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Half-time in team sports: An opportunity to influence subsequent performance?
- 1. Half-time in team sports: An opportunity to influence subsequent performance? @drmarkru55ell mark.russell@northumbria.ac.ukresearchgate.net/profile/Mark_Russell4 #NUTSRS15 Dr Mark Russell Programme Leader MSc Strength and Conditioning, Northumbria University National Lead for Applied Exercise Physiology, UK Deaf Sport
- 2. The primary purpose of half-time: A practitioners perspective Red: Recovery after first half Yellow: Preparation before second half Blue: Transitional period between the two halves #NUTSRS15
- 3. Towlson et al. (2013, JSS, 31, 1393-1401) #NUTSRS15
- 4. Mohr et al. (2005; JSS, 23, 593-599) #NUTSRS15 ?
- 5. Mohr et al. (2005; JSS, 23, 593-599) #NUTSRS15
- 6. Hawkins and Fuller (1996, BJSM, 30, 165-170) #NUTSRS15
- 7. Lovell et al. (2013, SJMSS, 23, 105-113) Temp ↓ 1°C #NUTSRS15
- 8. Mohr et al. (2004, SJMSS, 14, 156-162) 1.1°C ↓ core temperature over half-time correlated to a 2.4% ↓ in sprint performance #NUTSRS15
- 9. Resting for the entire 15 min half-time interval in soccer is not an optimal preparation for the second half (Mohr et al., 2005) #NUTSRS15 Half-time may provide an additional opportunity on the day of competition to benefit subsequent performance (Russell et al., 2014)
- 10. How can we improve body temperature before the second half?
- 11. Barriers to rewarm-ups Alternative methods of preserving body temperature may therefore be desirable Towlson et al. (2013, JSS, 31, 1393-1401)
- 12. Passive heat maintenance seeks to maintain muscle and body temperature by attenuation of temperature losses typically by specialised garments or heating methods. #NUTSRS15
- 13. A passive heat maintenance strategy implemented during a simulated half-time improves lower body power output and repeated sprint ability in professional Rugby Union players Russell et al. (2015, PLOS One) Investigate the effects of wearing a survival jacket during a simulated half-time period in professional Rugby Union players
- 14. A passive heat maintenance strategy implemented during a simulated half-time improves lower body power output and repeated sprint ability in professional Rugby Union players Russell et al. (2015, PLOS One) Repeated sprint test 1 DowntimeWarm-up First half Half-time intervention Repeated sprint test 2 Seated in normal kit + survival jacket Seated in normal kit ControlPassive Second half25 min 15 min
- 15. Russell et al. (2015, PLOS One) A passive heat maintenance strategy implemented during a simulated half-time improves lower body power output and repeated sprint ability in professional Rugby Union players Half-timeWarm-up Warm -up Downtime First half Second half -0.7% -1.5% -80% temp gained in warm-up
- 16. A passive heat maintenance strategy implemented during a simulated half-time improves lower body power output and repeated sprint ability in professional Rugby Union players Russell et al. (2015, PLOS One) Intervention 1.5%
- 17. A passive heat maintenance strategy implemented during a simulated half-time improves lower body power output and repeated sprint ability in professional Rugby Union players Russell et al. (2015, PLOS One) Start of second simulated half End of first simulated half Intervention 3.2%
- 18. Passive heat maintenance may be able to protect against losses of body temperature typically observed over a half-time period and protect subsequent exercise performance. #NUTSRS15
- 19. Hydro-nutritional strategies • Between 6 and 10% carbohydrate containing drinks recommended before and during intermittent exercise • Improve performance by delaying fatigue – Improving hydration status – Maintaining muscle glycogen stores – Increasing blood glucose concentrations #NUTSRS15
- 20. Russell et al. (2012, JSAMS, 15, 348-354) -30% #NUTSRS15 6.0% CHO drink (CHO):
- 21. Kingsley et al. (2014, JSAMS, 17, 239-243) -39% -30% #NUTSRS15 9.6% CHO–caffeine drink (H-CHO): 5.6% CHO drink (CHO): 57% of participants returned hypoglycaemic values (<3.80 mmol/L) at 60 min
- 22. * -40% #NUTSRS15 6.0% CHO drink (CHO):
- 24. High vs. low glycaemic index carbohydrate? 8 % PalatinoseTM (Low GI) vs. maltodextrin (High GI) electrolyte- containing beverages consumed before each half (~20 g∙h-1 CHO)
- 25. Low glycaemic index carbohydrates, when consumed before each half of soccer-specific exercise may offer an alternative strategy to high glycaemic index carbohydrate consumption due to more favourable physiological responses and potential benefits to skilled performance #NUTSRS15
- 26. #NUTSRS15
- 27. Prof. Liam KilduffDr Mike Kingsley Prof. David Benton Prof. Christian Cook Tony Pennock Liam Harper Dr Emma Stevenson Dr Anthony Watson Dr Dan West Gary Richards Acknowledgements
Editor's Notes
- First of all, welcome to this team sport symposium. Originally we anticipated about 20 attendees, but within a week of registration going live we had double that so it was a nice problem to have considering how we’d cope with such a great turnout but nevertheless, thank you for being here today. So I’m presenting on half time in team sports, and we all know that half time is period of between 10 and 20 minutes that separates consecutive halves of competition.
