High-intensity endurance exercise (HIE) induces negative emotions alongside fatigue, suffering, and changes in cardiovascular responses, and these regulations could be important for athletic performance. Previous studies have reported that limbic and brain stem regions, including the central nucleus of the amygdala (CeA), the paraventricular nucleus of the hypothalamus (PVH), and the nucleus tractus solitarii (NTS), play important roles in emotional response and autonomic cardiovascular regulation. However, how these brain regions interact during HIE remains unclear. In this study, Wistar rats were subjected to 90-min treadmill running sessions at different endurance exercise intensities (sedentary, low-intensity, and high-intensity: 0, 20, and 34 m/min, respectively; n = 9 per group). After exercise, brain tissues were extracted and examined for c-Fos immediate early gene expression in brain regions such as the CeA, PVH, and NTS at each exercise intensity. The c-Fos-positive cells were counted, and then a partial correlation analysis was performed to examine the functional connectivity during exercise. As a result, the numbers of c-Fos-positive cells in the CeA, PVH, and NTS increased in an exercise intensity-dependent manner. Furthermore, partial correlation analyses of c-Fos-positive cells between CeA and NTS (CeA-NTS), PVH and NTS (PVH-NTS), and CeA and PVH (CeA-PVH) exhibited significant correlation coefficients during HIE but not during sedentary and low-intensity endurance exercises. Thus, these results suggest that functional connectivity between CeA-PVH, PVH-NTS, and CeA-NTS may be enhanced during HIE. This enhanced functional connectivity may also be involved in emotional and cardiovascular regulation during exercise.

It is well known that myosin heavy chain (MyHC) phenotypes impact skeletal muscle function. Anterior cruciate ligament (ACL) tear, a common sport injury, induces skeletal muscle atrophy around the injured knee. However, the interrelationship between MyHCs and the functional recovery of ACL reconstruction surgery (ACL-R) remains unclear. The purpose of this study was to investigate the interrelationship between MyHC phenotypes and the functional recovery of leg extension force in patients with ACL-R. Under a clinical setting, 27 patients with ACL-R participated in this study. ACL-R in each patient was carried out using a semitendinous (ST) tendon autograft. During ACL-R, a small muscle sample was dissected from the ST tendon of each patient. MyHC phenotypes in the muscle sample were evaluated using SDS-PAGE. The leg extension force was evaluated 1 day before and then 3, 6, and 12 months after ACL-R. Based on the dominant (>40%) MyHC isoforms in the ST muscle, patients were classified into 4 groups as follows: Groups I, IIa, IId/x, and Even (E: all MyHC isoforms less than 40%). There is a positive correlation between the relative content of MyHC II (IIa + IId/x) and the leg extension force before ACL-R. Functional recovery of knee in subjects with ACL-R was facilitated in patients having the dominant MyHC IIa. This study suggests that the analysis of MyHC phenotypes in ST muscle dissected during ACL-R is a clinically useful index for the functional assessment of the knee in subjects with ACL injury.

The present study investigated the effects of wearing a non-woven face mask and performing a calculation task, while walking, on gait pattern, breathlessness, and calculation performance. Twenty-one healthy adult males walked 4.0 km/h and 6.0 km/h on a treadmill with and without wearing a face mask. A calculation task using a smartphone was added to the gait task, and the participants were asked to perform two-digit addition calculation tasks displayed on the screen as quickly and accurately as possible. Heart rate, perceived exercise intensity, breathlessness, and cadence during gait tasks were measured. Although wearing the mask did not significantly affect heart rate or cadence during gait, breathlessness and perceived exercise intensity were significantly increased. When the calculation task was performed during gait, wearing the mask significantly decreased the correct answer rate, although the number of responses was not affected. Wearing the mask therefore reduced the calculation performance during gait. These results suggest that wearing a mask during gait may increase breathlessness and may worsen mental demands such as performing a calculation task, even if it does not affect physiological responses or gait patterns. As walking in daily life requires a variety of cognitive/mental demands, the impact of wearing a mask on the implementation of these demands may need to be considered.