Evidence-based best-practice guidelines for preventing anterior cruciate ligament injuries in young female athletes: a systematic review and meta-analysis

Key points

1. 01Neuromuscular training is structured exercise (strength, plyometrics, balance, landing technique) aimed at improving movement control to prevent injury.
2. 02Across 18 studies, NMT roughly halved ACL injury risk (odds ratio 0.51), with similar effects in randomized and nonrandomized trials.
3. 03Interventions for middle and high school athletes (13 to 19 years) cut risk more (OR 0.38) than those for college or professional athletes (OR 0.65).
4. 04Programs with more landing stabilization and lower body strength exercises (Nordic hamstrings, lunges, heel-calf raises) were most effective, while balance, core, stretching, and agility added no measurable extra benefit for ACL prevention.
5. 05The authors built a simple checklist to score program quality, but note it is based on descriptive meta-regression and should be interpreted with caution rather than as proven causal recommendations.

How it was conducted

Design

Systematic review and meta-analysis of prospective controlled trials, using random-effects models and meta-regression

Search

PubMed and EBSCOhost (CINAHL Plus and MEDLINE) searched January 31, 2018; required a prospective controlled design, an NMT intervention, a comparison group, reported ACL injuries, and female participants

Intervention

Neuromuscular training programs aimed at reducing ACL injury incidence, with extraction of exercise type, volume, duration, timing, and implementer training

Outcomes

ACL injury odds ratio versus control; program quality assessed with the PEDro scale

Analysis

Univariate subgroup analyses (components in at least 25% of studies) plus meta-regression; publication bias tested via funnel plot asymmetry

What they found

• 18 studies with 27,231 participants and 347 ACL injuries; NMT reduced ACL injury risk from 1 in 54 to 1 in 111 (OR 0.51; 95% CI 0.37 to 0.69).
• Effects were similar for randomized (OR 0.54; 95% CI 0.35 to 0.83) and nonrandomized trials (OR 0.46; 95% CI 0.28 to 0.76); statistical heterogeneity was low (I2 = 23.3%).
• Middle and high school athletes: OR 0.38 (95% CI 0.24 to 0.60) vs college or professional athletes OR 0.65 (95% CI 0.48 to 0.89).
• In-season or combined preseason and in-season programs reduced risk (OR 0.50; 95% CI 0.36 to 0.70); preseason-only programs did not (OR 0.59; 95% CI 0.16 to 2.15, only 2 studies).
• Overall study quality was moderate (mean PEDro 5.45, SD 2.31 out of 10), and mean prescribed training was about 18.17 hours (around 24 minutes per session, 2.5 times per week).

Limitations

• The checklist and component recommendations come from descriptive meta-regression, not randomized comparison trials, so they should be interpreted with caution.
• Overall study quality was only moderate (mean PEDro 5.45) and 9 of the 18 included studies were nonrandomized.
• Only 2 studies informed the preseason-only estimate, leaving program timing effects uncertain.
• ACL injuries are rare events, so adequately powered randomized trials of specific components would need very large samples (over 8000).

Why it matters

For patients

If you are a young female athlete, doing a neuromuscular training program through the season can roughly halve your chance of an ACL injury.

For clinicians

Recommend in-season NMT led by trained implementers that emphasizes lower body strength (Nordic hamstrings, lunges, heel-calf raises) and landing stabilization, especially for school-age athletes, and use the checklist as a guide rather than a proven prescription.

For readers

Neuromuscular training reliably reduces ACL injury risk, but the detail of which exercises matter most rests on descriptive analysis and needs confirmation.