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Medicina dello Sport 2019 March;72(1):67-78

DOI: 10.23736/S0025-7826.18.03294-5


language: English, Italian

Effects of time-of-day strength training on plasma testosterone and cortisol concentrations in male amateur athletes

Majdi BOUAZIZI 1, Sarah CHÉOUR 2, Chouaib CHÉOUR 2, Nicola L. BRAGAZZI 3, 4, Julien S. BAKER 5, Salah SOUISSI 1, Fairouz AZAIEZ 2, Maamer SLIMANI 3, 4, Foued CHÉOUR 6

1 Faculty of Sciences of Bizerte, University of Carthage-Tunisia-Zarzouna, Zarzouna, Tunisia; 2 Higher Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia; 3 Department of Health Sciences (DISSAL), School of Public Health, Genoa University, Genoa, Italy; 4 Section of Psychiatry, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), Genoa University, Genoa, Italy; 5 Institute of Clinical Exercise and Health Science, University of the West of Scotland,, Hamilton, UK; 6 Institute of Applied Biology of Médenine, Médenine, Tunisia


BACKGROUND: The purpose of the present study was to examine the effects of time-of-day-strength training on plasma testosterone (T) and cortisol (C) concentrations in male amateur athletes.
METHODS: Forty-five male athletes (age, 21.2±0.3 years; height, 1.75±0.14 m; weight, 72±1.52 kg) participated in the present study. They were subjected to strength training of the knee extensor and flexor muscles. Following this, they were randomly assigned into three groups: morning strength training group (MSTG, 07:00-08:00 hours, N.=15), afternoon strength training group (ASTG, 16:00-17:00 hours, N.=15) and morning and afternoon strength training group (MASTG, 07:00-08:00 and 16:00-17:00 hours, N.=15). The concentration of T and C for each athlete was collected in all three conditions in the morning, noon and afternoon, before and after 8 weeks of strength training. The effects of group, time of the day and pre- to post-training were verified by a 3-way analysis of variance with repeated measures.
RESULTS: Our results indicate that strength training induces an increase of plasma T/C ratio in both groups of athletes who have always trained for only one session per day mainly in the afternoon compared with the MASTG (P<0.05). However, a reduction of the plasma T/C ratio was observed in the athletes who have always trained successively in the morning and in the afternoon (P<0.05). Plasma T/C ratio exhibit circadian rhythmicity in all groups showing a low level in the morning, whereas in the afternoon an increased value was more noted (P<0.05).
CONCLUSIONS: From an applied perspective, this study suggests that amateur athletes should train at the afternoon to maximize their performance gain.

KEY WORDS: Resistance training - Testosterone - Hydrocortisone - Circadian rhythm - Athletes

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