Manner of muscular relaxation in elbow flexion was observed on the subjects aged from 7 to 22 years old. Relation between surface electromyogram of m, biceps brachii and mechanogram of elbow flexion were used for the parameters of muscular relaxation.
Results were as follows: 1) At elder subjects, silence of surface electromyogram preceeded to the tension decrease. But discharge of surface electromyogram preceeded during muscular relaxation at younger subjects. 2) It could be observed the transient tension increase before muscular relaxation. The appearance rate of the transient tension increment increased as becoming elder.
From above results, it could be considered that the inhibitibility of spinal alpha motoneuron pool did not yet developed for about 7 years old.

The purpose of this study was to assess an impact of water immersion recovery after short distance swimming on the recovery process in pulmonary functions in individuals with the past history of bronchial asthma (PHA). Eleven Japanese healthy males with PHA (23 years) volunteered to perform two bouts of a 25-m maximal front crawl session in an indoor pool. The two bouts were separated by either 10-min of recovery on the land (L-session) or the same condition with water immersion to the neck (W-session), using a counterbalanced crossover design. Water temperature was 30 °C. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV_1.0) (%predicted) were measured according to the following time course; at baseline (REST), water immersion to the neck (WIN) before the swimming session, after 5-min (REC-5) and 10-min (REC-10) recovery with the assessment of dyspnea sensation (ADS) at the same time point. %FVC and %FEV_1.0 at WIN, REC-5 and REC-10 in the W-session were significantly lower than those REST. A similar reduction was observed at WIN in the L-session, and %FEV_1.0 at REC-5 was significantly different from those REST. The subjects had higher ADS at REC-5 in both sessions compared with those REST. %FVC and %FEV_1.0 at REC-5 and REC-10 in W-session were significantly lower than those at REC-5 and REC-10 in L-session. These results indicates a negative impact of not only water immersion recovery but also recovery on the land after short distance swimming on pulmonary function in individuals with PHA.

To clarify the mechanism responsible for the increase in stroke volume (SV) due to training, we investigated the effects of interval training on the left ventricle using M-mode echocardiography. Six healthy male subjects volunteered to undergo 48 training sessions for 12 weeks (4 sessions· week^-1) One session consisted of five periods of exercise of 3-min duration on a cycle ergometer at a power output of 100% maximal O₂ uptake (Vo₂max), interspersed with 2-min recovery cycling at 50%Vo₂max. The echocardiograms at rest and during mild exercise (100W) were recorded before and after the training. The interval training significantly increased Vo₂max. Although there was no significant difference in SV at rest before and after the training, the training increased SV significantly during exercise. Before the training, there was a significant difference in left ventricular enddiastolic dimension (LVEDD) and left ventricular end-diastolic volume (LVEDV) at rest and during exercise. However, after the training, LVEDD and LVEDV during exercise were significantly larger than those at rest. These results suggest that interval training for 12 weeks increases diastolic filling (elasticity) of the left ventricle during exercise in healthy young men, partly contributing to the increase in SV due to the training.

The purpose of this study was to determine the differences between walking stairs one step at a time versus using alternating feet by evaluating muscle tensions and joint forces. This quantitative basic knowledge will be useful in setting safe guidelines for stair walking in rehabilitation programs. Five healthy young males participated as subjects. Ascending and descending motions were measured by utilizing a 3 D motion analysis system, a force platform and an EMG telemetry system. Measurements were made for three conditions : 1) Both limbs during alternating feet walking (normal stair walking : NW), 2) The leading limb (LL) and 3) The trailing limb (TL) when walking stairs one step at a time. Moments of force on the joints, muscle tensions and joint forces were calcu-lated using two mathematical models (the link segment and musculoskeletal models, Yamazaki (1992) ) . When ascending, maximum flexion angles of three joints in the TL were smaller than during NW. Also, quadriceps tension in the TL and soleus tension in the LL were smaller than during NW. Except for joint force, which was directed toward the anterior of the tibia, knee joint forces in the TL were smaller than during NW. When descending, maximum flexion angles of the three joints of the LL were smaller than during NW. The quadriceps tension and the soleus tension in the LL were smaller than during NW. Knee joint forces in the LL were smaller than during NW. The results suggested that : 1) When ascending, if a patient has a failure in the system of knee extension, the unaffected side should be made the LL and the affected side the TL. Also, if there is a failure in the system of plantar flexion, the unaffected side should be the TL and the affected side the LL. 2) When descending, if there is a failure in one limb, the unaffected side should be the TL and the affected side the LL.

We investigated whether the autonomic nervous system (ANS) modulation contribute to the bradycardia induced by endurance training. First, the meta-analysis approach was used to collect group mean values of maximal oxygen consumption (Vo₂max) and heart rate variability (HRV) from 14 studies involving 30 groups and 485 subjects. Subsequently, we performed a cross-sectional (n=116) and intervention (n=training group : 10 and control group : 6) studies. In both studies, ANS modulation was estimated by spectral analysis of HRV. In the meta-analysis and cross-sectional study, HR and natural logarithmic high frequency power (In HF power) were correlated with Vo₂max or peak oxygen uptake (peak Vo₂) . The significant negative correlations were found between HR and In HF power (meta-analysis and the cross-sectional study ; r² = 0.42 and 0.44, respectively) . Endurance training in the intervention study increased peak Vo₂ and resting In HF power, and decreased resting HR. These results strongly suggest that endurance training induces an increase in resting ANS modulation especially parasympathetic modulation. Furthermore, about half of the variability of resting HR can be accounted for by difference in parasympathetic modulation.

