The purpose of this study was to examine the relationship between field-based simplified approaches and knee extensor muscle strength/size in young men. Knee extensor muscle thickness （MT） of 104 healthy university ...The purpose of this study was to examine the relationship between field-based simplified approaches and knee extensor muscle strength/size in young men. Knee extensor muscle thickness （MT） of 104 healthy university freshmen was measured at the anterior half of thigh length; maximal voluntary isometric contraction （MVIC） was measured when subjects performed knee extension. Field-based simplified approaches [sit-to-stand, standing long jump （SLJ）, handgrip and upper-leg-50% （thigh） girth] were also measured. MVIC was correlated with SLJ （r = 0.361, P 〈 0.001）, handgrip （r = 0.523, P 〈 0.001） and thigh girth （r = 0.401, P 〈 0.001）, but not with the sit-to-stand test （r = 0.126, P 〉 0.05）. MT was correlated with handgrip （r = 0.317, P 〈 0.001） and thigh girth （r = 0.632, P 〈 0.001）, but not with SLJ （r = 0.038, P 〉 0.05） or the sit-to-stand test （r = 0.145, P 〉 0.05）. A stepwise multiple-regression analysis was applied to the predictor thigh girth to predict knee extensor MT （R2 = 0.399）. To predict knee extensor MVIC, the predictor handgrip, thigh girth and SLJ were applied （R2 = 0.381）. In conclusion, knee extensor muscle strength/size could be evaluated by the field-based simplified approaches, in particular by the thigh girth measurement, which may be major determinant to maintain activities of daily living for healthy young men. However, the 4 field-based simplified approaches appear to be still not of high impact.展开更多
This paper studies the nonstationary filtering problem of Markov jump system under <span style="white-space:nowrap;"><i>l</i><sub>2</sub> - <i>l</i><sub>...This paper studies the nonstationary filtering problem of Markov jump system under <span style="white-space:nowrap;"><i>l</i><sub>2</sub> - <i>l</i><sub>∞</sub> </span>performance. Due to the difference in propagation channels, signal strength and phase will inevitably change randomly and cause the waste of signals resources. In response to this problem, a channel fading model with multiplicative noise is introduced. And then a nonstationary filter, which receives signals more efficiently is designed. Meanwhile Lyapunov function is constructed for error analysis. Finally, the gain matrix for filtering is obtained by solving the matrix inequality, and the results showed that the nonstationary filter converges to the stable point more quickly than the traditional asynchronous filter, the stability of the designed filter is verified.展开更多
文摘The purpose of this study was to examine the relationship between field-based simplified approaches and knee extensor muscle strength/size in young men. Knee extensor muscle thickness （MT） of 104 healthy university freshmen was measured at the anterior half of thigh length; maximal voluntary isometric contraction （MVIC） was measured when subjects performed knee extension. Field-based simplified approaches [sit-to-stand, standing long jump （SLJ）, handgrip and upper-leg-50% （thigh） girth] were also measured. MVIC was correlated with SLJ （r = 0.361, P 〈 0.001）, handgrip （r = 0.523, P 〈 0.001） and thigh girth （r = 0.401, P 〈 0.001）, but not with the sit-to-stand test （r = 0.126, P 〉 0.05）. MT was correlated with handgrip （r = 0.317, P 〈 0.001） and thigh girth （r = 0.632, P 〈 0.001）, but not with SLJ （r = 0.038, P 〉 0.05） or the sit-to-stand test （r = 0.145, P 〉 0.05）. A stepwise multiple-regression analysis was applied to the predictor thigh girth to predict knee extensor MT （R2 = 0.399）. To predict knee extensor MVIC, the predictor handgrip, thigh girth and SLJ were applied （R2 = 0.381）. In conclusion, knee extensor muscle strength/size could be evaluated by the field-based simplified approaches, in particular by the thigh girth measurement, which may be major determinant to maintain activities of daily living for healthy young men. However, the 4 field-based simplified approaches appear to be still not of high impact.
文摘This paper studies the nonstationary filtering problem of Markov jump system under <span style="white-space:nowrap;"><i>l</i><sub>2</sub> - <i>l</i><sub>∞</sub> </span>performance. Due to the difference in propagation channels, signal strength and phase will inevitably change randomly and cause the waste of signals resources. In response to this problem, a channel fading model with multiplicative noise is introduced. And then a nonstationary filter, which receives signals more efficiently is designed. Meanwhile Lyapunov function is constructed for error analysis. Finally, the gain matrix for filtering is obtained by solving the matrix inequality, and the results showed that the nonstationary filter converges to the stable point more quickly than the traditional asynchronous filter, the stability of the designed filter is verified.
