The purpose of this study was to clarify the effect of daily physical activity on maintaining mobility in the elderly. The subjects were residents (between 65 and 84 years old) in Shizuoka Prefecture. The first survey was carried out with a questionnaire composed of physical independency and daily physical activity in 1999 (1st survey). The second survey was carried out with the same questionnaire 3 years later in 2002 (2nd survey), and 11,462 people who returned both of them were analyzed. The difference from the 1st survey to the 2nd survey was evaluated on the changes of mobility. In addition we applied logistic regression analysis to evaluate the influence of mobility changes (independent variable) on daily physical activity (dependent variable). The analysis showed that the daily physical activity influenced the change of mobility. Among the daily physical activity, walk speed was the most influenced the changes of mobility. These results indicate that the daily physical activity was important in the maintaining mobility in the elderly.
Using a recumbent-type cycle ergometer, we investigated the validity of using a stepwise increment in load within a bout of exercise to determine the torque-velocity relation of pedaling movement. Fourteen healthy men and women performed pedaling exercise at their maximal effort on a recumbent-type cycle ergometer with an electromagnetic load control. Two types of loading were used: a conventional method (C) in which a varied load was applied to each bout independently; a “stepwise loading” method (S) in which the load was successively increased within a bout. In S, the external load was not applied initially, but when axial rotation velocity reached a maximum, it was increased in a stepwise manner until the velocity declined to 30% of the maximum. The torque-velocity relations obtained by both methods (C and S) were well described with linear functions and substantially identical, indicating that the present stepwise loading method is useful for a rapid evaluation of lower-limb muscle function.
The purpose of this study was to investigate kinetic characteristics such as ground reaction forces (GRFs) and joint torques of the lower limb joints in downhill running for distance runners on overground. Six male distance runners were asked to run at three running speeds (3.3, 4.2, and 5.0 m/s) on the slopes of different grades (0, -3.2, -6.4, and -9.1 %) in which two force platforms were mounted. A two dimensional link model was used to calculate joint torques and joint powers of the lower limb joints. In spite that the downward velocity of the CG at the foot contact increased consistently as the grade increased, the impact peak of vertical GRF and the peak loading rate defined as maximum rate of change of the vertical GRF did not increase consistently as the grade increased. The runners on steep downhill conditions would be able to avoid excessive impact load by contacting with the ground in more extended hip position and increasing knee flexion velocity after the foot contact. The negative power of the knee after the foot contact was larger for -9.1 % downhill than the level condition, which revealed the eccentric load on the knee extensors increased in the steep downhill condition. The hip extensors exerted negative power with hip flexion just after the foot contact in -6.4 and -9.1 % downhill conditions so that the runners could absorb the impact force and mechanical energy.
The purpose of this study was to investigate the effects of passive ankle and knee joint motions on the length of fascicle and tendon of the gastrocnemius muscle. The ankle joint was passively moved from maximal dorsiflexed position to maximal plantar flexed position, while the knee joint was fixed at 0° (fully extended position). Also, the knee joint was passively extended from 90° to 0°, while the ankle joint was fixed at 0° (neutral position). In each test condition, lengths of fascicle and external tendon of the medial gastrocnemius were measured by ultrasonography. The length of external tendon was significantly changed by the ankle joint motion, but not by the knee joint motion. This demonstrates that the length of the external tendon distal to the muscle belly is influenced only by the angle changes of the joint distal to the gastrocnemius muscle. The change in fascicle length during the knee joint motion was significantly larger than during the ankle joint motion in spite of a similar length change of total muscle-tendon complex between the two motions. This demonstrates that fascicles located proximally to the external tendon are more influenced by the angle changes of the joint proximal to the gastrocnemius muscle. These results reveal that angle changes of each joint located in the proximal and distal parts of a biarticular muscle have different effects on the length of fascicle and external tendon.
