Dynamic postural stability and muscle strength in patellofemoral pain: Is there a correlation?

BACKGROUND: Although females with patellofemoral pain (PFP) show a decrease in hip and knee muscle strength, there is a lack of studies that associates this with postural stability. The purpose of this study was to assess the dynamic postural stability and muscle strength in the hips and knees of females with and without PFP, and to verify the association between the postural stability and the muscle strength in the PFP group. METHODS: Two groups were tested: one with 25 PFP and one with 25 asymptomatic. Postural stability was evaluated during stepping up down tasks using a force platform to determine the center of pressure (COP) excursion and velocity. A handheld dynamometer was used to assess the muscles strength. The correlation analysis was conducted between the COP variables and the muscle strength. RESULTS: The PFP group demonstrated greater total and medial-lateral COP displacement (8887.7±761.7 vs. 8129.4±691.9mm, P<0.001; 32.3±5.5 vs. 21.7±2.7mm, P<0.001) and a higher total of medial-lateral COP velocity (22.2±5.2 vs. 17.0±1.6 P=0.001). The PFP group showed weaknesses in all muscles (P<0.05), and there was a good positive correlation between the anterior-posterior displacement and the velocity of the extensor hip muscle (r=0.52, P<0.01; r=0.55, P<0.001). CONCLUSIONS: Subjects with PFP have frontal dynamic postural stability deficit and show an association between hip extensor and sagittal plane stability.

The short-term effects of graded activity versus physiotherapy in patients with chronic low back pain: A randomized controlled trial.

BACKGROUND: Chronic low back pain is one of the most common problematic health conditions worldwide and is highly associated with disability, quality of life, emotional changes, and work absenteeism. Graded activity programs, based on cognitive behavioral therapy, and exercises are common treatments for patients with low back pain. However, recent evidence has shown that there is no evidence to support graded activity for patients with chronic nonspecific low back pain. AIM: to compare the effectiveness of graded activity and physiotherapy in patients with chronic nonspecific low back pain. METHODS: A total of 66 patients with chronic nonspecific low back pain were randomized to perform either graded activity (moderate intensity treadmill walking, brief education and strength exercises) or physiotherapy (strengthening, stretching and motor control). These patients received individual sessions twice a week for six weeks. The primary measures were intensity of pain (Pain Numerical Rating Scale) and disability (Rolland Morris Disability Questionnaire). RESULTS: After six weeks, significant improvements have been observed in all outcome measures of both groups, with a non-significant difference between the groups. For intensity of pain (mean difference = 0.1 points, 95% confidence interval [CI] = -1.1-1.3) and disability (mean difference = 0.8 points, 95% confidence interval [CI] = -2.6-4.2). No differences were found in the remaining outcomes. CONCLUSION: The results of this study suggest that graded activity and physiotherapy showed to be effective and have similar effects for patients with chronic nonspecific low back pain.