Factors influencing osteological changes in the hands and fingers of rock climbers

Phalangeal cortical bone distribution reveals different dexterous and climbing behaviors in Australopithecus sediba and Homo naledi

The evolution of the human hand is marked by a transition from a hand primarily used for locomotion to one primarily used for dexterous manipulation. The hand skeletons of Plio-Pleistocene hominins have different mosaics of human-like features associated with enhanced dexterity and ape-like features associated with locomotor hand use. However, the functional relevance of the ape-like features is debated, particularly due to a lack of complete and associated hand remains. Here, we investigate the internal phalangeal cortical structure of the nearly complete Australopithecus sediba MH2 hand and Homo naledi hand 1 to provide both insight into the manual behaviors of these fossil hominins and functional clarity regarding the mosaic features found within their hands. The phalangeal cortical structure demonstrates diversity in Plio-Pleistocene hand use, with A. sediba and H. naledi each indicating different dexterous abilities and different climbing strategies, supporting the functional importance of the ape-like features.

Macroscopic differences in adult human femora are linked to body mass index

Bone functional adaptation is routinely invoked to interpret skeletal morphology despite ongoing debate regarding the limits of the bone response to mechanical stimuli. The wide variation in human body mass presents an opportunity to explore the relationship between mechanical load and skeletal response in weight-bearing elements. Here, we examine variation in femoral macroscopic morphology as a function of body mass index (BMI), which is used as a metric of load history. A sample of 80 femora (40 female; 40 male) from recent modern humans was selected from the Texas State University Donated Skeletal Collection. Femora were imaged using x-ray computed tomography (voxel size ~0.5 mm), and segmented to produce surface models. Landmark-based geometric morphometric analyses based on the Coherent Point Drift algorithm were conducted to quantify shape. Principal components analyses were used to summarize shape variation, and component scores were regressed on BMI. Within the male sample, increased BMI was associated with a mediolaterally expanded femoral shaft, as well as increased neck-shaft angle and decreased femoral neck anteversion angle. No statistically significant relationships between shape and BMI were found in the female sample. While mechanical stimulus has traditionally been applied to changes in long bong diaphyseal shape it appears that bone functional adaptation may also result in fundamental changes in the shape of skeletal elements.

Analyzing Injury Patterns in Climbing: A Comprehensive Study of Risk Factors

Climbing, a sport with increasing popularity, poses diverse risks and injury patterns across its various disciplines. This study evaluates the incidence and nature of climbing-related injuries, focusing on how different disciplines and climbers' personal characteristics affect these injuries. Data on injury incidence, severity, and consequences, as well as climbers' personal attributes, were collected through a questionnaire and analyzed using generalized linear models and generalized linear mixed models, Cochran-Armitage tests, and multivariate analysis. Our findings indicate a direct correlation between time spent on bouldering and lead climbing and increased injury frequency, while injury incidence decreases with time in traditional climbing. Interestingly, personal characteristics showed no significant impact on injury incidence or severity. However, distinct patterns emerged in individual disciplines regarding the recent injuries in which age and weight of climbers play a role. While the phase of occurrence and duration of consequences show no significant variation across disciplines, the intensity of the required treatment and causes of injury differ. This research provides insights into climbing injuries' complex nature, highlighting the need for tailored preventive strategies across climbing disciplines. It underscores the necessity for further investigation into the factors contributing to climbing injuries, advocating for more targeted injury prevention and safety measures in this evolving sport.

Rehabilitation of Annular Pulley Injuries of the Fingers in Climbers: A Clinical Commentary

ABSTRACT

The annular pulley ligaments of the fingers are one of the most injured anatomical structures in those who participate in climbing. Despite this, there is a paucity of guidance clearly describing the rehabilitation and physical preparation parameters to return to sport following such injuries. The foundation of effective rehabilitation is the judicious application of progressive loading to increase the morphological and material properties of the damaged tissues. We maintain the optimal management of the climbing athlete after a traumatic annular flexor pulley system rupture should be grounded in the principles of strength and conditioning.

