Affiliations: [a] Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Izmir Katip Celebi University, Cigli, Izmir, Turkey | [b] Institute of Health Sciences, Dokuz Eylul University, Balcova, Izmir, Turkey | [c] School of Physical Therapy and Rehabilitation, Dokuz Eylul University, Balcova, Izmir, Turkey | [d] Faculty of Health Sciences, Cyprus International University, Nicosia, Cyprus
Correspondence:
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Corresponding author: Muge Kirmizi, Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Izmir Katip Celebi University, TR-35620, Cigli, Izmir, Turkey. Tel.: +90 5056013348; Fax: +90 2323293999; E-mail: mugekirmizi1@gmail.com.
Abstract: BACKGROUND: Flexible flatfoot is associated with altered plantar pressure distribution, but it is not clear how muscle fatigue affects plantar pressure characteristics in flexible flatfoot and normal foot. OBJECTIVE: To investigate the effects of calf muscles fatigue on plantar pressure variables in flexible flatfoot and normal foot. METHODS: Twenty-five people with flexible flatfoot and twenty-five people with normal foot were included. The unilateral heel-rise test was used to induce calf muscles fatigue. Plantar pressure variables were collected during preferred walking immediately before and after fatigue. The two-way mixed-design ANOVA was used to determine the main effect of fatigue and the interaction between foot posture and fatigue. RESULTS: Fatigue caused medialization of the contact area under the forefoot and the maximum force under the heel and forefoot (p< 0.05). When examining the differences in the effects of fatigue between groups, the contact area under the medial heel increased with fatigue in flexible flatfoot but decreased in normal foot; moreover, the contact area and maximum force under the midfoot and the maximum force under the third metatarsal decreased with fatigue in flexible flatfoot but increased in normal foot (p< 0.05). CONCLUSIONS: Calf muscles fatigue caused medialization of the maximum force and contact area. Especially the midfoot was affected differently by fatigue in flexible flatfoot and normal foot.
