[Objective] The purpose of this study was to determine whether icing treatment has an effect on muscle reaction time and functional performance of a sprained ankle. [Methods] Subjects were six persons (healthy group) and six persons who had an acute ankle sprain (patient group) . Anterior talar translation and talar tilt of the six patient group were evaluated by the stress X-ray measure. Ice treatment was applied for 20 minutes. [Results] The following points were clarified : 1) Reaction times of peroneus longus (PL) and peroneus brevis (PB) for the sprained ankle group (SA) were significantly longer than those for the non-sprained ankle group (NA) (p<0.05) . Length of time of standing on one leg with closed eyes for SA was significantly shorter than for NA (p<0.05) . 2) After icing treatment, reaction time of PL for SA tended to be shorter. Furthermore, PB significantly decreased after icing treatment (p<0.05) . Side-steps for SA were significantly increased after icing treatment (p<0.05) . 3) Reaction times of PL and PB for NA significantly increased after icing treatment (p<0.05) . Standing on one leg with closed eyes for NA significantly decreased after icing treatment (p<0.05) . [Conclusion] It was shown that icing treatment of a sprained ankle leads to a shorter muscle reaction time and an increase in the number of side-steps. Therefore, it was concluded that icing treatment of a sprained ankle might be able to improve incapacitated neuromuscular function and functional performance by acute trauma.
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 RTintegrateprogressively increased as SPM was increased, iEMG correspondingly decreased. Rate in utilization of elastic components of muscle and tendon assessed by RTintegrateat 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 purpose of this study was to determine the change in elbow flexor isometric torque at different phases of the menstrual cycle in humans. The subjects were six eumenorrheic females (age 22.0±3.5yr ; height 156.5±3.3cm ; body mass 50.2±4.9 kg) . The serum luteinizing hormone (LH), estradiol and progesterone levels, maximal voluntary contraction (MVC), integrated electromyographic activity (iEMG), interpolated twitch torque, evoked contractile properties, anthropometric parameters and Profile of Mood States (POMS) were measured at three different phases of the menstrual cycle, i. e., the menstrual, ovulatory and luteal phases. The MVC was significantly higher in the ovulatory phase than in the menstrual and luteal phases (P<0.05) . The iEMG, calculated voluntary activation and anthropometric parameters did not change significantly over the menstrual cycle. The MVC/iEMG ratio (electromechanical efficiency) and the evoked peak torque were also significantly higher in the ovulatory phase than in the menstrual and luteal phases (P<0.05, P<0.01) . In the menstrual phase, the fatigue and anger subscale score of POMS were significantly higher (P<0.05) and the vigor subscale score was significantly lower than in the other phases (P<0.05) . These results indicate that the variation in MVC observed over the menstrual cycle may be related to the intrinsic contractile properties rather than neural or psychological factors.
In previous studies, acute exercise might induce inflammatory cytokines from immunological cells, but it was not clear that tumor necrosis factor (TNF) -α in the liver was induced by acute exercise. In this study, we first measured the changes from acute exercise in plasma TNF-α, lipopolysaccharide (LPS), interferon (IFN) -γ and prostaglandin (PG) E2 ; from and investigated the effect of acute exercise on TNF-α expression in the liver. Then we examined the response of TNF-α to PGE2 in isolated Kupffer cells. Female Fischer 344 rats were run on a treadmill at 21 m/min for 60 min on a 15% grade. Although the portal venous plasma endotoxin concentration in the exercised group was higher than that in the resting group, plasma TNF-α was not detected in either group. In addition, plasma IFN-γ, which accelerates TNF-α production, was not detected. TNF-α mRNA expression in the liver didn't change significantly. On the other hand, plasma PGE2, which is an inhibitor of TNF-α production, markedly increased immediately after the exercise. In addition, PGE2 inhibited TNF-α production by LPS-stimulated Kupffer cells in in vitro. These results sug gest that LPS-induced TNF-α expression in rat liver is inhibited by an increase of PGE2 during acute exercise.
Pulmonary rehabilitation is a common therapy for improving both exercise tolerance and quality of life (QoL) in patients with chronic obstructive pulmonary disease (COPD) . Although exercise is an important rehabilitation strategy, walking, treadmill use, bicycling and respiratory muscle training can be monotonous. A comprehensive exercise program that includes recreational activities may be a more effective means to decrease the occurrence of dyspnea during daily activities and improve QoL in patients with COPD. The purpose of this study was to investigate the effects of our exercise therapy, including recreational activities and respiratory muscle training, on dyspnea and health related QoL (HRQL) in COPD patients. Thirty-eight male patients with COPD were randomly assigned to a control (C) (70.1±6.4yr) (n=12) . pulmonary rehabilitation (PR) (70.3±8.3yr) (n= 16), or exercise (EX) (68.7±4.6yr) (n=10) group. The following evaluations were performed at baseline and at 8 weeks: (1) cycle ergometer test ; (2) 6-min walking distance : (3) physical fitness (4) pulmonary function ; (5) dyspnea : and (6) HRQoL (SF-36) . The C group showed no significant changes in physical fitness, pulmonary function, dyspnea, and HRQoL scores throughout the observation period. There was a significant (P<0.05) improvement in 6-min walking distance. physical fit-ness, maximum rnspiratory pressure (MIP), and HRQoL for the PR group. The EX group demons-trated a significant (P<0.05) improvement in physical fitness, maximum expiratory pressure (MEP), dyspnea, and HRQoL. Moreover, the degree of improvement in each variable was greater for EX than for PR. There were significant (P<0.05) correlations between MIP and FEV1.0 (r=0.65), and between MEP and FEV1.0 (r=0.43) . Based on these results, it appears that our comprehensive exercise program, including recreational activities and respiratory muscle training, improves physical fitness, pulmonary function, dyspnea, and quality of life in COPD patients.
