Regular physical activity has been regarded as a possible means to minimize the adverse physiological changes associated with aging, as well as to contribute to mental health and well-being in later life. To encourage increased participation in exercise among elderly people, and to emphasize the value of exercise in geriatric health care, this article provides an overview of the effects of primary care based physical activity on healthy aging. It is clear from the number of recently published papers on this topic that daily participation in 30 minutes or more of moderate physical activity should be recommended for elderly people. The results of physical activity interventions focusing on balance and resistance training in both home- and group-based exercises suggest that it is possible to improve physical functions and to prevent falls and disabilities in daily living. Multiple-element interventions (e. g., advice, as well as strategies to increase self-efficacy and motivation, and to eliminate barriers to participation), tailored to individual activity preferences, are likely to be more successful than more prescriptive single-focus interventions. A home-based physical therapy program can successfully enhance the independence of the frail elderly in community dwellings.
Proprioception plays an important role in the maintenance of joint stability and regulation of joint motion. Previous studies have suggested that dysfunction of proprioception is related to causal factors of various diseases and injuries of the musculoskeletal system. In recent years, training of proprioceptive function has been introduced for the rehabilitation of motor function and prevention of the joint injuries. In this review paper, definition of proprioception, and morphologic and physiologic characteristics of the proprioceptors in the joint and adjacent tissues such as ligaments, muscles and tendons are described. Previous clinical studies on the relationships between proprioceptive dysfunction and joint diseases and injuries are also reviewed.
The aim of the study was to measure the cross-sectional area of the psoas major muscle (P-ACSA) in high school athletes and to produce a P-ACSA index independent of body size using an allometric modeling approach to examine the differences in gender and sport specialization. The subjects were 254 female (16.8±0.8 yrs) and 540 male (16.9±0.8 yrs) high-level high school athletes from 17 different sports. Fat-free mass (FFM) was measured by the Bod Pod system (LMI) and P-ACSA was determined by magnetic resonance imaging at the center of the L4-L5 transverse level. Since the power function model fit the data better than a simple linear model in the correlation between FFM and P-ACSA, and the power exponent parameter was almost equal to the theoretically anticipated 2/3 in both genders, the P-ACSA per FFM2/3 as well as the absolute P-ACSA was calculated. Both of the absolute P-ACSA and P-ACSA per FFM2/3 were significantly different according to gender and the sport specialization. While volleyball and badminton players and canoeists showed smaller P-ACSA, in accordance with the previous studies on senior sprinters, high school sprinters also showed predominant development of P-ACSA regardless of gender. These results suggested that regular involvement in sprinting activity could affect the size of the psoas major muscle in high school athletes.
To promote habitual participation in physical activity, a 3-month program for lifestyle physical activity intervention (L group) and structured exercise intervention (E group) was carried out in a community in Okayama Prefecture. One year later, we compared the two intervention groups in terms of cost-effectiveness and behavioral change in habitual physical activity. A total of 250 subjects voluntarily participated in the lifestyle physical activity intervention ; and a total of 42 subjects participated in the structured exercise intervention. The number of participants decreased to 115 (46%) and 21 (50%), respectively, one year later. However, the proportion of subjects who practice endurance exercise increased significantly in both L and E groups ; and an additional 35 subjects (30%) started to practice endurance exercise in L group and 5 (24%) in E group after the interventions. The cost-effectiveness for a person newly starting the endurance exercise practice in the L group intervention was 29,206 yen ; and the E group intervention was 124,731 yen, a ratio of 1/4.3. The study suggests that the cost-effectiveness for the lifestyle physical activity intervention was 4 times better than the structured exercise intervention.
The purpose of this study was to determine the effects of plyometrics on jump, footwork and chest pass ability in competitive basketball players. Ten male basketball players competing at the college level in Japan practiced plyometrics by using the drop jump and the medicine ball throw three sessions per week for seven weeks. All players had continued regular training and competition in basketball over ten years. Height and contact time of the rebound drop jump and the jump shot were tested for each player along with sprint running velocity in a straight direction and with four footwork phases for changing direction, ball velocity and contact time of hands for chest pass pre and post plyometrics. Drop jump training significantly shortened contact time but did not enhance jumping height of the jump shot with a basketball. Moreover, drop jump training significantly shortened average velocity of sprint running with four footwork phases for changing direction, but did not enhance sprint running in a straight direction. Medicine ball training significantly enhanced ball velocity and contact time of hands for the chest pass. These results suggest that plyometrics, by using the drop jump and medicine ball throw, are effective training methods for improving jump, footwork and chest pass ability in competitive basketball players.
