BACKGROUND
Muscle fatigue, characterized by a reduced ability to generate appropriate muscle force during cyclic contractile activity, disrupts the neuromuscular system, leading to decreased motor control and balance. This type of fatigue, common during physical activities, compromises performance and increases injury risk. While surface electromyography (sEMG) is the standard method for assessing muscle fatigue, its practical challenges limit its application in daily monitoring. Wearable plantar pressure sensors integrated into shoe insoles present a promising alternative for continuous and unobtrusive muscle fatigue monitoring.
OBJECTIVE
This study aimed to investigate the effects of calf muscle fatigue on plantar pressure measurements using a wearable plantar pressure system.
METHODS
Fifteen healthy participants underwent a 5-minute calf muscle fatigue protocol. Plantar pressures and sEMG activity of the right and left rectus femoris (RF) and gastrocnemius (GA) were recorded before and after the exercise. The plantar pressures were measured using a wearable plantar pressure device. Muscle fatigue was quantified by analyzing the median frequency of sEMG, while mean peak plantar pressures at six plantar regions (Hallux, Lesser Toe, First Metatarsal, Fifth Metatarsal, Arch, and Medial Heel) were evaluated.
RESULTS
The sEMG median frequency significantly decreased in both the left and right GA (p<0.05), indicating muscle fatigue, but no significant changes were observed in the RF. Notably, there was a significant decrease in mean peak plantar pressure in the Hallux region of both feet (p<0.05) after fatigue, as measured by the wearable plantar pressure device.
CONCLUSIONS
Calf muscle fatigue leads to a measurable decrease in plantar pressure at the Hallux, highlighting its potential as a novel indicator for monitoring muscle fatigue using wearable plantar pressure devices in daily life.