Examination of Muscle Oxygenation and Vascular Occlusion in the Tibialis Anterior Muscle with Isometric Dorsiflexion Using Near-Infrared Spectroscopy of the Ankle Joint.

Objective: We aimed to observe isometric dorsiflexion of the ankle joint during occlusion and non-occlusion conditions of the arteriovenous blood flow of the tibialis anterior muscle using a tourniquet. Design: An experimental study. Materials and Methods: We measured continuous changes in the muscle oxygenation and vascular occlusion of the tibialis anterior muscle during isometric dorsiflexion movement of the ankle joint. Using a paired Student-t test for analysis, changes in muscle oxygenation under occlusion and non-occlusion conditions at the end of the exercise and %MVC for 120 seconds were evaluated. The statistical relationship between oxygen dynamics, %MVC, and exercise time was calculated by one-way analysis of variance. Results: In both the occlusion and non-occlusion condition, muscle oxygenation levels decreased linearly immediately after the start of the exercise. The decrease in StO₂ was no longer observed when the MVC was about 35% or less under the non-occlusion condition. StO₂ plateaued after 60 seconds from the start of the exercise under the occlusion condition. Discussions: When MVC was approximately 35% or higher and the exercise continued for 60 seconds or longer, aerobic energy production in the muscle was insufficient. Conclusions: One of the factors defining muscle endurance of tibialis anterior muscle is sufficient oxygen must be supplied to muscles in order to produce aerobic energy more effectively. [ABSTRACT FROM AUTHOR]