Differences in the angle of the medial longitudinal arch and muscle activity of the abductor hallucis and tibialis anterior during sitting short-foot exercises between subjects with pes planus and subjects with neutral foot

Article type: Research Article

Authors: Lee, Ji-Hyun^a | Cynn, Heon-Seock^{a; *} | Yoon, Tae-Lim^b | Choi, Sil-Ah^a | Kang, Tae-Woo^a

Affiliations: [a] Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, Graduate School, Yonsei University, Wonju, Korea | [b] Department of Physical Therapy, College of Health Science, Cheongju University, Cheongju, Korea

Correspondence: [*] Corresponding author: Heon-Seock Cynn, Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, Graduate School, Yonsei University, Wonju, Gangwon-do 220-710, Korea. Tel.: +82 33 760 2427; Fax: +82 33 760 2496; E-mail:cynn@yonsei.ac.kr

Abstract: BACKGROUND AND OBJECTIVES: Excessive activity of the tibialis anterior muscle may be a causal mechanism in overuse injuries such as stress fracture in pes planus patients. However, information about this relationship is limited. In this study, we compared the angle of the medial longitudinal arch, the activities of the abductor hallucis and tibialis anterior muscles, and the activity ratio of tibialis anterior/abductor hallucis in individuals with pes planus and those with a neutral foot position during short-foot exercises conducted while sitting. METHODS: Differences between the groups were analyzed using an independent t-test. In all, 28 university students participated in this study (14 subjects in each group). RESULTS: The activity of the abductor hallucis muscle was significantly lower (p < 0.001), and the activity ratio of tibialis anterior/abductor hallucis was significantly greater (p = 0.012) in the pes planus group than in the neutral foot group during the exercise. CONCLUSIONS: Clinicians should recognize that pes planus patients may compensate for reduced activation of the abductor hallucis to maintain the angle of the medial longitudinal arch during the sitting short-foot exercise.

Keywords: Abductor hallucis, pes planus, short-foot exercise, tibialis anterior

DOI: 10.3233/BMR-160693

Journal: Journal of Back and Musculoskeletal Rehabilitation, vol. 29, no. 4, pp. 809-815, 2016