Content: Distance running is one of the most popular physical activities, and running-related injuries (RRIs) are also common. Foot strike patterns have been suggested to affect biomechanical variables related to RRI risks. Objective: To determine the effects of foot strike techniques on running biomechanics. Data Sources: The databases of Web of Science, PubMed, EMBASE, and EBSCO were searched from database inception through November 2018. Study Selection: The initial electronic search found 723 studies. Of these, 26 studies with a total of 472 participants were eligible for inclusion in this meta-analysis. Study Design: Systematic review and meta-analysis. Level of Evidence: Level 4. Data Extraction: Means, standard deviations, and sample sizes were extracted from the eligible studies, and the standard mean differences (SMDs) were obtained for biomechanical variables between forefoot strike (FFS) and rearfoot strike (RFS) groups using a random-effects model. Results: FFS showed significantly smaller magnitude (SMD, −1.84; 95% CI, −2.29 to −1.38; P < 0.001) and loading rate (mean: SMD, −2.1; 95% CI, −3.18 to −1.01; P < 0.001; peak: SMD, −1.77; 95% CI, −2.21 to −1.33; P < 0.001) of impact force, ankle stiffness (SMD, −1.69; 95% CI, −2.46 to −0.92; P < 0.001), knee extension moment (SMD, −0.64; 95% CI, −0.98 to −0.3; P < 0.001), knee eccentric power (SMD, −2.03; 95% CI, −2.51 to −1.54; P < 0.001), knee negative work (SMD, −1.56; 95% CI, −2.11 to −1.00; P < 0.001), and patellofemoral joint stress (peak: SMD, −0.71; 95% CI, −1.28 to −0.14; P = 0.01; integral: SMD, −0.63; 95% CI, −1.11 to −0.15; P = 0.01) compared with RFS. However, FFS significantly increased ankle plantarflexion moment (SMD, 1.31; 95% CI, 0.66 to 1.96; P < 0.001), eccentric power (SMD, 1.63; 95% CI, 1.18 to 2.08; P < 0.001), negative work (SMD, 2.60; 95% CI, 1.02 to 4.18; P = 0.001), and axial contact force (SMD, 1.26; 95% CI, 0.93 to 1.6; P < 0.001) compared with RFS. Conclusion: Running with RFS imposed higher biomechanical loads on overall ground impact and knee and patellofemoral joints, whereas FFS imposed higher biomechanical loads on the ankle joint and Achilles tendon. The modification of strike techniques may affect the specific biomechanical loads experienced on relevant structures or tissues during running.

Purpose: To examine the influence of hip abductor strength, neuromuscular activation, and pelvis and femur morphology in contributing to sex differences in hip adduction during running. In addition, we sought to determine the best predictors of hip adduction during running for both men and women. Methods: Fifteen female runners and 14 male runners underwent strength testing, instrumented overground running (e.g., kinematics and muscle activation), and computed tomography scanning of pelvis and femur. Morphologic measurements included bilateral hip width to femur length ratio, acetabulum abduction, acetabulum anteversion, femoral anteversion, and femoral neck-shaft angles. Sex differences for all variables were examined using independent t tests. Linear regression was used to assess the ability of each independent variable of interest to predict peak hip adduction during the late swing and stance phase of running. Results: Compared with men, women exhibited significantly greater peak hip adduction during both late swing (8.5°± 2.6°vs 6.2°± 2.8°, P = 0.04) and stance phases of running (13.4°± 4.2°vs 10.0°± 3.2°, P = 0.02). In addition, women exhibited significantly lower hip abductor strength (1.8 ± 0.3 vs 2.0 ± 0.3 N•m•kg −1 , P = 0.04), greater femoral neck-shaft angles (134.1°± 5.0°vs 129.9°± 4.1°, P = 0.01), and greater hip width to femur length ratios than men (0.44 ± 0.02 vs 0.42 ± 0.03, P = 0.03). Femoral anteversion was the only significant predictor of peak hip adduction during late swing (r = 0.36, P = 0.05) and stance (r = 0.41, P = 0.03). Conclusions: Our findings highlight the contribution of femur morphology as opposed to hip abductor strength and activation in contributing to hip adduction during running.

