Risk Factors For Sports Concussion: Only Concussion History, Game Action Certain To Increase Risk, Study Finds
12. Body checking (low level of certainty that a risk factor for concussion)
Body checking is thought to increase concussion risk, especially in younger players.
- 4 of the 6 studies showed a greater concussion risk due to body checking in ice hockey players ages 11 to 16
- A prospective study of 986 ice hockey players reported an increased concussion risk for those permitted to body check (13-14 and 15-16 years) compared to those who were not (9-10 years), but the age difference between the comparative groups makes drawing conclusions about the effect of checking on concussion risk difficult.
- Although prohibiting body checking at younger age groups is thought to increase injury risk due to poor technique, one study found no difference in concussion risk between players with body-checking experience (checking allowed at 9-10 years old) and novices (no checking alllowed)
- Only 2 of the 5 studies on body checking were of a high level of evidence of I, with the remaining studies being level II and III.
A limitation is that most lacked age-matched comparative groups, thus a low level of certainty was given for body checking as a concussion risk estimate.
13. Environment (low level of certainty that a risk factor for concussion)
3 studies analyzed whether environmental factors affect concussion risk:
- Neither of two level II studies comparing concussion risk on natural and artificial grass in elite soccer players found a significant difference in concussion risk between the two surfaces, although one noted a tendency for match concussion to be reduced on the artificial turf. Both lacked the large numbers of concussion often required to identify significant associations.
- A large scale level II retrospective study found that youth football-related concussions were more likely to occur at school compared with at a recreational facility or home.
“Owing to the limited number and size of studies observing the effect of playing environment, a low level of certainty was assigned,” the study said.
14. Other factors (low level of certainty that a risk factor for concussion)
The following risk factors that were assessed by a single study were assigned a low level of certainty:
- rugby union players with less training and below average body mass had higher concussion rates
- junior ice hockey players in the lowest body weight quartile were at increased concussion risk;
- players who used a wheelchair sustained less concussions
- trends for fewer concussions were reported in youth ice hockey winning teams and football players with low aerobic fitness
- a trend has been identified between the temporal side of the head and concussions in soccer and football, which may be due to the fact that impacts to the side of the head are often outside of the player’s field of vision, limiting the abilty to engage the neck muscles necessary to decrease head acceleration after impact, thus increasing concussion risk; the side of the head may also be biomechanically more vulnerable to an impact force.
Level of Certainty (high-low) Definitions Used for Risk Assessment
| Level of Certainty | Definition |
| High | The available evidence includes consistent results from level 1 studies (randomized controlled trials and high quality (large sample sizes, robust methodology) prospective cohort studies). These studies provide a good estimate of risk and are unlikely to be strongly affected by future studies. |
| Moderate |
The available evidence includes sufficient evidence to determine that there is risk associated with the injury, but confidence in the estimate is constrained by factors such as the sample size and quality of the studies, as well as inconsistency of findings of individual studies, as well as inconsistency of findings across individual studies. As more information becomes available, the magnitude of risk could change or even alter the conclusion. |
| Low | The available evidence is insufficient to assess risk. Evidence is insufficient because of the limited number or size of studies, and inconsistency of findings across individual studies. More information may allow an estimation of risk. |
“The investigation of risk factors is an important step towards understanding [what causes] concussion. Although several risk factors were identified in the appraised studies, poor study methodology caused constrained estimation of concussion risk for almost all of the investigated risk factors, except previous concussion and match play,” Abraham writes.
1. Abrahams S, McFie S, Patricios J, Posthumus M, September AV. Risk factors for sport concussion: an evidence-based systematic review. Br J Sports Med. 2014;48:91-97. doi:10.1136/bjsports-2013-0927734.
