The purpose of this study is to identify the effect of position (full can, empty can) and change of angle on the activity of shoulder muscles during scapular plane abduction ; and also to examine its application to exercises used for rehabilitation of shoulder muscles. Seven healthy subjects (23.4±1.4 yr) with normal shoulder function performed scapular plane abduction with external rotation (full can) and scapular plane abduction with internal rotation (empty can) . An electromyogram was recorded with a fine wire intramuscular electrode at the supraspinatus, deltoid anterior, middle, posterior and trapezius upper with bipolar surface. The EMG activity (RMS) of each muscle was normalized by the highest EMG activity (100%RMS) during a maximum manual muscle test for each muscle (%RMS) . The %RMS of each muscle remarkably increased with a change of the angle for empty can, whereas it showed a slight increase with a change of the angle for full can. This finding suggests that the position of full can and empty can in scapular plane abduction affects the function of shoulder muscles. In addition, full can exercise is recommended in order to improve function of the supraspinatus and the muscular activity balance between the supraspinatus and the deltoid. Empty can exercise is applied to sport-specific exercise for rehabilitation of shoulder muscles.
The purpose of this study was to examine the effect of active recovery between two strenuous anaerobic exercises separated by a short time interval. Eight healthy adult male volunteers (age: 24.8±1.8 yrs, height: 170.6±2.5 cm, weight : 70.1 ±2.5 kg) underwent five exercise sessions. Each session consisted of a warm-up, the first anaerobic exercise test (40 sec of exhaustive cycle ergometer exercise), a 30 min inactive (seated) or active recovery period, and a second anaerobic exercise test. During the active recovery period, subjects executed one of four different intensity pedaling tests (60, 80, 100, 120% of predetermined lactate threshold intensity) for 10 min. There were no significant differences in mean power and peak blood lactate concentration among sessions during the first anaerobic exercise test. Significant differences were found in the blood lactate concentration among sessions during the second anaerobic exercise test, and significant differences were found in mean power for the second anaerobic exercise. Optimal intensity related to the blood lactate removal rate was 83.3±7.1%LT, and that related to the working capacity recovery rate was 68.3±11.8%LT. From these results, concerning blood lactate removal rate, it was suggested that between 80%LT and 100%LT was an effective intensity. As for performance, the effective intensity was less than 100%LT.
The purpose of this study was to determine the effects of well-rounded exercise program (WREP) on cardiorespiratory fitness, muscular strength, flexibility, body composition, and serum lipid concentration in a group of older outpatients. WREP was composed of programmed aerobic/ anaerobic accommodating circuit exercise (PACE) and flexibility exercises. Twenty-two volunteers (69.6±3.2 yr) were used as subjects. All participants engaged in a supervised exercise program (50 min/day and 3 days/week) for 12 weeks. After 12 weeks of training, there was a significant increase in VO2 corresponding to lactate threshold (13.4%) but peak V02 did not change. There were significant increases for knee extension (17.1%) and flexion (12.3%), chest pull (10.9%), low back flexion (26.6%), and shoulder press (14.6%) after training. Side stepping agility (13%), trunk flexion (129%) and trunk extension (19%) were also significantly improved. There were significant decreases in percent of body fat (-8.3%), total cholesterol (-7.1%) and low-density lipoprotein cholesterol (-9.7%) . Blood pressure also decreased in SBP (-lOmmHg) and DBP (- 5 mmHg) . The decline in SBP was significant in thirteen hypertensive patients (-14 mmHg) compared to non-hypertensive patients (- 5 mmHg) . These results indicate that WREP elicits significant improvement of overall fitness in older outpatients.