A Life Dedicated to Climbing and Its Sequelae in the Fingers-A Review of the Literature

Fingers of sport climbers are exposed to high mechanical loads. This work focuses on the fingers of a 52-year-old active elite climber who was the first in mankind to master 8B (V13), 8B+ (V14) and 8C (V15) graded boulders, bringing lifelong high-intensity loads to his hands. It is therefore hypothesized that he belongs to a small group of people with the highest accumulative loads to their fingers in the climbing scene. Fingers were analyzed by means of ultrasonography, X-rays and physical examination. Soft tissue and bone adaptations, as well as the onset of osteoarthritis and finger stiffness, were found, especially in digit III, the longest and therefore most loaded digit. Finally, this article aims to provide an overview of the current literature in this field. In conclusion, elite sport climbing results in soft tissue and bone adaptations in the fingers, and the literature provides evidence that these adaptations increase over one's career. However, at later stages, radiographic and clinical signs of osteoarthritis, especially in the middle finger, seem to occur, although they may not be symptomatic.

Epidemiological Study of Foot Injuries in the Practice of Sport Climbing

Background. Climbing is a multidisciplinary sport, where the main objective is to reach the highest point of a rock wall or to reach the end of an established route. There are different types of modalities: sport climbing and traditional climbing. The risks and precautions taken with respect to this sport will directly affect the epidemiology of injuries related to its practice. The present study was designed to identify and characterize the most frequent injuries in the feet of climbers and to determine if there is a relationship between the injuries that appear and the time spent practicing the sport. Methods. A total of 53 people were collected, 32 men and 21 women, corresponding to the climbers of the FEXME (Extremadura Federation of Mountain and Climbing). To determine the diagnoses, exploratory tests, classified according to the variables to be studied, are carried out: inspection variables and questionnaire variables. Results. The average number of years of climbing was seven years, and the average number of hours of training per week was 6.6 h. Some type of alterations were presented in 70% of the respondents, and foot pain was present during climbing in 45% of the participants. The p-value showed a relationship between years of climbing and the occurrence of chronic foot injuries (p = 0.035), however, there is no relationship between the occurrence of injuries and chronological age. Conclusion. We can see that the most frequent injuries in the practice of climbing are claw toes, dermal alterations such as bursitis of the first toe and hallux limitus, followed by hallux valgus. Similarly, only a significant relationship was found between the number of years of climbing and the appearance of foot injuries.

Relative Contributions of Handgrip and Individual Finger Strength on Climbing Performance in a Bouldering Competition

PURPOSE

To determine the relative contributions of handgrip and individual finger strength for the prediction of climbing performance in a bouldering competition. A secondary aim was to examine the influence of body size, bouldering experience, and training habits.

METHODS

Sixty-seven boulderers (mean [SD], age = 21.1 [4.0] y; body mass = 69.5 [9.8] kg) volunteered for this study. Data collection occurred immediately before an indoor bouldering competition and involved the assessment of handgrip and individual finger maximal force production using an electronic handheld dynamometer. The bouldering competition consisted of 70 routes graded V0 to V8, with higher point values awarded for completing more difficult routes. Stepwise multiple regression analysis was used to examine the relative contributions of handgrip and individual finger strengths, body mass, height, bouldering experience, and bouldering frequency to the prediction of performance scores in the competition.

RESULTS

Ring finger pinch strength, bouldering experience, and bouldering frequency significantly (P < .05) contributed to the model (R2 = .373), whereas body mass; height; full handgrip strength, as well as index, middle, and little finger pinch strengths did not. The β weights showed that ring finger pinch strength (β = .430) was the most significant contributor, followed by bouldering experience (β = .331) and bouldering frequency (β = .244).

CONCLUSIONS

The current findings indicated that trainable factors contributed to the prediction of bouldering performance. These results suggest greater bouldering frequency and experience likely contribute to greater isolated individual finger strength, thereby optimizing preparation for the diverse handholds in competitive rock climbing.

Long-term evolution of cartilage abnormalities and osteophytes in the fingers of elite sport climbers: A cross-sectional 10-year follow-up study

