The difference between the dominant hand and the non-dominant hand in overarm throwing motions and ball-throwing distances were studied in student women. The subjects were divided into a trained group and an untrained group. A switch thrower, categorized in the training group, was also examined. The throwing time, moving distance and mean velocity of the ball in the overall throwing phase, back-swing phase and acceleration phase were determined by a high-speed video analysis system. Seven empirical parameters estimated from the overall throwing motion were also introduced. These physical quantities and parameters were compared between the dominant and non-dominant hands. The ball-throwing distances in the trained and untrained groups were 2.58 and 1.73 times higher for the dominant hand than for the non-dominant hand, respectively. The difference in these values for both the hands of the switch thrower, however, were very small. The throwing time, moving time, and mean ball velocity in the back-swing phase in the trained group were 1.16, 1.65 and 1.35 times higher for the dominant hand than for the non-dominant hand, respectively. These phenomena were not observed in the untrained group and the switch thrower. The mean ball velocities in the acceleration phase for the trained and untrained groups were 2.0 and 1.5 times higher for the dominant hand than for the non-dominant hand, respectively. These values were more highly correlated with the ball-throwing distance in the trained group than in the untrained group. Significant correlations between seven parameters and ball-throwing distance were all observed for the dominant hand. However, only three of these parameters showed significant correlations for the non-dominant hand. These results show that the relationship between ball-throwing distance and throwing motion is closer for the dominant hand than for the non-dominant hand. In the present paper, possible roles of the dominant and non-dominant hands in the relationship between throwing motion and ball-throwing distance are also discussed.

View full abstract

The purpose of this study was to clarify the validity of 12-min submaximal treadmill walk (TMW) and run (TMR) tests, as indirect measures of cardiorespiratory endurance, and to develop estimation equations of cardiorespiratory endurance using TMW or TMR performance and some other useful items correlating with cardiorespiratory endurance. Fifty-one young adult men, aged 20 -r34 years (22.8±3.6), walked or ran for 12 minutes on the treadmill at the intensity corresponding to the level 13 on the Borg's ratings of perceived exertion (RPE 13), and performed a maximal incremental exercise test. Mean (± SD) of oxygen uptake corresponding to anaerobic threshold (VO₂AT) and maximal oxygen uptake (VO₂max) were 42.0 ± 9.0 ml/kg/min and 55.9 ± 7.4 ml/kg/min, respectively, and mean (± SD) of 12-min walk and run distances were 1221 ± 103 m and 2108 ± 269 m, respectively. Cardiorespiratory endurance indices (VO_2AT and VO₂max) significantly correlated with TMW (r=0.49 and 0.48, respectively) and with TMR (r=0.69 and 0.68, respectively) . A stepwise multiple regression analysis was applied to determine the estimation equations of the cardiorespiratory endurance using VO_2AT or VO₂max as a dependent variable, and TMW or TMR distance, age, resting heart rate (HRrest), and exercise frequency in a week as independent variables. The multiple regression equations of VO_2AT and VO₂max were developed as follows : When TMW distance entered as an independent variable, VO_2AT = 20.781 X₁ + 2.298 X₃ - 0.29 X₄ + 31.855 (r = 0.83, SEE = 5.33 ml/kg/min) : VO₂max =19.941 X₁ + 1.127 X₃ - 0.208 X₄ - 0.656 X₅ - 0.853 X₆ + 77.884 (r = 0.88, SEE = 3.96 ml/kg/min), and when TMR distance entered as an independent variable, VO₂AT =15.443 X₂ + 2.158 X₃- 0.157 X₄ + 14.234 (r = 0.90, SEE = 4.18 ml/kg/min) ; VO₂max =10.817 X₂ + 1.274 X₃ - 0.1946 X4 - 0.504 X₅ + 55.234 (r = 0.89, SEE = 3.79 ml/kg/min), where X₁ : TMW distance (m), X₂: TMR distance (m), X₃ : exercise frequency in a week (d/wk), X₄: HRrest (b/min), X₅: age (yr) and X₆: BMI. It is concluded that cardiorespiratory endurance could be better estimated by a combination of submaximal exercise performance and some easily measurable items correlating with cardiorespiratory endurance such as exercise frequency, circulatory function, chronological age and body composition.

View full abstract

The principal objective of this paper is basic research on the development of an easy and rapid method to estimate physical fatigue levels. The focus of the research is to determine chronically fatigued conditions at an early stage for the prevention of chronic fatigue. Special attention was given to overtraining as one form of chronic fatigue in this paper. Long-distance runners representatives of a university in Tokyo nominated for Hakone-Ekiden were recruited as subjects. Examinations with informed consent were carried out on a once a month basis during 8 months and included the following; 1) physical characteristics ; body weight and body fat weight, 2) serum-biochemical test ; 6 parameters by the dry-chemistry method and the traditional method, 3) subjective fatigue levels ; the questionnaire of subjective symptom authorized by the Japan association of industrial health and the profile of mood state (POMS) . In this paper, data obtained from 19 male runners attending all 8 examinations were statistically analyzed.
Serum parameters obtained by the dry-chemistry method, an easy and rapid method which provides clinical values on site, showed significant correlations with the traditional method.
No correlation was observed between subjective fatigue scores and serum enzyme activity levels which were used as markers for estimation of physical fatigue levels in this study, however, monthly changes of enzyme levels and fatigue scores from July to August seemed to correlate in almost subjects. In contrast, using data obtained in the entire exprimental period, there was no relationship between the monthly changes of enzyme levels and fatigue scores. The results may indicate that some subjects exhibit gaps between physical fatigue and feelings of fatigue.
The above mentioned results suggest that measurements of serum enzyme activity levels using the dry-chemistry method are a useful indicator for the prevention of overtraining.