The present study examined the recruitment threshold of motor units (MUs) and the cold reflex activation of the cutaneous receptors at the first turning point (TP1) and the second turning point (TP2) of decreasing skin temperature. The skin temperatures of the biceps brachii were continuously reduced using a cooling chamber fixed at -10°C. TP1 and TP2 appeared at 25.5±0.5°C and 18.5±2.21°C, respectively. The data were collected at±1°C of TP1 and TP2 (TP1-B, TP1-A, TP2-B and TP2-A) . The MUs was collected during a slow ramp contraction for 3 sec to 20% maximal voluntary contraction (20%MVC) at the each measure points (TE) . The rates of decrease in skin temperature were 1.242±0.349°C min at slope-1 (TP1-B), 0.627±0.284°C rain at slope-2 (TP1-A and TP2-B), and 0.201±0.045°C/min at slope-3 (TP2-A) . The difference of the threshold force value (ΔTF= TE-control value) of LT-MUs were positive value, on the other hand, ΔF of HT-MUs were negative value at TP1-B, TP1-A, TP2-B and TP2-A. The changes of ΔTF of LT-MUs were a little at TP1-B, TP1-A, TP2-B, and increased markedly more at TP2-A than at TP1-B (p<0.05) . On the other hand, the ΔTF of HT-MUs decreased significantly more at TP1-B than at TP1-A and TP2-B (p<0.05), however, it did not significantly differ at TP2-A. These results suggested that the threshold force of HT-MUs depend on skin temperature and LT-MUs depend on decrease speed of skin temperature.
The purpose of this study is to help preventing mountaineering accidents. We conducted a questionnaire survey of middle-aged and senior mountaineers (over forty) on a nationwide scale and obtained 3781 significant responses. Both male and female respondents were in their mid-fifties on average. In terms of frequency of mountaineering, the twice-a-month group was the largest one. Approximately 70 percent did physical exercise regularly. Most of the respondents answered that they did not get so tired while mountaineering. However, troubles and/or disabilities while mountaineering occurred in 70% of them. Among them, “ache in the knee”and “wobbly legs”were the most frequent. They seems to be the causes for tumble accidents during descent which is the most common accident in middle-aged mountaineers. According to the results of cross tabulation and chi square testing, 4 items including regular physical training, regular mountaineering, optimum range of BMI (between 21 and 23) and abundant mountaineering experience were the key factors for preventing fatigue and troubles while mountaineering. On the contrary, age and sex were less important factors. However, in the case of some respondents who exercised regularly, they felt fatigue or had troubles while mountaineering. Additionally, some respondents who were confident in their physical fitness did not seem to have enough physical fitness to prevent fatigue and troubles. As stated above, inconsistent relationships were often observed among daily physical training, fatigue and troubles while mountaineering, and confidence in physical fitness, which will be one of the cause of mountaineering accidents.
This study hypothesized that gravity induced somatosensory input inhibits the spinal monosynaptic reflex circuit assessed by Hoffmann (H) reflex in man. To test this hypothesis, we investigated the effect of graded head-out water immersion (HOWI) on soleus H-reflex during upright standing. Eleven healthy male subjects aged from 21 to 28 (mean=23.8) without sensorymotor or orthopaedic history signed an informed consent. Subjects maintained an upright standing position without visual input and any background activities in soleus and tibialis anterior. H-reflex was elicited by constant current stimulation at popliteal fossa. The recruitment curve for H-reflex and motor (M) response was measured under the static tilt condition (from supine to standing) and the graded HOWI condition (the control condition, the navel condition, the neck condition, and post immersion condition) in that order. Under the HOWI condition, the water (34 degrees Celsius) was filled in a minute. No change in H- and M-wave form was observed. The amplitude of test reflex at 1.05 times motor threshold significantly decreased in the standing condition compared with the supine condition (P<0.01) . Furthermore, significant change was observed in the HOWI condition (P<0.01) . A contrast test reveled a significant increase in the navel condition (P=0.03) and the neck condition (P<0.01) compared with the control condition. The results showed that graded HOWI enhances soleus H-reflex during upright standing. It was suggested that gravity-induced somatosensory input from mechanoreceptors in the soles and joints inhibits the spinal H-reflex circuit and plays an important role for the static postural control mechanism in man.
