The purpose of this study was to examine relationships between age-associated loss of muscle mass (sarcopenia), muscle strength (dynapenia) and physical functions in community-dwelling older adults. This cross-sectional study included 400 older adults (73.7 ± 5.2 years) conducted in Kasama city, Ibaraki prefecture (2011-2012). Participants were classified to following four groups based on their appendicular skeletal muscle mass (sum of skeletal muscle mass in the arms and legs evaluated by bioelectric impedance analysis), and appendicular skeletal muscle strength (grip strength for upper extremity and peak reaction force during sit-to-stand movement for lower extremity): sarcopenic-dynapenia (SD), dynapenia (D), sarcopenia (S) and non-S/non-D (NSD). We evaluated participants’ physical function using 7 physical performance tests. We conducted partial correlation analysis and analysis of covariance adjusted for age, medical history of knee pain and low back pain. Appendicular skeletal muscle strength was significantly associated with all physical performance tests in both genders (P < 0.05), however appendicular skeletal muscle mass index was not. As for the results of analysis of covariance, one-leg balance with eyes open, standing time from long sitting position, functional reach, 5-repetition sit-to-stand, timed up and go, and 5-m habitual walk were significantly poorer in SD and D groups than S and NSD groups in men. On the other hand, standing time from long sitting position, functional reach, 5-repetition sit-to-stand, timed up and go, and 5-m habitual walk were significantly poorer in D group than the S group and NSD group in women. These results suggest that dynapenia has a stronger relationship with poor physical performance than sarcopenia.
Oxygen demand (OD) during supramaximal exercise is estimated by using linear relationship between power output (PO) and VO2 in submaximal exercises. In rowing, stroke rate (SR) rises curvilinearly against PO and achieves to about twofold in supramaximal exercise compared with submaximal. However it’s not considered in estimating. The aim of this study was to investigate the estimating method of OD in rowing with considering the influence of increasing SR. Ten male collegiate rowers (age: 20.6± 2.8 yrs, height: 174.7± 4.9cm, weight: 71.1±8.9 kg) participated in this study. They performed submaximal exercise tests in normal condition (N-Con) and increased SR condition (SR-Con) to estimate OD during 90 seconds rowing test that rowed in same PO of their 2000 m time trial. In N-Con, subjects freely chose SR in each stage. In SR-Con, SR was fixed as increasing linearly against PO. Moreover, we tried to correct OD by using physical activity level that determined by integrals of absolute value of the accelerometer output (IAA). OD estimated in SR-Con (ODSR:7.0 ± 0.8 lO2Eq) and corrected by IAA (ODIAA: 7.0 ± 0.7 lO2Eq) were significantly larger than OD in N-Con (OD: 6.6 ± 0.8 lO2Eq). In addition, there was not significant difference between ODSR and ODIAA, and they showed significant higher intra-class correlation coefficient (ICC (1, 1) = 0.93). These results suggested that OD in rowing is able to be corrected by fixing SR as linear increasing against PO, or using IAA.
This study aimed to examine the turn characteristics in the multistage 20-m shuttle running test and to investigate method of define to turn characteristics by individual differences among rugby players. Fifteen university rugby players and 4 university long distance runners underwent the multistage 20-m shuttle running test. The head of each subject was digitized and its two-dimensional coordinate data was reconstructed by using the direct linear transformation method. The running locus and acceleration during the turns in the shuttle were calculated from the two-dimensional data. The turning locus of the rugby players was different from that of the long distance runners. Almost all the rugby players turned with a linear locus, whereas all long distance runners, in contrast, turned with an ellipsoidal locus. However, there were no individual differences among the rugby players. Therefore, using mixed models assessed difference in increases of acceleration among individuals. The results of model comparison suggest that the turn characteristics during shuttle running were determined by increases of acceleration during the turn because individual differences have an effect on this particular characteristic. Thus, in the multistage 20-m shuttle running test, an account of the turn characteristics was important, with the exception of the number of shuttles.
In this article, the authors describe the historical changes that have taken place in hand and back-strength dynamometers in Japan, based on important testimonies and documents; they list the existing dynamometers. The back-strength dynamometer resembles the hand dynamometer in structure and function, and hence, they are often developed together. The dynamometers manufactured by Takei Kiki Kogyo have been widely used since the Tokyo Olympics in 1964; however, those manufactured by Yamakoshi Kosakusho, Shimadzu Corporation, and Ando Kenkyusho have been in use in the Taisho era and at the beginning of the Showa era. The dynamometers were imitations or modified products of European and American apparatuses. Through a project undertaken by the Japanese Psychological Association to investigate classical experimental apparatuses, the authors found several imported goods and prewar domestic products, which are stored in few Japanese universities. The authors conjecture that a dynamometer was first used in Japan in the early days of the Meiji era when G.A. Leland visited Japan and supervised a physical fitness test.
The purpose of this study was to clarify the changes in intra-abdominal pressure (IAP) and trunk muscle activity during front crawl swimming at submaximal and maximal swimming velocities. Subjects were 10 female collegiate recreational swimmers. All subjects performed front crawl swimming at very slow, normal, and maximal velocities for 20m. Swimming velocity (V), stroke rate (SR), and stroke length (SL) were measured as swimming performance indices. In addition, the IAP and EMG of the rectus abdominis (RA), erector spinae (ES), and transversus abdominis – internal oblique (TrA-IO) were measured as indices of trunk muscle activity. IAP was taken as the difference between the minimum and maximum values, and EMG was reported as the mean of 2 stable front crawl stroke cycles measured as root mean square values. There were significant differences in V and SR among all velocities. However, there were no significant differences in SL, IAP, and RA. These results suggested that recreational swimmers increase their swimming velocity without co-contraction of the trunk muscles