Table 1 Baseline characteristics of the participants
Variables | Categories | Median (IQR) | Total, N (%) | Low back pain, N (%) |
|---|---|---|---|---|
Total | 592 | 76 | ||
Gender | Male | 332 (56.1) | 35 (46.1) | |
Female | 260 (43.9) | 41 (53.9) | ||
Age (years) | 13.0 (12.0, 14.0) | |||
Body mass index | 18.3 (16.7, 19.8) | |||
Team levels | Recreation | 30 (5.1) | 2 (2.6) | |
Local competition | 376 (63.5) | 49 (64.5) | ||
Prefectural competition | 169 (28.5) | 22 (28.9) | ||
Tohoku district or national competition | 17 (2.9) | 3 (3.9) | ||
Training per week (days) | 5.0 (3.5, 6.0) | |||
Practice per day weekdays (hours) | 2.0 (2.0, 2.5) | |||
Practice per day weekends (hours) | 3.0 (3.0, 4.0) | |||
Frequency of participation in games | never | 31 (5.2) | 3 (3.9) | |
seldom | 57 (9.6) | 7 (9.2) | ||
sometimes | 175 (29.6) | 21 (27.6) | ||
often | 329 (55.6) | 45 (59.2) | ||
Practice intensity | Low-to-medium | 203 (34.3) | 18 (23.7) | |
High | 389 (65.7) | 58 (76.3) |