The study in question
The most frequently cited investigation is the work by Soligard and colleagues, published in 2008 in the British Medical Journal. It established the reputation of structured warm-ups.
For sports science, the study design was unusually robust: a cluster-randomised controlled trial involving 125 Norwegian clubs and 1,892 female players aged 13 to 17, divided into an intervention group and a control group. The intervention teams completed the programme now known as FIFA 11+: eight minutes of running drills, ten minutes of strength and balance, two minutes of running. The control teams warmed up as they had done previously.
What the study found – and what it didn't
It pays to take a closer look here, as nuance is usually lost in summaries.
Clear and statistically significant reductions were observed in severe injuries and overuse injuries. In other words, precisely the types of setbacks that sideline a player for weeks.
For the overall figure, the result was weaker than commonly cited claims suggest. Across all injuries, the rate ratio was 0.71 — mathematically a 29 per cent reduction — with a 95 per cent confidence interval of 0.49 to 1.03. This interval spans 1. That means: for the total number of all injuries, this single study did not reach standard statistical significance.
This is not an argument against prevention. It is an argument against relying solely on one study. The 30 to 50 per cent range comes from synthesising multiple investigations and later systematic reviews, not from this single figure.
The factor that determines effectiveness
The most practically relevant insight only emerged from follow-up analyses: The effect depends almost entirely on compliance.
Players with high programme compliance had an approximately 35 per cent lower injury risk in the analyses. Teams that only ran the programme sporadically came nowhere near this figure. The literature suggests a minimum threshold of around twice per week.
From this follow three key takeaways that matter more in daily training than any percentage:
The effect builds up over time. Depending on training frequency, it takes around ten to twelve weeks before results become noticeable. If you abandon the programme after four weeks because nothing has changed, you never truly tested it.
The effect fades again. Prevention isn't a course you complete once; it's a habit you maintain. Once you stop, risk levels gradually return to baseline.
Execution quality makes all the difference. These programmes work through neuromuscular control, not through the sheer volume of repetitions. A sloppily executed lunge achieves nothing. To see what this looks like in practice, see integrating 11+ into training and core training for footballers.
What this means for your coaching practice
- In the warm-up, not at the end. The programmes studied are warm-up routines. At the end of a session, fatigue compromises technical execution.
- At least twice a week. Below that, the data is sparse and the effect correspondingly low.
- Ten to twelve weeks of patience. It makes no sense to evaluate before then.
- Watch closely and correct. Half the benefit lies in correct technique, not just going through the motions.
- It costs nothing. No equipment, no licence, no specialised expertise. The only investment is ten to fifteen minutes of training time.
Where the evidence remains thin
Honesty is essential, otherwise this article is just another presentation slide.
The baseline study examined girls aged 13 to 17. Applying the findings to boys, adults, and grassroots youth football is plausible and supported by further research, but it is not equivalent to direct evidence. What makes sense in children's football can be found in injury prevention in youth football.
Compliance is hard to measure. Studies rely on self-reporting by coaches. Believing you run the programme consistently doesn't necessarily mean you actually do.
Individual injury types vary in how well they are documented. The evidence is particularly strong for hamstring injuries, but weaker for other areas. Details on this can be found in knee injuries and ankle injuries.
Summary
- The standard figure of "30 to 50 per cent" stems from synthesising multiple studies, not just one.
- The most cited single study (Soligard and colleagues, BMJ 2008) clearly demonstrated fewer severe injuries and fewer overuse injuries. For total injuries, the confidence interval was 0.49 to 1.03, which crosses 1.
- The most reliable finding is not the percentage figure, but its dependence on regularity: high programme compliance yields roughly one third less risk.
- At least twice a week, during the warm-up, ten to twelve weeks of patience, and pay close attention to execution.
Frequently Asked Questions
Is the 30 to 50 per cent figure accurate or not?
As a ballpark figure across multiple studies: yes. As the result of a single investigation: not with that level of certainty. Anyone citing the number should present it as a range drawn from the wider body of research.
How long does it take before you notice results?
Around ten to twelve weeks when completed twice a week. The effect relies on neuromuscular adaptation, which takes weeks to develop.
Is once a week enough?
The data does not support this. Twice a week is considered the minimum threshold; below that, the proven benefit is negligible.
Does this also apply to boys and adult players?
The baseline study examined girls aged 13 to 17. Subsequent studies support transferring the conclusions to other groups, but the evidence there is less conclusive.
What happens when we stop?
The protective effect wears off. Adaptations regress just like any other training adaptation. Prevention is therefore an ongoing habit, not a short phase in pre-season.
Practical questions on injury prevention
How do you identify overload in your players before injuries occur?
Pay attention to subjective warning signals from your players in daily training, such as increasing muscle soreness, poor sleep, or persistent fatigue. Tracking these factors daily on a scale of 1 to 5 helps you identify critical developments early. From U11 upwards, recording subjective post-training load provides additional insight. With the Player OS app, your players enter this data independently so you can manage workload in time.
How do you permanently integrate preventive warm-up routines into your weekly training?
Perform the exercises at the start of every session as a fixed component instead of including them erratically. Schedule warm-ups with a consistent structure throughout the entire season. As soon as your players know the routines, they save time and execute movements more cleanly. Manage intensity and rest periods purposefully through your session planning so warm-ups do not drain too much energy before the main part.
How do you safely manage a player's return from injury?
Increase workload gradually and divide the return to play into clear phases. Before taking the next step, verify that your player completes movement patterns pain-free and without compensatory movements. Rely on documented assessments to evaluate load tolerance objectively. Consult with medical staff and adjust training volumes individually before returning the player fully to team sessions.