The functional roles of six foot sole regions were examined during one-legged standing in four center-of-foot pressure (CFP) positions in the anteroposterior direction. These positions were determined according to the distance of the CFP from the heel in relation to total foot length (%FL). Fifteen participants maintained the one-legged standing positions at 30%FL, 45%FL, 60%FL, and 70%FL for 12 seconds. In the 30%FL and 45%FL positions, the pressure values were higher in the heel and the lateral sole than in the medial forefoot. Negative correlations were observed between the pressure variation in the lateral forefoot_and medial forefoot, and between the mid foot and medial forefoot. Pressure variation in the medial forefoot and peroneus longus muscle activity was correlated, as was pressure variation in the medial forefoot and abductor pollicis muscle activity. In the 60%FL and 70%FL positions, the forefoot region had the greatest pressure. There was a negative correlation between medial forefoot and lateral forefoot pressure variation. There was a significant correlation between the pressure variation in the medial forefoot and peroneus longus muscle activity. This suggests that the lateral sole in the 30%FL and the 45%FL positions and the forefoot in the 60%FL and 70%FL positions played the role of the fulcrum for weight bearing. In addition, it is likely that the medial forefoot in the 30%FL and the 45%FL positions, and the medial forefoot and the lateral forefoot in the 60%FL and the 70%FL positions play important roles of the point of application for postural control.
In the present study, we attempted to clarify the brain activity three different situations involved in a coincidence anticipation timing task using a downward moving visual target. The subjects were ten healthy adult males. All the subjects were right-handed. The tasks consisted of a non-coincidence anticipation timing task as the control task and a coincidence anticipation timing task using a downward moving visual target. Both tasks were carried out on a computer display. An electroencephalogram (EEG) was recorded from electrodes placed at 128 sites on the subjects’ scalp. The EEG was analyzed by fast Fourier Transform (FFT) analysis. In addition, the beta components (13-30Hz) were each compared for the three situations on 18 sites, based on the international 10-20 system without Cz between the control task and the coincidence anticipation timing task.
The results showed that the beta component increased significantly in the visible situation at F3, T3 and T5, in the first half of the masking situation at F8, T3, P3 and T5, in the second half of the masking situation at T3. Also the beta component significantly decreased in the first half of the masking situation at Fp1 and Fp2. These results of a comparison between the two tasks, suggest that memorization about the shape and velocity of a visual target in the visible situation, and retrieval of the shape and velocity of a visual target in the masking situation involved with the execution of the coincidence anticipation timing task using a downward moving visual target.
Purpose: The purpose of this study is to investigate the effects of sympathovagal activity balance induced by a change of heart rate (HR)/breathing rate (BR) ratio during repeated bouts of moderate exercise. Methods: Sixteen healthy subjects (age: males, 27.1 ± 3.3 yrs; females, 33.1 ± 3.7 yrs) performed repeated ramp-load leg cycling exercise (RLE) and constant-load leg cycling exercise (CLE) for 4 min×5 times at work rates (WR) corresponding to 90% ventilation threshold (VT) after VT was determined by incremental ramp test. Subjects were divided into two groups of HR/BR increasing slope (HBRi) and not changing slope (HBRn) from initial exercise to VT point. Results: During CLE, LF/HF gradually increased in HBRn which was significantly higher at the 4th bout of exercise than at the 1st bout (p<0.05). HF/(LF+HF) was significantly lower at the 5th bout of exercise in HBRn than at the 1st bout of exercise (p < 0.05). The change with repeated, HBRi versus HBRn interaction of LF/HF and HF/(LF+HF), was confirmed on RLE (p < 0.05, p < 0.01). However, HR and ΔRRI did not change during the bouts of RLE in both HBR. During CLE, a significant correlation between oxygen consumption (VO2)/WR and HF/(LF+HF) (r=0.565) was observed in HBRi (p < 0.05). Conclusion: These results suggest that autonomic nerve activity is changed by BR rhythms and the type of exercise during repeated bouts of cycling exercise.
The readiness latency for the movement in athletes was shorter than in non-athletes (Kita et al., 2001). The purpose of this study was to compare the differences of the source location of athlete’s MRCPs with those of the same aged subject’s MRCPs (non-athletes) using the EEG-dipole localization method. The athletes who participated in this study were kendoists and gymnasts. They are top rank athletes in Japan. They use their wrist extensively in daily training. The task was a right wrist extension. EEGs were recorded from 19ch on the scalp according to the international 10-20 system, and averaged during the period from 2.0 sec before to 0.5 sec after the EMG onset. The MRCPs of each subject was grand-averaged for each group. The MRCPs of each group were analyzed by the equivalent current dipole localization, respectively. As a result, in the non-athletes, the dipoles of MRCPs were localized on the prefrontal cortex, and then the movement-related cortical areas (CMA, PM, SMA and MIcx).In the other and, in the athletes, the dipoles were not localized on the movement-related cortical areas except MIcx. These results suggest that, in the athletes, the neural network of the brain becomes short circuit through the training required quick motion changes of the wrist, and the localized areas were more specific than in the non-athletes. In both groups, the dipoles were localized in the prefrontal cortex prior to those movement-related cortical areas. It is likely that the localization is represented a signal to start up action.
The present study investigated effect on saccadic reaction time after repeated neck flexion. Twelve healthy young subjects participated in this experiment, in which eye movement task was pro-saccade and anti-saccade. Before the neck flexion movement, saccadic reaction time at the rest neck position for 30 s was measured three times with a 30-s rest between each measurement. Twenty-degree neck flexion was repeated twelve times for 120 s. After the neck flexion movement, above-mentioned saccadic reaction time was measured five times. In both saccadic tasks, reaction time in the first trial after the neck flexion movement was significantly shorter than that before the flexion movement. The shortening time was significantly larger in the anti-saccade than in the pro-saccade. These suggested that after the repeated neck flexion movement, the saccadic reaction time decreased due to persistent enhancement of the non-specific brain activation, and the larger shortening effect was found in the anti-saccade regulated by higher nervous system.