Resistance training is accompanied by increases in hip strength and changes in lower extremity biomechanics during running.
ABSTRACT Movement and muscle activity of the hip have been shown to affect movement of the lower extremity, and been related to injury. The purpose of this study was to determine if increased hip strength affects lower extremity mechanics during running.
Within subject, repeated measures design. Fifteen healthy women volunteered. Hip abduction and external rotation strength were measured using a hand-held dynamometer. Three-dimensional biomechanical data of the lower extremity were collected during running using a high-speed motion capture system. Measurements were made before, at the mid-point, and after a 6-week strengthening program using closed-chain hip rotation exercises. Joint range of motion (rearfoot eversion, knee abduction, hip adduction, and internal rotation), eversion velocity, eversion angle at heel strike, and peak joint moments (rearfoot inversion, knee abduction, hip abduction, and external rotation) were analyzed using repeated measures analysis of variance (P <or= 0.05). The independent variable was time (pre-, week 3, and week 6). A separate analysis of variance was conducted with the dependent variables of peak hip abduction and external rotation strength.
Hip abduction (P=0.009) and external rotation strength (P<0.0005) increased by 13% and 23%, respectively. Eversion range of motion decreased (P=0.05), hip adduction range of motion increased (P=0.05), and a trend of decreased hip internal rotation range of motion (P=0.08) were found. Rearfoot inversion moment (P=0.02) and knee abduction moment (P=0.05) decreased by 57% and 10%, respectively.
The hip abductors and external rotators were strengthened, leading to an alteration of lower extremity joint loading which may reduce injury risk. These exercises could be used in the rehabilitation, or prevention, of lower extremity injuries.
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ABSTRACT: Purpose: The purpose of this study was to investigate the relationship between hip and knee strength with knee valgus angle during drop jump in elite female athletes. Methods: Forty female athletes (mean ± SD age, 21.5 ± 1.99 years; height, 169.08 ± 8.25 cm; body mass, 61.05 ± 10.06 kg) participated in this study. Isometric hip and knee muscles strength were evaluated using standard clinical procedures and a handheld dynamometer. Knee valgus angle was assessed using a 6-camera motion analysis system during a drop jump task. Pearson correlation analyses were performed to determine the relationship between hip and knee muscles strength and knee valgus angle at initial contact (P≤0.05). Results: Hip abductor strength and knee flexor-extensor ratio were found to be negatively correlated with knee valgus angle (r = –0.229, P = 0.04 and r = –0.446, P = 0.002, respectively). Conclusion: No relationship between measure of hip external rotation strength and knee valgus angle was observed (P = 0.39). Strength training of the hip and knee musculature may still need to be addressed in prevention programs, but it also should be combined with teaching proper neuromuscular control through balance, plyometrics and sport-specific exercise.
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ABSTRACT: Background: Risk factors have been proposed for running injuries including (a) reduced muscular strength, (b) excessive joint movements and (c) excessive joint moments in the frontal and transverse planes. To date, many running injury prevention programs have focused on a "top down" approach to strengthen the hip musculature in the attempt to reduce movements and moments at the hip, knee, and/or ankle joints. However, running mechanics did not change when hip muscle strength increased. It could be speculated that emphasis should be placed on increasing the strength of the ankle joint for a "ground up" approach. Strengthening of the large and small muscles crossing the ankle joint is assumed to change the force distribution for these muscles and to increase the use of smaller muscles. This would be associated with a reduction of joint and insertion forces, which could have a beneficial effect on injury prevention. However, training of the ankle joint as an injury prevention strategy has not been studied. Ankle strengthening techniques include isolated strengthening or movement-related strengthening such as functional balance training. There is little knowledge about the efficacy of such training programs on strength alteration, gait or injury reduction. Methods: Novice runners will be randomly assigned to one of three groups: an isolated ankle strengthening group (strength, n = 40), a functional balance training group (balance, n = 40) or an activity-matched control group (control, n = 40). Isokinetic strength will be measured using a Biodex System 3 dynamometer. Running kinematics and kinetics will be assessed using 3D motion analysis and a force platform. Postural control will be assessed by quantifying the magnitude and temporal structure of the center of pressure trace during single leg stance on a force platform. The change pre- and post-training in isokinetic strength and postural control variables will be compared following the interventions. Injuries rates will be compared between groups over 6 months. Discussion: Avoiding injury will allow individuals to enjoy the benefits of participating in aerobic activities and reduce the healthcare costs associated with running injuries.BMC Musculoskeletal Disorders 12/2014; 15. DOI:10.1186/1471-2474-15-407 · 1.90 Impact Factor
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ABSTRACT: Study Design Observational prospective cohort study with 1-year follow-up. Objectives To investigate the relationship between eccentric hip abduction strength and the development of patellofemoral pain (PFP) in novice runners, during a self-structured running regime. Background Recent research indicates gluteal muscle weakness in individuals with PFP. However, current prospective research is limited to evaluation of isometric strength, producing inconsistent findings. Considering hip muscles including gluteus maximus and medius activate eccentrically to control hip and pelvic motion during weight-bearing activities such as running, evaluating the potential link between eccentric strength and PFP risk is needed. Methods 832 novice runners were included at baseline and 629 participants were included in the final analysis. Maximal eccentric hip abduction strength was measured using a handheld dynamometer prior to initiating a self-structured running program. The diagnostic criteria to classify knee pain as PFP were based on a thorough clinical examination. Participants were followed for 12 months and training characteristics was gathered with a Global Positioning System (GPS). Results Results from the unadjusted generalized linear regression model for the cumulative risk at 25 and 50 kilometres indicated differences in cumulative risk of PFP between high strength, normal strength, and low strength (P< 05), with higher strength associated with reduced risk. Conclusion Findings from this study indicate that among novice runners a level of peak eccentric hip abduction strength higher than normal reduces the risk of PFP during the first 50 kilometres of a self-structured running program. Level of Evidence Prognosis, level 1b-. J Orthop Sports Phys Ther, Epub 27 Jan 2015. doi:10.2519/jospt.2015.5091.Journal of Orthopaedic and Sports Physical Therapy 01/2015; DOI:10.2519/jospt.2015.5091 · 2.38 Impact Factor