This study aimed to investigate the mechanisms of mechanical work and power enhancement of muscle-tendon complex (MTC) in rebound exercise by quantifying in vivo behavior of fascicle and tendinous tissue of human medial gastrocnemius muscle (MG). Subjects jumped on a sledge apparatus using only ankle joint with the following two conditions: plantar flexion without counter movement (PFJ) and rebound jumping from a height of 26 cm (RJ). The behavior of fascicle and tendinous tissue of MG in vivo was determined using ultrasonography. The relative contribution of tendinous tissue to the mechanical work of MTC during plantar flexion phase (PF phase) was 85% in RJ. The maximal mechanical power of tendinous tissue during the PF phase in RJ was about three times greater compared to that in PFJ. There was no significant difference in the mechanical power of fascicle during PF phase between the two conditions, while the mechanical work of fascicle in PFJ was less than that in the PF phase of RJ. In RJ, fascicle was stretched during the dorsiflexion phase. These findings indicated that, in rebound exercise using ankle joint, (1) the enhancement of mechanical work and power of MTC was due to the reuse of elastic energy stored in tendinous tissue during dorsiflexion phase, and (2) fascicles were stretched during dorsiflexion phase.
The aim of this study was to compare the radius of curvature and the estimated head speed as measured by sensors attached to a hammer with those calculated by video image analysis. The participant was the Japanese record holder(83m47). He threw a hammer with sensors which measured the force exerted along the length of the hammer cable using a tension meter made of a metal plate to which strain gauges were affixed, and the angular velocity perpendicular to the hammer cable using two IC accelerometers whose axes were aligned together with the hammer cable. The radius and speed obtained using the sensors were similar to those obtained from video analysis in values, but were slightly out of phase. This is because measuring the angular velocity by sensors eliminates translational motion and only produces results for rotational motion. The length of time required to obtain these results was shortened by the use of a hammer with sensors. Therefore, the system using sensors attached to a hammer will enable athletes and coaches to interpret the data about each throw while it is still fresh in their minds.
The relationships between critical power (CP) and anaerobic work capacity (AWC), and the rowing performance in a 2000 m ergometry rowing effort were assessed. Nine male university rowers performed three tests: 1) critical power determination, 2) 2000 m simulated rowing and 3) VO2max test. The CP and AWC were determined from the regression between work and time to exhaustion, derived from three exhaustive trials at 70, 60, and 50% of the maximal power. The 2000 m simulated rowing performance was higher for subjects with higher CP independent of AWC. The mean power throughout the 2000 m simulated rowing correlated significantly with CP (r = 0.87) and the absolute VO2max (r = 0.71), but not with AWC. CP also influenced the pattern of changes in power over the 2000 m simulated rowing. We conclude that the CP is a useful indicator of rowing performance and may be efficacious for monitoring the training effects in rowing.
Under the rule of the Cheikhs, before Tunisia became a French colony, such traditional sports as El Koura and El'Efga took place at the village community level, but after the introduction of modern sports in accordance with French colonial policy, their existence was threatened. On the other hand, modern sports, particularly football, spread rapidly as the only opportunity for the colonized Tunisians to oppose the western European nations, especially France. As a result of the introduction of modern sports, national organizations were born, crossing regional boundaries; this contributed to a consciousness of being “Tunisian,” that is, to the formation of national identity. It can even be thought that it influenced the later independence movement. After independence from France, the regime of President Habib Bourguiba introduced policies of modernization and centralization, as well as a modern educational system, in the process of forming a national state, and traditional sports, which included many magical elements, were thrown out as being pre-modern and backward, along with religious cultures peculiar to Tunisia, such as worship of the saints and Sufism. Modern sports, however, came to be positioned as having the function of forming national identity in the international sphere: that is, forming a national identity in awareness of the nation as a part of the international community. However, in 1987, under the new regime of President Ben Ali, a new policy of creating national identity was created, rooted in a unique traditional culture modeled on a pre-Islamic culture.
The purpose of this study was to determine a predictive validity of an expired gas dynamics (EGD) model during intermittent exercise using by system dynamics, individually. Five healthy males performed an incremental exercise test to determine maximal oxygen uptake (VO2max) and anaerobic threshold (AT). Subjects then undertook intermittent load tests with three degrees of intensity (60 %VO2max, 80 %VO2max and 100 %VO2max) using cycle ergometer. The EGD model was constructed using the incremental load test data. Data obtained from intermittent load tests were used as validity criterion of simulation. In simulation of the EGD model, oxygen uptake (VO2), carbon dioxide output (VCO2) and lactate (La) showed significantly high determination coefficient to validity criterion (R2 > 0.84, P < .05). In the comparison of simulation errors, there were no significant differences in VO2, VCO2 and La during 60 %VO2max intensity exercise. At recovery period of 80 %VO2max and 100 %VO2max intensities simulation errors of VO2 and VCO2 were significant. It was inferred that time constant of VO2 kinetics was slowed down by effect of excess post-exercise oxygen consumption (EPOC). Conclusively, the EGD model for individual was valid and accurate predictor of VO2, VCO2 and La during moderate intermittent load exercise.
