Fatigue of the plantar intrinsic foot muscles increases navicular drop
- 1 June 2008
- journal article
- Published by Elsevier BV in Journal of Electromyography and Kinesiology
- Vol. 18 (3), 420-425
- https://doi.org/10.1016/j.jelekin.2006.11.004
Abstract
Our purpose was to assess the effect of foot intrinsic muscle fatigue on pronation, as assessed with navicular drop, during static stance. Twenty-one healthy young adults participated. Navicular drop was measured before and after fatiguing exercise of the plantar foot intrinsic muscles. Surface electromyography of the abductor hallucis muscle was recorded during maximum voluntary isometric contractions (MVIC) in order to find the baseline median frequency (MedF). Subjects then performed sets of 75 repetitions of isotonic flexion contractions of the intrinsic foot muscles against a 4.55 kg weight on a custom pulley system. After each set an MVIC was performed to track shifts in MedF. After a MedF shift of at least 10%, navicular drop measurements were repeated. Subjects exhibited 10.0+/-3.8mm of navicular drop at baseline and 11.8+/-3.8mm after fatigue (p<0.0005). The change in navicular drop was significantly correlated with change in MedF (r=.47, p=.03). The intrinsic foot muscles play a role in support of the medial longitudinal arch in static stance. Disrupting the function of these muscles through fatigue resulted in an increase in pronation as assessed by navicular drop.Keywords
This publication has 20 references indexed in Scilit:
- Effects of plantar fascia stiffness on the biomechanical responses of the ankle–foot complexClinical Biomechanics, 2004
- Intrinsic pedal musculature support of the medial longitudinal arch: an electromyography studyThe Journal of Foot and Ankle Surgery, 2003
- Force and EMG power spectrum during and after eccentric and concentric fatigueJournal of Electromyography and Kinesiology, 2000
- Spectral compression of the electromyographic signal due to decreasing muscle fiber conduction velocityIEEE Transactions on Rehabilitation Engineering, 2000
- Reconstruction Operations for Acquired Flatfoot: Biomechanical EvaluationFoot & Ankle International, 1998
- The Use of Surface Electromyography in BiomechanicsJournal of Applied Biomechanics, 1997
- Effect of the Posterior Tibial Tendon on the Arch of the Foot During Simulated Weightbearing: Biomechanical AnalysisFoot & Ankle International, 1997
- Gross, Histological, and Microvascular Anatomy and Biomechanical Testing of the Spring Ligament ComplexFoot & Ankle International, 1996
- Biomechanical Evaluation of Longitudinal Arch StabilityFoot & Ankle, 1993
- Pes Cavus and Pes PlanusPTJ: Physical Therapy & Rehabilitation Journal, 1987