Thyroid Hormone Responses to Repeated Wingate Exercise Versus a Non-Exercising Comparison Group

This two-group, non-randomized study investigated the acute effects of repeated Wingate exercise on free thyroid hormone concentrations in male amateur soccer players. Twenty healthy male amateur soccer players completed a standardized repeated Wingate exercise protocol, and a separate group of twenty male amateur soccer players provided two morning blood samples without exercising. Blood samples were collected immediately before and immediately after the exercise session or the resting interval to determine free triiodothyronine (fT3), free thyroxine (fT4), and thyroid-stimulating hormone (TSH) concentrations. Including a non-exercising comparison group allows the observed changes to be evaluated against the change expected across a comparable interval in the absence of exercise.

Inclusion Criteria: * Male amateur soccer players. * Age between 18 and 25 years. * At least 6 years of licensed soccer experience. * Actively participating in amateur soccer training. * Apparently healthy and free from acute or chronic disease on medical history review. * Willingness to participate and provision of written informed consent. Exclusion Criteria: * Acute illness or musculoskeletal injury at the time of testing. * Neurological, auditory, visual or vestibular disorder. * Reduced physical capacity due to injury, or a sedentary lifestyle. * History of nutritional or pharmacological ergogenic aid use. * Failure to complete the study procedures or all required blood sample collections.