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.

Comparison of isometric ankle strength between females with and without patellofemoral pain syndrome.

INTRODUCTION: Proximal and distal influences on the knee may be related as etiological factors of patellofemoral pain syndrome (PFPS). The distal factors include subtalar excessive pronation as well as medial tibia rotation, but no study has investigated whether ankle weakness could lead to alterations that influence the patellofemoral joint. Thus, the purpose of this study was to compare the ankle dorsiflexor and invertor muscles strength, as well as rearfoot eversion and the Navicular Drop Test (NDT) in females with PFPS to a control group of females of similar demographics without PFPS. METHODS: Forty females, between 20 and 40 years of age (control group: n=20; PFPS group: n=20) participated. Rearfoot eversion range of motion and the NDT were assessed for both groups. The Numeric Pain Rating Scale and the Anterior Knee Pain Scale were used to evaluate the level of pain and the functional capacity of the knee during activities, respectively. Isometric ankle dorsiflexor and invertor strength was measured using a handheld dynamometer as the dependent variable. RESULTS: The isometric strength of the dorsiflexor and invertor muscle groups in females with PFPS was not statistically different (P>0.05) than that of the control group. There was no statistically significant difference between groups for rearfoot eversion and NDT (p>0.05). DISCUSSION/CONCLUSION: These results suggest that there is no difference between isometric ankle dorsiflexion and inversion strength, the NDT, and rearfoot eversion range of motion in females with and without PFPS. LEVEL OF EVIDENCE: 3-b.

Efficacy of graded activity versus supervised exercises in patients with chronic non-specific low back pain: protocol of a randomised controlled trial.

BACKGROUND: Low back pain is a relevant public health problem, being an important cause of work absenteeism worldwide, as well as affecting the quality of life of sufferers and their individual functional performances. Supervised active physical routines and of cognitive-behavioral therapies are recommended for the treatment of chronic Low back pain, although evidence to support the effectiveness of different techniques is missing. Accordingly, the aim of this study is to contrast the effectiveness of two types of exercises, graded activity or supervised, in decreasing symptoms of chronic low back pain. METHODS/DESIGN: Sample will consist of 66 patients, blindly allocated into one of two groups: 1) Graded activity which, based on an operant approach, will use time-contingent methods aiming to increase participants' activity levels; 2) Supervised exercise, where participants will be trained for strengthening, stretching, and motor control targeting different muscle groups. Interventions will last one hour, and will happen twice a week for 6 weeks. Outcomes (pain, disability, quality of life, global perceived effect, return to work, physical activity, physical capacity, and kinesiophobia) will be assessed at baseline, at treatment end, and three and six months after treatment end. Data collection will be conducted by an investigator blinded to treatment allocation. DISCUSSION: This project describes the randomisation method that will be used to compare the effectiveness of two different treatments for chronic low back pain: graded activity and supervised exercises. Since optimal approach for patients with chronic back pain have yet not been defined based on evidence, good quality studies on the subject are necessary. TRIAL REGISTRATION: NCT01719276.