title: Soccer half-time strategy influences thermoregulation and endurance performance.
abstract: OBJECTIVE
  In the first 15 min of the second half in professional soccer, there is a reduction of high intensity distance covered and a high incidence of injuries sustained, possibly due to a reduction in body temperature during the half-time (HT). The aim of this study was to investigate the effect of active and passive re-warm-up strategies on cardiovascular (heart rate, HR) and thermoregulatory stress, and second-half soccer-specific endurance performance (SSEP).
  
  
  METHODS
  Seven professional players performed two intermittent field tests of 16.5 min duration, with a 15 min HT. On separate, randomised occasions, 4 trials were completed during which different HT strategies were undertaken between minutes 7 and 14 of the HT interval. Two passive trials were completed: rest control trial (CON), or players were immersed to the gluteal fold in a hot bath (approximately 40 degrees C-passive heating, PH); in the active trials, players performed at 70% maximum HR, either steady-state non-specific active heating (cycling, NSAH) or intermittent soccer-specific active heating (sprinting repeatedly, SSAH). HR and core temperature (Tc) were measured every 5 min, and body weight was recorded pre and post each trial.
  
  
  RESULTS
  Active re-warm-up strategies maintained SSEP in the second period with respect to CON (P<0.01), whereas PH did not reduce the decrement in performance (P>0.05). Active heating strategies increased HR during HT in comparison to CON, whereas PH did not. During the HT period in the CON trial, T(c) decreased by 0.97+/-0.29 degrees C, PH and SSAH trials did not attenuate this decrease (P>0.01), whereas NSAH increased T(c) in respect to CON (P<0.01). These differences in HR and T(c) between re-warm-up strategies during HT were not apparent at the end of the trials.
  
  
  CONCLUSIONS
  Active re-warm-up strategies during HT attenuated the decrement in second-half SSEP that was observed during passive trials.
authors.affiliation: Department of Sport, Health and Exercise Science, University of Hull, Hull, UK. r.j.lovell@hull.ac.uk
authors.forename: R J
authors.initials: RJ
authors.lastname: Lovell
authors.forename: I
authors.initials: I
authors.lastname: Kirke
authors.forename: J
authors.initials: J
authors.lastname: Siegler
authors.forename: L R
authors.initials: LR
authors.lastname: McNaughton
authors.forename: M P
authors.initials: MP
authors.lastname: Greig
mesh_terms: D000293:Adolescent; D001831:Body Temperature; D001833:Body Temperature Regulation; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D008297:Male; D010807:Physical Endurance; D011446:Prospective Studies; D012916:Soccer; D013178:Sports Medicine; D013647:Task Performance and Analysis; D013995:Time