Research Review: Can the gastrocnemius and tibialis anterior produce both eversion & inversion?

By Jinny McGivern DPT, PT, Certified Yoga Instructor

Edited by Brent Brookbush DPT, PT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Lee, S. S., & Piazza, S. J. (2008). Inversion–eversion moment arms of gastrocnemius and tibialis anterior measured in vivo. Journal of biomechanics41(16), 3366-3370.  ABSTRACT

Eversion and Inversion (Valgus and Varus) and relative line of pull of the calf complex Eversion and Inversion (Valgus and Varus) and relative line of pull of the calf complex -

Why is this relevant?:

This research provides information about two commonly addressed lower extremity muscles and their function in the frontal plane.  Alterations in frontal plane mechanics of the foot/ankle have been linked to foot/ankle injury, knee pathology, alterations in hip muscle recruitment strategies, and may be associated with lumbosacral dysfunction.  Further, these muscles play a role in supination and forefoot rigidity and may be the focus of performance enhancement programming.  It is essential for the human professional to have a detailed understanding of the gastrocnemius and tibialis anterior to inform their decision making process when choosing the best exercise, technique or modality for their patient, client or athlete.

Study Summary

Study Design Descriptive Laboratory Study
Level of Evidence 2b - Individual Cohort Study
Subject Demographics

  • Age: 21-32 yrs
  • Gender: 5 male/5 female
  • Characteristics: Healthy, Uninjured for 6 months prior to testing
Outcome MeasuresTendon excursion via ultrasonography was obtained for the tibialis anterior (TA), medial gastrocnemius (MG) & lateral gastrocnemius (LG) for the following conditions:

  • 3 different frontal plane joint angles: 15 degrees eversion, 0, 20 degrees inversion
  • 3 different sagittal plane joint angles: 0, 15 & 30 degrees plantar flexion
  • 3 muscle activity levels: at rest, light contraction & max voluntary