The purpose of this study was to investigate the effects of short-term living and training at an altitude of 1, 300 to 1, 800 m on physiological responses of high school elite endurance athletes. Fifteen male and seven female senior high school elite athletes, aged from 15 to 18, from three different sports (cross-country skiing, long-distance running and endurance cycling), participated in our study. The short-term (6 days) altitude exposure did not elicit abnormal responses of body tempera-ture, body weight, blood pressure or urine samples. There were also no significant changes in blood parameters examined before and after altitude exposure. Resting heart rate (HR) increased at altitude and presented an initial peak value followed by a steady decline on the following days of altitude exposure. Blood lactate concentration and exercise peak llR examined by submaximal 20-m shuttle run test decreased after the ascent to altitude and still showed lower values at postaltitude than at prealtitude. We conclude that 6-day living and training at an altitude of 1, 300 to 1, 800 m elicits positive decrements of exercise blood lactate and exercise peak HR as well as adaptive changes of resting IlR for these high school elite endurance athletes, which are probably related to an attenuation of muscle glycogen utilization and alterations in the autonomic neural system taken at altitude.

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The contractile and morphological effects of chronic overload induced by synergist gastrocne mius and soleus ablation were studied in regenerating plantaris muscle of rats after injuries produced by eccentric exercise. Rats were randomly divided into control (C), eccentric exercise (E) synergistic ablation (S) and eccentric exercise+synergistic ablation (ES) groups. At 6 weeks after the experimental treatment, contractile or morphological muscle properties were measured. The maximum tetanic tension of ES group was significantly larger than that of S group (p<0.05), although there was not significant difference between C and E groups. There was not significant difference in contraction time between S group and ES group. While there was not significant difference in mean cross-sectional area of any fiber types between C group and E group, all fiber types of ES group were significantly smaller than that of S group (p<0.05) . It is concluded that the overload on injured muscle by eccentric exercise may restrain muscle hypertrophy.

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This study investigated the effect of habitual snacking on the diet-induced thermogenesis (DIT) in non-obese young women. Thirteen women aged 1823 yrs old were divided into two groups group one was of six women who consumed snacks; candy, cookies, chocolate, etc., “very frequently” between meals almost everyday, group two was of seven women who seldom consumed snacks. The BMI of both groups were matched (19.7±1.0kg/m²) . The DIT was measured 5 h after ingestion of a meal (2220 kJ=531 kcal) using the Douglas bag technique. Each subject had their DIT measured on eight occasions to obtain average DIT values because DIT had large intra-individual variability. Indeed, each subject's DIT values were markedly different (the mean intra-individual CV=39.6%) . There was no significant difference between the two groups in percentage of body fat, resting metabolic rate (RMR), or RMR/body weight. The mean value of DIT (± SD) of group one (6.4±1.2%) was lower than that of group two (7.8±0.9%) (p<0.05) . Also, the main effects of the groups and the time after ingesting the test meal on postprandial energy expenditure were significant (two-way ANOVA; p<0.001), but the interaction between the group and the time after ingesting the test meal was not significant. In conclusion, eating habits with habitual snacking blunt DIT in young women.

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The present study examined the effect of the long-term intake of chicken breast extract (CBEX), which contains carnosine and anserine, on carnosine content in skeletal muscles of humans and on short-period exercise performance with high intensity.
Before and after CBEX was orally given to 13 healthy male subjects for 30 days, pieces of their muscle (M. vastus lateralis) were excised and carnosine concentration in the muscle was measured. Before and after the test period, the subjects exercise performance (mean and peak power body weight) was determined by pedaling for 30 sec. On the basis of baseline concentrations of carnosine, the subjects were classified into two groups: low (n=8) and high (n=5) carnosine-baseline groups. In the former group, intake of CBEX increased carnosine concentration in the muscle (p<0.05), resulting in significant correlation between increased rate of carnosine concentration and mean power. These results suggest that exercise performance depends on carnosine concentration in the muscle, and that taking carnosine-containing foods may improve exercise performance.

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This study examined total energy expenditure (TEE) of Japanese firefighters under normal working conditions, and also evaluated several field methods for measuring TEE in comparison with the doubly labeled water (DLW) method. Ten male subjects belonging to Tokyo metropolitan firefighters departments, aged 30.0±2.8 yrs (mean±SD), were monitored for five consecutive days. While TEE was assessed by an accelerometer (AC) and activity records (AR) in additoin to DLW, energy intake (El) was evaluated by dietary record. There were three emergency calls over the assessment period, but no real operation of fire suppression. TEE obtained by the DLW method (4009±611 kcal/d) was significantly higher than that estimated by AC (2531±186 kcal/d) or AR (3704±476kcal/d) ; but significantly correlated with AR (r=0.876, p<0.01) . El (3539±286 kcal/d) showed no significant relationship with DLW. These results suggest that compared with AC, AR would be more feasible for estimating TEE of firefighters, who perform special activities carrying heavy equipment. The mean value of physical activity level (PAL) (2.2±0.3) indicates that firefighters can be categorized as heavy workers like soldiers or policemen.

