The purpose of this study was to examine the relationship between physical fitness and ability to coordinate exertion of force (ACEF) in 82 healthy middle and old-aged people aged 54 to 78 years (male 41, female 41), and to examine its sex differences. The ACEF test was conducted with the subject fitting the exertion value of grip strength to a changing demand value appearing on the display of a personal computer. The variable estimating ACEF was the total sum of the differences between the demand value and the produced strength value. The physical fitness items measured were : grip strength, shoulder arm strength (push and pull), vertical jump, vital capacity, foot balance with eyes open, trunk flexion, trunk rotation, whole body reaction time, finger tapping, and stepping. To clarify the relationship between the ACEF and physical fitness, multiple regression analysis was used after age-controlled partial correlations were computed. No sex difference was found in nervous function based on the exertion of maximal ability, but there was with the ACEF based on the exertion of sub-maximal strength. Also the relationship between the ACEF and age differed in men and women. The tests of nervous function and grip strength had little relation to the ACEF test. Each physical fitness factor and the fundamental physical fitness had low relation to the ACEF. It was inferred that ability measured by the ACEF test differs from that measured by general physical fitness tests based on the exertion of maximal ability. It is necessary to examine the relationship between the ACEF test and a similar test based on the exertion of sub-maximal strength.

The aim of this study was to clarify the relationship between physical fitness elements in healthy older adults, considering the differences between gender and between age. Subjects were 1042 active and non-injured people aged from 60 years to under 90 years. The subjects were classified into two different age groups of under 75 years group and 75 years and over group. A total of 11 variables representing four physical fitness elements (muscular, joint, neural, and respiratory functions) were selected through examination of safety and validity. Two-way ANOVA was used to examine gender and age differences in each physical fitness element. Pearson's correlation coefficient and partial correlation coefficient excluding age factor were calculated for each gender and age group.
As a result of examining the relationship among physical fitness elements, the correlation coefficients within variables consisting of the following each function, muscular function, joint function and agility of extremities, were significant in both age groups, and these tendencies were consistent in both gender groups. Similarly, significant correlation coefficients between standing-reach and muscular function variables, and between trunk twist and foot balance with eyes open and reaction time were found in the under 75 years group, but not in the over 75 years group. On the other hand, different tendencies between genders were found in the relationship between the muscular function variables and trunk twist and foot balance with eyes open, and between the reaction time and stepping and muscular function variables. As the relationships among physical fitness elements tended to decline in the over 75 years group, it is inferred that this tendency is influenced by the change with aging of physical fitness characteristics and environmental factors around the older adults.

This study aims to examine the effects of kinesio taping (KT) on explosive muscle and sustained maximal muscle exertions of lower limbs in pre- and post-strenuous exercises (SE) up to exhaustion. Twenty healthy college males (mean age 20.4 ± 1.08 yr) participated in the experiment for both the conditions of strapping KT (KT group) and no strapping KT (control group) . They all took pre- and post-SE isokinetic tests (IK test) .
The KT was strapped around muscle groups related to flexion and extension motions of a knee joint before the experiment. The effects of KT were confirmed on the exertion of the explosive muscle strength in flexion motion of post-SE, and the sustained muscle strength in pre- and post-SEs. It was inferred that the effects of KT relate to the fatigue state of muscle groups related to motion and motion types, and interpretation of these effects differs by the load intensity and the variables used for evaluation.

The evaluation of muscular power function has been mainly limited to dynamic contraction, but force-time parameters in static explosive contraction may be useful. The purpose of this study was to examine the trial-to-trial differences of exertion pattern and the reliability of the force-time parameters in the development phase of static maximal explosive grip (SEG) using seventy healthy young male subjects (age 18.8±2.3yr) . In SEG measurement, subjects were instructed to exert maximal isometric force with a dominant hand as fast and forcefully as possible. Data was collected from two trials with 3 minutes rest between trials. Eleven variables (time to fixed level, average force, integrated area, maximal rate of force development, and equivalent for mechanical power parameter) were selected as force-time parameters.
The reliability of maximal grip strength (MAX) was very high (ICC=0.944, p<0.05) . In the above-stated instruction condition, the trial-to-trial difference expanded from 0.1- 0.4 sec, then re-duced in the vicinity of MAX during SEG exertion. Significant differences, however, were not found at any exertion time and reproducibility of SEG exertion pattern was very high between the two trials. The trial-to-trial reliability in all force-time parameters was significant (ICC=0.346-0.878, p<0.05) .
Reliability of the parameters measuring the earlier phase (about 0.1-0.5 sec) was low or moderate (ICC<0.7), while reliability of the parameters measuring the MAX vicinity tended to be high. The MAX relationship to force-time parameters in the MAX vicinity is high, but is low or moderate for the other parameters. It was suggested that the force-time parameters in the vicinity of MAX in SEG exertion might be useful for evaluating static power function in a clinical setting.

