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- Cook, C. J., et al.
(författare)
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Morning based strength training improves afternoon physical performance in rugby union players
- 2014
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Ingår i: Journal of Science and Medicine in Sport. - : Elsevier BV. - 1878-1861 .- 1440-2440. ; 17:3, s. 317-321
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivesTo determine if a morning training session could alter afternoon physical performance. Moreover, as testosterone (T) and cortisol (C) concentrations are significant predictors of physical performance, and both show circadian declines across the day, we examined the effects of morning training on diurnal T and C responses. DesignEighteen semi-professional rugby union players completed this randomised and counter-balanced study. MethodsFollowing morning saliva collection (0900. h), players completed a control (rested), Sprint (5 × 40 m) or Weights (3 repetition-maximum [RM] bench press and squat) trial. In the afternoon (15:00. h) of each trial, a further saliva sample was collected before players completed a performance test (3RM back squat and bench press, 40. m sprint, countermovement jump [CMJ]). ResultsSalivary T concentrations declined from am to pm under Control and Sprint, but not under Weights. Delta T, from am to pm, was greater under Control (-10.9±2.4pgml-1) compared to Sprints (-6.2±7.1pgml-1) and Weights (-1.2±5.5pgml-1) (p≤0.001). Delta C, from am to pm, was greater under Control compared to both Sprint and Weights (p<0.05). Players elicited better CMJ peak power, 40-m time, 3RM bench and squat performance under Weights compared with Control and Sprint (p<0.05). Faster 40-m times were seen under Sprint, when compared to Control (p<0.05). ConclusionsPerforming morning strength training is associated with improved physical performance in the afternoon. Additionally, the circadian decline in T concentrations appeared offset by morning training. However, it is unclear if T concentrations are, in part, causal of these improved responses or simply a reflective marker. © 2013 Sports Medicine Australia.
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- West, Daniel J., et al.
(författare)
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THE INFLUENCE OF THE TIME OF DAY ON CORE TEMPERATURE AND LOWER BODY POWER OUTPUT IN ELITE RUGBY UNION SEVENS PLAYERS
- 2014
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Ingår i: JOURNAL OF STRENGTH AND CONDITIONING RESEARCH. - 1533-4287. ; 28:6, s. 1524-1528
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Tidskriftsartikel (refereegranskat)abstract
- Core temperature typically displays a low circadian in the morning before peaking later in the day, and these changes occur within small physiological ranges. Body temperature plays an important role in physical performance, and some athletes may be required to train and compete in both the morning and evening. However, the influence of the circadian change in body temperature and its influence on physical performance in elite athletes are unclear. This study examined the effects of the time of day on core temperature and lower body power output in elite rugby union sevens players. Sixteen elite rugby union sevens players completed morning (in AM) countermovement jump and core temperature (T-core) measurement, which were then repeated later the same day (in PM). Countermovement jump was processed for peak power output (PPO). Data were analyzed using paired samples t-test and Pearson's product moment correlation and are presented in mean +/- SD. T-core significantly increased from AM to PM (AM, 36.92 +/- 0.23 vs. PM, 37.18 +/- 0.188 degrees C; P < 0.001) with PPO significantly increasing from AM to PM in all 16 players (AM, 5248 +/- 366 vs. PM, 5413 +/- 361 W; P < 0.001). The delta change in T-core (0.26 +/- 0.138 degrees C) and PPO (164 +/- 78 W) was significantly related (r = 0.781; P < 0.001). In conclusion, small circadian changes in core temperature can influence physical performance in elite athletes. Coaches should seek to use strategies, which may raise morning body temperature to offset the circadian low in the morning.
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