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[Purpose] A leg press generally included in a weight training program to develop the quadriceps. However little is known about the mechanism of the load in lower extremity by the different knee alignment. The purpose of this study is to compare the muscle activity in the different knee align ment during leg press exercise. [Methods] Four normal knee and Five gene varum performed the leg press using three stance of narrow, medium and wide stance with the load of 75%/1 RM. Surface EMG date were collected (1000Hz) from vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), adductor longus (AL), biceps lemons (HF), tibialis anterior (TA), gastrocnemius (GAS), soleus (SQL) . Integrated EMG (iEMG) values were calculated for each muscle during each rep. A video camera recorded the performing form during leg press from the frontal plane. [Results and Discussion] As the leg press was to strengthen of the thigh muscle, VM, VL and RF of both groups worked strongly. However SQL of genu varum worked as strong as the level of activity of the thigh, iEMG of the SQL showed low value significantly by using wide stance. When the genu varum group performed maximal knee flexion using the narrow, their ankle was valuus on the video screen. This result may become cause of SQL higher activity during leg press. From this we can derive the argument that it will be necessary to take that stance into consideration when athletes who are genu varum performs leg press.

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本研究の目的は, 中距離走者を対象に間欠的な漸増負荷走行テスト (MART) を行い, La動態から推定されるパワーと中距離走能力との関係を検討することであった.
結果の要約を以下に示す.
(1) V800m, V1500mと実験時の走力を表す最大パワー (Pmax) との間に有意な相関関係が認められた.
(2) V800mとピークLa (PBLa) の60%値 (60%PBLa) を基準に算出したパワー (P60%La) , V1500mとPBLaの40%値 (40%PBLa) を基準に算出したパワー (P40%La) およびP60%Laとの間に有意な相関関係が認められた.
以上のことから, MARTが中距離走能力を反映するテストとして有用であること, また, P60%Laが800m走能力, P40%LaおよびP60%Laが1500m走能力を反映する評価指標の一つとして利用可能であることなどが示された.

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The purpose of the present study was to develop a new method that enables individualized determination of the optimal exercise intensity for health promotion. Our study was based on the following observations : (1) physical activity at ventilatory threshold (VT) has been useful for enhancing physical fitness and even improving medical conditions such as heart failure, hypertension and diabetes, (2) exercise intensity at VT is characterized by suppressed vagal activity, and (3) vagal activity can be evaluated by analyzing heart rate variability (HRV) . In the first study we defined a criteria for determining the exercise intensity corresponding to VT using HRV analysis (heart rate variability threshold, THRV) . In 16 normal subjects, a time series of ECG RR interval were recorded and the means of the sum of the squared differences in successive RR intervals (MSSDs) were calcu-lated during a ramp exercise test with a cycle ergometer. Based on the values of MSSD and the dif-ferences in successive MSSDs (ΔMSSD) at the intensity of VT, we defined the criteria of THRV as follows : MSSD<25 msec²and ΔMSSD<6 msec². Another exercise test with a cycle ergo-meter was performed to evaluate the relationship between THRV and VT in 63 normal subjects. Heart rate (HR) and oxygen uptake (VO₂/wt) at THRV were 111.8±13.2 beats/min and 15.2±4.4 ml/kg/min, and HR and VO₂/wt at VT were 116.2±11.6beats/min and 16.5±3.7ml/kg/min, respectively. There was a significant correlation between THRV and VT (HR : r=0.82, p<0.001, VO₂/wt : r=0.88, p< 0.001) . Thus, THRV and VT provided almost identical exercise intensities. As a result, we propose that, similar to VT, THRV can be used as an indicator of the optimal exercise intensity suitable for health promotion in normal subjects.

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Purpose : We examined the effect of therapeutic exercise on osteoarthritis (OA) of the knee. Objects and Method : We evaluated seven women with bilateral OA of the knees of over Grade I on the Kellgren and Lawrence scale. The patients were instructed in therapeutic exercise for both knees. The exercise was to tie a Thera-Band ^® around the leg just above both ankles in the 8 figure, and then, in a sitting position, extend one leg while simultaneously retracting the other, repeating alternatively every 5 seconds. One set consisted of repeating this motion 10 times, and 2 sets were performed per day. Before exercise, 1 month, and 3 months after exercise, we evaluated the effect of this therapy by the JOA score, isokinetic muscle strength of knee extensors and flexors, and surface EMG signals recorded from rectos femoris (RF), vastus medialis (VM), vastus lateralis (VL), and biceps lemons (BF) . The integrated signal, the root mean square (RMS), and the mean power frequency (MPF) parameters were extracted.
Result : The parameters of the JOA score, muscle strength of knee flexors, integrated EMG from RF, VM, VL, and RMS from VM, VL were significantly increased at 3 months after exercise. MPF from VM at 3 months after exercise decreased significantly.
Conclusion : We thought a proper balance of knee extensors and flexors are related to the improvement of symptoms of OA of the knee. The decrease of MPF might suggest the possibility of muscle fiber type change. It is also possible that pain reduction results from the improvement of balance between knee extensors and flexors as well as from the increase of knee joint stability. Therapeutic exercise with the Thera-Band R is extremely easy and is effective in promoting con-tinuous exercise.

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