Rethink your warm-up: Make the most of pre-game and half-time warm-up strategies

OBJECTIVE
A warm-up routine has been suggested to be critical in increasing preparedness for subsequent effort and thus maximising performance. An active warm-up consists of using physical activity, while a passive warm-up depends on the use of external means. However, the effectiveness of the warm-up routine appears to be dependent on many factors: such as the type of sport, athlete fitness and experience, tasks to be performed, environmental conditions, and constraints imposed by event organisers. The aim of this systematic review was to analyse research findings on the effects of warm-up, post-warm-up
(time between the end of a warm-up and the start of the match), and re-warm-up (half-time break) strategies on explosive efforts in team-sports.
WHAT THEY DID
Of 330 studies, 30 articles were included. 19 used a warm-up strategy, 5 used a post-warm-up strategy and 6 used a re-warm-up strategy. Any peer-reviewed publication that had a warm-up intervention in team-sports were included.
WHAT THEY FOUND
A wide range of warm-up routines showed improvements in performance with a large effect size. For example, 8x50m sprints, a 5-minutes jog with 5RM leg press, or completing back squats at the end of a typical warm-up improves explosive performance. This shows that a short, specific warm-up is as effective as a long, specific warm-up for sprint performance. In addition, 7-minutes of dynamic exercises after 5-minutes of jogging was associated with general improvement in explosive tasks such as sprinting, jumping, and agility performance. Small-sided games and whole-body vibration may also improve explosive task performance. Static stretching was the least effective at improving sprint performance and agility.
For post-warm-up strategies, a progressive decrease in performance was observed in resting situations with a 4-6% decrease in sprint performance and 12-20% decrease in jump performance. The use of a heated garment had a moderate effect on sprint performance, but when combined with 3x5 jumps with 20% bodyweight, a large effect was observed on sprint performance. No strategy was found to be effective in improving jump performance. Similarly, a decrease in performance was identified when passive rest was implemented during the re-warm-up. Heat garments had the best effect size compared with resting in sprint and jump performance. Eccentric exercises was the only intervention found to be detrimental to sprint and jump performance.

Practical Takeaways
Of the 19 warm-up articles, 69% showed an improvement in sprint performance, 87.5% showed an improvement in jump performance, and 83% showed an improvement in agility performance. This suggests that a properly structured warm-up strategy can increase athlete performance in many different sports. However, comparing results between studies is difficult due to different control groups and different warm-up protocols. Therefore, to define a properly structured warm-up strategy, it is important to know which variables are critical for optimising subsequent explosive performance. Research tends to recommend a short, active warm-up that progresses in intensity (see Science for Sport article below for practical strategies) until maximal effort close to the end of the warm-up. Shortly afterward, passive strategies should be implemented before the game and the re-warm-up should include short sprints and jumps before entering the game.

Warm-up strategies:

1) Research suggests a short warm-up (<20 minutes) has the same benefits on performance as a long warm-up (>20 minutes).
2) Warm-ups performed at an intensity too high for too long could result in fatigue and impair subsequent exercise.
3) However, what must be considered is the athlete. Some athletes feel psychologically more prepared after a 25-minutes warm-up than a shorter warm-up, regardless of performance decreases.
4) Explosive tasks such as sprints and jumps require a more strenuous warm-up intensity (~90% of Max HR). For example, sprint tasks performed at the end of the warm-up have shown a 2-3% improvement in sprint and jump performance.
5) An optimal strategy may look like this: 10-15-minutes increasing intensity (~50-90% HRmax) ending with sprints.
6) Reducing warm-up time and intensity may delay fatigue and lead to overall higher performance during the match.

Post-warm-up strategies:

Post-warm-up strategies:

1) After 20-minutes rest, athletes decreased jump performance by approx. 15%. After 40-minutes rest, jump performance decreased by approx. 20% and sprint performance by 6%.
2) Standing up 20-minutes after the warm-up may reduce the decrease in performance compared with sitting on the bench. However, this would depend on the rules of the organisers and whether standing is allowed.
3) Passive strategies such as heat garments after warm-up can significantly maintain the benefits gained from the warm-up or at least reduce the decline.
4) Combining a passive strategy with an active one (e.g. 3x5 jumps) has been found to be even more beneficial.

Re-warm-up strategies:

1) Team-sport half-times are usually between 10-20 minutes. Passive rest of this time has been shown to decrease physical and cognitive performance.
2) Very little research has investigated the effects of different re-warm-up protocols. Of the few studies, 4x5 jumps and 7-8 minutes of running at ~70% HRmax have been shown to increase subsequent performance.
3) Theoretically, a re-warm-up could consist of a combination of heat maintenance strategies (active and/or passive), hormonal priming (feedback, video clips), caffeine, and carbohydrate consumption. These separate strategies have been shown to reduce performance decrements in the second half.
4) While these strategies haven’t been tested together, some sort of heat garment and/or an active re-warm-up routine should be performed before subsequent activity.