The purpose of this study is to show clearly whether the complexity of the cycle of head fluctuation during walking is influenced with walking speed. Thirty young healthy males and females volunteered as subjects for this study. Subjects walked 40 m, and they were instructed to walk “slowly”, “a little slowly”, “usual speed”, “a little fast” and “fast” depending on their subjectivities. The head fluctuation of the right-and-left direction during a walk was measured by using an accelerometer. In addition, the complexity of the head fluctuation of the right-and-left direction cycle was calculated by utilizing Approximate Entropy (ApEn). After the value of ApEn was standardized at the walking speed, each walking speeds were compared. As a result, the value of ApEn increased at the slowly speed, and decreased with the increases in the walking speed. And the value of ApEn showed plateau or decrease at a little faster than free walking speed. From our results, it thought a possibility that Central Pattern Generator is optimized at the free walking speed. In conclusion, it is clear that walking speed have influenced on the complexity of the walking cycle.

The purpose of this study was to clarify the effects of different frequencies of skipping rope on the elastic components of muscle and tendon in human triceps surae. Six male subjects performed ten rounds of skipping rope. Skipping tempos were with in a range of 100-170 skips per minute (SPM) . The vertical ground reaction force and the surface EMG of triceps surae muscles were recorded during each skipping round. Elastic components of muscle and tendon were estimated by Residual Time (RT : lag time difference between the vanishing point of muscle discharge and disappearance of EMG, and the end of the ground reaction force wave) and RTintegrate (integration of ground reaction force while RT still appears) . RT and RTintegrate at 100 SPM were the smallest values for all jump frequencies. On the other hand, integrated EMG (iEMG) at 100 SPM was the largest value for all jump frequencies. Although RT and RT_integrateprogressively increased as SPM was increased, iEMG correspondingly decreased. Rate in utilization of elastic components of muscle and tendon assessed by RT_integrateat 170 SPM corresponds to 150% at 100 SPM. These results suggest that the rate in utilization of the elastic components of muscle and tendon while skipping rope, depend on jump frequency.

The aim of this studv was to clarify the effects of water immersion on the cardiovascular recovery process following submaximal steady state exercise on land. Seven male subjects (23 yrs old) underwent experiments under four separate conditions on separate days (15 minutes of cycling exercise at 50% and 80% maximal oxygen consumption followed by 16 minutes of recovery in a sitting position in water and out of water) . Concerning conditions in water, mean water temperature was 29.4 degrees, and the immersion level was set at xiphoid. Mean room temperature in out of water conditions, and during all conditions of exercise, was 24.4 degrees. Oxygen consumption (VO₂), heart rate (HR) and blood pressure (systolic: SBP, diastolic: DBP) were measured under each condi tion. Mean blood pressure was calculated from SBP and DBP (MBP=1/3× ( SBP-DBP) +DBP) . Stroke volume (SV) was measured by Doppler echocardiography, and then cardiac output (CO=SV×HR), total peripheral resistance (TPR=NIBP/CO) and arteriaVmixed venous oxygen difference (a-v O₂diff=VO₂/CO) were calculated. In comparison with the same exercise intensity condition, there were no significant differences between recovery processes of VO₂, HR, SBP, DBP and MBP in and out of water. SV and CO were significantly higher (p<0.05) during the recovery process in water than out of water (SV: at 50 and 80% maximal oxygen consumption conditions, CO: at 80% condition) . The TPR and a-v O₂diff were significantly lower (p<0.05) during the recovery process in water than out of water at 80% oxygen consumption condition. These results indicate that water immersion facilitates circulating blood volume during the recovery process without increasing blood pressure, especially during recovery after high intensity exercise. Therefore, we suggest that increased left ventricular preload with immersion would be an important factor in cardiovascular regulation not only at rest but also during recovery after exercise.

The purpose of the present study was to indicate the relationship between health-related quality of life (HRQOL) measures, the daily rhythm of oral temperature (OT), and lifestyle. Five-hundred young men volunteered to participate in this study. Their OT, measured using a digital thermometer, was recorded every 2h from the time they woke up to the time they went to sleep for 1 week. The daily rhythm of OT was calculated as a quadratic function using the 1-week data. The HRQOL was measured using the Short-Form 36-Item Health Survey version 2 (SF-36v2). The participants were divided into 3 groups: a high-value group (HG) with ≥ 55 points of each summary score and each subscale score, a middle-value group (MG) with score > 45 and < 55 points, and a low-value group (LG) with score ≤ 45 points. Lifestyle was assessed in terms of eating habits, sleeping and exercise, and the presence of unidentified complaints. At the mental component summary, the OT at the time of waking up and the peak OT in the HG were significantly higher than those in the LG. At the physical and mental component summary, lifestyle in the HG was more favorable. These data suggest that the daily rhythms of OT may reflect the mental health status of an individual. The entraining factors in circadian variation might play a role in improving mental health and reducing unidentified complaints. In conclusion, there appears to be an association between mental health status, lifestyle, and daily rhythms of OT.

The purpose of this study was to determine the effects of supine floating on rectal temperature and cardiac autonomic nervous system activity after exercise. Seven healthy males volunteered for this study. Subjects performed supine position for 30 minutes in both control condition (C-condition) and water condition (W-condition) after exercise with a cycle ergometer for 15 minutes. Exercise intensity was high (80%VO₂max) and moderate (60%VO₂max). Water temperature was 30 degrees Celsius. Rectal temperature of post exercise showed no significant differences under the W-condition, as compared to the C-condition. Delta rectal temperature (point 0-0 was end of exercise) was significantly reduced (p<0.05) under the W-condition, as compared to the C-condition. Log HF was significantly increased (p<0.05) under the W-condition, as compared to the C-condition. These data suggested that supine floating after high and moderate intensity exercise could promote recovery of rectal temperature and increased in cardiac parasympathetic nervous system activity.