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The Effect of Training at the Same Time of Day and Tapering Period on the Diurnal Variation of Short Exercise Performances

Chtourou, Hamdi1,2; Chaouachi, Anis1; Driss, Tarak3; Dogui, Mohamed4; Behm, David G5; Chamari, Karim1; Souissi, Nizar1,6

Journal of Strength & Conditioning Research: March 2012 - Volume 26 - Issue 3 - pp 697-708
doi: 10.1519/JSC.0b013e3182281c87
Original

Chtourou, H, Chaouachi, A, Driss, T, Dogui, M, Behm, DG, Chamari, K, and Souissi, N. The effect of training at the same time of day and tapering period on the diurnal variation of short exercise performances. J Strength Cond Res 26(3): 697–708, 2012—The purpose of this investigation was to assess the effects of training and tapering at the same time of the day on the diurnal variations of short exercise performances. Thirty-one physically active men underwent 12 weeks of lower-extremity resistance training and 2 weeks of tapering. These subjects were matched and randomly assigned to a morning training group (MTG, training times 0700–0800 hours, n = 10), an evening training group (ETG, training times 1700–1800 hours, n = 11), and a control group (CG, completed all tests but did not train, n = 10). Muscular strength and power testing was conducted before (T0) and after 12 weeks of training (T1) and after 2 weeks of tapering (T2) in the morning (0700–0800 hours) and in the evening (1700–1800 hours). All morning and evening tests were performed in separate sessions (minimum interval = 36 hours) in a randomized design. In T0, the oral temperature and performances during the Wingate, vertical jump (squat jump and countermovement jump), and maximal voluntary contraction tests were higher in the evening than in the morning for all the groups. In T1, these diurnal variations were blunted in the MTG and persisted in the ETG and CG. In T2, the 2 weeks of tapering resulted in further time of day–specific adaptations and increases in short-term maximal performances. However, there was no significant difference in the relative increase between the MTG and the ETG after both training and tapering. From a practical point of view, if the time of competition is known, training and tapering sessions before a major competition must be conducted at the same time of the day at which one's critical performance is programmed. Moreover, if the time of the competition is not known, a tapering phase after resistance training program could be performed at any time of the day with the same benefit.

1Tunisian Research Laboratory “Sports Performance Optimization” National Center of Medicine and Science in Sports (CNMSS), Tunis, Tunisia; 2Research Unit, High Institute of Sport and Physical Education, Sfax, Tunisia; 3Research Center on Sport and Movement, UFR STAPS, Paris Ouest Nanterre University, Paris, France; 4Research Unit “Neurophysiology of Vigilance, of Attention and Performances” 99/UR/08-23, Service of Functional Exploration of the Nervous System, CHU Sahloul, Sousse, Tunisia; 5School of Human Kinetics and Recreation; Memorial University of Newfoundland, St. John's Newfoundland, Canada, A1C 5S7; and 6High Institute of Sport and Physical Education, Manouba University, Ksar-Said, Tunisia

Address correspondence to Hamdi Chtourou, h_chtourou@yahoo.fr.

© 2012 National Strength and Conditioning Association