Repeatability and validity of a standardised maximal step-up test for leg function-a diagnostic accuracy study

<p>Abstract</p> <p>Background</p> <p>Objectively assessed physical performance is a strong predictor for morbidity and premature death and there is an increasing interest in the role of sarcopenia in many chronic diseases. There is a need for robust and valid functional tests in clinical practice. Therefore, the repeatability and validity of a newly developed maximal step up test (MST) was assessed.</p> <p>Methods</p> <p>The MST, assessing maximal step-up height (MSH) in 3-cm increments, was evaluated in 60 healthy middle-aged subjects, 30 women and 30 men. The repeatability of MSH and the correlation between MSH and isokinetic knee extension peak torque (IKEPT), self-reported physical function (SF-36, PF), patient demographics and self-reported physical activity were investigated.</p> <p>Results</p> <p>The repeatability between occasions and between testers was 6 cm. MSH (range 12-45 cm) was significantly correlated to IKEPT, (<it>r </it>= 0.68, <it>P </it>< 0.001), SF-36 PF score, (<it>r </it>= 0.29, <it>P </it>= 0.03), sex, age, weight and BMI. The results also show that MSH above 32 cm discriminates subjects in our study with no limitation in self-reported physical function.</p> <p>Conclusions</p> <p>The standardised MST is considered a reliable leg function test for clinical practice. The MSH was related to knee extension strength and self-reported physical function. The precision of the MST for identification of limitations in physical function needs further investigation.</p

Improvement of spatial and temporal coherence of a broad area laser diode using an external-cavity design with double grating feedback [Elektronisk resurs]

We demonstrate a novel technique for narrow bandwidth and highly improved lateral mode operation of a high-power broad area laser diode. The system uses simultaneous feedback from the first diffracted order and the zeroth reflected order of a diffraction grating. The two feedback paths lead to simultaneously improvement of the spectral and spatial properties of the laser diode. The laser system operates in the well-known asymmetric double-lobed far field pattern with the larger lobe being extracted as the output. The bandwidth of the output beam is measured to 0.07 nm, which corresponds to an improvement of a factor of 17 compared to the bandwidth of the freely running laser. The output from the system contains 54% of the energy reaching the grating, or 75% of the power reflected into the zeroth order. The improvements in both the spatial and temporal coherence opens the possibility of using this laser system in applications such as frequency doubling and pumping of optical parametric oscillators. (C) 2004 Optical Society of America