Scales to measure ‘enjoyment’, ‘belief of benefit’, and ‘psychological barriers’ to exercise and sports of junior high and high school students were developed using the item response theory (IRT). The purpose of this study was to construct the item pools for the scales and to estimate their validity. Eight hundred and seventy junior high school students and 675 high school students participated in the study. They answered a questionnaire including items about exercise habits, stage of change for exercise, enjoyment, benefit, and psychological barriers. IRT parameters—discrimination power and difficulty level—were estimated using the graded response model of IRT, and characteristics of items were investigated. The developed item pools of the scales included items with diverse parameters; 31 items for enjoyment, 27 items for benefit, and 17 items for psychological barriers. In order to investigate the validity of the scales, means of scale score for subjects were compared between the group participating exercise or sports (exercise group) and the non-participating group (non-exercise group). The results showed significantly higher enjoyment and benefit (t-test; p<0.001), and lower psychological barriers (p<0.001) in exercise group. The one-way analysis of variance for the scale score was executed with the stage of change as the factor. The scale scores of all three scales were significantly related to the stage of change (ANOVA; p<0.001). Since the scales correlated with each together, a t-test between the exercise and non-exercise group was executed for the original factor of a scale (residual) while controlling the other two scale scores by multi-regression analysis. The significant differences between groups were observed for the enjoyment and psychological barrier scales. The results indicate the scales have concurrent validity.
The purposes of this study were: (1) to describe students' physical activity level (PAL), students' learning behavior (LB), students' formative class evaluation (FCE) score during 2 fitness units; (2) to compare the students' PAL, the students' LB, and the students' FCE in both units (aerobic and non-aerobic units); and (3) to check the relationship among students' PAL, students' LB, and students' FCE inside the fitness units. Data were collected from PE classes for 6th graders at T and K elementary school in Ibaraki Prefecture (Japan). The classes were videotaped using 12 seconds interval (GTS recording format), and evaluated by using 2 measures: (1) students' FCE questionnaire, and (2) pedometer or Lifecorder. Results indicated that: (1) the aerobic unit provided students with significantly higher PAL (averagely 2498.6 steps, 2.47 levels of intensity, and 54.17% of MV-PAL engagement) than the non-aerobic unit (averagely 1243.0 steps, 1.17 levels of intensity, and 31.1% of MV-PAL engagement); (2) the aerobic unit provided students with significantly more learning engagement (averagely 86.4%) than the non-aerobic unit (averagely 50.3%); but (3) students in the aerobic unit give FCE score to their PE classes significantly lower (averagely 2.72) than those in the non-aerobic unit (averagely 2.88); (4) although it was not significant because of less number of data, there were clear relationships in between students' PAL and students' FCE and in between students' MV-PAL engagement and students' LB inside both units, but the relationship between students' LB and students' FCE score was not clear; (5) the relationships tendency inside the aerobic unit was more clear than those in the non-aerobic unit; and (6) thus, related the results from previous study, it was fail to reconfirm the close relationships in between variable PAL and LB, and in between variable PAL and FCE, but it was found more clear relationship between variable PAL inside motor learning (A2) episode of aerobic unit and FCE.
The purpose of this study was to examine the effects of a group contingency strategy on student behaviors in elementary physical education classes. The study was conducted in an elementary school within metropolitan Korea. Eighty 6th-grade students (2 classes) and one teacher participated in this study. To investigate the effects of group contingency (intervention), two classes were separately designated as the experimental group (n=40) and control group (n=40). A multiple-baseline design across student target behaviors was used to determine the effects of exposure to behavioral intervention on student behaviors. Comparison was also made with the absence of the intervention. Data collected through each class observation and videotaping of 17 lessons of ball game and gymnastics showed that a group contingency strategy was effective in increasing the percentage of on-task behavior (motor activity) and reducing student waiting time and off-task in the experimental group. Compared to the experimental group, the control group showed no significant behavioral changes. Results also showed that the strategy was effective in decreasing inappropriate behavior and increasing appropriate behavior, which consequently builds on new forms of behavior by applying these contingencies consistently with effective consequences.
