title: Relationship between limb and trunk muscle hypertrophy following high-intensity resistance training and blood flow-restricted low-intensity resistance training.
abstract: We examined the relationship between training-induced limb and trunk muscle hypertrophy in high-intensity resistance training (HIT) or blood flow-restricted low-intensity resistance training (LI-BFR) programmes. Thirty young men were divided into three groups: HIT (n = 10), LI-BFR (n = 10) and non-training control (CON, n = 10). The HIT and LI-BFR groups performed 75% and 30%, respectively, of one-repetition maximal (1-RM) bench press exercise, 3 days per week for 6 weeks. During the training sessions, the LI-BFR group wore elastic cuffs around the most proximal region of both arms. Muscle cross-sectional area (CSA) and 1-RM bench press strength were measured before and 3 days after the final training session. Total training volumes (lifting weight × number of repetitions) for all of the sessions were similar between the two training groups. The training led to a significant increase (P < 0·05) in bench press 1-RM in the two training groups, but not in the CON group. Triceps brachii and pectoralis major muscle CSA increased 8·8% and 15·8% (P < 0·01), respectively, in the HIT group and 4·9% (P < 0·05) and 8·3% (P < 0·01), respectively, in the LI-BFR group, but not in the CON group (-1·1% and 0·0%, respectively). There was significant correlation (r = 0·70, P < 0·05) between increases in triceps brachii and pectoralis major muscle CSA in the HIT group; however, the correlation was lower and non-significant in the LI-BFR group (r = 0·54). Our results suggest that limb and trunk muscle hypertrophy occurs simultaneously during HIT but not during LI-BFR, possibly owing to individual differences in activation of the arm and chest muscles during the training sessions.
authors.affiliation: Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yasuda
authors.forename: Riki
authors.initials: R
authors.lastname: Ogasawara
authors.forename: Mikako
authors.initials: M
authors.lastname: Sakamaki
authors.forename: Michael G
authors.initials: MG
authors.lastname: Bemben
authors.forename: Takashi
authors.initials: T
authors.lastname: Abe
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000704:Analysis of Variance; D006801:Humans; D006984:Hypertrophy; D008279:Magnetic Resonance Imaging; D008297:Male; D009119:Muscle Contraction; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000473:pathology* / Q000503:physiopathology; D010369:Pectoralis Muscles / Q000098:blood supply / Q000473:pathology; D012039:Regional Blood Flow; D055070:Resistance Training; D013997:Time Factors; D034941:Upper Extremity; D055815:Young Adult