Affiliations: [a] Department of Health Sciences, Program of Exercise Science, CUNY Lehman College, Bronx, NY, USA | [b] Sport Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand | [c] Kinesiology Program, Arizona State University, Phoenix, AZ, USA | [d] School of Rehabilitation Science, McMaster University, Hamilton, ON, Canada | [e] School of Health, Physical Education, and Leisure Services, University of Northern Iowa, Cedar Falls, IA, USA
Correspondence:
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Corresponding author: Brad J. Schoenfeld, 250 Bedford Park Blvd West, Bronx, NY 10462, USA. Tel.: +1 718 960 1999; E-mail:brad@workout911.com
Abstract: OBJECTIVE: The purpose of this study was to compare activation of the upper
body musculature during the barbell bench press at varying training
intensities. METHODS: Twelve young, resistance-trained men performed sets of the bench
press to momentary muscular failure with two different loads: a high-load
(HIGH) set at 80% of 1RM and a low-load (LOW) set at 50% 1RM. Exercise
order was counterbalanced so that half the subjects performed the LOW
condition first and the other half performed the HIGH first. Surface
electromyography (EMG) was used to assess mean, peak, and iEMG muscle
activation of the anterior deltoid, triceps brachii, and sternal and
clavicular heads of the pectoralis major. RESULTS: The main effects for trials were significant for mean EMG (p < 0.001) and iEMG matched (p < 0.001) favoring HIGH and iEMG total favoring LOW
(p = 0.001) across all muscle groups in both conditions with varying effect
sizes. All other main effects and interactions were not statistically
significant. CONCLUSION: Despite similarities in peak EMG amplitude, the greater results
for mean and iEMG matched in HIGH suggests that heavier loads may produce
greater muscle activation.
Keywords: Size principle, low-load, light weights, muscle hypertrophy, training intensity
