The thoroughbred horse is a remarkable animal, with both speed and endurance abilities during running. Muscle adaptation associated with training and growth has been examined using various physiological, histochemical and biochemical measurements. We have emphasized the importance of type IIX fiber recruitment in training program for thoroughbred. Because type IIX fiber provides the greatest contribution to total muscle volume in the gluteus medius muscle and increases in oxidative enzymes of the fibers would markedly improve the whole-muscle oxidative capacity. Based on these concepts, we examined the adaptations of type IIX fiber including hybrid fiber to various training programs. It is considered that scientific information about optimal training of these excellent abilities can provide significant insights into exercise physiology and health science not only for thoroughbred horses, but also for human beings.
The aim of this paper is to investigate the effect on the physiological response of fluid ingestion before walking in a swimming pool. Nine healthy students were candidates for this study. First of all, they were divided into two groups water ingestion (W(+))(300Ml) before pool walking group and no water drinking (W(-)) beforehand. Body temperature was measured in the tympanic space and venodilation was measured in the fingers. Walking conditions were 3 km/h for 1,750 m in an indoor pool with a water temperature of 29.7±0.5°C, at a room temperature of 25.4±1.4°C and relative humidity of 79.4±4.3%. The pool was 25 m in length and 1.0 m deep. The following results were obtained: The values for tympanic temperature in the W(-) group were significantly higher than that of pre-walking (p<0.05). Vasodilation of the veins in the fingers significantly expanded in the group of W(+)(p<0.05). The values of systolic blood pressure(SBP) in the W(-) group decreased significantly in comparison partially (p<0.05). We could conclude that fluid ingestion before walking in a swimming pool has a good effect on tympanic temperature, venous dilation and systolic blood pressure.
Keeping upright stance is important to other complex motions like locomotion and running for human beings. The mechanism of balance-keeping control in upright standing is still unknown. This study was conducted to analyze the body sway by using a simple PID (proportional, integral, derivative) control model and to investigate the influence of vision on its gains. Ten healthy subjects took part in the study. The upright body was modeled as one-link inversed pendulum model. While determining the model parameters according to subject's physical statue, the gain of PID parameters, (KP, KD, KI are gains of proportion, derivative, and integral respectively.) could be estimated. Four kinds of visual patterns, (three for central visual field stimulation, one is eyes closed) were designed for visual stimulation. The results showed that the gain of KD was decreased significantly in eyes closed (131.5±37.6 Nms/rad in eyes open and 90.4±26.0 Nms/rad in eyes closed, p<0.001), and, KP, KI were not changed. The results suggested that the PID control model was a promising means for individual balance ability analysis and that the visual effect on balance-keeping control in upright standing was analogized to a damper in the mechanical system.
Leukocytes are divided into two major types, granulocytes and lymphocytes. Granulocytes are activated in number and function under sympathetic nerve stimulation, whereas lymphocytes are activated under parasympathetic nerve stimulation. We analyzed the ratio of leukocytes and the time-domain (%RR50) from R-R interval variability to investigate the differences in autonomic nervous system activity in 10 healthy female subjects (age 51.2±8.7 years). The purpose of this study was to investigate whether or not variation in the ratio of leukocytes in the blood was equivalent to the variation in %RR50, and whether the autonomic nervous system, endocrine secretion and immune mechanism interacted. The subjects were grouped according to the mean values of the ratio of lymphocytes among the leukocytes when in a sitting position. The granulocytes group (GG : 5 persons) had below average values for the ratio of lymphocytes among the leukocytes, and the lymphocytes group (LG : 5 persons) had above average values. The measurements were taken during spontaneous breathing for 15 min at rest, followed by YOGA breathing (voluntary control of abdominal breathing : expiration to inspiration time ratio was 2 to 1) for 15 min and recovery with spontaneous breathing in a sitting position for 30 min. The R-R intervals were measured 8 times for 60 min as well as heart rate (HR), blood pressure (BP), and respiratory frequency (f). Blood was drawn 3 times for 60 min and the erythrocyte·leukocyte·thrombocyte·hemoglobin (Hb) and hematocrit (Hct) levels were examined. The leukocytes were classified as neutrophil, eosinophil, basophil, monocyte or lymphocyte. Furthermore the catecholamine : adrenaline, noradrenaline and dopamine (CA : Adr, Nad and DA), cortisol and immunoglobulin A (IgA) levels were observed. It was confirmed that the variation in the ratio of leukocytes was equivalent to the variation of %RR50, both of GG and LG. With regard to the characteristics of each group, the following were observed : GG showed an accelerated trend of sympathetic nervous system activity and high values were obtained in the measurements of BP, Adr, Nad, cortisol and low values in the measurements of IgA and %RR50 at rest. LG showed an accelerated trend of parasympathetic nervous system activity and high values were obtained in the measurements of IgA and %RR50 and low values in the measurements of BP, Adr, Nad, and cortisol at rest. LG was characterized by consistently low blood pressure and respiratory frequency. These results indicated that there were natural differences in each subject in their autonomic nervous system activity and physiological function at rest. However, it was found that YOGA breathing (voluntary control of abdominal breathing) enhanced vagal modulation of the heart rate and the lymphocytes gradually increased in subjects who showed an accelerated trend of sympathetic nervous system activity. During all of the trials, it has been shown that activities of the autonomic nervous system, endocrine secretion and immune mechanism interacted. It was suggested that the distribution of leukocytes is not only related to immunity, but also is an indication of physical and mental stress and physical condition.
