ABSTRACT
In this study, the influence of self-weight exercise on changes in the bone mass was evaluated in young Japanese women. The subjects were 69 female university students(age: 21.20±0.30). They were assigned to an exercise intervention (Ex, n=26) or control(C, n=43) group according to their requests. Group Ex performed two sets of 10 sit-up, 10 back-extensions, and 10 squats every day for six months. The height, weight, body fat percentage (TANITA, TBF102), bone mass (quantitative ultrasound, Lunar, A-1000EXPRESS), and urinary deoxypyridinoline (DPD) were measured, and their previous and present exercise habits were examined. Group Ex showed no differences in the bone mass or DPD after the training. Group C, on the other hand, showed a significant decrease in the bone mass (p<0.01) and an increase in DPD (p<0.01) after the training. It was suggested that the bone mass can be possibly maintained through self-weight exercise.
ABSTRACT
The college years are an opportune timepoint of intervention in the primary prevention of osteoporosis. However, the effects of anthropometrical measures and lifestyle-related factors on the changes in bone mass during college years are unclear. The purpose of this study was thus to identify the determinants of the changes in calcaneal quantitative ultrasound (QUS) bone parameters (stiffness index: SI, speed of sound: SOS, broadband ultrasound attenuation: BUA) over 2 years in healthy Japanese college women (n=128). Correlation analysis revealed several significant relationships between the change rates in QUS parameters and anthropometry. Particularly, the changes in SI and BUA are highly correlated with the 2-year change in lean body mass (LBM). The subsequent multiple liner regression analysis also supported that the change in LBM was the significant predictor for the incremental rate of SI and BUA. All subjects then categorized into some grades, concerning about following lifestyle-related and physical variables during the last 2 years, living condition, sleeping time, alcohol consumption, smoking, meal skipping, dairy foods intake, instant foods intake, regular physical activity, regularity of menstruation, history of fracture, and history of dieting to reduce body weight. The incremental rates of all QUS parameters (i. e., SI, SOS, BUA) were positively associated with participation in regular physical activity. In addition, women who have continuously participated in regular physical activity from high school to college showed significant increases in SI and SOS compared with those who are not physically active or whose level of physical activity decline during college years. In conclusion, our study indicates that changes in QUS parameters in college-aged women were influenced by changes in anthropometric measures, especially LBM. It might suggest the importance of participation in regular physical activity to increase skeletal muscle mass. Our results also support the view that college women should maintain or increase regular physical activity before and after entering the college to maximize peak bone mass or lessen the age-related loss in bone mass in adulthood.
ABSTRACT
In this study, we investigated the effects of prolonged voluntary running training on bone mass in the tiba of growing male SD rats. At 5 weeks old, the rats were divided into 4 groups : group 15 VE (n=7) exercised voluntarily on a running wheel for 10 weeks from 5- to 15-weeks old ; group 35 VE (n=7) exercised voluntarily on a running wheel for 30 weeks from 5- to 35-weeks old ; in groups 15SC (n=6) and 35 SC (n=5), rats were housed individually in normal plastic cages for the same periods as groups 15 VE and 35 VE, respectively. At the end of each experimental period, the right tibia from each rat was used for bone- mass analysis using peripheral quantitative cumputed tomography (pQCT) . The evaluated portions were the proximal methaphysis and the diaphysis, with total, cortical, and trabecular data from these portions being obtained as volumetric bone mineral content (vBMC) and volumetric bone mineral density (vBMD) . The results indicated that 1) although voluntary running distance tended to decline during the later period (1635 wk old) in 35 VE rats, some mean values obtained for bone mass parameters using pQCT were significant greater in 35 VE than in 35SC ; 2) the mean values from those parameters in 15 VE were not significantly different from those in 15 SC. These results suggest that the continuation of voluntary exercise may be important for bone- mass enhancement in rat tibia.
ABSTRACT
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.
ABSTRACT
The purpose of this study was to examine the effect of a continual cycling exercise program on endurance and body mass index (BMI) in persons with residual type schizophrenia. Twenty-one inpatients (14 males and 7 females, 50.0±7.2 years of age, height of 161.4±9.4 cm, weight of 67.0 ±9.5 kg, duration of illness : 23.8±8.6 years) participated in this study. The subjects were prescribed a cycling exercise program, and endurance and weight were assessed at the beginning, as well as at six months, twelve months, and twenty-four months after starting the program. Endurance was measured by the sub-maximal bicycle exercise test, and body mass index (BMI) was calculated as body weight in kilograms/ (height in meters) <SUP>2</SUP>. The exercise program consisted of 30 to 45 minutes of cycling once or twice per week. As a result, eleven subjects (7 males and 4 females, 51.5±8.5 years of age : exercise group) underwent cycling exercise regularly for twenty-four months ; seven subjects (4 males and 3 females, 49.7±5.7 years of age: control group) dropped out within six months ; three subjects were discharged from the hospital and discontinued participation in the study. The exercise group showed an increase in endurance after six months and a significant increase after twenty-four months (p<0.05) . Concerning BMI, the exercise group showed a tendency to decrease ; however the control group showed an increase in BMI after twenty-four months. These results suggest that long-term and continual regul ar exercise is important for inpatients with residual type schizophrenia to increase their endurance. This study's findings indicate that a cycling exercise program is effective for such patients.
