Eight studies researched body weight and/or BMI (6, 8, 18, 26, 28, 32, 35, 37). Of these, three prospective studies (1–3 years in length) with relatively high study quality scores (SQS) (17/32–19/32) found no association between body weight or BMI and climbing injury (8, 18, 35). Additionally, three cross-sectional studies also showed no associated risk of climbing injury with BMI (26, 28, 37), whilst one cross-sectional study with a study quality score of 16/32 did indicate increased risk of injury with increased BMI (6). Furthermore, a single study determined that increased BMI was associated with a higher risk of hand injuries, although the data was cross-sectional (SQS: 14/32) (32).

A total of 11 studies investigated the type of climbing and associations with injury (6, 8, 9, 24, 25, 27, 28, 39, 44, 46, 47). Overall, three studies indicated that bouldering as a climbing activity was associated with an increased risk of injury, when compared with other forms of climbing (6, 46, 47). In addition, one further study found that bouldering increased the risk of injury in a univariate analysis (p = 0.046), but not in a secondary multivariate analysis (8). Bouldering frequency was also associated with overuse injury in two further studies (9, 27). In two studies, outdoor injuries were more prevalent than indoors, namely 61% vs. 27% in boulderers (28), and 74% of outdoor male climbers (25). Two studies showed that traditional climbing was not associated with injuries, whilst other forms of climbing such as lead and sport were (27, 39). Finally, one study showed no associations between type of climbing and injury risk, although the study had a relatively low SQS and sample size (11/32; n = 50) (44).

Eight studies measured climbing volume in some form, as a potential risk factor for injury (6, 8, 21, 22, 35–37, 48). A single 5-year prospective study with a relatively high SQS (18/32) suggested that hours of training per week and training units per week were significantly associated with finger stress reactions (48). This is contradicted by evidence in two different longitudinal prospective studies (SQS: 14/32 and 19/32), showing that there were no significant associations between climbing time per month/per week and the development of a climbing injury (8, 35). Five cross-sectional investigations revealed an increased risk of injury with increased climbing volume (6, 21, 22, 36, 37), in particular for recurrent ankle sprains potentially relating to chronic ankle instability (21), and injures of the wrist/fingers (22). Nelson et al., (2017) reported that the odds of sustaining an injury in people climbing every week were 2.49 times higher (95% CI: 1.27–4.90) compared to those who climb at most once a month (36).

A total of 21 studies investigated climbing intensity and its relationship to injury, usually measured by climbing grade or level of climbing (e.g., intermediate vs. elite climbers) (2, 8, 9, 19, 21, 23, 25, 27, 29, 32, 33, 35–37, 40, 42, 44–48). Except for one prospective study (SQS: 14/32) (35), and a retrospective survey studying specifically injuries of the foot (SQS: 11/32) (29), the remaining 19 studies indicated some level of association between climbing intensity and an increased risk of injury, and the direction of this relationship was linear and positive (i.e., increased intensity = increased injuries). This evidence is supported by two longitudinal prospective studies (SQS: 18/32 and 19/32), specifically for finger stress injuries (48), and injuries of the entire upper extremity (8). Higher climbing intensity was associated with injuries in specific anatomical areas of the foot in three cross-sectional studies (21, 23, 33), the low back (47), and with degenerative changes in the shoulder (19). A single prospective study over one winter season highlighted that intermediate ice climbers were more likely to get injured than advanced ice climbers (2), however this finding is likely specific to ice climbers and probably alludes to the prevalence of traumatic injuries in the intermediate cohort as a result of lower skill.

Nine studies researched strength and conditioning measures as ether a risk factor or preventative strategy against climbing injuries (8, 22, 28, 30–32, 38, 42). Two studies reporting from the same randomized controlled trial (SQS: 18/32) showed that an injury prevention program based upon closed chain eccentric and strength exercises performed 3–4 times per week for one year, could reduce the likelihood of shoulder injuries (30) and elbow injuries (31). Additionally, prospective evidence (SQS: 14) suggests that weight training can reduce injuries in boulderers, although regular yoga practice had no positive effect (28). Cross-sectional evidence showed that the injured hand in climbers had weaker grip strength than the contralateral hand (22). An additional cross-sectional investigation adds weight to these findings (38) (SQS: 15/32), illustrating 7% mean deficits in maximal voluntary isometric contraction of the previously injured finger flexors. In contrast, prospective data (SQS: 19/32) indicates that higher strength of the middle finger and campus board training of the fingers is predictive of injury in the upper extremities (8). A different one-year prospective study (SQS: 19/32) found that fingerboard training was not associated with an increased risk of injury in boulderers (18). A single study examined cardiovascular training as preventive measure against hand injuries, and found no significant association (32). Finally, a single study discussed weak spinal musculature, strength training, and pull-up technique as indicators for climbing injury (42).