The circadian rhythm of heart rate is well known. The purpose of this study was to investigate the characteristics of the relation between heart rate and oxygen uptake during a graded exercise testing with and without previous exercise. Eight healthy male students, aged 18 to 21 years, performed the graded sub-maximal exercise two times using a treadmill, after walking on a treadmill at a speed of 60 m/min for a total of 4 hours (2 hours in the morning, 2 hours in the afternoon) and without previous prolonged walking. The apparent resting heart rate after one hour of walking in the afternoon (82.3±9.1 beats mm) was higher than in the morning (71.3±5.8 beats/min), and this phenomenon was observed continuously exercise heart rate at the end of 2 hours of walking (afternoon : 96.4±5.4, morning: 87.2±7.3 beats min) . On the other hand, the oxygen uptake during exercise did not alter at the end of walking (afternoon: 622±85, morning: 600±133 ml/min) . This walking intensity ranged from 17.1 to 26.6, with a mean of 20.5 percent of maximal oxygen uptake. The pre-exercise resting heart rate before the exercise testing altered from -4.8 to 13.1 beats/min with and without the presence of walking. The observed individual regression line between heart rate and oxygen uptake from the testing shifted along with the altered resting heart rate. Therefore, the calculated individual new regression lines with and without walking between net heart rate, excluding pre-exercise rest, and oxygen uptake were approximate to a constant line. It was concluded that the exercise energy expenditure could be calculated accurately (-2 to 7 % of errors) using net heart rate, as compared with overestimations of the actual energy cost using the higher resting heart rate.
In the context of energetics related to a pendular model, the mechanical power (W) and ‘pendular motion efficiency’ (PME) were determined during walking of the subjects who consist of 37 healthy elderly women (65-85 years) and 21 young women (18-25 years) . Using a force plate, the potential and kinetic energies of the body's centre of mass were measured at various constant speeds. Walking speeds were selected and controlled by a newly devised pace-maker. PME, which is equivalent to ‘% recovery’ by Cavagna (1976), indicates a sort of efficiency in transforming potential energy into kinetic energy and vice versa. The external power to accelerate the body (Wext ), which is thought to be supplied by muscles, increased with walking speed, and the rate of increase in Wext tended to be greater in the elderly than in the young subjects. It was noted that the maximal PME values at the optimum speed in both age groups were comparable, but PME values in the elderly decreased more markedly than in the young subjects as walking speed deviated from the optimum. This fact suggests that an adaptability to different walking speeds reduced in the elderly population.
Recently, supplements for athletes are being increasingly used. To clarify the current status of supplement intake, we conducted a survey in female university long-distance runners. An anonymous questionnaire survey was conducted in runners who participated in the 18th Japan Inter-University Women's EKIDEN Championship, We investigated 99 respondents. The survey showed that 86 runners (87%) took supplements. Iron was most frequently taken (68 runners, 69%) . The common purpose was to reduce fatigue (amino acids, vitamin C) and prevent ane mia (iron) . However, some supplements were taken after their effects were realized, while others were taken without an effect. In some cases, the purpose was not consistent with the effects. Most runners (73%) purchased supplements in shops stores. Fifty percent of them took supplements for supplementation of nutrients deficient in diets. More than 50% of the runners obtained information on nutrition from their coaches. Furthermore, most runners began to take supplements when they were senior (55 runners, 56%) or junior (31 runners, 31%) high school students. About 70% of them have taken iron. In the highest percentage of them, their coaches recommended the use of supplements. The results of this survey showed that most female university long-distance runners took supplements, and that a high proportion of them began to take them when they were senior or junior high school students, suggesting the widespread use of supplements among young athletes. In addition, their instructors markedly influenced the runner's nutritional outlook, by being the source of information on nutrition.
The purpose of this study was to examine the effects of anthropometric measures, including body height, body weight, body mass index (BMI), fat mass (FM), and lean body mass (LBM), on quantitative ultrasound (QUS) parameters of calcaneus in 358 Japanese university women. Ultrasonic bone densitometer (Achilles, Lunar corp.) was utilized to measure broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI) of the right calcaneus. The average of SI in this study showed a slight lower value (84, 3±12.1, mean±SD) compared with that in age-matched university women as previously reported. The contradictive finding may suggest the need for a large-scale further investigation on SI in young women. Correlation analysis revealed that both BUA and SI are significantly correlated with all anthropometric measures. However SOS had only weak correlation with LBM. In consideration of the high colinearities of body weight and BMI with FM and LBM, the multiple liner regression analysis was conducted with BUA, SOS, and SI as dependent variables. Body height, FM, and LBM were then entered to a forward stepwise regression model. The analysis proved that the significant predictor of BUA, SOS, and SI is LBM. It also suggested BUA to be stronger correlated with LBM than the other QUS parameters, SOS and SI. In conclusion, our re sults support the view that QUS parameters appear to be influenced by anthropometric measures, especially by LBM in Japanese university women. It is conceivable that an increase in skeletal mus cle mass chiefly induced by physical exercise contributes to the improvement of bone mass as measured by QUS in young women.