Effects of hyperoxia on dynamic muscular endurance are associated with individual whole-body endurance capacity

Abstract

Low-intensity training involving high repetitions is recommended to enhance muscular endurance. Hyperoxic conditions could increase the number of repetitions until exhaustion and thereby improve the results of muscular endurance training. This study aimed to investigate the acute effects of hyperoxia on dynamic muscular endurance, and determine individual factors that may be related to these effects. A single-blinded, counterbalanced crossover design was used. Twenty-five young men performed repetitions of the one-arm preacher curl at 30% of their 1-repetition maximum until exhaustion under hyperoxic and normoxic conditions. The maximum number of repetitions was recorded as an index of muscular endurance. Electromyogram (EMG) and near-infrared spectroscopy parameters were measured in the biceps brachii. The maximum number of repetitions was greater (P < 0.001) under hyperoxic conditions (132 ± 59 repetitions) than under normoxic conditions (114 ± 40 repetitions). The root mean square amplitude of EMG and oxygenated hemoglobin concentration for the last five repetitions under normoxic conditions were greater than those under hyperoxic conditions (P = 0.015 and P = 0.003, respectively). The percent change in the maximum number of repetitions between hyperoxic and normoxic conditions had significant positive correlations with individual maximal oxygen uptake measured using an incremental cycle ergometer test (r = 0.562, 95% confidence intervals [CI] = 0.213-0.783, P = 0.003), but not with muscle strength (τ = −0.124, 95% CI = −0.424-0.170, P = 0.387). The 95% CI for the correlation coefficient between the percent change in the maximum number of repetitions and muscular endurance included 0 (τ = 0.284, 95% CI = −-0.003-0.565, P = 0.047); this indicated no significant correlation between the two parameters. The results suggest that hyperoxia can acutely enhance dynamic muscular endurance, with delayed elevation of EMG amplitude due to fatigue, and the effects are associated with individual whole-body endurance capacity.

Distinct adaptations of muscle endurance but not strength or hypertrophy to low‐load resistance training with and without blood flow restriction

“…The measurement characteristics of its prototype were analysed previously using Monte Carlo simulation and a phantom experiment (Niwayama & Unno, 2021). Optical probes consisting of light‐emitting diodes with wavelengths of 770 and 830 nm and photodetectors located 20 and 30 mm from the light source were placed on the long head of the biceps brachii, two‐thirds of the distance from the medial acromion to the antecubital fossa (Kojima et al., 2020). We used surgical tape to secure the device and a light‐shielding band to minimize the influence of ambient light.…”

Muscle Oximetry in Sports Science: An Updated Systematic Review

“…basketball, football, rugby). Of note, a total of eight studies included more than three sports [185][186][187][188][189][190][191][192] and a total of nine studies did not report the sporting discipline in their design [193][194][195][196][197][198][199][200][201]. The most common sports activities used in the 191 studies are cycling (n = 55), running (n = 23), and climbing (n = 11).…”