Two longitudinal prospective studies (SQS: 19/32) found that finger taping is not an effective intervention for the prevention of injuries in boulderers (18, 28). Meanwhile, one of these prospective studies indicated that wrist taping might have a protective effect (28). Three studies (two of which were prospective designs) indicated that performing a warm-up has no impact on the prevalence of climbing injuries (8, 28, 32), whilst a separate prospective study (SQS: 19/32) actually reported increased odds of injury when conducting a finger-specific warm-up (18) though this finding was attributed to confounding variables not measured within the study design. Performing a cool-down appeared to have no effect on injury in a single cross-sectional study (32), whilst a prospective study (8) (SQS: 19/32) showed that cooling-down was associated with increased risk of injury. Stretching was non-protective against climbing injury in two studies (28, 32). Two studies discussed the repetitive use of a “crimp grip” as a potential risk factor for injuries of the hand and fingers (20, 45), and found a significant association with injury risk. A single study reported a strong correlation between shoe size reduction and neurological symptoms in the foot e.g., tingling, although shoe size reduction was not correlated with pain or discomfort (SQS: 11/32) (29). Lastly, hydration was investigated in a single-study and found not to be associated with injury risk in climbers (32).

Age and years of experience are considered together, as they are likely somewhat colinear and may confound each other e.g., older people are more likely to have more years climbing experience. A total of 12 studies considered age as a risk factor for climbing injury, whilst ten studies examined years of climbing experience. Five studies identified older age as a significant risk factor for the development of climbing injury (6, 8, 22, 40, 41), whereby one of these studies was a higher-quality prospective study investigating upper extremity injuries only (8) (SQS: 19/32). Conflictingly, six studies (9, 18, 35–37, 46) including two prospective studies in boulderers (18) (SQS: 19/32) and a broad population of climbers (35) (14/32) found no significant relationship with increasing age and risk of climbing injury. Although, Lutter et al., (2019) only included a sample of four people in the 65 + years group (35). Interestingly, a single study indicated a higher risk of forearm bone marrow edema in younger climbing populations compared to their older peers, as measured via magnetic resonance imaging (34). Regarding years of climbing experience, two prospective studies propose that development of bone marrow edema in the hand is associated with increasing years of experience (34) (SQS: 17/32), and that male climbers who report more years of experience also have an increased risk of injury (35) (SQS: 14/32). Additionally, there is further cross-sectional evidence indicating increased risk of medial epicondylitis (41), injuries of the foot (21, 23), and general musculoskeletal injury (37), with increasing years of climbing experience. However, an additional four studies revealed no association between increasing years of climbing experience and injury risk (6, 9, 18, 28), whereby two of these were prospective investigations in boulder specific populations (18, 28) (SQS: 14/32; 19/32). It should be noted that the average age of participants in these two studies was relatively young (24.7–30 years).

13 studies examined biological sex as a risk factor for climbing injury and provided conflicting results (6, 8, 9, 21, 22, 25, 28, 34, 35, 37, 40, 41, 46). A total of seven studies discovered a significant relationship between male sex and the risk of injury (6, 21, 22, 25, 35, 40, 46). One of these studies was conducted in a prospective design over a three-year period (35) (SQS: 14/32), and showed a male to female ratio of 3:1 in terms of injury rate, whereby males also had significantly higher climbing levels and years of experience which could be considered as confounding factors. One study added nuance to the results, indicating that male sex is indeed a risk factor for chronic elbow and finger injuries, but that females are at greater risk of chronic ankle injuries (SQS: 13/32) (25). In contrast, six studies suggested no relationship between biological sex and injury risk (8, 9, 28, 34, 37, 41), and three of these studies were prospective designs with relatively high quality scores (8, 28, 34) (SQS: 14/32–19/32). These studies were conducted to determine risk factors on hand bone marrow edema (34) and general injury risk in boulderers (28) and a broad climbing population (8).

