Table 1 Characteristics of cases and controls and event around injury. Values are numbers (percentages)

Characteristic
 Cases with head injuries (n=693)
 Cases with neck injuries (n=131)
 Controls (n=3295)
Age (years):



<15
257 (37.1)
65 (49.6)
1277 (38.7)
15-25
287 (41.4)
49 (37.4)
1185 (36.0)
≥26
149 (21.5)
17 (13.0)
832 (25.3)
Missing data
—
—
1 (0.03)
Sex:



Male
421 (60.8)
55 (42.0)
1457 (55.8)
Female
272 (39.3)
76 (58.0)
1837 (44.2)
Missing data
—
—
1 (0.03)
No of days participated in activity in season:



1
160 (23.1)
31 (23.7)
929 (28.2)
2-10
333 (48.1)
49 (37.4)
1690 (51.3)
≥11
168 (24.2)
41 (31.3)
591 (17.9)
Missing data
32 (4.6)
10 (7.6)
85 (2.6)
Previous head or neck injury:



No
515 (74.3)
96 (73.3)
2643 (80.2)
Yes
171 (24.7)
35 (26.7)
631 (19.2)
Missing data
7 (1.0)
—
21 (0.6)
Hours of participation in activity before injury:



<2
239 (34.5)
50 (38.2)
1322 (40.1)
2-5
396 (57.1)
80 (61.1)
1688 (51.2)
≥6
57 (8.2)
1 (0.8)
284 (8.6)
Missing data
1 (0.1)
—
1 (0.03)
Damage to non-helmet equipment:



No
626 (90.3)
119 (90.8)
3062 (92.9)
Yes
53* (7.7)
9 (6.9)
189{dagger} (5.7)
Missing data
14 (2.0)
3 (2.3)
44 (1.3)
Self reported speed:



Slow
155 (22.4)
33 (25.2)
1005 (30.5)
Average
206 (29.7)
46 (35.1)
1171 (35.5)
Fast
231 (33.3)
41 (31.3)
739 (22.4)
Missing (and other{ddagger})
101 (14.6)
11 (8.4)
380 (11.5)
Mechanism of injury:



Collision or jump
344 (49.6)
56 (42.8)
1321 (40.1)
Fall
346 (50.0)
75 (57.3)
1949 (59.2)
Missing
3 (0.4)
—
25 (0.8)
Non-helmet protective equipment:



No
652 (94.1)
122 (93.1)
3159 (95.9)
Yes§
 41 (5.9)
9 (6.9)
136 (4.1)

* Excludes 28 individuals who had damaged either their goggles or sunglasses. These individuals were considered not to have had equipment damage.

{dagger} Excludes 5 individuals who had damaged either their goggles or sunglasses. These individuals were considered not to have had equipment damage.

{ddagger} For example, injured on lift.

§ Excludes all yes answers with only "goggles" or "sunglasses" specified.