ABSTRACT
The purpose of this study was to clarify the interaction between environmental and genetic factors on bone. Using an ultrasound bone densitometer, the stiffness of calcaneus was measured in 52 postmenopausal Japanese women. The VDR gene polymorphism was defined by PCR-RFLP using the endonuclease BsmI. Daily walking steps as a physical activity was measured in these subjects with a pedometer for 7 days and calculated as walking steps per day. Simple regression analysis showed that stiffness was significantly correlated with age, years since menopause, weight, and walking steps. There was no significant association between BsmI VDR genotypes and stiffness. The association between VDR genotypes and stiffness was analyzed in high and low walking steps groups (HW. LW) separated by the mean walking steps in each genotype and we found that VDR genotype had the most significant effect on stiffness (p< 0.01) as indicated by using two-factors (VDR genotypes × walking steps) mixed design analysis of covariance (ANCOVA) with the age, years since menopause and weight as covariates. A significant interaction of VDR genotype with walking steps was also observed (p 0.01) . Stiffness of HW was significantly higher than that of LW in both genotypes (Bb: p<0.01, bb: p<0.05) . Our findings showed that the correlation of walking steps with stiffness by simple regression analysis varied with VDR genotypes, but that the slope in Bb did not differ significantly from that in bb and this result did not change after adjustment for age, years since menopause and weight. From now on, further investigations will be needed to clarify the interaction between VDR genotypes and environmental factors in an effect on stiffness.
ABSTRACT
It has been shown that there were the changes of H-reflex prior to the rapid voluntary movement. The present paper is designed to examine the changes of H-reflex about the time course prior to the rapid voluntary movement (dorsiflexion and plantarflexion), and premotor silent period in detail.<BR>H-reflexes were elicited from subjects' right foot at varying intervals after the response signal (sound stimulus) of reaction time task when the response involved the rapid dorsiflexion or plantarflexion of the foot. In plantarflexion, H-reflexes were elicited from two response situations ; one was the situation which subjects were not given the preparatory stimulus (without warning = W -), the other was given the preparatory stimulus (with warning= W+) .<BR>The following results were obtained ;<BR>1) Dorsiflexion and plantarflexion<BR>In case of dorsiflexion, although there were no obvious changes of H-reflex prior to EMG onset, in case of plantarflexion the damping phenomenon of H-reflex prior to EMG onset was observed and this phenomenon was the inhibitory one. Especially, under w-situation, it was obviously and it was about 70-80msec prior to EMG onset.<BR>2) Silent period<BR>The damping phenomenon of H-reflex was observed in accordance with silent period but this value was much the same of control level. This value of the damping of H-reflex was smaller than that of premotor silent period (about 30-40msec) . The time when the damping of H-reflex was observed was in accordance with that of prior to EMG onset of simple plantarflexion and this damping of H-reflex was the inhibitory phenomenon.<BR>These results suggest that the upper center sents some inhibitory motor commands to cotralateral agonist motorneurons in advance of the voluntary movement in spite of the peripheral motor set, and those from the upper center precede the voluntary movement by ahnnt 70-80msec.
ABSTRACT
In this study, it was attempted to clarify the neurophysiological mechanism of voluntary movement (phonation) recording evoked EMG (H-wave) which have been studied by Magladery and others basing on the Hoffman's study about monosynaptic reflex. The indicator was the amplitudes of H-wave which were evoked on M. soleus by stimulation on the afferent nerve fibers contained in N. tibialis. Variations of H-wave amplitudes were plotted in relation to the time elapsed from initiation of phonation and were investigated about the central nervous system in relation to it.<BR>As the results of this study, following conclusions were led;<BR>1) At the stage of pre-phonation period, average values of H-wave amplitude were higher than those of control. This result was understood as impulses which were commanded to contract the muscles for phonation raised alpha motoneurones in reflex arc of lower limbs, simultaneusly.<BR>2) The damping phenomenon of H-wave amplitudes were observed just prior to pre-phonation. But the neurophysiological mechanism of it is unknown in detail, now.<BR>3) The H-wave amplitudes showed the highest value in agreement with initiation of phonation. This phenomenon was called as Jendrassik's Maneuver. This effect was understood that Jendrassik's Maneuver had some functional connection to the reticular formation of brain stem.<BR>4) After the initiation of phonation, the inhibitory phenomenon of H-wave amplitudes (this level was lower than that of control) was observed at most of subjects. The neurological mechanism of this phenomenon is unknown.
ABSTRACT
EVOKED EMG which had been initiated by Hoff man and Magladery was applied with central nervous disorders in attempting to determine the level of lesions.<BR>Also there were not many reports on basical studies without clinical reports. The purpose of this study was attempting to research the variability in normal healthy individuals (aged 18 to 34yr., six men) on (1) relationship between stimulus intensity and amplitude, (2) thresholds, (3) amplitudes in repetitive stimulations and (4) H-wave recovery curve.<BR>All stimulating durations were lmsec. and each stimulating intervals were 3 sec. One of the subjects wes stimulated by two electrodes-needle (inside) and rod (surface) electrode-for getting a thorough going over the dependence on both methods at the beg-inning of this study. As this results, there was no significants once without the differences on stimulating intensity by skin impedance. Therefore, there was no doubtfulness using the surface electrode, and it was used for all this studies.<BR>Thresholds of H-wave were 36 to 68V on six subjects and the maximum H-wave amplitudes (1.2 to 2.3mV) were found at 55 to 100V.<BR>On the variaiton of H-wave amplitudes with repetitive stimulations (stimulating intensity 50 to 95V), average amplitudes were 1.18 to 2.33mV (S.D. ; 0.19 to 0.3mV) and the coefficient of variation was 11 to 16.<BR>Refractory periods on H-wave recovery curves were 60 to 90msec. and a few ones was shown the pattern like as the patient's with thyrotoxicosis and cerebellar tumor.<BR>Although H-wave recovery rates were constant over 300 msec. (65.01±10.14% on 300 msec., 66.20±10.21% on 400msec., 67.29-9.9% on 500msec. average ± S.D.), variation was twice on 150msec. (53.82±26.08%) like as many reports. So, there may be some factors on this period.