Proportion of cases and controls exposed to the number of graded exercises in each time period
| No of exercises | Activity grade 1 (probably strengthen/maintain quadriceps) | Activity grade 2 (possibly strengthen/maintain quadriceps) | Activity grade 3 (generally not strengthen/maintain quadriceps) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Period 1–n (%) | Period 2–n (%) | Period 1–n (%) | Period 2–n (%) | Period 1–n (%) | Period 2–n (%) | ||||||||||||
| Cases | Controls | Cases | Controls | Cases | Controls | Cases | Controls | Cases | Controls | Cases | Controls | ||||||
| 0 | 162 (75.0) | 667 (77.2) | 139 (64.4) | 570 (66.0) | 142 (65.7) | 599 (69.3) | 135 (62.5) | 589 (68.2) | 140 (64.8) | 571 (66.1) | 132 (61.1) | 543 (62.8) | |||||
| 1 | 30 (13.9) | 117 (13.5) | 45 (20.8) | 175 (20.3) | 39 (18.1) | 184 (21.3) | 44 (20.4) | 189 (21.9) | 45 (20.8) | 177 (20.5) | 53 (24.5) | 202 (23.4) | |||||
| 2 | 9 (4.2) | 27 (3.1) | 13 (6.0) | 50 (5.8) | 12 (5.6) | 25 (2.9) | 15 (6.9) | 27 (3.1) | 15 (6.9) | 59 (6.8) | 16 (7.4) | 60 (6.9) | |||||
| ⩾3 | 4 (1.9) | 16 (1.8) | 8 (3.7) | 32 (3.7) | 11 (5.1) | 19 (2.2) | 10 (4.6) | 22 (2.5) | 4 (1.9) | 20 (2.3) | 3 (1.4) | 22 (2.5) | |||||
| Missing | 11 (5.1) | 37 (4.3) | 11 (5.1) | 37 (4.3) | 12 (5.6) | 37 (4.3) | 12 (5.6) | 37 (4.3) | 12 (5.6) | 37 (4.3) | 12 (5.6) | 37 (4.3) | |||||