Purpose:The purpose of the current study was to: 1) evaluate sex differences in peak hip adduction during the late swing and stance phases of running and 2) determine if peak hip adduction during late swing is predictive of peak hip adduction during stance.Methods: 15 female and 16 male heel strike runners ran over ground at a speed of 4 m/s. Hip joint kinematics during running were quantified using a 3D motion capture system. Sex differences in peak hip adduction during the late swing and stance phases were compared using independent sample t-tests. Linear regression analysis was used to determine the relationship between late swing and stance phase hip adduction.Results: Compared to males, females exhibited significantly greater peak hip adduction during both the late swing (8.5 ± 2.6 vs 6.1 ± 2.8°, p = 0.019) and stance phases of running (13.3 ± 4.2 vs 9.6 ± 3.4°, p = 0.011). Furthermore, late swing peak hip adduction was predictive of subsequent stance phase peak hip adduction (r = 0.63, p < 0.001). Conclusion:Sex differences in hip adduction during stance are influenced in part by late swing phase hip adduction. Further studies are needed to identify potential causes of excessive hip adduction during the late swing phase of running.

Purpose: To examine the influence of hip abductor strength, neuromuscular activation, and pelvis &amp; femur morphology in contributing to sex differences in hip adduction during running.Methods: Fifteen female and 14 male runners underwent strength testing, instrumented overground running (e.g., kinematics and muscle activation), and computed tomography scanning of pelvis and femur. Morphologic measurements included bilateral hip width to femur length ratio, acetabulum abduction, acetabulum anteversion, femoral anteversion, and femoral neck-shaft angles. Sex differences for all variables were examined using independent t-tests. Linear regression was used to assess the ability of each independent variable of interest to predict peak hip adduction during the late swing and stance phase of running. Results: Compared to males, females exhibited significantly greater peak hip adduction during both late swing (8.5 ± 2.6° vs 6.2 ± 2.8°, p = 0.04) and stance phases of running (13.4 ± 4.2° vs 10.0 ± 3.2°, p = 0.02). In addition, females exhibited significantly lower hip abductor strength (1.8 ± 0.3 vs 2.0 ± 0.3 Nm/kg, p=0.04), greater femoral neck-shaft angles (134.1 ± 5.0° vs 129.9 ± 4.1°, p=0.01), and greater hip width to femur length ratios than males (0.44 ± 0.02 vs 0.42 ± 0.03, p=0.03). Femoral anteversion was the only significant predictor of peak hip adduction during late swing (r=0.36, p=0.05) and stance (r=0.41, p=0.03).Conclusion: Our findings highlight the contribution of femur morphology as opposed to hip abductor strength and activation in contributing to hip adduction during running.

No abstract

No abstract

PurposeTo determine the most relevant pelvis and femur morphological characteristics for differentiating runners with high versus low hip adduction during running.MethodsFifteen female and 14 male runners underwent instrumented kinematics analysis of overground running and computed tomography scanning of pelvis and femur. The peak hip adduction angle during the stance phase of running was identified for each participant. Using the cohort average of the peak hip adduction angle as the classifying threshold, participants were categorized into high or low hip adduction groups. To determine the most relevant morphologic features for discriminating high and low hip adduction runners, a feature selection-based support vector machine classification analysis was performed.ResultsOf the 15 morphology variables examined, femoral head anteversion and femur length were shown to be the best discriminant variables for group classification. Together, these variables achieved a prediction accuracy of 0.93, sensitivity of 1.0, and specificity of 0.88.ConclusionsOur results highlight the importance of femur morphology in contributing to increased hip adduction during running.