Warming up again at half time in team sports
Peter Reaburn, Department of Health and Human Performance, Central Queensland University
While warming-up has recently been suggested by research to have little benefit on injury prevention, sport science research has shown that warm-up before playing sport positively benefits performance. But what about warming-up again before the second half of a game? Few players or coaches seem to do it, especially at the local level. A 2004 study I recently came across from Scandinavia examined muscle temperature and sprint performance in soccer players to see what affect a re-warm-up would have on second half performance in an actual match.
The two-part study involved 25 players aged 27.0±1.5 years from the Danish Fourth Division. Part one examined changes in muscle temperature during a competitive game where muscle temperature was measured when players were subbed off. In part two, both the muscle temperature and sprint performance were measured during a competitive but friendly match. In this match, eight players performed moderate-intensity activities (running and drills at 70% of maximal heart rate) at half-time (re-warm-up). Another eight players did no warm-up before the second half. Sprint performance was measured electronically using a repeated sprint test that consisted of three 30m sprints separated by a 25-second active recovery period during which the players jogged back to the start line. These tests were carried out on all 16 players after the pre-game warm-up, when players came off just before half-time, five minutes before they went on for the second half (after the re-warm-up for the eight re-warm-up players), and again just before full-time.
In all the 25 players, muscle temperature was 36.0±0.2°C at rest and increased significantly to 39.4±0.2°C before the game and remained unaltered during the first half. At half-time, the muscle temperature decreased significantly to 37.4±0.2°C, and again increased to 39.2±°C during the second half. In the second friendly competitive game, the muscle temperatures were similar before and after the first half in both groups. However, muscle temperature was significantly 2.1±0.1°C higher in the re-warmed-up players prior to the second half. At the onset of the second half, the sprint performance was significantly reduced by 2.4% in the group who did not re-warm-up, but unchanged in the re-warmed-up group. The decrease in muscle temperature was correlated to the decrease in performance.
This study demonstrated that in soccer, and therefore possibly in most team sports where sprint speed is crucial, the decrease in muscle temperature during half-time is associated with lower sprint ability at the onset of the second half. In contrast, sprint performance appears to be maintained when low-moderate intensity activities are done at half-time to maintain muscle temperature. The message is obvious: players should ideally be warmed-up again before the second half to maintain performance in the second half.
Mohr, M, Krustrup, P, Nybo, L, Nielsen, JJ and Bangsbo, B 2004. 'Muscle temperature and sprint performance during soccer matches: beneficial effect of re-warm-up at half-time', Scandinavian Journal of Medicine and Science in Sports, 14(3):56-62.