Associação da função muscular dos inversores e eversores do tornozelo com postura do pé, dados antropométricos e características do treino em corredores recreacionais

Abstract

Introduction- running has become popular due to its practicality, accessibility, low cost, and physical and mental health benefits. The runner's relationship with training characteristics and anatomical variations, such as foot posture and anthropometry, can impact muscle function. Objectives- to evaluate the association between ankle invertor and evertor muscle function and foot posture, anthropometric factors, and training characteristics in recreational runners. Methods- this is a cross-sectional study conducted with 34 recreational runners. Data were collected on training characteristics, anthropometric data, foot posture, through the 6-item Foot Posture Index (PPI-6), electromyographic activity (EMGs - Miotoll 3) and muscle strength (Biodex System Pro 4 dynamometer) of the ankle evertor and invertor muscle group. The variables of interest were: electromyographic activity and muscle strength of ankle evertors and inverters, training characteristics (weekly volume and practice time) and foot posture. Results- the sample had a mean age of 39 (± 9.5 years) years and was mainly composed of men (71%), with a mean height of 1.72 (± 0.06), who had been running for approximately 3.9 (± 5.9 years) years and a weekly volume of 20.63 (± 15.42 km) kilometres. The neutral foot posture was the most frequent (59%), followed by supination (23%) and pronation (18%). The invertor muscles showed a higher activation level than the evertor muscles for the pronated foot posture, with an evertor/invertor ratio of 0.79 mV. In the neutral feet, activation was balanced, with an evertor/invertor ratio of 0.94 mV. In the supinated feet, the evertor group was the most active, with an evertor/invertor ratio of 1.14 mV. Height and time of running practice appear to influence the increased activation of the evertor muscle compared to the inverter. Analysis of muscle strength showed a balanced torque between the evertor and inverter muscles in the three foot postures. The variables time of running practice and height were significantly related (p<0.01 and p<0.002) with the increase in electromyographic activity. Conclusion- the muscle activation profile reveals a different pattern depending on foot posture, which is not the case with muscle strength. Pronated feet show greater activation of the invertor muscle, supinated feet show greater activation of the evertor muscle, and in neutral feet, activation is balanced, with a slight predominance of the invertor muscle. Muscle strength was balanced across the three foot postures.