Table 3.
Results of subgroup analysis.
| Moderator | Within-subgroup comparison | Heterogeneity (Chi2 test) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| No. of effect sizesa | Total player exposures | IRR | 95% CI | p-value | Possible risk reduction, % | Q-value | p-value | I2 | |
| STUDY DESIGN AND QUALITY (SENSITIVITY ANALYSIS) | |||||||||
| Study design | |||||||||
| Cluster RCTs | 13 | 1,277,433 | 0.59 | 0.47–0.74 | <0.001 | 41 | 49.81 | <0.001 | 76 |
| Cohort studies | 4 | 147,324 | 0.52 | 0.27–1.00 | 0.050 | 48 | 4.4 | 0.22 | 32 |
| Test for subgroup differences | 0.14 | 0.71 | 0 | ||||||
| Study quality | |||||||||
| Low (PEDro ≤ 4) | 7 | 389,003 | 0.37 | 0.23–0.6 | <0.001 | 63 | 9.3 | 0.1 | 46 |
| Medium (PEDro 5–7) | 5 | 577,713 | 0.6 | 0.44–0.82 | 0.002 | 40 | 14.41 | 0.006 | 72 |
| High (PEDro ≥ 8) | 5 | 458,041 | 0.74 | 0.56–0.98 | 0.040 | 26 | 14.72 | 0.005 | 73 |
| Test for subgroup differences | 5.9 | 0.05* | 66.1 | ||||||
| MODERATOR ANALYSIS (DOSE-RESPONSE) | |||||||||
| Neuromuscular training dosage | |||||||||
| Session duration | |||||||||
| Low (10–15 min) | 5 | 175,445 | 0.55 | 0.42–0.72 | <0.001 | 45 | 4.34 | 0.36 | 8 |
| Medium (20–30 min) | 10 | 1,152,336 | 0.6 | 0.46–0.76 | <0.001 | 40 | 44.56 | <0.001 | 80 |
| High (<30 min) | 1 | Not estimable | |||||||
| Test for subgroup differences | 0.21 | 0.65 | 0 | ||||||
| Training frequency | |||||||||
| 1x/wk | 3 | 408,770 | 0.76 | 0.53–1.10 | 0.140 | 24 | 12.71 | 0.002 | 84 |
| 2x/wk | 6 | 695,605 | 0.5 | 0.29–0.86 | 0.010 | 50 | 16.96 | 0.005 | 71 |
| 3x/wk | 5 | 157,332 | 0.4 | 0.31–0.53 | <0.001 | 60 | 1.02 | 0.91 | 0 |
| >3x/wk | 1 | Not estimable | |||||||
| Test for subgroup differences | 7.69 | 0.02* | 74 | ||||||
| Weekly training volume | |||||||||
| Low (20–30 min) | 6 | 500,196 | 0.67 | 0.51–0.90 | 0.007 | 33 | 17.83 | 0.003 | 72 |
| Medium (30–60 min) | 6 | 688,655 | 0.45 | 0.25–0.81 | 0.008 | 55 | 19.16 | 0.002 | 74 |
| High (>60 min) | 4 | 188,258 | 0.54 | 0.32–0.90 | 0.020 | 46 | 11.41 | 0.01 | 74 |
| Test for subgroup differences | 1.7 | 0.43 | 0 | ||||||
| Intervention volume and period | |||||||||
| Total number of training sessions | |||||||||
| Low (18–29 sessions) | 2 | 83,681 | 0.48 | 0.27–0.85 | 0.010 | 52 | 0.67 | 0.41 | 0 |
| Moderate (30–60 sessions) | 8 | 1,055,386 | 0.57 | 0.41–0.79 | 0.001 | 43 | 42.17 | <0.001 | 83 |
| High (90+ sessions) | 4 | 140,348 | 0.51 | 0.28–0.90 | 0.020 | 49 | 9.13 | 0.03 | 67 |
| Test for subgroup differences | 0.29 | 0.87 | 0 | ||||||
| Intervention period | |||||||||
| Short term (1.5–6 months) | 6 | 324,742 | 0.57 | 0.41–0.79 | 0.001 | 43 | 11.21 | 0.05 | 55 |
| Long term (7–12 months) | 10 | 1,043,399 | 0.57 | 0.42–0.76 | <0.001 | 43 | 42.21 | <0.001 | 79 |
| Test for subgroup differences | 0 | 0.95 | 0 | ||||||
*
Significant subgroup difference;
a
Number of individual IRRs considered for each subgroup comparison; IRR, injury rate ratio; CI, confidence interval; RCT, randomized controlled trial; wk, week.