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Incidence, mechanism and risk factors for injury in youth rock climbers
  1. Kaikanani Y Woollings1,
  2. Carly D McKay1,
  3. Jian Kang1,
  4. Willem H Meeuwisse1,2,
  5. Carolyn A Emery1,3,4
  1. 1Faculty of Kinesiology, Sport Injury Prevention Research Centre, University of Calgary, Calgary, Alberta, Canada
  2. 2University of Calgary Sport Medicine Centre, University of Calgary, Calgary, Alberta, Canada
  3. 3Faculty of Medicine, Alberta Children's Hospital Research Institute for Child & Maternal Health, University of Calgary, Calgary, Alberta, Canada
  4. 4Faculty of Medicine, Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
  1. Correspondence to Kaikanani Woollings, Faculty of Kinesiology, Sport Injury Prevention Research Centre, University of Calgary, 2500 University Dr. NW, Calgary, Alberta, Canada T2N 1N4; n.woollings{at}ucalgary.ca

Abstract

Background Rock-climbing participation has grown globally in recent years, and the sport was officially recognised by the International Olympic Committee in 2010. The epidemiology of climbing injuries in adults has been examined, but few studies have investigated injury in youth climbers.

Objective To examine the incidence, mechanisms and risk factors for injury in recreational and elite sport climbers and boulderers aged 11–19 years.

Study design Cross-sectional.

Methods Youth (n=116) were recruited from climbing facilities across Alberta, Canada. Participants completed an anonymous questionnaire from October 2012 to March 2013. Climbing injury incidence proportions and incidence rates (IR) were calculated. ORs with corresponding 95% CIs were estimated for possible risk factors.

Results The injury IR was 4.44 injuries/1000 climbing hours (95% CI 3.74 to 5.23). Sprains (27%) and strains (26%) were the predominant injury types, and repetitive overuse was the primary mechanism of injury (42%). Hands and fingers were the most commonly injured locations (21%). Exploratory analyses showed three risk factors for injury: older age (15–19 vs 11–14 years; OR=11.30, 95% CI 2.33 to 54.85), injury in a sport other than climbing (OR=6.46, 95% CI 1.62 to 25.68) and preventive taping (OR=5.09, 95% CI 1.44 to 18.02).

Conclusions Injury risk is high in youth climbers. Findings are consistent with the reported rates, types and mechanisms in adults. Modifiable risk factors warrant further investigation to inform the development of injury prevention strategies, targeting high-risk climbers including adolescents and those with previous injury.

  • Children
  • Sport climbing
  • Epidemiology
  • Injury
  • Rock climbing

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Introduction

Rock climbing has been steadily gaining popularity worldwide, both as a recreational activity and as a competitive sport. Climbing includes a variety of disciplines that utilise unique movement forms, resulting in distinct injury patterns. Sport climbing is a discipline in which routes are normally a maximum of 30 m in height. The climber is attached to a rope that is clipped into permanent bolts spaced intermittently from the bottom up (lead climbing), or anchored at the top of the climb (top roping). This allows climbers to incur frequent falls safely. Bouldering, however, uses large crash mats instead of ropes to protect climbers from falls, as ‘boulder problems’ are usually short and low to the ground. Bouldering allows climbers to practise difficult and powerful moves repeatedly. Both disciplines are performed outdoors on rock and indoors on artificial holds and surfaces.

Previous research has focused on injuries sustained in traditional rock climbing, ice climbing, mountaineering and alpine settings in adult participants.1–5 Injuries sustained in these activities consist largely of trauma resulting from falls or overhead rock fall, injuries from weather (eg, frostbite) and negative altitude effects, with some mention of training-related injuries.2 ,6 The existing studies involving sport climbers and ‘boulderers’ report high injury rates ranging from 103 injuries/100 participants/year to 137 injuries/100 participants/year, and 4.2 injuries/1000 climbing hours in adult climbers.7–9 There is a paucity of epidemiological research examining injuries and risk factors in youth climbers specifically.10–12 Existing studies are mostly case reports or focused on one single type of injury (eg, epiphysial fractures, finger injuries).10–14 Greater knowledge regarding injury patterns and risk factors for youth climbers would help to inform the development of injury prevention strategies in this population.

The purpose of this study was to examine injury rates, types, mechanisms and risk factors for injury in youth who participate in recreational and elite sport climbing and bouldering.

