Aerobic exercise produces changes in cerebral oxyhaemoglobin (OHb) concentration; however, the effects of exercise on OHb during the post-exercise period remain to be established. The aim of the present study was to evaluate OHb levels during and after a 20-min bout of moderate-intensity cycling exercise. After a 3-min rest period, 12 healthy volunteers (9 women, 3 men) cycled for 20 min at an intensity corresponding to 50% of their VOmax, after which they were monitored during a 15-min post-exercise rest period. OHb levels in the right (R-PFC) and left prefrontal cortices (L-PFC), right (R-PMA) and left premotor areas (L-PMA), supplementary motor area (SMA), and primary motor cortex (M1) were measured using near-infrared spectroscopy. A one-way repeated-measures analysis of variance (ANOVA) was performed to compare mean pre-exercise OHb levels with OHb levels during the last 5 min of exercise and the last 5 min of the post-exercise rest period. OHb levels increased significantly (p < 0.01) between the pre-exercise rest period and the last 5 min of the exercise session for each region of interest (range: 0.040-0.085 mM·cm). OHb levels did not return to pre-exercise values during the 15-min post-exercise rest period. OHb levels during the last 5 min of the post-exercise rest period were significantly higher than pre-exercise values in the L-PFC, L-PMA, SMA, and M1 (p < 0.01). Our results indicate that cortical oxygenation persists for at least 15 min following a 20-min bout of moderate-intensity cycling, and that aerobic exercise may facilitate neuroplasticity.

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Excessive rearfoot eversion during running is likely to lead to excessive midfoot dorsiflexion, and such abnormal kinematic coupling between the rearfoot and midfoot may be associated with mechanisms for the occurrence of injuries.

Near-infrared spectroscopy (NIRS) is a widely used noninvasive method for measuring human brain activation based on the cerebral haemodynamic response. However, systemic changes can influence the signal's parameters. Our study aimed to investigate the relationships between NIRS signals and skin blood flow (SBF) or blood pressure during dynamic movement. Nine healthy volunteers (mean age, 21.3 ± 0.7 years; 6 women) participated in this study. The oxyhaemoglobin (O2Hb) signal, SBF, and mean arterial pressure (MAP) were measured while the volunteers performed multi-step incremental exercise on a bicycle ergometer, at workloads corresponding to 30, 50, and 70 % of peak oxygen consumption (VO2peak) for 5 min. The Pearson's correlation coefficients for the O2Hb signal and SBF at 50 and 70 % VO2peak were 0.877 (P < 0.01) and -0.707 (P < 0.01), respectively. The correlation coefficients for O2Hb and MAP during warm-up, 30 % VO2peak, and 50 % VO2peak were 0.725 (P < 0.01), 0.472 (P < 0.01), and 0.939 (P < 0.01), respectively. Changes in the state of the cardiovascular system influenced O2Hb signals positively during low and moderate-intensity exercise, whereas a negative relationship was observed during high-intensity exercise. These results suggest that the relationship between the O2Hb signal and systemic changes is affected by exercise intensity.

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