- Evidence from match analysis studies tend to demonstrate that the initial stages of the second half elicit different responses to other parts of the game. Now it is worth noting here that the optimal “reference time-point” against which comparisons should be made remains unclear, and that tactical and match-specific factors have been proposed to account for such differences, but Mohr et al observed that 20% of a sample of European football players demonstrated their least intense match period between 45-60 min. Similarly some of Matt Weston’s work has also explored these differences and confirmed similar findings in 2013 by using a more robust statistical approach
- Evidence from match analysis studies tend to demonstrate that the initial stages of the second half elicit different responses to other parts of the game. Now it is worth noting here that the optimal “reference time-point” against which comparisons should be made remains unclear, and that tactical and match-specific factors have been proposed to account for such differences, but Mohr et al observed that 20% of a sample of European football players demonstrated their least intense match period between 45-60 min. Similarly some of Matt Weston’s work has also explored these differences and confirmed similar findings in 2013 by using a more robust statistical approach
- From an injury perspective, of the number of actual injuries observed in the second half of professional matches, with Hawkins and Fuller observing increased numbers of treatments in players in the 1994 World Cup finals.
- One of the key areas of interest over the last decade or so has been the examination of muscle temperature responses to the cessation of activity over the half-time break and how this affects subsequent exercise.
- Unsurprisingly, Mohr and colleagues highlighted that reductions in muscle temperature over half-time were associated with a reduced sprint time thereafter.
- Consequently, a number of studies have sought to examine the efficacy of half-time active rewarm-up strategies with up to 7 minutes of exercise demonstrating ergogenic effects on markers of both physical and technical performance.
- However, despite overwhelming support of practitioners about the physiological benefits of a secondary WU during half-time, a number of barriers exist to implementing such strategies; including “lack of time” and “unwillingness of the coach/manager.”
- Conversely, passive heat maintenance may offer alternative means of preventing temperature losses
- In a study led by Prof. Liam Kilduff at Swansea University and in collaboration with Biarritz Rugby, we recently examined the response of 18 professional rugby players exercising in ambient conditions to the application of a survival garment in the time separating consecutive repeated sprint tests.
- Significant increases in core temperature occurred following the warm-up (approx. 2%), but following the rest period that preceded the start of exercise, most of the temperature gained was lost. The first repeated sprint test elevated core temperature but less temperature was lost in the passive heat maintenance trial when compared to the control condition.
- What does this mean for performance? Well as you’d expect there were no differences between trials prior to the intervention being administered but passive heat maintenance improved sprint times in the first two 40 m repeats by approximately 1.5%. Similar findings were also observed for countermovement jump heights achieved after the simulated half-time.
- What does this mean for performance? Well as you’d expect there were no differences between trials prior to the intervention being administered but passive heat maintenance improved sprint times in the first two 40 m repeats by approximately 1.5%. Similar findings were also observed for countermovement jump heights achieved after the simulated half-time.
- Worth noting at this point that further work is needed to examine the effects of heat maintenance strategies over prolonged periods of subsequent exercise as it is unclear whether alleviating a chance for “temperature recovery” during half-time has detrimental effects. May also be implications given the upcoming venue of World Cup in Qatar
- Empirical evidence and as highlighted by Towlson, a perceived behaviour at half-time relates to the consumption of nutritional products. Carbohydrate-containing fluids, typically between 6 and 10% concentration, consisting of primarily high-glycaemic index carbohydrates are typically consumed during match-play and at half-time.
- However, while the effects of such drinks are proposed to maintain blood glucose concentrations throughout the full duration of match-play, we have rarely seen this when experimental protocols include a half-time break. In a study where a 6% sucrose-electrolyte beverage was consumed before and every 15 min during each half of normal time, we noticed elevated blood glucose concentrations in CHO trial up until half-time. However, recommencing exercise following a passive half time period induced a transient decline of 30% in glucose concentrations at 60 min; a response we termed the exercise-induced rebound glycaemic response, which was present until latter stages of a match.
- 142 ± 3 g h−1, 54 ± 2 g h−1 and 5 ± 1 g h−1 throughout exercise during H-CHO, CHO and PL, respectively.
- To try and optimise half time interventions, we have recently compared a high versus a low glycaemic index carbohydrate to a placebo beverage when consumed in a more ecologically valid manner (ie., during the warm-up and at half-time) before and during intermittent exercise.