The aim of this study was to investigate the differences between male and female in the activity level of trunk and lower limb muscles during basic daily physical actions. Six young adult male and six female subjects performed 14 daily life actions, i. e. postural maintenance and change, and body weight transfer actions. The surface EMG of six muscles of the trunk and the lower limb was recorded using a portable electromyography apparatus. Maximal EMG response (EMGmax) during isometric maximal voluntary contraction for each muscle was used to normalize the EMG signal. In the performed actions, the average activity level of each muscle corresponded to 20% EMGmax or less in male and 30% EMGmax or less in female subjects, though there were some actions which exceeded 40% EMGmax in the soleus muscle. As a result of 3-way ANOVA, significant effects for each of the 3 factors (action, muscle and sex) for muscular activity level were recognized and there were significant interactions among each pair of factors. The mean activity level of leg muscles in actions which support and transfer body weight was significantly higher in females than males. In the case of identical actions, the total time taken to reach a high muscular activity level was longer in females than males. From these results, it can be assumed that the load on the lower limb muscles is larger for females than males in the case of supporting and transferring body weight in daily life.
Background : The incidence of anemia in the female athlete is high, and anemia causes not only a decrease in performance, but also various subjective symptoms. It is said that the cause of hemolysis -a type of anemia- is a decrease in antioxidants and an increase in the reactive oxygen species caused by exercise. Purpose : This study investigated the effect of acute exercise on hemolysis and oxidative stress in female athletes. Methods : On the basis of basal body temperature (BBT) data and urinary ovulation tests of the subjects (age 20.5±1.0 yr ), they were divided into two groups : eumenorrheic athletes (Eu, n=12) group, and irregular menstrual athletes (Am, n=9). The subjects performed an acute period of exhausting exercise on a bicycle ergometer. Lactate, hemoglobin, hematocrit, RBC, serum estradiol, haptoglobin, thiobarbituric acid reactive substances (TBARS) were determined in blood samples collected at rest and after exercise. Results : Lactate increased and hemoglobin, hematocrit, RBC, haptoglobin decreased after exercise in both the Eu and Am groups (p<0.05). However, serum TBARS did not show a significant change after exercise in both the Eu and Am groups. Conclusion : These results suggest that hemolysis may have developed, because haptoglobin decreased as a result of acute exercise. However, it is thought that the effect of oxidative stress is small because TBARS were not changed by acute exercise in both Eu and Am groups. In addition, there was no significant correlation between hemolysis and estrogen.
It has recently demonstrated that central fatigue during sustained maximal voluntary contraction (MVC) progresses faster in the presence of delayed onset muscle soreness due to eccentric contractions than in normal states (Endoh et al., 2005). However, it remains to be clarified whether these findings are related to muscle damage or muscle pain induced by eccentric contractions. The present study investigated which factor plays a more critical role in the earlier onset of central fatigue during sustained MVC with muscle pain induced by injecting hypertonic saline. Ten healthy male right-handed subjects (age, 21~32 yrs.) were asked to perform brief MVCs (~3 sec) before and after injection of isotonic saline (0.9%, 1.0 ml, ISO) or hypertonic saline (5.25%, 1.0 ml, HYP) into the left biceps brachii. The subjects then performed 1 min MVC (fatigue test) with isometric elbow flexion was done in ISO or HYP condition or intact control condition (CON). During these contractions, transcranial magnetic stimulation was delivered to the contralateral motor cortex to evaluate voluntary activation (VA), the motor evoked potential (MEP) and electromyographic (EMG) silent period (SP). Ratio of root mean square of the EMG and elbow flexion force (EMGrms/F) was also measured. The peak pain induced by the injection of HYP was significantly higher than that of ISO (p<0.01). There was no significant difference in either the maximum size of the M response or the twitch force between ISO and HYP (p>0.05). However, during the brief MVCs, both maximal force (p<0.01) and VA (p<0.05) for HYP were significantly decreased compared to those for ISO. During the fatigue test, although MVC, VA, MEP and SP were significantly altered (p<0.05~0.01), there was no significant difference among CON, ISO and HYP (p>0.05). There was no significant difference in EMGrms during the fatigue test (p>0.05). These results suggest that peripheral force-producing capacity remained intact after the injection of ISO and HYP during sustained MVC, and that progression of central fatigue during sustained MVC was less affected by the increased group III and IV afferent activity induced by HYP.