Methods

Study design

This was a cross-sectional study, based on the completion of an anonymous questionnaire, and was approved by the Conjoint Health Research Ethics Board of the University of Calgary (ethics ID 24718).

Participants

An estimated target sample size of 206 participants was calculated. The questionnaire was distributed to recreational and elite youth climbers at 10 indoor climbing facilities in Alberta, Canada from October 2012 to March 2013. This time frame encompassed most of the indoor competitive climbing season. Participants were males and females aged 11–19 years. Written consent was obtained from participants and parents/guardians (if less than 18 years). Participants were recruited from competitive junior teams, recreational programmes, lessons and workshops. In addition, convenience sampling was conducted at two youth competitions. Participants were classified as recreational or elite as per the inclusion criteria below.

Inclusion criteria

  1. Recreational: Participation in sport climbing or bouldering at a climbing facility in Alberta, and participation in sport climbing or bouldering at least once per month during the previous year.

  2. Elite: Participation in competition climbing during the 2012–2013 competition season and for a minimum 2 years prior, or participation in an international competition during the previous 12 months.

  3. Elite: Climbers participated in regular season climbing competitions during the 2012–2013 competition season and for a minimum 2 years prior, or participated in at least one international climbing competition during the previous 12 months.

Data collection procedure

Study questionnaire

Participants completed the questionnaire either online or in a paper format. Demographic information, including climbing experience, discipline (ie, bouldering or sport climbing) and venue (ie, outdoors or indoors), was collected. The questionnaire included items regarding exposure time (eg, hours per day, days per week, months per year), injury types, anatomical locations, and mechanisms of injury incurred in the previous 12 months. The questionnaire was face validated through interviews with researchers, climbers, parents, coaches, physicians, physiotherapists and one occupational therapist (n=20).

Primary analyses

The primary outcome measure was climbing injury, defined as any physical complaint that resulted from sport climbing or bouldering, indoors or outdoors, irrespective of the need for medical attention or time loss from climbing activities. This definition was adapted from the consensus statement on injury definitions and data collection procedures in studies of football injuries,15 and from the definition used by the International Mountaineering and Climbing Federation (UIAA) Medical Commission Injury Classification for Mountaineering and Climbing Sports, modified for sport climbing and bouldering.16 Injuries requiring medical attention and injuries resulting in time loss from full climbing participation were also calculated. Time-loss injury was categorised according to severity using groups defined by Fuller et al:15 Slight injury (no time loss), minimal (1–3 days), mild (4–7 days), moderate (8–28 days), severe (>28 days) and career ending.

Exploratory analyses

The potential intrinsic risk factors examined were climbing level (ie, recreational or elite), age, sex, height, weight, the difficulty at which participants climbed using the Yosemite Decimal System converted to the standardised metric scale, injury in other sports and risk-taking behaviours (ie, smoking tobacco, alcohol consumption, seatbelt non-use) that have been shown to be related to youth injury in sport.17 The potential extrinsic risk factors included socioeconomic status, specific discipline of climbing, participation in other sports, helmet use, preventive taping, use of a cool-down and climbing exposure hours collected for indoor and outdoor climbing. Exposure hours were also used to estimate the injury incidence rates (IR).

Statistical methods

STATA V.12 (Statacorp, College Station, Texas, USA) was used to perform statistical analyses. Injury types, mechanisms and anatomical locations were described using means or medians. The primary analysis included univariate logistic regression analysis (offset for exposure hours) to examine the difference in injury risk in recreational climbers compared with elite climbers. This study was powered to detect a clinically important difference in injury incidence proportion (IP) of 20% between elite and recreational groups. Exploratory univariate logistic regression analyses (offset for exposure hours) were used to assess potential risk factors for injury, chosen for this analysis based on previous literature.3 ,4 ,6–10 ,12 ,14 ,17–25 Risk factors for time-loss injury were also examined for comparison purposes. A multivariate logistic regression analysis offset for exposure hours was conducted for covariables that demonstrated a 20% difference in crude OR with 95% CI and a significance level of 5% (α=0.05). This percentage was chosen arbitrarily as a reasonable cut-off for clinical importance. Confounding and effect modification were examined for covariables.

Results

Participants

Sixty-two competitive and 223 recreational climbers were approached (N=285). Of these, 126 climbers (44%) consented to participate, and 116 (41%) completed the questionnaire (figure 1).

Figure 1

Recruitment flow chart.

