Effects of Gastrocnemius Fatigue on Muscle Elasticity and Jumping

This study investigates the acute and 24-hour recovery effects of localized muscle fatigue on the viscoelastic properties of the medial gastrocnemius (MG) muscle and vertical jump performance. The research aims to quantify the changes in muscle stiffness, tone, and elasticity immediately after a standardized fatigue protocol and to monitor the recovery of these parameters 24 hours later. Additionally, the study evaluates the impact of fatigue on explosive power, measured by countermovement jump (CMJ) height, across these time points.

Participants undergo a structured experimental procedure to evaluate the changes across three time points: Baseline Assessment: Passive muscle tone (Hz), stiffness (N/m), and elasticity (logarithmic decrement) of the medial gastrocnemius (MG) are measured using the MyotonPRO device. Initial vertical jump height is determined through countermovement jump (CMJ) tests. Fatigue Protocol \& Acute Assessment: Participants perform standardized standing calf raises until task failure. Immediately following the protocol, MG myotonometric properties and CMJ performance are re-measured to determine the acute fatigue-induced changes. 24-Hour Follow-up: Participants return to the laboratory exactly 24 hours later. All measurements (MyotonPRO and CMJ) are repeated to assess the return to baseline levels and the recovery status of the muscle-tendon unit. The statistical analysis focuses on the differences between baseline, post-fatigue, and 24-hour recovery measurements.