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Table 2 Summary of trial characteristics

From: The efficacy of exercise in preventing injury in adult male football: a systematic review of randomised controlled trials

References country

Primary outcome measure/means of reporting

Participants

Intervention

Follow-up period

Compliance

Effect of intervention (95% CI)

Conclusion

Comments

Askling et al. [52] Sweden

Time loss Injuries to the hamstring% Injury occurrence

IG: 15 CG: 15 Mean age IG: 24 CG: 26

10 weeks preseason intervention encompassing 16 sessions of hamstring training using concentric and eccentric actions, after a standardized warm-up

1 season of 10 months

NR

IG 20% CG 67% Significantly fewer injuries in the IG (p < 0.05)

Eccentric hamstring training may result in a lower occurrence of hamstring strains

High injury rate in the CG (67%) No loss to FU

Engebretsen et al. [12] Norway

Time loss Injuries to the ankle, knee, groin, or hamstring in high-risk players Mean injury Incidence per 1,000 h/RR)

High-risk players IG: 193 CG: 195 Mean age NR

Progressive exercise program for the ankle, knee, groin, and/or hamstring 3 × a week for 10 weeks then × 1 a week for the rest of the season

1 season of 7 months

19–30% during the preseason intervention

IG = 4.9 CG = 5.3 RR 0.93 (0.71–1.21) This was NS (p = 0.50)

The risk of injury in players deemed at higher risk was not changed with a targeted training program

19 of the 31 teams already performed preventive exercises in regular training ITT analysis conducted 3% players lost to FU

Fredberg et al. [51] Denmark

All injuries to the Achilles and/or patellar tendon% Injury risk/RD

IG: 98 CG: 146 Mean age 25

Eccentric exercise and stretching program of Achilles and patellar tendons All exercises performed for 10 min 3 times a week

12 months

2.25/week

Patella = RD 0% (p = 1.0) Achilles = RD 2% (p = 0.86) These were NS

Eccentric exercise had no positive effects on the risk of Achilles or patella tendon injury

CG ‘allowed to continue with the different types of flexibility training that they all used’ No ITT analysis 17% team withdrawn

Hölmich et al. [53] Denmark

All injuries to the groin Time to first groin injury/HR

IG: 524 CG: 453 Mean age IG: 24 CG: 25

6 exercises including hip adduction and abdominal strengthening, coordination and stretching, 2–4 times a week

1 season of 10 months

NR

HR 0.69 (0.40–1.19) This was NS (p = 0.18)

Intervention resulted in no significant reduction in groin injury risk

No ITT analysis Injured players censored 56% teams and 7% of remaining players withdrawn

Mohammadi [55] Unclear

All ankle inversion sprain re-injuries RR of injury per 1,000 h

Each IG: 20 CG: 20 Mean age 25

Progressive ankle disc training for 30 min daily (PT) Isometric and dynamic specific evertor strength training (ST).

1 season after injury

NR

PT − RR 0.13 (0.003–0.93) significantly fewer injuries in the IG (p = 0.02) ST − RR 0.5 (0.11–1.87) This was NS (p = 0.27)

Progressive ankle disc training may reduce the risk of recurrent ankle inversion injuries

Information on much of the study design is lacking No ITT analyses No loss to FU

Petersen et al. [50] Denmark

All hamstring injuries Injury rates per 100 player seasons/rate ratio

IG: 461 CG: 481 Mean age IG: 23 CG: 24

10 weeks of progressive eccentric hamstring training followed by a weekly program

1 season (2 half seasons over 12 months)

91% of the initial 27 sessions

IG 3.8 CG 13.1 Rate ratio 0.292 (0.136–0.631) Significantly fewer injuries in the IG (p < 0.001)

Additional eccentric hamstring training significantly reduced the risk of hamstring strain

No ITT analysis 7% teams and 8% of remaining players withdrawn

Tropp et al. [56] Sweden

Time loss ankle sprains in those with a history of sprain% Injury risk

CG: 75 IG: 65 Mean age NR

10 min of ankle disc training 5 times a week for 10 weeks. Then 5 min, 3 times a week

6 months

NR

IG 5% CG 25% Significantly fewer re-injuries in the IG (p < 0.01)

In players with a history of ankle sprain, ankle disc training is indicated to reduce the risk of re-injury

Information on key aspects of study design lacking No loss to FU

van Beijsterveldt et al. [54] Holland

All injury incidences Injury incidence per 1,000 sports h

IG: 223 CG: 233 Mean age IG: 24 CG: 25

10 exercises, used at each training session, 2/3 times a week. Included core stability, muscle strengthening, proprioceptive, stabilization and plyometric exercises

1 season of 9 months

71% player compliance

IG: 9.6 (8.4–11.0) CG: 9.7 (8.5–11.1) This was NS (p > 0.05)

No significant differences found in the overall injury incidence or injury severity between the IG and CG

No ITT analysis 6% players lost to FU

  1. CG control group, CI confidence interval, FU follow-up, HR hazard risk, IG intervention group, ITT intention-to-treat analysis, NR not reported, NS not significant, RD risk difference, RR relative risk, ST strength training, PT proprioceptive training.