The influence of resistance bands on frontal plane knee mechanics during body-weight squat and vertical jump movements.
ABSTRACT The purpose of this study was to examine the impact of wearing a resistance band around the distal thigh on frontal plane knee mechanics during bodyweight squat and jumping exercises. Three closed-kinetic-chain exercises were examined, including: (1) bodyweight squat, (2) countermovement jump, and (3) squat jump. For each exercise, three experimental conditions were tested: (1) control condition with no band; (2) light-tension band applied around the distal thighs; and (3) medium-tension band applied around the distal thighs. Two dependent measures were used for analyses: (1) knee width normalized to ankle width and (2) peak external knee moment. In the absence of any feedback, application of the resistance bands failed to promote 'neutral' knee alignment when squatting and jumping. The stiffest resistance band resulted in significantly lower (p = 0.002) peak-width index values during the ascent phase of the countermovement jump. Additionally, the use of the medium-tension band resulted in significantly larger (p = 0.002) peak knee abduction moments compared to the no bands condition during the descent portion of the bodyweight squat and countermovement jump exercises. These findings conflict with previous clinical case reports on the proprioceptive response induced by resistance bands.
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ABSTRACT: During the last decade, there has been a growing body of literature suggesting that proximal factors may play a contributory role with respect to knee injuries. A review of the biomechanical and clinical studies in this area indicated that impaired muscular control of the hip, pelvis, and trunk can affect tibiofemoral and patellofemoral joint kinematics and kinetics in multiple planes. In particular, there is evidence that motion impairments at the hip may underlie injuries such as anterior cruciate ligament tears, iliotibial band syndrome, and patellofemoral joint pain. In addition, the literature suggests that females may be more disposed to proximal influences than males. Based on the evidence presented as part of this clinical commentary, it can be argued that interventions which address proximal impairments may be beneficial for patients who present with various knee conditions. More specifically, a biomechanical argument can be made for the incorporation of pelvis and trunk stability, as well as dynamic hip joint control, into the design of knee rehabilitation programs. LEVEL OF EVIDENCE: Aetiology/therapy, level 5.Journal of Orthopaedic and Sports Physical Therapy 02/2010; 40(2):42-51. · 2.95 Impact Factor
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ABSTRACT: Proprioception and neuromuscular control of the knee are compromised after ligament injury and must be regained if the athlete is to return to high level sports at a normal injury risk level. The anterior cruciate ligament deficient and reconstructed knee will be used as a model to describe differences in proprioception and neuromuscular control to those of an uninjured knee. The purpose of the current review is threefold. First, the basic science of proprioception and neuromuscular control specific to the knee will be summarized and reviewed. The review will include an overview of terminology, neurophysiology, and the effects of injury on the function of both lower limbs. Second, tools used for assessment and rehabilitation of proprioceptive deficits will be evaluated. Specific rehabilitation procedures that incorporate prophylactic conditioning that focus on transitioning the injured athlete back into sport will be presented. Finally, the literature with respect to gender variation in proprioception and neuromuscular control will be evaluated. The goal of the current review is to provide the clinician and the clinical scientist with sufficient background information for the development of quantitative methods to evaluate a patient's functional capacity and to assist in preventative, preoperative, and postoperative decision-making strategies.Clinical Orthopaedics and Related Research 10/2002; · 2.79 Impact Factor
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ABSTRACT: Female athletes participating in high-risk sports suffer anterior cruciate ligament injury at a 4- to 6-fold greater rate than do male athletes. Prescreened female athletes with subsequent anterior cruciate ligament injury will demonstrate decreased neuromuscular control and increased valgus joint loading, predicting anterior cruciate ligament injury risk. Cohort study; Level of evidence, 2. There were 205 female athletes in the high-risk sports of soccer, basketball, and volleyball prospectively measured for neuromuscular control using 3-dimensional kinematics (joint angles) and joint loads using kinetics (joint moments) during a jump-landing task. Analysis of variance as well as linear and logistic regression were used to isolate predictors of risk in athletes who subsequently ruptured the anterior cruciate ligament. Nine athletes had a confirmed anterior cruciate ligament rupture; these 9 had significantly different knee posture and loading compared to the 196 who did not have anterior cruciate ligament rupture. Knee abduction angle (P<.05) at landing was 8 degrees greater in anterior cruciate ligament-injured than in uninjured athletes. Anterior cruciate ligament-injured athletes had a 2.5 times greater knee abduction moment (P<.001) and 20% higher ground reaction force (P<.05), whereas stance time was 16% shorter; hence, increased motion, force, and moments occurred more quickly. Knee abduction moment predicted anterior cruciate ligament injury status with 73% specificity and 78% sensitivity; dynamic valgus measures showed a predictive r2 of 0.88. Knee motion and knee loading during a landing task are predictors of anterior cruciate ligament injury risk in female athletes. Female athletes with increased dynamic valgus and high abduction loads are at increased risk of anterior cruciate ligament injury. The methods developed may be used to monitor neuromuscular control of the knee joint and may help develop simpler measures of neuromuscular control that can be used to direct female athletes to more effective, targeted interventions.The American Journal of Sports Medicine 05/2005; 33(4):492-501. · 4.44 Impact Factor