The effect of closed-kinetic chain exercises and open-kinetic chain exercise on the muscle activity of vastus medialis oblique and vastus lateralis.

Patellofemoral pain syndrome (PFPS) is one of the most prevalent musculoskeletal conditions of the lower limb. The muscle imbalance between the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles is one of the main factors leading to the development of PFPS. The disparity in research and the necessity to add to the existing literature base led to the development of this study. The aim of this study was to investigate the effect of 2 closed kinetic chain exercises and 1 open kinetic chain exercise on VMO and VL muscle activity. Twenty-two healthy asymptomatic individuals participated in this study. The surface electromyography (EMG) of VMO and VL was measured and used to calculate the VMO:VL ratio during 3 different quadriceps-strengthening exercises (a double leg squat with isometric hip adduction exercise, an open kinetic chain knee extension exercise, and a lunge exercise). The double leg squat with isometric hip adduction exercise was shown to produce a significantly greater VMO:VL ratio (1.14:1) than the other 2 exercises (p = 0.015 and p = 0.005). The open kinetic chain knee extension exercises produced significantly greater activation of VL than the lunge exercise (p = 0.001 and p = 0.036). The lunge exercise produced the VMO:VL ratio (1.18:1) closest to the idealized ratio of 1:1. Potential clinical recommendations can be made proposing the lunge exercise as a key tool in early rehabilitation when restoring preferential VMO:VL ratio is essential. The double leg squat with isometric hip adduction exercise would be useful in maintaining correct patella tracking and selectively strengthening VMO.

Effects of respiratory muscle weakness on daily living function, quality of life, activity levels, and exercise capacity in mild to moderate Parkinson's disease.

OBJECTIVE: To investigate respiratory muscle strength in mild to moderate Parkinson's disease in comparison with prediction equations and age-matched controls. To identify correlations between respiratory muscle strength and daily living function, activity levels, quality of life, and exercise capacity. DESIGN: A total of 66 participants with Parkinson's disease and 32 age-matched, healthy controls participated. Respiratory mouth pressures (representing respiratory muscle strength) were compared with predicted values. A comparison was also made between participants with Parkinson's disease and age-matched controls. Respiratory mouth pressures were correlated with results of the Barthel index (daily living function), a modified Baecke activity questionnaire (activity levels), the Parkinson's disease questionnaire (quality of life in Parkinson's disease), peak heart rate, peak oxygen consumption, blood lactate thresholds, and the number of stages completed during an incremental cycle ergometer test (representing exercise capacity). RESULTS: Respiratory mouth pressures were significantly lower (P < 0.05) in the Parkinson's disease group, but this did not influence the measures of daily living function, activity levels, and quality of life. Respiratory mouth pressures correlated with lactate thresholds (r = 0.308, P < 0.01) and the number of completed stages of the cycle ergometer test (r = 0.490, P < 0.01). CONCLUSIONS: In mild to moderate Parkinson's disease, there is a significant weakness of the respiratory muscles. This can affect the individual during exercise but has no apparent effect on activities that do not require a large effort of the respiratory muscles.