DIFFERENCES IN UNILATERAL CHEST PRESS KINEMATICS ON A STABLE VERSUS UNSTABLE SURFACE WHILE HOLDING 1 VERSUS 2 DUMBBELLS

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Description
The following study evaluated the effectiveness of the COR Bench, to determine if its unstable surface allows for both greater range of motion and greater tendency towards co-contraction, in comparison to a traditional flat bench. An initial session assessed the

The following study evaluated the effectiveness of the COR Bench, to determine if its unstable surface allows for both greater range of motion and greater tendency towards co-contraction, in comparison to a traditional flat bench. An initial session assessed the 19 participants’ (age, 22.364 ± 2.480 years; mass, 77.850 ± 18.328 kg; height, 1.787 ± 0.0923 m) current one- repetition maximum strength levels for the unilateral chest press. Four different conditions were used to test the kinematic variables such that each participant completed 5 repetitions of unilateral chest presses at 70% of their max with one and two dumbbells on both the COR Bench and traditional flat bench. Differences in ROM were evaluated by measuring an angular representation of the shoulder complex. Levels of co-contraction were determined by analyzing the middle trapezius EMG. The results indicate a significant difference in ROM between the conditions (p = .00); specifically, a greater ROM during the one dumbbell condition versus the two dumbbell condition on the COR and the flat benches (p = .002, 0.001 respectively); greater ROM with two dumbbells on the COR bench compared to the flat bench (p = .022). The middle trapezius EMG data showed a significant difference in co-contraction levels between conditions (p = .00); specifically, a greater co-contraction during the one dumbbell condition versus the two dumbbell condition on the COR and the flat benches (p = .001, 0.008 respectively); greater co- contraction with one dumbbell on the COR bench compared to the flat bench (p = .010). This lends support for the future use of the COR bench as a means for more efficient exercise through a full range of motion; however, it also suggests that more practice is necessary to master the movement on the bench to decrease co-contraction activity.
Date Created
2013-12
Agent

Differences in Unilateral Chest Press Muscle Activation and Kinematics on a Stable Versus Unstable Surface While Holding One Versus Two Dumbbells

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Description

Training the bench press exercise on a traditional flat bench does not induce a level of instability as seen in sport movements and activities of daily living. Twenty participants were recruited to test two forms of instability: using one dumbbell

Training the bench press exercise on a traditional flat bench does not induce a level of instability as seen in sport movements and activities of daily living. Twenty participants were recruited to test two forms of instability: using one dumbbell rather than two and lifting on the COR bench compared to a flat bench. Electromyography (EMG) amplitudes of the pectoralis major, middle trapezius, external oblique, and internal oblique were recorded and compared. Differences in range of motion (ROM) were evaluated by measuring an angular representation of the shoulder complex. Four separate conditions of unilateral bench press were tested while lifting on a: flat bench with one dumbbell, flat bench with two dumbbells, COR Bench with one dumbbell, and COR Bench with two dumbbells. The results imply that there are no differences in EMG amplitude or ROM between the COR bench and traditional bench. However, greater ROM was found to be utilized in the single dumbbell condition, both in the COR bench and the flat bench.

Date Created
2015-10-27
Agent