. Every subject completed the prescribed warm-up of three sets of push-ups before testing. Subjects then completed their assigned bench press with either a narrow, moderate or wide grip width. All subjects performed the bench press with all grip widths using a counterbalanced design, over a three week testing time. Subjects performed 3-5 max. repetitions (RM) without knowledge of the weight they were lifting for each grip width, and predicted 1 RM lifts were subsequently calculated for each lift.
Independent variables included grip width, gender, and the last 3 repetitions performed for the 3-5 rep max lift. Grip width was set at a percent of wingspan and included 20, 40 and 55 % widths. The performance variables were the weight lifted at each grip width, the last three repetitions of the 3-5 repetition bench max, and the bar path, examined through bar displacement, peak velocity in the ascent phase, peak acceleration in the ascent phase, first local minimum acceleration in the ascent phase and the timing of peak velocity, peak acceleration and minimum acceleration after beginning the ascent phase.
Bench press performance was analyzed via videotape and a 2D Motion Measurement System (collected at 30 Hz, filtered at 3.7 Hz with a lowpass Butterworth type filter). A repeated measures ANOVA was used to examine statistical significance for grip and gender, for each performance variable, as well as the repeated measure of repetition. Significance was set at the .05 level for all tests.
Twenty four subjects (12 men and 12 women) successfully completed the lifts over the three week period. For the predicted 1 RM, a 2 x 3 ANOVA (grip x gender) was used to examine if statistically significant differences were seen in the maximum weight lift for each grip width and across gender. No statistical significance was displayed across grip width (F=.65, p=.507).
However, for both men and women the most weight lifted was for the moderate grip, with the greatest difference between grips being 6.45 kg for men and 1.45 kg for women (Figure 1).
Figure 1. Average 1 RM mass (kg) predicted at each grip width for men and women.
Results of the repeated measures ANOVAs for the main effect of grip width demonstrated statistical significant differences for max velocity (F=6.18, p=.003), max acceleration (F=7.44, p=.001), and for the first local minimum acceleration (F=14.07, p=.000) during ascent.
Across gender statistically significant differences for max acceleration (F=68.70, p=.000) and min acceleration (F=4.80, p=.031) were noted. There was statistical significance in the repeated measure of repetition for max velocity (F=21.98, p=.001) with max velocities decreasing for each grip width over the last three repetitions, for max acceleration (F=7.40, p=.001), and for min acceleration (F=8.20, p=.000), with the last repetition producing less acceleration.
No statistical significance was observed across grip width for time to max velocity, max acceleration or min acceleration. Across gender the women took more time to reach max velocity, max acceleration and min acceleration. One trend noted was the time to reach min acceleration increased with each repetition across all grip widths.
Twenty-two of the 24 subjects indicated a preference for the moderate grip width. Though not statistically significant, on average, subjects were able to lift the most weight for the moderate grip width. Examining bar path through the variables of max velocity and acceleration during ascent demonstrated each grip width required different rates of movements in spite of the fact that the weights lifted were relatively similar. The highest velocities and accelerations were noted on average for the narrow grip. The first local minimum acceleration indicates the sticking point in the ascent phase of the lift, and this minimum acceleration was also the greatest for the narrow lift.
Men and women also varied from each other the most on the narrow grip lift (Figure 2) The min acceleration noted at the sticking point of the ascent phase of the lifts were smallest for women at the narrow grip while the min acceleration for the men was smallest at the wide grip. Though no significant interactions were noted, a trend demonstrates men and women may have different techniques for the different grip widths.
Figure 2. Max velocities, accelerations and min accelerations for men and women over the three grip widths. (Units are m/s and m/s 2 ).
The timing of the events did not change across grip width for the men or women, so while the size of the sticking point, for example, varied, the time it occurred between grip widths did not change significantly for the novice lifters.
In conclusion, sport specificity may be the deciding factor for the appropriate grip width, for although the amount of velocity and acceleration changed for the different grips, preference remained the same for the majority of the lifters. The higher accelerations may be more appropriate for power movements, but also will require higher forces on the shoulder joint, so that trade off should be noted.
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