On the basis of the inclusion criteria, participants were categorised as elite (n=50) or recreational (n=66). Table 1 summarises the participant characteristics.

Table 1

Baseline characteristics for recreational and elite climbers

Climbing participation

The mean amount of time reported for indoor climbing was 7 h/week, 9 months/year. Overall, less time was spent outdoor climbing (mean 6 h/week, 3 months/year). Elite climbers spent more time climbing than recreational climbers (table 2).

Table 2

Participation hours per week by venue for recreational and elite climbers

Climbing injury IR and IP

Seventy-three (63%) participants sustained at least one new climbing injury in the 12 months prior to the study, including those reporting ‘pain or discomfort’. Thirty-six (31%) reported multiple injuries. The total number of injuries incurred was 142, resulting in an IP of 122/100 participants/year (95% CI 98 to 147). The overall IR was 4.44/1000 participation hours (95% CI 3.74 to 5.23).

Forty-one (82%) elite climbers sustained 84 injuries (IP=168/100 participants/year (95% CI 134 to 208)), compared with 32 (48%) recreational climbers who sustained 58 injuries (IP=88/100 participants/year (95% CI 67 to 114)). The IR for elite climbers was 4.27/1000 h (95% CI 3.45 to 5.29), and for recreational climbers it was 4.71 injuries/1000 climbing hours (95% CI 3.64 to 6.09).

Time-loss injuries

Overall, 109 (77%) injuries resulted in at least 1 day of time loss from climbing (IP=94/100 participants/year (95% CI 72 to 116); IR=1.81/1000 h (95% CI 1.38 to 2.34)). The median amount of time loss was 14 days (IQR 7, 61), including ongoing injuries where participants had not yet returned to full activity. Figure 2 shows the proportions of injuries incurring time loss from climbing, according to severity groups.

Figure 2

Proportion of injuries incurring time loss from climbing in days.

Medically treated injuries

Seventy-six (54%) participants received medical attention (IP=66/100 participants/year (95% CI 46 to 85); IR=2.62/1000 h (95% CI 2.09 to 3.25)), including first aid, treatment by an emergency medical technician/paramedic, physician, physiotherapist, chiropractor, athletic therapist, massage therapist or ‘other’ treatment (eg, acupuncture, osteopathic manual therapy, regular icing of the injury). Physiotherapy was the most common treatment reported (33%).

Injuries by climbing venue and by discipline

Tables 3 and 4 describe the proportion of injuries sustained by climbing venue (ie, indoor or outdoor) and discipline (ie, sport climbing or bouldering).

Table 3

Injury IP and IR by venue

Table 4

Injury incidence proportion (IP) by discipline

Injury characteristics

Injury types are summarised in table 5. There were 85 self-reported injuries, 22 (26%) of which were reinjuries. These did not include other ‘pains or discomforts’ as these were not classified by injury type or mechanism. ‘Pains or discomforts’ were described by open answer (eg, low back pain, general pain in a specific area during climbing). The predominant self-reported injury type was ligament sprain, followed by muscle or tendon strain. Of the 142 injuries and ‘pains or discomforts’, the highest proportion reported was to the hands and fingers (21%), followed by the shoulders (15%), knees (9%) and ankles (9%).

Table 5

Self-reported climbing injury by type

The most commonly reported mechanism of injury was repetitive overuse, followed by falls, and those incurred during strenuous moves (ie, any physically demanding climbing move). Most repetitive overuse injuries involved the upper body, while most fall-related injuries involved the lower extremity (figure 3).

Figure 3

Climbing injury by mechanism of injury and anatomical location.

Risk factors

Preliminary univariate analyses, summarised in table 6, indicated several potential risk factors to include in the multivariate model. Results from univariate analyses for time-loss injury yielded largely the same findings as for all climbing injuries, with the exception of height, weight and alcohol consumption. On the basis of multivariate logistic regression (table 7), climbers aged 15–19 years were at 11.3 times greater risk of injury (95% CI 2.33 to 54.85) than those aged 11–14 years. Compared with those who had no other injuries, the OR of injury was 6.46 times greater (95% CI 1.62 to 25.68) for those who had also sustained an injury from another sport. Finally, the OR of injury for those who used preventive taping was 5.09 times greater (95% CI 1.44 to 18.02) than for those who did not. Age group and sport climbing grade were not found to modify the relationship between injury and climbing level. There was no evidence of confounding by other covariables.

