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The effect of short-term resistance training on hip and knee kinematics during vertical drop jumps.
J Strength Cond Res. 2012 May; 26(5):1257-64.JS

Abstract

The purpose of this study was to determine the effect of a weight-bearing free weight resistance training program alone on knee flexion, hip flexion, and knee valgus during unilateral and bilateral drop jump tasks. Twenty-nine young adult females with previous athletic experience were randomly divided into a control (n = 16) and a resistance training (n = 13) groups. The resistance training group completed 8 weeks of lower extremity, weight-bearing exercises using free weights, whereas the control group did not train. A pre- and posttest was conducted to measure knee valgus, knee flexion, and hip flexion during unilateral (30 cm) and bilateral (60 cm) vertical drop jumps for maximum height. Joint angles were determined using 3-dimensional electromagnetic tracking sensors (MotionMonitor; Innovative Sports Training, Inc., Chicago, IL, USA). Initial training intensity for the bilateral squat was 50% of the subject's 1 repetition maximum (RM), which increased 5% each week to 85% during the final week. Sets and repetitions ranged from 2 to 4 and from 4 to 12, respectively. The training loads for all other exercises (lunge, step-up, unilateral squat, and Romanian deadlift) increased from 15RM to 6RM from the initial to the final week. A repeated measures analysis of variance was used to determine differences in the hip and knee joint angles. No significant differences for knee valgus and hip flexion measures were found between the groups after training; however, knee flexion angle significantly increased in the training group from the pretest (77.2 ± 4.1°) to posttest (83.2 ± 3.7°) during the bilateral drop jump. No significant changes occurred during the unilateral drop jump. Bilateral measures for knee flexion, hip flexion, and knee valgus were significantly (p < 0.05) greater than the unilateral measures during the drop jump task, which indicate an increased risk for anterior cruciate ligament (ACL) injury during unilateral drop jumps. The data support that the strength and conditioning specialist can implement resistance training alone during a short-term training period to reduce the risk of ACL injury by increasing knee flexion during a bilateral drop jump task. Increased knee flexion angles after resistance training may indicate a reduced risk for knee injury from improved neuromuscular control, resulting in a softer landing.

Authors+Show Affiliations

Department of Health and Human Performance, Texas State University, San Marcos, Texas, USA. km55@txstate.eduNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22344064

Citation

McCurdy, Kevin, et al. "The Effect of Short-term Resistance Training On Hip and Knee Kinematics During Vertical Drop Jumps." Journal of Strength and Conditioning Research, vol. 26, no. 5, 2012, pp. 1257-64.
McCurdy K, Walker J, Saxe J, et al. The effect of short-term resistance training on hip and knee kinematics during vertical drop jumps. J Strength Cond Res. 2012;26(5):1257-64.
McCurdy, K., Walker, J., Saxe, J., & Woods, J. (2012). The effect of short-term resistance training on hip and knee kinematics during vertical drop jumps. Journal of Strength and Conditioning Research, 26(5), 1257-64. https://doi.org/10.1519/JSC.0b013e31824f2386
McCurdy K, et al. The Effect of Short-term Resistance Training On Hip and Knee Kinematics During Vertical Drop Jumps. J Strength Cond Res. 2012;26(5):1257-64. PubMed PMID: 22344064.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The effect of short-term resistance training on hip and knee kinematics during vertical drop jumps. AU - McCurdy,Kevin, AU - Walker,John, AU - Saxe,Joseph, AU - Woods,Jonathan, PY - 2012/2/21/entrez PY - 2012/2/22/pubmed PY - 2012/9/13/medline SP - 1257 EP - 64 JF - Journal of strength and conditioning research JO - J Strength Cond Res VL - 26 IS - 5 N2 - The purpose of this study was to determine the effect of a weight-bearing free weight resistance training program alone on knee flexion, hip flexion, and knee valgus during unilateral and bilateral drop jump tasks. Twenty-nine young adult females with previous athletic experience were randomly divided into a control (n = 16) and a resistance training (n = 13) groups. The resistance training group completed 8 weeks of lower extremity, weight-bearing exercises using free weights, whereas the control group did not train. A pre- and posttest was conducted to measure knee valgus, knee flexion, and hip flexion during unilateral (30 cm) and bilateral (60 cm) vertical drop jumps for maximum height. Joint angles were determined using 3-dimensional electromagnetic tracking sensors (MotionMonitor; Innovative Sports Training, Inc., Chicago, IL, USA). Initial training intensity for the bilateral squat was 50% of the subject's 1 repetition maximum (RM), which increased 5% each week to 85% during the final week. Sets and repetitions ranged from 2 to 4 and from 4 to 12, respectively. The training loads for all other exercises (lunge, step-up, unilateral squat, and Romanian deadlift) increased from 15RM to 6RM from the initial to the final week. A repeated measures analysis of variance was used to determine differences in the hip and knee joint angles. No significant differences for knee valgus and hip flexion measures were found between the groups after training; however, knee flexion angle significantly increased in the training group from the pretest (77.2 ± 4.1°) to posttest (83.2 ± 3.7°) during the bilateral drop jump. No significant changes occurred during the unilateral drop jump. Bilateral measures for knee flexion, hip flexion, and knee valgus were significantly (p < 0.05) greater than the unilateral measures during the drop jump task, which indicate an increased risk for anterior cruciate ligament (ACL) injury during unilateral drop jumps. The data support that the strength and conditioning specialist can implement resistance training alone during a short-term training period to reduce the risk of ACL injury by increasing knee flexion during a bilateral drop jump task. Increased knee flexion angles after resistance training may indicate a reduced risk for knee injury from improved neuromuscular control, resulting in a softer landing. SN - 1533-4287 UR - https://www.unboundmedicine.com/medline/citation/22344064/The_effect_of_short_term_resistance_training_on_hip_and_knee_kinematics_during_vertical_drop_jumps_ L2 - https://doi.org/10.1519/JSC.0b013e31824f2386 DB - PRIME DP - Unbound Medicine ER -