View full abstract

Effects of neck muscle training and their changes after discontinuation of training (detraining) were studied in 22 athletes (college American football players) and 19 non-athletes. The subjects underwent narrow grip shoulder shrug training using free weights (NGSS group), isometric training of the neck in pairs (PAIR group), or both types of training (COMB group) for 14 weeks, and were then detrained during the following 14 weeks. Extension and flexion muscle strength (maximum isometric muscle strength) of the neck were measured using a method in which subjects pulled a wire attached over the head in a sitting position at 2-week intervals after the start of training.The following results were obtained.
1. In the athletes, the flexion muscle strength increased by 16.9±5.6% (mean±standard deviation) in the COMB group and by 14.8±5.2% in the NGSS group, and the increases in these groups were significantly greater than the increase in the PAIR group (p<0.01) . The extension muscle strength also increased, most notably in the COMB group (12.2±4.7%) .
2. In the non-athletes, the flexion muscle strength increased by 29.4±7.2% in the COMB group, and this increase was significantly greater than that in the PA1R group (p<0.01) . This increase was also significantly greater than that in the COMB group of the athletes (p<0.01) . The extension muscle strength increased by 19.1±5.2% in the COMB group.
3. In the athletes, the flexion muscle strength of the COMB group was increased by 8.3% after 14 weeks of training and 14 weeks of detraining as compared with that at the start of training. In the non-athletes, the flexion and extension muscle strength of the COMB group increased by 17.4% and 9.8%, respectively, after the start of training.
These results suggest that narrow grip shoulder shrug training used for the development of muscle strength in the lower neck is effective for improving flexion as well as extension muscle strength, and that the decrease in muscle strength due to detraining can be reduced by combining this training with isometric training performed by the PAIR group.

View full abstract

The present study attempted to define a dynamic muscle contraction against viscosity resistance in which force is proportional to velocity of movement, and to determine its mechanical properties in comparison with isotonic and isokinetic muscle contraction. This dynamic contraction was referred to as the “isoviscous contraction” . A loading mechanism consisting of a directly-driven electromagnetic motor and an electronic control circuit was developed to enable three patterns of dynamic contraction to be performed. The torque, joint angle and joint angular velocity in the three types of dynamic contraction were measured in 8 healthy male volunteers during knee joint extension. The isoviscous contraction was not accompanied by any abrupt change in torque during the movement observed regularly in isotonic and isokinetic contraction. The instructed movement for isoviscous contraction could be performed over a wide range of joint motion at all levels of contraction. In addition to its unique mechanical properties, since the viscosity resistance produces a better damping effect against an abrupt change in torque, isoviscous contraction is considered to be a useful method of rehabilitation training in disabled patients and aged individuals. However, the great inertial force produced by isoviscous contraction corresponding to that in isotonic contraction should be further investigated.

View full abstract

Cold-induced vasodilation (CIVD) and heat-induced vasoconstriction (HIVC) were examined in 8 Germans who were living in the suburban areas of the central Germany and 7 Japanese who were staying in the suburban areas of central Germany for the mean length of 2.7±0.6 years. CIVD were measured during the middle finger immersion in cold water at 0.2°C for 30 minutes. The finger blood flow for HIVC was measured by laser Doppler flowmetry (LDF) in water from 35°C to 43°C every 10 minutes. HIVC represented as the percentage of the LDF volts after immersing as compared with the values before immersing (finger blood flow %, FBF%) . The daily energy intake of the subjects were also investigated.
The mean skin temperature and the resistance index as a value of CIVD were significantly higher in the Germans than Japanese, but the values of the Japanese living in Germany were higher than those of the Japanese living in Japan. The HIVC appeared at 35°C and 38°C and FBF% was the lowest at 40t both in the Germans and the Japanese. The finger skin temperature increased during jmmersion in both groups but was significantly higher in the Germans at 43°C. The decrease in FBF% per minute and the increase in the finger skin temperature per minute at 38°C and 40°C were greater in the Germans. The increase in FBF% per minute was greater in Japanese but the increase in finger temperature per minute were smaller in Japanese at 43°C. The daily protein intake of the Japanese living in Germany was higher than the average intake of the Japanese living in Japan, and their daily protein intake per body weight was approximately equal to that of the Germans.
It is inferred that CIVD is affected by the living circumstances and the state of nutritional intake, and HIVC by the thermal sensation and also by the living circumstances.

View full abstract