Table 6

Exploratory univariate analyses

Table 7

Exploratory multivariate logistic regression predicting climbing injury

Discussion

This is the first study to examine IR, injury types, mechanisms of injury and risk factors for injury in recreational and elite youth climbers. Sport climbing and bouldering are highly male-dominated at the elite level. The findings in the present study appear to be consistent with this disparity, though we cannot know if a similar proportion of male and female climbers declined in each category. The mean age of elite climbers was older than that of recreational climbers, explaining the greater mean height and weight as well as the higher grades at which this group climbed (ie, higher skill level).

The injury IP we found was high (122 injuries/100 participants/year), but similar to that for adult sport climbers7 and boulderers.20 However, as exposure is critical in examining the injury risk, the injury IR was calculated and found to be 4.44 injuries/1000 climbing hours. This rate is high and similar to the 4.2 injuries/1000 h reported by Backe et al9; it is similar to the injury IR reported in youth ice hockey (4.13 injuries/1000 participation hours),26 and slightly lower, though comparable, to that reported in youth soccer following the same injury definition with clinical verification of injuries in a prospective design (5.59 injuries/1000 participation hours).21

The IR for medically treated injuries was 2.62 injuries/1000 climbing hours, while for time-loss injury it was 1.81 injuries/1000 climbing hours. The distribution of injuries by time loss in this study suggests a greater time loss than was previously reported in youth ice hockey and other sports.21 ,22 ,26 This is most likely due to the nature of these climbing injuries, a high proportion of which were ongoing overuse injuries or injuries from traumatic falls. It is possible that there was an under-reporting of minor injuries due to negative attitudes around injury, as well as related to the recall bias, resulting in an over-representation of time-loss injuries.

Sprains and strains were the most commonly occurring injuries in these young climbers, followed by tendonitis. ‘Repetitive overuse’, being any injury caused by repeated movements or stress and usually beginning with an insidious onset, was found to be the most commonly self-reported mechanism of injury, followed by fall-related injuries. However, it is unknown to what extent there was consistent interpretation among participants as to the meaning of ‘repetitive overuse’. The highest proportion of injuries occurred in hands, fingers and shoulders. Stratifying by the mechanism of injury, repetitive overuse injuries occurred predominantly in the upper extremities. This is consistent with previous research involving adult climbers in which overuse injuries, sprains and strains to the upper body were found to be the most common.6 ,8 ,10 ,18 ,20 ,23 ,27 The high proportion of fall-related injuries (32%) reported in the present study was mainly lower extremity injuries, which accounted for 50% of the knee and ankle injuries reported. Neuhof et al18 reported a similar proportion of 39.9% for fall injuries, and Josephsen et al7 reported that 23% of injuries occurring outdoors and 50% of injuries occurring indoors resulted from falls.

Examination of the crude and exposure hours-adjusted ORs supports evidence that the risk of injury increases with the participation hours in sport.22 The results of the multivariate logistic regression identify three potential risk factors for injury: being 15–19 years old, having had an injury in another sport or using preventive taping.

The wide CI for the OR reported for the older age group may be due to the low number of participants in this group with the combination of variables in the multivariate model. Injury in other sports has not been previously examined as a risk factor for climbing injuries. It is uncertain whether this finding is related to physiological factors, the amount of exposure time to sport in general, risk behaviours or other variables. The temporal association between ‘other sport injury’ and ‘climbing injury’ remains unclear in the context of this cross-sectional study; however, the sport injury literature demonstrates that previous injury is a predictor of subsequent injury.22 ,24 ,28 Preventive taping was used by 41% of participants, and in this study it was found to be a marker of susceptibility to injury. This result was contrary to previous findings by Josephsen et al7 who found that finger and wrist taping in adults decreased the risk of injury. Our result may be due to the fact that climbers who sustained previous injuries or who were injured used taping as a preventive measure for reinjury. Unfortunately, in a cross-sectional design, the temporal relationship cannot be established. Similarly, those participants already at a higher risk of injury (eg, older, elite climbers) may use more tape, causing taping itself to be indicative of a higher risk of injury. Lastly, these results may be explained by risk compensation, previously studied in several sports including skiing and snowboarding.29 In the context of youth climbing, it could be argued that individuals who use preventive taping may engage in more aggressive or riskier climbing behaviour. Further research is needed to prospectively examine this relationship.

Although this multivariate analysis was exploratory and underpowered to reach conclusive results, it did introduce potentially clinically significant findings that may inform future studies.