The sequelae of high mechanical stress to the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints of the fingers in elite sport climbers and its contribution to the development of osteoarthritis are still relatively unknown. The purpose of this study was to investigate the evolution of cartilage abnormalities of the PIP and DIP joints, as well as the progress of osteophytes, in the fingers of elite sport climbers with a minimum of 25 years of climbing history over the time period of the last 10 years. Moreover, their actual cartilage abnormalities and osteophyte occurrence were compared to non-climbing age-matched controls. Thirty-one elite male sport climbers and 15 male non-climbers underwent a sonographic examination of the PIP and DIP joint cartilage and osteophyte thickness in the frontal and sagittal plane of digits II-V of both hands. The same cohort had already been measured with an identical protocol 10 years earlier (follow-up rate of 100%). Compared to the baseline assessment 10 years earlier, the cartilage thickness of sport climbers has significantly decreased; however, it was still greater than in age-matched controls. Moreover, sport climbers showed significantly higher relative frequencies of osteophyte occurrence than non-climbers (all fingers and joints). Nevertheless, despite a substantial (and compared to baseline a further increased) occurrence of osteophytes in elite sport climbers, there was no association between the radiological signs of osteoarthritis and pain within the last six months prior the follow-up investigation.Highlights Long-term elite climbers show thicker cartilage and occurrence of Osteophytes in their fingers (especially Digit III) compared to controls already early in their career.Later occurrence of osteophytes increases (especially Digit II and IV) and cartilage decreases but is still thicker compared to controls. No association between those findings and pain was found.

Biomechanical Study of the Development of Long Bones: Finite Element Structure Synthesis of the Human Second Proximal Phalanx Under Growth Conditions

Torsional loads are a possible mechanical explanation for the architecture of long bone. Finite element structure synthesis (FESS) has previously successfully been used as a deductive technique using Wolff's Law by applying expected loads to an unspecific homogeneous solid and eliminating stress free parts to verify muscle forces. The extended approach presented in this article includes further mechanobiological rules to model the development from a cartilage model to a finger bone. In contrast to former computational models, simulation of processes leading to both external growth and internal differentiation are included. Combined axial and torsional loads synthesize a complete human secondary proximal phalanx model comparable to form and internal structure to that observed in vivo. While the computational model is very sensitive to initial alterations of loads, changes after growth have a minor effect as observed in animal models. Predictions of cartilage growth and ossification during FESS showed significant similarities to ontogeny indicating the importance of mechanical factors for the morphogenesis of bone during growth. Anat Rec, 302:1389-1398, 2019. © 2018 Wiley Periodicals, Inc.

ACTN3 Genotype in Professional Sport Climbers

Ginszt, M, Michalak-Wojnowska, M, Gawda, P, Wojcierowska-Litwin, M, Korszeń-Pilecka, I, Kusztelak, M, Muda, R, Filip, AA, and Majcher, P. ACTN3 genotype in professional sport climbers. J Strength Cond Res 32(5): 1311–1315, 2018—The functional RR genotype of the alpha-actinin-3 (ACTN3) gene has been reported to be associated with elite sprint/power athlete status. Although large and rapidly increasing number of studies have investigated the associations between the ACTN3 genotypes and athletic performance in various sport disciplines, there is a lack of studies on the genetic predisposition in sport climbing, which was selected to be part of the next Summer Olympic Games in Tokyo 2020 with three subdisciplines (“lead climbing,” “speed climbing,” and “bouldering”). The aim of the study is to determine the frequency distribution of ACTN3 genotypes and alleles in professional lead climbers and boulderers. 100 professional sport climbers from Poland, Russia, and Austria were divided into 2 equal groups: professional boulderers and professional lead climbers were involved in the study. ACTN3 allele frequencies and genotypes were compared with 100 sedentary controls. Genotypes were determined using polymerase chain reaction–restriction fragment length polymorphism method. The percent distribution of RR genotype in the boulderers was significantly higher than in lead climbers and controls (62 vs. 26%; 33%, respectively; χ² = 17.230, p = 0.0017). The frequencies of ACTN3 R allele in boulderers differed significantly from lead climbers and controls (77 vs. 51%; 58%, respectively; χ² = 15.721, p = 0.0004). The proportion of the ACTN3 RR genotype is significantly higher in boulderers than in lead climbers and may be related to the specific type of predisposition to this subdiscipline.

Long-Term Radiographic Adaptations to Stress of High-Level and Recreational Rock Climbing in Former Adolescent Athletes: An 11-Year Prospective Longitudinal Study

BACKGROUND

In the past few years, competition climbing has grown in popularity, and younger people are being drawn to the sport.

PURPOSE

While radiographic changes in long-term climbers are known, there are little data available on adolescent climbers. The question arises as to whether climbing at high levels at a young age leads to radiographic changes and possibly an early onset of osteoarthritis of the finger joints.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 19 members of the German Junior National Team (GJNT group) and 18 recreational climbers (RC group) were examined clinically and radiographically in 1999. In 2011, these climbers were re-examined (mean follow-up, 11.3 ± 1.2 years). Radiographs were evaluated using a standard protocol, searching for physiological adaptations such as cortical thickness of the middle phalanx and an increased adopted Barnett-Nordin index, as well as for early-onset osteoarthritic changes of the hand. In contrast to the Kellgren-Lawrence scale, subchondral sclerosis was added to the group of physiological, adaptive stress reactions and was not defined as osteoarthritis. Osteoarthritis was defined by a Kellgren-Lawrence grade ≥2.

