Acute Physiological Responses to Moderate-Load Resistance Exercise in Hypoxia.
Scott, BR, Slattery, KM, Sculley, DV, Lockhart, C, and Dascombe, BJ. Acute physiological responses to moderate-load resistance exercise in hypoxia. J Strength Cond Res 31(7): 1973-1981, 2017-This study assessed whether hypoxia augments anabolic responses to moderate-load resistance exercise. Fourteen trained men performed moderate-load resistance exercise in normoxia (NORM; fraction of inspired oxygen [FIO2] = 21%) and moderate-level hypoxia (MH; FIO2 = 16%). Exercise comprised 3 sets of 10 repetitions of squats and deadlifts at 60% of 1 repetition maximum, with 60-second interset rest. Blood lactate (BLa) was quantified after each exercise, whereas arterial oxygen saturation and heart rate (HR) were assessed after each set. Thigh circumference was measured before and after exercise. Muscle activation and oxygenation were monitored by surface electromyography (EMG) and near-infrared spectroscopy, respectively. Relative BLa concentrations were significantly higher following squats (p = 0.041) and deadlifts (p = 0.002) in MH than NORM. Arterial oxygen saturation was lower after each set in MH compared with NORM (p < 0.001), although HR and thigh circumference were not different between conditions. Integrated EMG was higher in MH than in NORM for the squat during several repetitions (p ≤ 0.032). Measures of muscle oxygen status were not significantly different between conditions (p ≥ 0.247). The main findings from this study suggest that hypoxia during moderate-load resistance exercise augments metabolite accumulation and muscle activation. However, a significant hypoxic dose was not measured at the muscle, possibly because of the moderate level of hypoxia used. The current data support previous hypotheses that have suggested hypoxia can augment some physiological responses that are important for muscular development, and may therefore provide benefit over the equivalent training in normoxia.
1School of Psychology and Exercise Science, Murdoch University, Perth, Western Australia, Australia; 2New South Wales Institute of Sport, Sydney Olympic Park, New South Wales, Australia; 3Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Ourimbah, New South Wales, Australia; 4Priority Research Center in Physical Activity and Nutrition, University of Newcastle, Callaghan, New South Wales, Australia; 5Applied Sports Science and Exercise Testing Laboratory, Faculty of Science and Information Technology, University of Newcastle, Ourimbah, New South Wales, Australia; and 6Department of Rehabilitation, Nutrition and Sport, La Trobe University, Bundoora, Victoria, Australia.
Brendan R
BR
Scott
Katie M
KM
Slattery
Dean V
DV
Sculley
Catriona
C
Lockhart
Ben J
BJ
Dascombe
D000328:Adult; D004576:Electromyography; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010100:Oxygen / Q000097:blood; D055070:Resistance Training / Q000379:methods*; D012146:Rest; D019265:Spectroscopy, Near-Infrared; D013848:Thigh / Q000502:physiology; D055815:Young Adult
D019344:Lactic Acid; D010100:Oxygen