Risk factors for hamstring muscle injury in male elite football: medical expert consensus

Key points

1. 0121 potentially preventable risk factors were identified; 12 were extrinsic (coaching/club) and 9 were intrinsic (player-related)
2. 02Lack of communication between medical and coaching staff scored the highest overall weighted average (3.7 out of 4)
3. 03Lack of regular exposure to high-speed football during training was the second-ranked factor (weighted average 3.6)
4. 04Clubs with higher hamstring injury rates rated fatigue (3.6 vs 2.6) and player wellness (3.0 vs 2.0) as more important than lower-burden clubs
5. 05Residual weakness after a previous hamstring injury was the top-rated intrinsic player factor (weighted average 3.5)

How it was conducted

Design

Observational cohort study with prospectively collected injury data and a retrospective two-stage expert survey

Participants

15 chief medical officers from 15 European male professional football clubs (from 9 countries) that qualified for UEFA Champions League or Europa League in both 2019/2020 and 2020/2021

Survey process

Stage 1: open question to elicit suggested risk factors; Stage 2: 5-point Likert scale rating of all 21 suggested factors

Groups

LOW group (n=7 clubs with below-average hamstring injury burden) vs HIGH group (n=8 clubs with above-average burden) over two seasons

Primary outcome

Weighted average importance score (0-4) for each of 21 modifiable risk factors, compared between LOW and HIGH groups

What they found

• 21 modifiable risk factors were identified: 12 extrinsic and 9 intrinsic; mean weighted average was 3.1 for extrinsic vs 2.9 for intrinsic factors
• Lack of communication between medical and coaching staff: overall weighted average 3.7 (LOW group 3.6, HIGH group 3.8)
• Lack of regular exposure to high-speed football during training: overall 3.6 (LOW 3.8, HIGH 3.5)
• Load on players: overall 3.5 (LOW 3.1, HIGH 3.8)
• Lack of in-season recovery strategies: overall 3.5 (LOW 3.6, HIGH 3.4)
• Residual weakness after previous hamstring injury (intrinsic): overall 3.5 (LOW 3.6, HIGH 3.5)
• Fatigue (intrinsic): overall 3.1 (LOW 2.6, HIGH 3.6) -- HIGH group rated it 38% higher than LOW group
• Player wellness (intrinsic): overall 2.5 (LOW 2.0, HIGH 3.0)
• Style of coach leadership: overall 2.7 (LOW 2.1, HIGH 3.3) -- HIGH group rated it 57% more important than LOW group
• Average match-play hamstring injury incidence: LOW group 2.9, HIGH group 5.4, all teams 4.3 per 1000 player hours

Limitations

• Small sample of only 15 clubs limits generalisability to other elite or semi-professional levels
• Hamstring injury definition was heterogeneous, grouping structural and functional injuries with different mechanisms
• The study is descriptive and cannot establish causality between expert opinions on risk factors and actual injury rates
• Short two-season observation period (2019/2020 and 2020/2021) may not capture longer-term trends

Why it matters

For patients

Players in clubs where coaching and medical staff communicate well and training includes regular high-speed work may face lower hamstring injury risk, even though injury prevention programmes already exist.

For clinicians

Medical staff should prioritise building structured communication pathways with coaches and advocate for balanced training load and high-speed exposure, especially in clubs with elevated hamstring injury rates.

For readers

Club culture and coaching decisions, not individual player traits, appear to drive most preventable hamstring injuries at elite level, pointing to organisational rather than purely physical interventions.