This study examined the effect of prolonged exercise with and without hyperthermia on cognitive function. In this study, 9 male subjects cycled at 50% watt max for 60 min in a room maintained at 23°C. Water-perfused suits with water at 7°C (COOL) and 47°C (HOT) were randomly used during the 2 cycling periods. Rectal temperature, skin temperatures, heart rate, ratings of perceived exertion (RPE), and thermal sensation were evaluated during exercise. The Stroop color-word test (SCWT) and executive processing test (EPT) were conducted every 15min during exercise to evaluate cognitive function. In the COOL trial, the core temperature stabilized at 37.5 ± 0.1°C (mean ± SE), whereas in the HOT trial, the core temperature increased to 39.1 ± 0.1°C, with a concomitant increase in RPE and thermal sensation. Although the reaction time for the simple task of the SCWT improved when the body temperature increased slightly during the COOL trial, the conflict task of the SCWT was impaired during the latter stages of exercise during the HOT trial. The reaction time for the HOT trial was significantly longer than that for the COOL trial. Compared to the bigining of exercise the reaction time for the EPT was impaired at 60 min during the HOT trial, and this reaction time was longer than that for the COOL trial. The present findings indicate that exercise-induced hyperthermia during the latter stages of exercise impairs cognitive as well as physiological functions.
This study investigated the effects of exercise intervention with a 12-week slightly-weighted shoe on lower-limb skeletal muscle and gait patterns in the elderly. A total of 29 healthy elderly Japanese who had irregular walking habits were randomly assigned to either slightly-weighted-shoe (WS group, n = 14; Age, 70.6 ± 5.7 years; WS, 493 g) or normal-shoe (NS group, n = 15; Age, 69.3 ± 6.9 years; NS, 293 g) intervention groups. The participants were instructed to maintain their normal daily physical activity (PA) during the intervention period. Segmental intracellular water (ICW) and muscle thickness (MT) were measured as an index of skeletal muscle mass in the lower limb, and kinematic gait data were acquired by motion analysis. Walking stability was assessed as a standard deviation of the vertical fluctuation in whole-body center of mass (COM fluctuation). The daily PA was monitored using an accelerometer and an activity record. ICW in the upper leg and MT of rectus femoris increased significantly in the WS group compared with the NS group (ICW: 13.8% vs. 2.2%, MT: 12.1% vs. 1.3%), while COM fluctuation was significantly reduced in the WS group (p<0.05) during normal walking. The present study demonstrated that interventions with a slightly-weighted-shoe may be able to increase muscle volume in the upper leg and change gait patterns in the healthy elderly.
The purpose of this study was to compare age and gender differences of lower limb muscle thickness among healthy young children. Five hundred and sixty-one healthy young children aged 3 to 8 years old (284 boys and 277 girls) participated in this study. Anterior thigh, posterior thigh, and calf muscle thicknesses (MTa, MTp, MC) were determined using a B-mode ultrasound. The thickness of each muscle increased significantly as age increased, except in the MTa in the 5-year-old boys' group. A significantly main effect was found in MTa, and there was a higher value in girls than boys, except in the 4-year-old group. A significant age × gender interaction was also observed in MTa, with higher values found in boys than girls, except in the 3- and 5-year-old groups. There was no significant gender different in MC. In addition to the Mt/Tmt ratio, the ratio of each muscle thickness to the total amount of MTa, MTp, and MC was calculated. As a result, in girls, the Mt/Tmt ratio remained constant as age increased in all muscles. On the other hand, in boys, MTa decreased and MTp increased as age increased. From these results, it was suggested that gender differences exist in lower limb muscles thickness among healthy young children aged between 3 and 8 years old. It was also suggested that the muscle development of MTa and MTp was different in boys, while lower limb muscle development in girls stayed constant.
Although decreased dorsiflexion range of motion (DROM) is linked to ankle inversion sprains and other lower limb injuries, the mechanisms underlying these links are not well understood. The purpose of this study was to examine the relationships between DROM and the ankle dorsiflexion and inversion, and the foot progression angles during a sidestep cutting maneuver. Nineteen healthy subjects participated in this study. The loaded DROM in a flexed- knee position was measured. The foot and ankle motions were assessed during the sidestep cutting maneuver using a 3D motion analysis system. The low DROM group displayed smaller dorsiflexion and inversion angles, and greater external foot rotation, and performed the task using a significantly greater percent of their DROM than the high DROM group during the sidestep cutting maneuver. In addition, the smaller DROM was associated with smaller dorsiflexion angles, greater external foot rotation, and greater maximum dorsiflexion angles as a percentage of DROM during the sidestep cutting maneuver. The decreased DROM may prevent the ankle from becoming stable during the sidestep cutting maneuver, therefore the ankle may be vulnerable position to an inversion sprain. The kinematic patterns displayed by individuals with a decreased DROM may be a compensatory strategy for dorsiflexion deficits, which may be associated with ankle and knee injuries.
The purpose of the present study was to observe the parameter which contributed to the improvement in a physical function to resistance training for local living elderly people. Randomly-selected 24 local elderly people of 69.4±3.8 years of age went through a three month exercise program of Comprehensive Geriatric Training, which is one of the resistance training programs focused on care prevention. During intervention, physical function, blood composition and dietary survey were researched simultaneously. Any dietary changes were not observed among the 24 seniors after three months of training. Compared to the control group, however, their maximum walking speed increased, which is strongly correlating to their increase in BMI and body weight. Their sit and reach performance increased as well, which is negatively correlating to their serum triglyceride increase. Their blood albumin did not change before and after the training period. In conclusion, measuring BMI, body weight and serum triglyceride during the resistance training period may lead to positive results of the main outcomes in local living elderly men and women.