山田 晃司

This study aimed to elucidate the effects of the tibialis anterior (TA) muscle contraction on the medial longitudinal arch (MLA) and hallux valgus (HV) angle, primarily focusing on the potential functional role of the TA in foot alignment. Twenty-five healthy adults (mean age: 20.7 ± 1.0 years) participated. Electrical stimulation was applied to the TA without ankle dorsiflexion. A triaxial accelerometer was attached to the skin over the navicular bone, and electrogoniometers were placed over the interphalangeal joints of the hallux and ankle. The navicular displacement was calculated through double integration of the acceleration data. Contraction of the TA caused navicular displacement in the supination direction (upward, posterior, and medial), suggesting a temporary elevation of the MLA. The hallux showed an average varus shift of 1.36°; the shift was observed in 24 of 25 participants (p < 0.001). A significant positive correlation was found between upward displacement of the navicular bone and the extent of varus change in the HV angle (r = 0.463, p = 0.020). Additionally, a greater initial HV angle was associated with a larger varus shift in the hallux after TA contraction (r = 0.433, p = 0.030). No significant correlations were observed between the HV angle change and ankle dorsiflexion, suggesting that the medial hallux shift may result from structural changes in the MLA rather than isolated joint motion. These findings provide novel evidence that TA contractions can elevate the MLA and induce varus displacement of the hallux. These findings further suggest that the TA contributes to foot biomechanics not only as an isolated muscle but also as part of a coordinated muscle system involved in arch dynamics and toe alignment. This suggests the potential clinical applications of TA activation in noninvasive interventions for mild-to-moderate HV, such as exercise therapy or neuromuscular electrical stimulation.

Mild cognitive impairment (MCI) is associated with age-related alterations in neural oscillatory activity and cerebral hemodynamics, while mobility limitations often restrict participation in conventional exercise-based interventions. This study investigated exploratory, single-arm, within-subject short-term neurovascular and electrophysiological responses to a combined visual and vibration stimulation protocol in older adults with MCI. Cerebral blood flow was assessed using near-infrared spectroscopy (NIRS) in 27 participants, and electroencephalography (EEG) was additionally recorded in a subgroup of nine participants (n = 9) drawn from the same cohort. The intervention consisted of simultaneous 40 Hz visual flicker and low-frequency mechanical vibration delivered during a seated condition. Changes in total hemoglobin concentration and EEG power in predefined frequency bands were analyzed before and after the intervention, with additional time-window analyses to examine temporal dynamics. At baseline, NIRS revealed higher total hemoglobin levels in the left prefrontal cortex compared with the right. Following the intervention, total hemoglobin decreased significantly in both hemispheres, with a larger reduction observed in the right hemisphere. Time-resolved analyses demonstrated an earlier hemodynamic response in the right hemisphere, followed by a delayed response in the left. EEG analyses showed a reduction in frontal gamma-band power accompanied by an increase in theta-band power in temporoparietal regions after the intervention. These electrophysiological changes were stable across time windows. Together, these findings suggest that short-term combined visual and vibration stimulation was associated with asymmetric and time-dependent changes in cerebral hemodynamics and neural oscillatory activity in older adults with MCI. This non-volitional stimulation approach may provide a feasible experimental framework for investigating brain responses in aging populations with limited mobility. Given the exploratory, uncontrolled design, acute measurement window, and small EEG subgroup, these findings should be interpreted as hypothesis-generating rather than as evidence of clinical or neuroplastic efficacy.

Aging-associated cognitive decline remains a major challenge in gerontology; few non-invasive interventions provide both mechanistic insight and translational feasibility. We investigated whether low-frequency "theta-shaking" whole-body vibration (5 ​Hz) could modulate cognitive function, emotional behavior, and metabolic plasticity in a senescence-accelerated mouse model. Senescence-accelerated mouse prone-10 mice were exposed to theta-shaking stimulation for 30 weeks. Spatial memory was assessed using Y-maze spontaneous alternation test, and anxiety-related behavior was evaluated using marble burying test. Histological and immunohistochemical analyses were conducted to assess neuronal density and protein expression in specific brain regions. Theta-shaking subjected mice exhibited delayed yet significant improvements in spatial memory at 20 (p ​= ​0.017) and 30 (p ​= ​0.018) weeks. Anxiety-related behavior shows a biphasic pattern: an initial increase at 20 weeks (p ​< ​0.001) followed by stabilization at 30 weeks. Histological analysis revealed preserved neuronal density in the subiculum (p ​< ​0.001) and elevated proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) expression in the Cornu Ammonis 1, subiculum, and lateral septum (all p ​< ​0.05). Notably, mitochondrial biogenesis appeared to be intervention's primary target, as shown by robust PGC1α upregulation, while brain-derived neurotrophic factor revealed a trend-level increase (p ​= ​0.062), and neurotrophin-3 expression remained unchanged. Frequency-tuned mechanical stimulation induced region-specific neural neurometabolic adaptations, supporting theta-shaking as a non-pharmacological, low-exertion strategy to counteract brain aging. These findings offer promising translational potential, especially for individuals with limited mobility.

Constipation is a prevalent condition that negatively impacts health and quality of life. Inadequate physical activity is a known contributing factor, often associated with reduced gut motility. However, the physiological mechanism linking physical activity and constipation remains unclear. Particularly research on the immediate effects of physical activity on peristalsis is scarce. Therefore, we aimed to elucidate this mechanism by examining the immediate effects of physical activity on gut motility in healthy adults. Twenty-one participants were instructed to walk on a treadmill for 20 min. Bowel sounds were assessed at rest and at intervals up to 15 min after walking. Bowel sounds were used as indirect markers of gut motility. We calculated the sum of the absolute signal amplitudes of bowel sounds, the percentage of bowel sounds duration, and number of discrete bowel sounds, which have been proposed as indices of gut motility. All the indices increased significantly 1-2 min post-exercise compared to resting values. This increase may be attributed to changes in the autonomic nervous system and local reflexes caused by biomechanical oscillations. In addition, gut motility activation might explain the effects of physical activity intervention on constipation and offer insights into its potential role in managing the condition.

OBJECTIVE: To elucidate the relationship between social participation and quality of life (QOL) in patients with traumatic brain injury. METHODS: This study included 128 community-dwelling patients with head injuries (average age: 41.8 years; average time since injury: 3126 days). We employed the Community Integration Questionnaire (CIQ; scoring range 0-29), a disease-specific scale for head injury patients, along with the Quality of Life after Brain Injury (QOLIBRI; scoring range 0-100%). An adjusted nonlinear regression analysis was used to explore the relationships between the CIQ (total score and subscales: home integration, social integration, productivity) and QOLIBRI (total score and subscales). RESULTS: A significant relationship was observed only between the Total CIQ and the Self subscale of the QOLIBRI (p=0.006). The Self subscale score of the QOLIBRI increased with the Total CIQ score up to 15, after which it plateaued. Additionally, a significant positive relationship was found between the Social Integration subscale of the CIQ and the Self subscale of the QOLIBRI (p=0.018). The QOLIBRI Self score increased with the CIQ Social Integration score up to 8, beyond which it remained stable. No associations were found between the CIQ's Home Integration and Productivity subscales and the QOLIBRI scores. CONCLUSION: The findings indicate that for individuals with traumatic brain injury, an increase in social participation, particularly in social integration, correlates with an enhanced sense of self-satisfaction up to a certain point. However, beyond this level, further advances in social participation do not yield additional gains, suggesting that factors other than social participation play a role in enhancing QOL. This underscores the multifaceted nature of QOL in this context.