A total of four studies explored previous injury as a risk factor for the development of future injury or reinjury (18, 22, 27, 28). Three prospective studies with relatively high quality scores (SQS: 14/32–20/32) indicated a history of prior injury to be a significant predictor of future injury and/or reinjury (18, 27, 28). Jones et al., (2015) reported a 63% average probability for reinjury in climbers reporting a previous overuse injury, which was particularly evident for the fingers. In support of this data, Josephson et al., (2007) specifically indicated that a history of finger injury was predictive of a reinjury. A single cross-sectional study on 37 participants (22) (SQS: 13/32) contradicts the above findings, showing no relationship between past and current injury.

In a previous systematic review by Woollings et al., (2015), the authors concluded that a higher BMI was likely to be associated with increased risk of injury in climbers. However, this conclusion was primarily based on data from Backe et al., (2009) due to its methodological rigor compared to other studies in the analysis. Since this review was published, three prospective investigations in a total of 1,138 climbers (8, 18, 35) have subsequently reported no association between increased BMI/body weight and risk of climbing injury. This strong evidence, supported by additional cross-sectional findings (26, 28, 37), suggests that practitioners working with climbing athletes should avoid strong recommendations on weight loss strategies in the pursuit of injury prevention. Furthermore, weight loss programs are commonly initiated in the pursuit of performance goals, however, associations between reduced BMI and improved climbing performance also seem limited (26). Therefore, such programs should be implemented with extreme caution, especially considering the risk of poor bone health and associated disorders in athletic populations (49). Hence, the health of the climbing athlete should be prioritized above all else (50). It should be acknowledged that weight loss strategies in the pursuit of performance goals will likely continue to be a staple in sports performance, especially in sports such as climbing where the strength to body weight ratio could still be assumed to influence performance for some athletes. Additionally, the data from Gronhaug (2019) showing no effect of low BMI on climbing performance is only cross sectional and retrospective, which weakens the findings substantially.

Bouldering appears to be a risk factor for the development of climbing injury when compared to other disciplines such as lead climbing, as indicated by evidence in six studies (6, 8, 9, 27, 46, 47). However, the majority of the studies are cross-sectional in design, therefore strong conclusions cannot be drawn. Nonetheless, this contrasts with previous findings from Woollings et al., (2015) who suggested that lead climbing was associated with an increased risk of injury in climbers. The conflicting results can potentially be explained on two fronts. Firstly, some of the evidence in the current study has emerged since the publication of this previous systematic review. Secondly, the focus of the current study was overuse injuries, whereas the review from Woollings et al., (2015) also included all traumatic injuries by methodology. It could be speculated that lead climbing might result in more traumatic injuries due to the higher risk of larger falls, compared to bouldering which might be associated with a higher amount of overuse related injuries, and traumatic injuries to the leg/ankle during falling. Bouldering is typified by repetitive intense bouts of dynamic climbing, and this specific pattern of highly demanding effort may put climbers at a greater risk of developing an overuse injury (18). Practically, boulderers should be encouraged to take sufficient rest periods between intense bouts of climbing to allow for recovery and mitigate fatigue.

The amount of time spent climbing (climbing volume) was shown to be associated with finger stress injuries in one prospective study (48), though the sample size was small with only 20 participants (SQS: 18/32). This is contrasted in two prospective studies (8, 35) (n = 198; n = 434), which showed no relationship between total climbing volume and general injury risk in climbers (SQS: 14/32; 19/32). It might be important to note that the average age of the sample in the study by Schöffl et al., (2007) (48) was much younger (20 to 21 years old) than in the other two prospective studies (32 to >65 years old), perhaps indicating that large climbing volume may be a risk factor for younger climbing athletes specifically. Despite further evidence from five cross-sectional studies suggesting an association between increased volume and injury risk (6, 21, 22, 36, 37), it is difficult to state that a clear relationship exists in the context of findings from this review. The conflicting results on training volume in the current study support previous conclusions published in a systematic review by Woollings et al., (2015). The discrepancy in findings from the included studies could be explained by variation in the methodologies of reporting training volume, whereby information collected in the form of questionnaires is known to be subject to recall and/or response bias. Future studies could incorporate wearable sensor technology to monitor training volume, which might enable more accurate measurement of time spent training (51). Additionally, it could be considered that training volume may also offer a protective stimulus against injury (52), which might also explain the paradoxical findings. When applied consistently, large training volumes will induce physiological adaptations in athletes which prepare them for their sport and competition, and therefore might actually assist in the prevention of injuries (52). Whilst it must be acknowledged that increased training volume has been suggested to be associated with injury risk in athletes (53), it has equally been debated whether sudden and rapid spikes in training volume may be responsible for the increased injury risk, as opposed to training volume when considered as a consistent variable over a period of time (54). The results of the current study and others (5, 9, 55), indicate that future studies should be conducted to investigate the relationship between training volume and climbing overuse injuries, with an enhanced focus on the quality of the data collected.