The purpose of this study was to examine sex differences in subjective symptoms of fatigue (SSF) in high school and college students by considering the relationship between subjective feeling of fatigue and life habits.
A questionnaire on SSF (54 items), dealing with subjective feeling of fatigue and life habits (frequency of exercise, going to sleep, waking in the morning and physical condition) was administered to 5622 healthy students aged 15-20 yr, and data of 5335 properly completed questionnaires was analyzed.
The following was determined :
1) Sex differences were confirmed in most SSF items. SSF complaints for females was generally higher than that of males.
2) The relationship between SSF and the age was low in both sexes.
3) Subjective feeling of fatigue is somewhat related to SSF.
4) The going to sleep last night influence on SSF was different in both sexes and related largely to the next day SSF in males.
5) Waking this morning and today's physical condition are related to SSF in both sexes.
6) In males, the influence of exercise habits on SSF regarding drowsiness is relatively large.

This study aimed to examine the effect of linear polarized near-infrared light (PL) irradiation on the recovery of isokinetic muscle exertion and subjective fatigue sensation in muscles after strenuous exercise. Eighteen healthy college students participated in the experiment for all conditions of meridian point irradiation (MPI), femurs muscles irradiation (FMI), and no irradiation (NI) . They all took isokinetic knee extension and flexion tests (IK test) before and after strenuous exercise up to exhaustion. Each subject was irradiated at the meridian point or in femurs muscles after the second IK test. The third IK test was carried out after ten-minutes rest.
The effects of PL irradiation were confirmed on the recovery rate of muscle fatigue in knee extension motion with high load intensity (PT 60 d/s and TW 60 d/s : MPI, FMI> NI, p<0.05 16.2%, 13.4%>8.5%, and 16.1%, 14.1%>8.3%, respectively) . Also, in flexion motion, significant differences in the recovery-degree for each condition were found, and the effect of PL irradiation was suggested. There was no difference between the effect of MPI and FMI. In addition, subjective fatigue sensation in muscles after rest decreased significantly in MPI as compared with NI (MPI: 52.1%>NI : 36.6%, p<0.05) . From the above, it was suggested that PL irradiation is effective on recovery in muscle fatigue after strenuous exercise regardless of irradiation conditions, MPI or FMI.

The purpose of this study was to examine the individual differences in relative grip-strengthendurance (RGE) variables and relations between force, endurance time and level of subjective musclefatigue sensation (SMS) of RGE. Endurance time and SMS during grip-strength exertion using various relative demand values to the maximal grip-strength-value (MAX) were analyzed. Subjects were 23 healthy adults (male 10 and female 13) . Four demand values of 25, 35, 50 and 75% were selected as relative demand values to MAX. The grip-strength-exertion value was input into a personal computer using the system of grip-strength with a strain-gauge (Yagami : ED-D 100 R) . The results are summarized as follows:
1) Muscle group related to grip-strength exertion recovered up to about 60% of initial within 10-15 sec after grip-strength exertion stopped regardless of the degree of relative demand values.
2) The SMS in any relative demand values reached a peak after continuing relative demand values became impossible, and the tendency is stronger with a higher demand value.
3) With about 25% relative demand values, physiological muscle fatigue and SMS advanced at almost the same time, and the grip-strength exertion was possible for a little while after the SMS reached a peak.
4) With the lower relative demand values under 50%, the influence of SMS appeared stronger by extending the endurance time and the decline-delay of grip-strength-exertion.
5) With relative demand values over 50%, continuing relative demand values became impossible within a short time, and the peak SMS appeared earlier than that of relative demand values. On the other hand, the continuing the lower relative demand values was possible to some extent, and individual differences in the continuance and peak arrival-times of SMS were large.

OBJECTIVESThe purpose of this study was to quantitatively and qualitatively examine a gender difference of subjective symptoms of fatigue (SSF) in healthy students.

METHODSThe subjective fatigue scale for young adults (SFS-Y) consisted of the following 6 subscales: concentration thinking difficulty, languor, reduced activation, reduced motivation, drowsiness and feeling of physical disintegration. The SFS-Y was administered to 5,435 students aged 15 to 20 yr. Student's t test was used to examine quantitative gender differences for items and factor scores. The qualitative gender difference was examined by comparing factor structures obtained from confirmatory factor analysis. A similarity in the factor structure was evaluated from: 1) interpreted factor names, 2) factor loadings, 3) degree of fit, and 4) congruence coefficient.

RESULTSA complaint of SSF shows gender differences, but the difference is not remarkable. The factor structure of SSF in males and females is suggested to be the same, because six factors with the same name were interpreted in both groups and the similarity of factor structure was very high.

CONCLUSIONThere are some qualitative gender differences in SFS, but no qualitative gender differences in factor structure.