The Effect of High Velocity Low Amplitude Hip Mobilization on Strength in Subjects With Lower Extremity Pathology

Introduction: Lower extremity weakness associated with musculoskeletal pathology can cause activity limitations. Physical therapy intervention in the form of exercise is commonly directed at improving muscular performance, however, neuromuscular adaptations may limit the effectiveness of traditional strengthening exercises. Manual therapy techniques have been used as a disinhibitory intervention to increase muscle activation and strength before participating in strengthening exercises or performing functional tasks While there is recent evidence to support joint mobilization as a valuable manual therapy disinhibitory intervention Currently, there is no evidence to substantiate anecdotal experience that a HVLAT hip distraction mobilization improves muscle performance in subjects with lower extremity pathology and lower extremity weakness. The purpose of this study was to determine if a HVLAT hip distraction mobilization would result in an immediate change of maximal force output of the quadriceps, gluteus maximus and gluteus medius.

Methods: Forty individuals with a lower extremity pathology volunteered for this study. Inclusion criteria were having a unilateral musculoskeletal pathology, being greater than 18 years of age, 10% decrease in muscle strength in symptomatic side compared to healthy side, and absence of medical precautions that would prevent a maximal effort strength test and exclusion criteria included individuals with a history lower extremity recent muscle or tendon ruptures (within the past 6 months) and postoperative knee, hip and ankle surgery. Demographic data, including diagnosis from referring physician were collected. All subjects completed the Lower extremity function scale (LEFS). A single evaluator blinded to the involved extremity was responsible for quadriceps, gluteus medius and maximus strength analysis pre and post mobilization of both symptomatic and non-symptomatic sides. The subject underwent the HVLAT hip distraction mobilization of the symptomatic side, and an immediate re-assessment of strength of both symptomatic and non-symptomatic sides followed the mobilization.