Climbing intensity was usually measured indirectly via climbing level or grade, whereby a higher grade indicates a higher intensity. A total of 19 studies showed an association between increased climbing intensity and an increased risk of overuse injury (2, 8, 9, 19, 21, 23, 25, 27, 32, 33, 36, 37, 40, 42, 44–48), whereby two of the studies were prospective (8, 48) in a total of 454 climbers (SQS: 18/32 and 19/32). A single prospective study conflicted with this evidence (35) (SQS: 14/32), though this research included a much older population of athletes compared to other studies. This may have confounded the findings as older athletes generally reported lower climbing grades. The findings of the current study support previous work by Woollings et al., (2015), who also described a relationship between increased climbing intensity/grade and an increase in injury risk, and this association has been discussed in other reviews in the literature (14). High intensity training maintained over long periods of time (52) or when introduced abruptly during the training process (54) appears to increase the likelihood of sustaining an overuse injury in athletes, and this risk likely exists in climbers. This result underlines the need for training to be programmed and monitored in a sensible and accurate way, in accordance with currently known best practice in training periodization and planning (52, 56, 57). Approaches should emphasize a balanced training paradigm, which includes periods of intense training sessions to elicit the desired physiological adaptations, counteracted with “easier” sessions which allow for adequate recovery (52, 56). Research in this area specifically for climbers is notably scarce, and more studies are required with a focus on more valid methodological approaches for measuring climbing “intensity”. People working in climbing could adopt the “Climbing Intensity Score” (=climbing grade/level × climbing volume), as suggested by Logan et al., (2005). Such a score may provide a more comprehensive measurement of the total load experienced by climbing athletes and help to inform future climbing studies and load management strategies.

Two RCTs conducted on the same study cohort, reported that closed chain eccentric and strength exercises performed 3–4 times per week for one year, could reduce the likelihood of shoulder injuries (30) and elbow injuries (31) (SQS: 18/32). This is the first and seemingly only study which has implemented an injury prevention program in climbers and showed positive effects of a strength and conditioning program on injury reduction. Strength and neuromuscular training programs are broadly supported in the literature as an injury prevention modality in multiple sports (55), and it has been shown in a recent systematic review and meta-analysis that climbing-specific resistance training can also improve climbing performance (58). Therefore, it would seem appropriate to implement strength training programs in climbers. However, the results of the two included studies in this review had a relatively small sample size (n = 84) focusing on injuries of the elbows and shoulders (30, 31). Correspondingly, these findings cannot be applied to injuries of the fingers, which is known to be the most common site of injury in climbers (14). Furthermore, there is cross-sectional evidence in two studies that the injured hand is weaker than the contralateral healthy hand (22, 38), and an additional two prospective studies showed conflicting findings regarding finger strength and injury risk (8, 18). The prospective study by van Middelkoop et al., (2015) reported that increased strength of the middle finger and campus board training was actually predictive of injury risk. However, this might be understood as confounded noise in the data, whereby people with previous injuries to the fingers have adopted specific finger flexor training modalities in an attempt to prevent reinjury. This highlights the need for future RCTs investigating injury prevention programs specifically for the hand and fingers in climbers.

Two high-quality prospective trials including a total of 658 climbers showed that taping did not protect against overuse injury risk (18, 28). Josephsen et al., (2007) did reveal that wrist taping could have a beneficial effect for boulderers, although confidence limits for the incidence rates indicated a weak effect. Taping is widely adopted in climbing gyms as means to prevent injury, but the results of this review cannot support its use. Warm-ups and cool-downs are commonly implemented in climbers to reduce the risk of overuse injury. However, based upon data from four studies (8, 18, 28, 32), two of which were prospective studies (8, 18), both warming up or cooling down had no protective effect against overuse injuries. The ritual of a warm-up or cool-down is likely to have other effects on athletic physiology, and there is some evidence that it may improve athletic performance (59). However, based upon the results of this review and others similar (5), traditional warm-ups or cool-downs cannot be recommended with the explicit goal of reducing overuse injury risk. Another commonly practiced injury prevention technique is stretching, usually performed prior to climbing in a static or dynamic manner. Two studies included in this review (28, 32) including one prospective investigation (28) indicate that stretching offers no protective effect against risk of overuse injury. This finding is commonly reported across other sporting disciplines (55) and supports results of a previous systematic review in climbing (5). Given evidence that static stretching doesn't confer a beneficial effect on muscle performance, and may even have a negative effect at longer duration stretch routines (>60 s) (60), it would seem problematic to advise climbers to engage with a stretching routine prior to training sessions and competition.

