Kinematic Analysis of Heel Raise Exercise With Three Foot Positions

Document Type

Article

Publication Date

6-3-2010

Publication Title

Medicine and Science in Sports and Exercise

DOI

10.1249/01.MSS.0000385128.37496.d9

ISSN

1530-0315

Abstract

Prior research revealed activation differences between the medial (MG) and lateral (LG) gastrocnemius when performing heel raise exercise with three different foot positions, neutral (N), internally-rotated (IR) and externally-rotated (ER). Studying underlying kinematics and kinetics may help provide explain the activation differences.

PURPOSE: To compare ankle (AN), knee (KN), and hip (HI) contributions to achieving the start positions, ankle flexion-extension (FL-EX) range of motion (ROM), repetition time (RT), % cycle concentric-eccentric transition (%CT) and ankle extension mechanical energy expenditure (MEE) between N, IR and ER heel raise exercise.

METHODS: Twenty healthy subjects (11 male, 9 female; 22.7±3.13yrs) with resistance training experience performed 12 repetitions of free-weight (135% body mass) heel raise exercise using N, IR and ER foot positions in a counterbalanced order. Repetitions began with forefeet elevated.05m onto separate forceplates. Electromagnetic sensors (Motion Monitor, IST, Inc) secured onto dominant foot, shank and thigh recorded kinematic data. Dependent variables were averaged across five selected repetitions. Temporal events (initiation, transition, end) were defined by AN FL-EX angular velocity. At repetition initiation, AN adduction/abduction (adduction positive), KN and HI rotation (IR positive) were determined. AN extension MEE was calculated as the absolute sum of the angular concentric and eccentric work.

RESULTS: No significant differences existed for RT (P=.209), %CT (P=.668), MEE (P=.590), and AN FL-EX ROM (P=.129) between foot positions. Post hoc comparison of a significant start position angle joint by foot position interaction (P<.001) demonstrated IR>N>ER for HI and KN angles, whereas for AN, ER>IR and N. Comparing between joints, AN

CONCLUSION: Peak FL-EX ROM, MEE, RT, %CT are not affected by altering foot position during heel raise exercise. Although it was expected the IR/ER/N positions would induce large start AN angle changes, our results reveal the greatest changes at the HI, followed by the KN. The relatively small AN differences may be explained by beginning in a dorsiflexed position (closed pack). Further research is needed to explain the MG and LG activation differences previously reported.

Comments

© 2010 American College of Sports Medicine

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