Preliminary observations examining the acute effect of a range of motion during a barbell-bench press exercise on markers of post-exercise regional hyperemia of the pectoralis major

Introduction: Full range of motion (fROM) exercise during resistance training (RT) is the traditional approach to increasing muscle strength and hypertrophy. Partial range of motion (pROM) has been used in RT environments and there are recent reports showing an influence regional muscle growth. However, there is limited evidence examining how pROM may stimulate regional muscle growth. Purpose: The purpose of this study is to investigate the effects of different ranges of motion (ROM) during flat (FB) and incline (IB) barbell bench press exercises, to identify any potential regional or local differences in regional post- exercise hyperemia of the pectoralis major (PM). Methods: Two male and female subjects (Age:22.2±0.9y; Height:170.0±3.4cm; Weight:71.3±7.1kg; Body Fat:17.60±4.2%) were sequentially randomized to fROM and pROM during FB and IB (45° inclination) bench pressing exercises utilizing a Smith Machine (SM) barbell bench press. The SM barbell was fitted with an EliteFTS™ shoulder saver pad during pROM bouts, and individuals were instructed to touch the pad to their chests and ”not to lockout,” their elbows. 7-days prior to each ROM bout, strength testing (1RM) was completed to determine 75-80% intensity for ROM bouts. Pre-bout (Pre), immediate post-bout (IP), and 24 h post-ROM-bout measures of reactive hyperemia in the regional areas of the right-side PM were collected at 10, 25, 40, 50, and 60 % distal to the suprasternal notch in males and 10 and 25% were used for females. Ultrasound (US; GE Logiq E9) measures cross-sectional area (CSA) collected in duplicate using panoramic capability (LOGIQView®). Discussion/Conclusion: Using a 2-way RMANOVA (time x condition), no CSA differences were found at 10 and 25% (n=4) and no CSA differences were found at 10, 25, 50, and 60% (n=2) for the male subjects. Interestingly, one trained female subject showed an average 11.6% increase in CSA at 10% in both the pROM conditions suggesting a potential training effect.