Post-resistance training detraining: time-of-day effects on training and testing outcomes |
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| Authors: | Hamdi Chtourou Achraf Ammar Pantelis Theodoros Nikolaidis Osama Abdel Karim Nizar Souissi Karim Chamari |
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| Institution: | 1. Research Laboratory “Sports Performance Optimization”, National Center of Medicine and Science in Sports (CNMSS), Bp263, Ave Med Ali Akid, 1004 El Menzah, Tunis, Tunisia;2. High Institute of Sport and Physical Education, Sfax University, Sfax, Tunisia;3. High Institute of Sport and Physical Education, Sfax University, Sfax, Tunisia;4. Institute of Sport Science, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany;5. Department of Physical and Cultural Education, Hellenic Army Academy, Athens, Greece;6. Exercise Physiology Laboratory, Nikaia, Greece;7. Institute of Sport Science, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany;8. Faculty of Physical Education, Assiut University, Assiut, Egypt;9. Research and Education Centre, Aspetar, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar |
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| Abstract: | The aim of this study was to examine the effects of 3 and 5 weeks of detraining after 14 weeks of resistance training at a specific time of day on performances during the squat jump (SJ) and the maximal voluntary contraction (MVC). Thirty-one healthy male physical education students (age: 23.1 ± 1.0 years; height: 176.1 ± 6.3 cm; weight: 74.9 ± 10.9 kg) were randomly assigned to either a morning training group (MTG, training between 07:00 and 08:00 h, n = 10), an evening training group (ETG, training between 17:00 and 18:00 h, n = 11) or a control group (CG, no training, n = 10). Participants then performed eight test sessions (twice per day, at 07:00 and 17:00 h) over the course of four phases: during pre-training, immediately post-training, and after 3 and 5 weeks of detraining. Before each test session, oral temperature was recorded. During the first 12 weeks of resistance training, participants performed 3 sets of 10 repetitions to failure (10-RM) for 4 exercises (squat, leg press, leg extension and leg curl, with 2 min of recovery between each exercise); during the last two weeks, training intensity increased to 8-RM with 3 min of recovery between each exercise. Oral temperature was significantly higher at 17:00 than 07:00 h during all test periods (p < 0.05). Likewise, SJ and MVC performances were significantly higher at 17:00 h than 07:00 h during all four test days in ETG and CG, and before training and 3 and 5 weeks after training in MTG (p < 0.05). For both training groups, most SJ and MVC performances (except MTG at 07:00 h and ETG at 17:00 h) returned to baseline values after 5, but not after 3, weeks of detraining. This study showed that 14 weeks of training at a specific time of day blunted the diurnal variation of MVC and SJ in the MTG. The improvement in performance brought about by resistance training was partially retained after 3 weeks of detraining (unless training had taken place at a non-habitual time of day) but was lost after 5 weeks of detraining. There was no effect of the time of training on core temperature. |
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| Keywords: | time-of-day muscle power muscle strength sports competitions |
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