Analysis of the Activation of Upper-Extremity Muscles During Various Chest Press Modalities

Christian, JR, Gothart, SE, Graham, HK, Barganier, KD, and Whitehead, PN. Analysis of the activation of upper-extremity muscles during various chest press modalities. J Strength Cond Res 37(2): 265-269, 2023-The most effective way to increase muscular strength is through the implementation of resistance training programs. The purpose of this study was to determine the level of muscle activation of the anterior deltoid (AD), medial deltoid (MD), and pectoralis major (PM) during various bench press scenarios. Twenty subjects (10 male and 10 female subjects; age, 24.0 +/- 3.0 years) with a minimum of 1 year of resistance training were recruited to participate. Six surface electromyographical sensors were placed bilaterally on the targeted muscles. Subjects performed a 1 repetition maximum (1RM) of dumbbell (DB) and barbell (BB) flat bench press across 2 sessions followed by 6 repetitions at an incline, flat, and decline position at a submaximal 70% 1RM BB and DB. Mean peak values for muscle activation were analyzed for each variation. A repeated-measures 1-way analysis of variance was used to compare muscle activation patterns across conditions. Significance was set at p <= 0.05. Activation of AD was significantly higher during incline BB compared with decline BB and decline DB (p <= 0.019). Activation of MD was significantly lower than that of AD across all modalities (p <= 0.040). Activation of PM was significantly lower during incline DB compared with decline DB (p = 0.011). Differences among AD and PM may have been the result of the stability stipulation variations between DB or BB and the large biacromial breadth requirement. Lack of differentiation of muscle fibers within the PM during sensor placement could have led to lesser muscle activation recordings during decline. As significance was evident for PM when comparing genders (p <= 0.021), and no significance was found among AD or MD, it can be inferred that the larger amounts of adipose tissue in the female subjects caused irregularities in the PM data.

Automated summary

The purpose of this study was to determine the level of muscle activation of the anterior deltoid (AD), medial deltoid (MD), and pectoralis major (PM) during various bench press scenarios. The results showed that the activation level of AD was significantly higher during incline bench press compared to other scenarios, while the activation level of MD was significantly lower. There were also differences in the activation level of PM between different scenarios. The higher amount of adipose tissue in female subjects may have caused irregularities in the PM data.