Validation of a method to measure the proprioception of the knee.

INTRODUCTION: Proprioception is an important mechanism in knee stability and function. After an injury like an anterior cruciate ligament (ACL) rupture changes appear in knee proprioception which play a major role in rehabilitation. There are several methods to measure proprioception; the threshold to detect passive motion (TTDPM) is often used to quantify proprioception. In this study the reliability and validity were tested of an apparatus, which measures the TTDPM based on the Lund technique of Fridén and Roberts (Sweden). MATERIALS AND METHODS: Sixteen healthy participants were tested on both legs, from start position 20 degrees and 40 degrees, towards extension (TE) and flexion (TF). The same measurement was repeated 12 (6-21) days later. RESULTS: An overall mean TTDPM of 0.58 degrees (95% confidence interval CI=0.53-0.62 degrees ) was found. Thresholds were different depending on direction of motion and start position. TTDPM in 20 degrees TE (0.51 degrees, CI=0.48-0.56 degrees) and in 40 degrees TF (0.54 degrees, CI=0.50-0.58 degrees ) were significantly lower than TTDPM in 40 degrees TE (0.68 degrees , CI=0.63-0.74 degrees) and in 20 degrees TF (0.58 degrees, CI=0.54-0.63 degrees). Thresholds were rising with age. Women had higher thresholds than men. CONCLUSION: The method is a reliable and valid way to measure proprioception. The next step is to use this method on patients with an ACL-rupture and compare these results with healthy subjects.

Effects of positive expiratory pressure breathing during exercise in patients with COPD.

The effect of breathing with a positive expiratory pressure of 5 cm H2O was investigated in eight patients with COPD (mean [SD]FEV1 = 54 [13] percent predicted). Specific work of breathing (Wsp) and myoelectrical activity of the following respiratory muscles were measured at rest: scalene muscle, parasternal muscle, and abdominal muscles. Minute ventilation (VE), end-tidal CO2 (FETCO2), physiologic dead space ventilation (VD/VT), oxygen uptake (VO2), and carbon dioxide output (VCO2) were measured at rest and during an incremental bicycle exercise test. Dyspnea sensation during exercise was quantified using the CR10 Borg-scale. All measurements were performed with and without positive expiratory pressure (PEP). During PEP breathing at rest mean (SEM) Wsp increased from 0.54 (0.13) J/L to 1.08 (0.10) J/L. The SEM VE decreased from 12.4 (1.0) L/min to 10.5 (1.1) L/min, and SEM VD/VT decreased from 0.39 (0.03) to 0.34 (0.03). There was a tendency for an increased phasic respiratory muscle activity during PEP breathing of all three muscles as compared with undisturbed breathing, but the changes were not statistically significant. During the exercise test with PEP, VE, VD/VT, VO2, and VCO2 were significantly lower, and FETCO2 was significantly higher as compared with the values obtained during the exercise test with undisturbed breathing. Dyspnea sensation during the exercise test with PEP, however, was higher than during the test with undisturbed breathing. The PEP breathing at rest may be useful in patients with COPD as it increases the efficiency of ventilation by reducing dead space ventilation. This beneficial effect also occurs during exercise, but here it is accompanied by increased dyspnea sensation.