Reproducibility of Acute Steroid Hormone Responses in Men to Short-Duration Running
in International Journal of Sports Physiology and PerformancePurpose: Progressively overloading the body to improve physical performance may lead to detrimental states of overreaching/overtraining syndrome. Blunted cycling-induced cortisol and testosterone concentrations have been suggested to indicate overreaching after intensified training periods. However, a running-based protocol is yet to be developed or demonstrated as reproducible. This study developed two 30-min running protocols, (1) 50/70 (based on individualized physical capacity) and (2) RPETP (self-paced), and measured the reproducibility of plasma cortisol and testosterone responses. Methods: Thirteen recreationally active, healthy men completed each protocol (50/70 and RPETP) on 3 occasions. Venous blood was drawn preexercise, postexercise, and 30 min postexercise. Results: Cortisol was unaffected (both P > .05; 50/70, = .090; RPETP, = .252), while testosterone was elevated (both P < .05; 50/70, 35%, = .714; RPETP, 42%, = .892) with low intraindividual coefficients of variation (CVi) as mean (SD) (50/70, 7% [5%]; RPETP, 12% [9%]). Heart rate (50/70, effect size [ES] = 0.39; RPETP, ES = −0.03), speed (RPETP, ES = −0.09), and rating of perceived exertion (50/70 ES = −0.06) were unchanged across trials (all CVi < 5%, P < .05). RPETP showed greater physiological strain (P < .01). Conclusions: Both tests elicited reproducible physiological and testosterone responses, but RPETP induced greater testosterone changes (likely due to increased physiological strain) and could therefore be considered a more sensitive tool to potentially detect overtraining syndrome. Advantageously for the practitioner, RPETP does not require a priori exercise-intensity determination, unlike the 50/70, enhancing its integration into practice.
Leal and Hough are with the Inst of Sport and Physical Activity Research, School of Sport and Physical Activity, University of Bedfordshire, Bedford, United Kingdom. Leal is also with Research Center in Sports Sciences, Health Sciences and Human Development, University Inst of Maia, Maia, Portugal. Taylor is with the Athlete Health and Performance Research Center, Aspetar, Qatar Orthopedic and Sports Medicine Hospital, Doha, Qatar, and the School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom. Hough is also with the School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom.
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