Background: The aim of the present study was to investigate the effects of restricted muscular oxygenation on VO2max, peak power output (PPO), and maximum heart rate (HRmax).
Methods: Six young healthy male subjects participated in four testing sessions within a 2-week period. On four separate days, participants performed stepwise incremental exercise tests to exhaustion (VO2maxNor) on a cycle ergometer under control condition and with thigh cuffs inflated to external pressure of 60, 90 and 120 mmHg, respectively (Cuff60, Cuff90, Cuff120), following a counterbalanced order. Respiratory gas exchange responses, heart rate and near infrared spectroscopy (NIRS) measurements of muscle oxygenation from rectus femoris muscle were continuously monitored during the four tests.
Results: A decrease proportional to the degree of cuff inflation was observed in VO2max (Nor = 42.9 ± 3.7, Cuff60 = 34.5 ± 5.8, Cuff90 = 33.4 ± 3.5, Cuff120 = 31.2 ± 6.8 ml·kg-1·min-1; p<0.05). Lower values of PPO (Nor= 298 ± 64, Cuff60 = 252 ± 35, Cuff90 = 213 ± 26, Cuff120 = 210 ± 20 Watts, P<0.05) and HRmax (Nor = 183.7 ± 4.8, Cuff60 = 177.5 ± 7.7, Cuff90 = 168.8 ± 14.0, Cuff120 = 170.8 ± 17.1 beats·min-1, p<0.05) were recorded in cuff conditions. Final values of muscle deoxygenation and rate of perceived exertion were not different among the four conditions.
Conclusions: It appears that with cuff application, muscle oxygenation is compromised leading to premature sensation of maximum effort, which in turn prevents the heart and the muscle from attaining their maximum capacity.
2010. Vol. 4, 9-16 p.