Cross-sectional growth and developmental data on physique and motor fitness in preschool children aged 3.75 to 6.25 years were obtained at ten year intervals between 1969 and 1999. This study attempted to verify the secular trends in growth and development in preschool children (four- and five-year-old boys and girls) using the wavelet interpolation method (WIM). Height and weight were used for physique, and 20 m dash, standing long jump, and tennis ball throwing for motor fitness. The growth distance and velocity curve for physique and motor fitness of children aged 3.75 to 6.25 years in 1969, 1979, 1989, 1999 were described using the WIM, and the age at local peak velocity (LPV) was derived from the velocity curve. The age at LPV of the physique in boys and girls shifts annually, as does that of motor fitness. Thus, the maturation level was inferred to be early. However, no clear association was shown with age at LPV of physique and motor fitness. A trend was shown for the velocity curve to become more gradual on an annual basis for motor fitness, and a decrease in exercise stimulation of the body was inferred to reflect individual biological variation.
The purpose of this study was to investigate changes in sarcoplasmic reticulum (SR) Ca2+-sequestering capacity in rat fast-twitch plantaris (PL) and slow-twitch soleus (SOL) muscles during recovery after high-intensity exercise. The rats were subjected to treadmill runs to exhaustion at the intensity (10% incline at 50 m/min) estimated to require 100% of maximal O2 consumption. The muscles were excised immediately after exercise, and 15, 30 and 60 min after exercise. Acute high-intensity exercise evoked a 27 % and 38 % depression (P<0.05) in SR Ca2+-uptake rate in the PL and SOL, respectively. In the PL, uptake rate remained lower (P<0.05) at 30 min of recovery but recovered 60 min after exercise. These alterations were paralleled by those of SR Ca2+-ATPase activity. On the other hand, SR Ca2+-uptake rate in the SOL recovered 15 min after exercise. Unlike the PL, discordant time-course changes between SR Ca2+-ATPase activity and uptake occurred in the SOL during recovery. SR Ca2+-ATPase activities were unaltered with exercise and elevated (P<0.05) by 25, 30 and 30% at 15, 30 and 60 min of recovery, respectively. These results demonstrate that SR Ca2+-sequestering ability is restored faster in slow-twitch than in fast-twitch muscle during recovery periods following a single bout of high-intensity exercise and suggest that the rapid restoration of SR Ca2+-sequestering ability in slow-twitch muscle could contribute to inhibition of disturbances in contractile and structural properties that are known to occur with raised myoplasmic Ca2+ concentrations.
The purpose of this study was to investigate the circulation responses (heart rate (HR), systolic blood pressure (SBP) and second derivative of photoplethysmogram waveform index (|d/a|)) during 90 seconds continuous isometric contraction on trunk muscle. Subjects were 10 healthy male (22±1 years). Subjects performed 90 seconds continuous isometric contraction on Rectus Abdominus. Contraction intensity was 55.4±13.8% maximal voluntary contraction. HR and SBP were a significant increase after contraction beginning, immediately. |d/a| (one of the peripheral blood vessel contraction index) was a significant increase at 60 seconds after contraction beginning. After that, HR was an increase more, |d/a| showed a decline tendency. But, SBP was an increase more. The followings are suggestive by these results. When the contraction beginning, HR was increased immediately by central command, muscle mechano reflex and so on. The other hand, the peripheral blood vessel contraction was late by the accumulation of metabolism product from active muscle was late. When the prolong contraction time, the peripheral blood vessel was extension. But, SBP was increased more by increasing the cardio output, muscle tension and so on.
Various statistical techniques are used increasingly by researchers in the fields of physical fitness and sports medicine. Nowadays, most researchers have a tendency to rely on statistical packages and distant memories of poorly understood lectures on statistics. Researchers need not know how to calculate the statistics from the data but are required to select the most appropriate technique from the statistical packages and interpret the statistical results accurately. Therefore, this lecture focused on proper usage of statistical techniques and appropriate interpretation of statistical results for the researchers of physical fitness and sports medicine.