Baseline characteristics for included players (n=502)
| Extended Knee Control (n=197) | Adductor programme (n=125) | Comparison group (n=180) | |
| Age (years), mean±SD | 19.3±5.0 | 20.5±5.8 | 20.5±6.3 |
| Sex, n male; female (% male) | 71;126 (36.0) | 22;103 (17.6) | 62;118 (34.4) |
| Response to baseline questionnaire presented below* | n=178 responses | n=120 responses | n=164 responses |
| Participating in other sports, n (%) | 40 (22.5) | 30 (25.0) | 33 (20.1) |
| Estimation of training volume, median (IQR) | 5 (1) | 5 (1) | 5 (1) |
| Estimation of training load, median (IQR) | 5 (1) | 5 (1) | 5 (1) |
| Current injury/complaint, ankle, n (%) | 24 (13.5) | 24 (20.0) | 25 (15.2) |
| Previous injury/complaint, ankle, n (%) | 70 (39.3) | 37 (30.8) | 67 (40.9) |
| Current injury/complaint, knee, n (%) | 28 (15.7) | 27 (22.5) | 34 (20.7) |
| Previous injury/complaint, knee, n (%) | 74 (41.6) | 41 (34.2) | 61 (37.2) |
| Current injury/complaint, hamstrings, n (%) | 9 (5.1) | 5 (4.2) | 13 (7.9) |
| Previous injury/complaint, hamstrings, n (%) | 41 (23.0) | 20 (16.7) | 31 (18.9) |
| Current injury/complaint, groin, n (%) | 21 (11.8) | 6 (5.0) | 13 (7.9) |
| Previous injury/complaint, groin, n (%) | 54 (30.3) | 38 (31.7) | 47 (28.7) |
Estimation of training volume and training load was made on a 1–7 Likert scale, where 1 represents low and 7 high-training volume or load (amount of training and intensity of training). Current and previous complaints describe the number of players who, at baseline, indicated current or previous complaints in the location of interest.
*Missing data from 19 players in extended Knee Control, 5 players in the adductor group and 16 players in the comparison group who did not respond to the baseline questionnaire.