Snyder KR, Earl JE, O'Connor KM, Ebersole KT. Resistance training is accompanied by increases in hip strength and changes in lower extremity biomechanics during running

University of Northern Iowa, Waterloo, IW, USA.
Clinical biomechanics (Bristol, Avon) (Impact Factor: 1.88). 11/2008; 24(1):26-34. DOI: 10.1016/j.clinbiomech.2008.09.009
Source: PubMed

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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    • "These results support the use of hip strengthening exercises to improve function in women with PFPS. The strengthening of the hip muscles, mainly targeting the extensors, abductors, and external rotators, is widely used for the correction of dynamic knee valgus, decreased peak adduction, and internal rotation of the hip (Herman et al., 2009; Snyder et al., 2009; Greska et al., 2012). "
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    ABSTRACT: The aim of the present study was to determine the relationship between knee pain severity and function with the frontal plane projection angle (FPPA) and trunk and hip peak torque (PT) in women with patellofemoral pain (PFPS). Twenty-two women with PFPS were assessed. Knee pain severity (KPS) was assessed with an 11-point visual analog scale and function with an Anterior Knee Pain Scale. The FPPA was recorded with a digital camera. PT of extensors, abductors, and the lateral rotators of hip and lateral core stability were measured with a handheld dynamometer. FPPA was the only predictor for the KPS. Regarding predictors of function, PT of lateral core stability and the extensor and abductor of the hip explained 41.4% of the function. Increase in FPPA was associated with greater KPS, and the lowest PT of lateral core stability, hip abductors, and extensors was associated with lower function in women with PFPS. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Journal of bodywork and movement therapies 07/2015; 19(3):558-64. DOI:10.1016/j.jbmt.2015.01.004
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    • "There would be no axial rotations of the talus in the talocrural joint (Michaud, 1993). Although bone-pin studies questioned these mechanisms at individual joints (Arndt et al., 2004; Nester et al., 2007; Lundgren et al., 2008), the whole ankle complex makes lower-limb internal rotation and rearfoot eversion to be relatively interdependent and simultaneous (Snyder et al., 2009; Souza et al., 2010). Therefore, hip soft tissues that resist internal rotation may also resist foot pronation indirectly. "
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    ABSTRACT: Health professionals are frequently interested in predicting rearfoot pronation during weight-bearing activities. Previous inconsistent results regarding the ability of clinical measures to predict rearfoot kinematics may have been influenced by the neglect of possible combined effects of alignment and mobility at the foot-ankle complex and by the disregard of possible influences of hip mobility on foot kinematics. The present study tested whether using a measure that combines frontal-plane bone alignment and mobility at the foot-ankle complex and a measure of hip internal rotation mobility predicts rearfoot kinematics, in walking and upright stance. Twenty-three healthy subjects underwent assessment of forefoot-shank angle (which combines varus bone alignments at the foot-ankle complex with inversion mobility at the midfoot joints), with a goniometer, and hip internal rotation mobility, with an inclinometer. Frontal-plane kinematics of the rearfoot was assessed with a three-dimensional system, during treadmill walking and upright stance. Multivariate linear regressions tested the predictive strength of these measures to inform about rearfoot kinematics. The measures significantly predicted (p ≤ 0.041) mean eversion-inversion position, during walking (r(2) = 0.40) and standing (r(2) = 0.31), and eversion peak in walking (r(2) = 0.27). Greater values of varus alignment at the foot-ankle complex combined with inversion mobility at the midfoot joints and greater hip internal rotation mobility are related to greater weight-bearing rearfoot eversion. Each measure (forefoot-shank angle and hip internal rotation mobility) alone and their combination partially predicted rearfoot kinematics. These measures may help detecting foot-ankle and hip mechanical variables possibly involved in an observed rearfoot motion or posture.
    Manual therapy 10/2013; 19(5). DOI:10.1016/j.math.2013.10.003 · 1.76 Impact Factor
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    • "The mean force (N) of the three MVIC trials was then normalized as a percentage of body weight (%BW). The hip abductors strength and hip external rotators strength were tested similarly to Snyder et al. (2009). The hip extensors strength test was performed with the subject lying in prone with the right knee in 90° of flexion. "
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    ABSTRACT: Background The increased injury risk in older runners has been associated with alterations in muscle strength, flexibility, and gait biomechanics. This study investigated whether older runners exhibit changes in muscle strength, flexibility and running biomechanics compared to younger runners, and possible relationships between these changes. Methods Thirty-five young (20-36 yrs) and 35 older (55-71 yrs) recreational runners participated in the study. Measures of three-dimensional biomechanical data during treadmill running at 2.7 m/s and measures of muscle strength and flexibility were compared between groups. A correlation analysis between biomechanical and clinical variables was also performed. Findings Older runners demonstrated an overall reduction in muscle strength and flexibility, and altered running patterns compared to young runners but correlations between clinical and biomechanical variables were scarce. Reduced hip, ankle and trunk excursions along with reduced knee and ankle positive work were found in older runners. Older runners also exhibited increased knee abduction impulse, ankle abduction impulse and vertical loading rates. In contrast, older runners did not present a distal-to-proximal lower extremity joint moment redistribution. Interpretation We observed age-related reduced strength and flexibility concomitant with alterations in running biomechanics, but a lack of correlation between these variables. This finding hampers the use of single, or even a subset of characteristics to better understand age-related changes in runners. The observed changes are complex and multivariate in nature. Clinicians will most likely have to monitor both clinical and biomechanical characteristics to optimize care. However, future studies need to prospectively address what are biomechanical age-related risk factors in runners.
    Clinical biomechanics (Bristol, Avon) 01/2013; DOI:10.1016/j.clinbiomech.2013.12.007 · 1.88 Impact Factor
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