Results from this review indicate conflicting findings, when considering age and years of climbing experience as a risk factor for overuse injury. There is strong prospective evidence in a sample of 434 climbers that increasing age might exacerbate injury risk (8) (SQS: 19/32), which is contrasted by two prospective studies including a total of 704 climbers indicating no increased risk of injury with older age (18, 35) (SQS: 19/32, 14/32) (n = 229). Furthermore, two prospective studies showed a positive relationship between increased years of climbing experience and injury (34, 35), which conflicts with two prospective studies showing no relationship (18, 28) (n = 658). The mixed findings might be attributed to the large variety of injuries included within this review (see Table 3), whereby age and years of climbing experience might be a risk factor for certain injuries, but not for others. In a systematic review, Woollings et al., (2015) concluded that older age was a risk factor for injury in climbing, however, they also suggested that certain injuries may be more prevalent in younger populations when compared to older climbers. To this point, a recent prospective study included in this review indicated that younger climbers may be at a higher risk of bone marrow edema (34), although there were only 31 participants included in the study. This may be especially relevant for the physis of the proximal inter-phalangeal joint during adolescent growth, and practitioners should be vigilant for these issues in younger climbers. An additional consideration might be that older climbers tend to “self-moderate” the intensity of their climbing, by selecting lower grades as they age. This seems to be the pattern in the prospective analysis of Lutter et al., (2019), though this is only speculation and would require further study to verify this claim.

The findings relating biological sex to injury risk are also very conflicting. One prospective study with 198 participants showed that males were more likely to obtain an injury at a 3:1 ratio compared to females (35) (SQS: 14/32). However, in this sample males also reported higher climbing levels and years of experience when compared to females, which have also been discussed as risk factors for overuse injury. A cross-sectional study indicated that males are more at risk for chronic elbow and finger injuries, whereas females appear to have a higher risk of chronic ankle injuries (SQS: 13/32) (25). The author highlights that this may be due to climbing shoe design which is typically male-centric, therefore, shoes designed specifically for female feet should be developed and tested in future studies. In this same paper, male sex was seen to interact with bouldering grade, whereby a higher prevalence of chronic injuries was found in males with higher bouldering grades, however this interaction was not as obvious in females. In fact, the highest prevalence of injuries was amongst the male outdoor climbing group (74%), which is speculated to be reflective of the increased risk-taking behaviours of males when compared to females, especially when climbing outdoors. In contrast, three prospective studies with a total of 617 participants reported no differences for injury risk between the male and female sexes (8, 28, 34) (SQS: 14/32–19/32). Sex-specific differences in injuries have been revealed to some degree in team sports (61), though the differences seem marginal. It should also be noted that most of the studies included samples that were disproportionately male-biased, and therefore future research needs to be mindful of conducting research in female climbing populations. According to this review, there is conflicting evidence regarding sex-specific differences in risk factors for overuse injuries in climbers. In future studies, biological sex should be studied alongside other interacting factors, such as climbing grade and type of climbing e.g., indoors vs. outdoors, so as to reveal how these factors might coalesce and effect injury risk.

Three relatively high quality prospective studies (18, 27, 28) (SQS: 14/32–20/32) identify previous injury as a risk factor for future injury or reinjury. This supports evidence in other sports (62), whereby the mechanism is supposed to occur in altered neuromuscular physiology associated with the injured anatomical site and potentially unresolved structural pathology in the local tissue. However, some studies included within the current review are not clear whether participants reinjured the same specific anatomical site that was injured previously, or whether injury risk is more generally heightened in individuals who have obtained previous injuries. These details should be the subject of future investigations. Nonetheless, it would be advised that climbers who have previously acquired an overuse injury should be aware of the increased risk of reinjury and follow the advice of their healthcare practitioner, and potentially implement a secondary injury prevention program with appropriate load management. Return to sport guidelines in climbing post-injury have yet to be deciphered, but there is some data available which could help inform decision-making (63, 64).