Objectives : The present study investigates the effects of body iron stores upon indices of biosynthesis and destruction of red blood cells (RBC) induced by a single session of cycling exercise. Design : Eight sedentary female students were divided into groups depending on their body iron stores : normal (C group, n=5) and iron deficient (D group, n=3) . Blood samples were collected at five time points of before (pre), immediately after (0 hours), then 1, 3 and 6 hours after exercise (248±31 kcal, 70% V02 peak level) . Osmotic fragility and serum haptoglobin (hp) concentration served as of for degradation, and δ-aminolevulinate dehydratase (ALAD) activity, erythropoietin concentration and number of reticulocytes served as indices of RBC biosynthesis. Results : A single session of cycling exercise did not affect the level of RBC, hemoglobin, hematocrit, serum iron, ferritin, transferrin saturation, hp and osmotic fragility in either groups. The δ-ALAD activity increased at 3 (p<0.05) and 6 hours (p<0.01) after exercise compared with that at 0 hours in the C group. In contrast, δ -ALAD activity in the D group was significantly lower at 3 hours after exercise than that of C group (p<0.001) . Reticulocytes and erythropoietin concentration increased gradually in the C group after exercise, but not in the D group. Conclusions : A single session of cycling exercise under our experimental conditions enhanced RBC biosynthesis indicated by δ -ALAD activity, whereas exercise-induced hemolysis was not evident. Body iron stores affect the δ -ALAD activity induced by a single bout of cycling exercise.
In this study, we investigated total sweat rate per unit area of body surface per hour (TSR), the percentage of total sweat loss to initial body weight (%TSL) and the percentage of fluid intake volume to total sweat loss (%FIV) in children (during baseball or basketball practice), young adults (during softball or baseball practice), and the elderly (during gateball practice) in summer. During the practice all participants were given access to drink sports drink or Japanese tea ad libitum. In the basketball group of children no sex difference was observed in TSR, %TSL and %FIV. Although TSR and %TSL in the baseball group of children were significantly higher than in the basketball group due to a higher WBGT, there was no group difference for %FIV. Children drank sports drinks (with carbohydrate-electrolyte) of the similar volume with total sweat loss. The baseball group of children showed a significantly greater %FIV compared to the young adult group regardless of simi lar %TSL, when they drank sports drinks. Children showed a significantly higher %FIV in sports drinks than in Japanese tea, whereas the %FIV of young adults was not affected by the type of beverage. The TSR, %TSL and %FIV of the elderly group were significantly lower than in young adults and children. These results suggest that children can prevent voluntary dehydration by con-suming sports drinks with carbohydrate-electrolyte ad libitum regardless of sex and WBGT, and that periodic drinking should be actively encouraged for the elderly because of their blunted rehydration ability, to prevent heat disorders during sports activity in summer.
The purpose of the present study was to investigate the relation between the deterioration of walking speed and physical fitness. Sixty-two elderly women (80.4±4.0 years old) volunteered to participate as subjects. Walking speeds at normal and fast speeds on a 10 m straight course, as well as muscular strength, flexibility, agility and balance were measured. Normal and fast walking speeds decreased through aging, and mostly depended on the strength of lower extremity muscles (hip extensor, hip abductor, knee extensor and ankle plantar flexor ; normal walking : r=0.596-0.666, p<0.01, fast walking : r=0.623-0.727, p<0.01) . However, the distributions of walking speed to the strength of each measured muscle were divided into two phases. The weaker group of lower extremity muscle strength had much slower walking speed. The two groups, divided according to muscular strength (the sum of the T scores of the four muscular strengths of the lower extremity) showed the following differing results. In the “high” muscular strength group (n=31) the highest factor was lower extremity muscle strength, but it was the delay of nerve reaction time in the “low” muscular strength group (n=31) . From these results, it was clarified that the main factor in the deterioration of walking speed in elderly women was the decline of lower extremity muscle strength. However, it was suggested that the functional decline of the nervous system would greatly affect the decrease of walking speed in elderly with weaker muscular strength.