Delayed reoxygenation after maximal isometric handgrip exercise in high oxidative capacity muscle

Abstract

We hypothesized that after maximal short-term isometric exercise, when O(2) demand is still high and O(2) supply is not fully activated, higher oxidative capacity muscle may exhibit slower muscle reoxygenation after the exercise than low oxidative capacity muscle. Seven healthy male subjects performed a maximal voluntary isometric handgrip exercise for 10 s. The reoxygenation rate after the exercise (Reoxy-rate) in the finger flexor muscle was determined by near infrared continuous wave spectroscopy (NIRcws) while phosphocreatine (PCr) was measured simultaneously by (31)P magnetic resonance spectroscopy. Muscle oxygen consumption (muscle VO(2)) and muscle oxidative capacity were evaluated using the rate of PCr resynthesis post-exercise. The forearm blood flow (FBF) index at the end of exercise was measured using NIRcws. There was a significant positive correlation between the Reoxy-rate, which ranged between 0.53% s(-1) and 12.47% s(-1), and the time constant for PCr resynthesis, which ranged between 17.8 s and 38.3 s (r(2)=0.939, P<0.001). At the end of the exercise, muscle VO(2) exceeded the resting level by approximately 25-fold, while the FBF index exceeded the resting level by only 3-fold on average. The Reoxy-rate closely correlated with muscle VO(2) (r(2)=0.727, P<0.05), but not with the FBF index. Also, the estimated O(2) balance (muscle VO(2) index/FBF index) was negatively correlated with the Reoxy-rate (r(2)=0.820, P<0.001). These results support our hypothesis that higher oxidative capacity muscle shows slower muscle reoxygenation after maximal short-term isometric exercise because the Reoxy-rate after this type of exercise may be influenced more by muscle VO(2) than by O(2) supply.

Performance and physiological responses during a sprint interval training session: relationships with muscle oxygenation and pulmonary oxygen uptake kinetics

“…In the present study, during the 2-min between-sprint recovery periods, muscle oxygenation returned to pre-exercise levels (Fig. 4), indicating a possible recovery of muscle PCr (McCully et al 1994;Kime et al 2003). Previous data have nevertheless shown that the 2 min duration may be insufficient for the complete recovery of muscle metabolites related to repeated-sprint ability.…”

Comparison between electrically evoked and voluntary isometric contractions for biceps brachii muscle oxidative metabolism using near-infrared spectroscopy

“…However, it seems likely that oxidative metabolism during maximal contractions was similar between EMS and VOL in this study, which resulted in the similar recovery responses of DTOI and DtHb. Since recovery of DTOI after exercise is related to PCr resynthesis and/or rate of blood flow/oxygen supply (Hamaoka et al 2007;Kime et al 2003), the similar Fig. 2 Changes (mean ± SEM) in biceps brachii DTOI during 30% MVC and maximal intensity repetitive isometric contractions of the elbow flexor muscles for the electrically evoked (EMS) and VOL sessions.…”

Effect of endurance training on performance and muscle reoxygenation rate during repeated-sprint running

“…In the present study, we used a linear model (adapted from Kime et al 2003a), which was well suited to both TSI changes and the short between-sprints recovery periods. The most important finding is that, once adjusted for changes in S1 performance, the improvements in repeated-sprint ability (%Dec was substantially improved during both RS adj and RS post, Table 1) were moderately-to-largely related to improvements in Reoxy rate (r = -0.52 and -0.40).…”

“…1, 2). Therefore, for simplicity and to use a similar (and more appropriate) modeling for both S1 and S2, a linear model was fitted to the linear part of the TSI (both absolute and normalized values) versus time relationship within the first 15 s of recovery (adapted from Kime et al 2003a). The slope of the relationship was retained as an index of reoxygenation rate (Reoxy Rate, % s -1 ).…”