The purpose of this study was to determine the validity of a dynamic prediction (DP) model that predicts oxygen uptake (VO2) during supra maximal intermittent (SMI) exercise based on non-linearity of VO2 dynamics in comparing a heart rate (HR) model. Five male participants (20±1 yrs) performed incremental exercise test used by cycle ergometer for the aim of developing individualized HR- VO2 and workload- VO2 regression equations. The DP model was defined as a first order system to workload- VO2 relationship. Participants then completed SMI test corresponding at 140 % VO2max while HR and VO2 data were collected continuously for 20 min. The HR model predicted VO2 during SMI test used by HR, while the DP model also predicted VO2 from workload. Predicted values (VO2) were compared with measured values (VO2) obtained via a metabolic measurement system. The DP model showed a significantly higher relationship with measured VO2 (R2 = 0.95, SEE = 149 ml/min) in comparison with the HR model (R2 = 0.83, SEE = 275 ml/min). The HR model showed significant systematic error (r = 0.41, P < .05), whereas the DP model did not (r = 0.06, P > .05). For comparison of prediction errors of both models, the error of the DP model (-1.3±8.8 %) was significantly smaller than the HR model (-8.0±16.5 %). The DP model also accurately estimated total energy expenditure. Therefore, the DP model is an accurate predictor of VO2 during supra maximal intermittent exercise.
The goal of this study was to investigate the expression of angiogenesis-associated genes in heart tissue in response to short-term exercise. Twenty-six male mice were divided randomly into sedentary and swimming-trained groups. Mice swam without a load for 50 min/day. Swimming training was carried out in six 50-min training sessions over a 9-day period. The mRNA for angiogenesis-related factors, including hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), fms-like tyrosine kinase (Flt-1), and kinase insert domain-containing receptor/fetal liver kinase-1 (KDR/Flk-1), was analyzed using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Also, semi-quantitative RT-PCR was carried out to further determine which of the VEGF isoforms changed in heart tissue. Swimming training significantly increased HIF-1α (1.5-fold), VEGF (2.2-fold), Flt-1 (1.9-fold), and KDR/Flk-1 (2.4-fold) mRNA levels. Also, VEGF188 and VEGF164 mRNA levels were elevated but their relative abundance was the same as in sedentary mice. These results suggest that short-term swimming training stimulates not only the expression of VEGF mRNA, which may be due to increases in VEGF188 and VEGF164 mRNAs, but also Flt-1 and KDR/Flk-1 mRNAs in the heart.
The purpose of this study was to estimate genetic and environmental effects on physical fitness and motor performance. Subjects for this study were 90 pairs of monozygotic twins (MZ) and 68 pairs of dizygotic twins (DZ), a total of 316 subjects between 10 to 15 years old. Six items were used for physical fitness and motor performance data: grip strength, sit-ups, sit and reach, side step, 50 meter run and standing broad jump. The correlation analysis and the model-fitting analysis have been done based on the type of each set of twins. For the model-fitting analysis, models that give effects of additive genes (A), nonadditive genes (D), common environment (C), and specific environment (E) on phenotypes of physical fitness and motor performance have been applied. The following could be presumed as a result of a correlation analysis: the results showed for the grip strength and the side step that rMZ was greater than rDZ, and rDZ was greater than half of rMZ, therefore, it could be stated that there were effects from additive genetic and common environmental factors. The results from the sit-ups and the 50 meter run showed that rMZ and rDZ were almost equal to each other, therefore, it could be stated that there was no genetic effect. The correlation ratio of rMZ and rDZ was 2:1 for the category of sit and reach, therefore, the resemblance among MZ was from the genetic effect only. As for the standing broad jump, rDZ was smaller than half of rMZ, therefore, there were effects of additive genetic and nonadditive genetic factors. From the results of the model-fitting analysis, the following could be stated: the best fitting models for grip strength, sit and reach, and the standing broad jump, where additive genetic and specific environmental factors affect phenotypes, were the AE model, and the coefficient of determination of additive genetic factor, at between 52.2% and 76.9%, was relatively high. For the side step, where additive genetic, common environmental and specific environmental factors have effects on phenotypes, the best fitting model was the ACE model, and each coefficient of determination was 32.4%, 39.4% and 28.1%. No genetic effect was observed for sit-ups and the 50 meter run. The coefficient of determination for sit-ups was 51.1% in a common environment and was 48.9% in a specific environment. S-CE was the best fitting model for the 50 meter run, where the effect varies depending on sex, and the coefficient of determination for boys were 75.5% for common environment and 24.4% for specific environment, whereas those for girls were 53.0% and 46.9% respectively.