Limitations

Cross-sectional studies are subject to limitations inherent in their design. Specifically, it is not always possible to establish temporal relationships between risk factors and injuries.

Selection bias is possible in this study, as injured climbers may not have been attending indoor climbing facilities, where sampling took place, due to their injury.

Self-report designs are subject to potential self-diagnosis. Responses were subjective and injuries were not always diagnosed by a medical practitioner. To mediate this problem, injuries were objectively categorised by anatomical location and mechanism. Recall bias was possible, leading to under-reporting of minor injuries and comparative over-representation of more memorable traumatic injuries. This may explain the high proportion of medically treated and time-loss injuries. However, given that the largest proportion of injuries in this study were non-acute overuse injuries, the effect of recall bias is unclear.

The power for this study was limited, as the target sample size of 206 was not achieved. Although the anticipated compliance rate was 70%, only 116 of 285 climbers who were approached returned a questionnaire (41%). Emery et al22 reported compliance rates for their cross-sectional study as low as 41% for schools requiring signed parental consent. This may have been the reason for the low compliance in this study. However, given that the effect size found was much larger than expected (80% difference based on elite and recreational IPs), a statistically significant and clinically relevant difference was found.

The questionnaire was completed throughout the competitive season, and it is possible that this varying timing may have affected the reporting or recall of injuries. However, as injuries from the previous 1 year were captured, this did encompass one full competitive season and one full off-season for all participants.

The small outcomes and uneven clusters limited our ability to control for cluster. This study was not powered for a multivariate analysis, and thus the analyses examining risk factors were exploratory.

Conclusions

This is the first study to examine injury IRs, mechanisms of injury and risk factors for injury in youth climbers. The overall climbing injury IR was high. Hand, finger and shoulder ligament sprains and muscle strains were the most common injuries. Repetitive overuse was the primary mechanism of injury followed by falls. The results of this study indicate that adolescents (15–19 years) are at a greater risk of injury than younger adolescents (11–14 years). Youth who have been injured in a sport other than climbing and those who use preventive taping may also have a greater risk of injury.

Climbing injury research will benefit from future prospective cohort studies to establish temporal relationships between injuries and risk factors. Further examination of risk factors observed in this analysis, as well as additional modifiable potential risk factors, is warranted to inform the development of injury prevention strategies.

What are the new findings?

  • The findings demonstrated a high climbing injury incidence rate of 4.44 injuries/1000 climbing hours (95% CI 3.74 to 5.23) in young climbers, a rate similar to that in ice hockey and soccer players in the same age group.

  • Hand, finger and shoulder ligament sprains and muscle or tendon strains were found to be the most common injuries.

  • Repetitive overuse was reported as the primary mechanism of injury followed by falls.

  • Older age (15–19-year-olds), injury in a sport other than climbing and preventive taping were shown to be significant risk factors for injury.

How might this impact on clinical practice in the near future?

  • Healthcare providers will require familiarity with climbing injuries in order to recognise and manage these injuries as this sport continues to grow in global popularity. This growth will inevitably result in a greater number of injuries and consequent time loss from activity.

  • High injury incidence rates, especially of overuse injuries and fall-related injuries, will increase the long-term burden on the healthcare system.

  • Knowledge around the main mechanisms of injury and the possible risk factors for injury will lead to the development of injury prevention measures that clinicians can begin to implement in their practice.

Acknowledgments

The Sport Injury Prevention Research Centre is one of the International Research Centres for Prevention of Injury and Protection of Athlete Health supported by the International Olympic Committee. The authors acknowledge and thank the participants in this study, their parents, and the climbing facilities that helped facilitate this research.

References

Footnotes

  • Contributors KYW, CDM, JK, WHM and CAE contributed to the planning, conduct of analysis and reporting of the results. CAE and KYW are responsible for the overall content of this research as the co-guarantors.

  • Funding The authors acknowledge the funding provided by Alberta Innovates Health Solutions and the Alberta Children's Hospital Research Institute for Child & Maternal Health through the Talisman Energy Research Fund in Healthy Living and Optimising Health Outcomes. CAE is supported by a Population Health Investigator Award from Alberta Innovates Health Solutions and a Professorship in Pediatric Rehabilitation in the Faculty of Medicine, University of Calgary (Alberta Children's Hospital Foundation).

  • Competing interests None.

  • Ethics approval The Conjoint Health Research Ethics Board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Elements of this data are available on request.

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