RESULTS

Overall, 15 of 19 (follow-up rate, 78.9%) climbers in the GJNT group and 13 of 18 in the RC group (follow-up rate, 72.2%), with a mean age of 26.8 years, were examined at the 11-year follow-up. Five climbers (33%) in the GJNT group presented with a decreased range of motion for the finger joints, in contrast to only 1 climber (8%) in the RC group. Radiographic stress reactions of the hand were found in 80% of the GJNT group and 46% of the RC group, including cortical hypertrophy (GJNT: 73%; RC: 23%), subchondral sclerosis (GJNT: 80%; RC: 31%), a broadened proximal interphalangeal joint base (GJNT: 67%; RC: 38%), and a broadened distal interphalangeal joint base (GJNT: 53%; RC: 31%). Training intensity in 1999 and body weight in 1999 were significant for the development of radiographic stress reactions in 2011 (P < .05 for both). Signs of early-stage osteoarthritis were seen in 6 climbers: 4 (27%) in the GJNT group and 2 (15%) in the RC group. Significant statistical influences for the development of early-onset osteoarthritis were found for overall total training years (P = .024), use of campus board training in 1999 (P = .033), and climbing level (P = .030).

CONCLUSION

One-quarter of climbers who performed at a high level in their youth showed a "mild" form of osteoarthritis (Kellgren-Lawrence grade 2). In analyzing the training regimens of our climbers for longer than 10 years, we conclude that intensive finger training (eg, campus board training) can lead to early-onset osteoarthritis of the hand. We also demonstrate that a high Union Internationale des Associations d'Alpinisme (UIAA) climbing level correlates with the risk for early-onset osteoarthritis of the hand and therefore must be seen as a risk factor for developing early-onset osteoarthritis of the finger joints.

Laterality and grip strength influence hand bone micro-architecture in modern humans, an HRpQCT study

It is widely hypothesized that mechanical loading, specifically repetitive low-intensity tasks, influences the inner structure of cancellous bone. As such, there is likely a relationship between handedness and bone morphology. The aim of this study is to determine patterns in trabecular bone between dominant and non-dominant hands in modern humans. Seventeen healthy patients between 22 and 32 years old were included in the study. Radial carpal bones (lunate, capitate, scaphoid, trapezium, trapezoid, 1st, 2nd and 3rd metacarpals) were analyzed with high-resolution micro-computed tomography. Additionally, crush and pinch grip were recorded. Factorial analysis indicated that bone volume ratio, trabeculae number (Tb.N), bone surface to volume ratio (BS.BV), body weight, stature and crush grip were all positively correlated with principal components 1 and 2 explaining 78.7% of the variance. Volumetric and trabecular endostructural parameters (BV/TV, BS/BV or Tb.Th, Tb.N) explain the observed inter-individual variability better than anthropometric or clinical parameters. Factors analysis regressions showed correlations between these parameters and the dominant side for crush strength for the lunate (r² = 0.640, P < 0.0001), trapezium (r² = 0.836, P < 0.0001) and third metacarpal (r² = 0.763). However, despite a significant lateralization in grip strength for all patients, the endostructural variability between dominant and non-dominant sides was limited in perspective to inter-individual differences. In conclusion, handedness is unlikely to generate trabecular patterns of asymmetry. It appears, however, that crush strength can be considered for endostructural analysis in the modern human wrist.

Feet injuries in rock climbers

While injuries of the upper extremity are widely discussed in rock climbers, reports about the lower extremity are rare. Nevertheless almost 50 percent of acute injuries involve the leg and feet. Acute injuries are either caused by ground falls or rock hit trauma during a fall. Most frequently strains, contusions and fractures of the calcaneus and talus. More rare injuries, as e.g., osteochondral lesions of the talus demand a highly specialized care and case presentations with combined iliac crest graft and matrix associated autologous chondrocyte transplantation are given in this review. The chronic use of tight climbing shoes leads to overstrain injuries also. As the tight fit of the shoes changes the biomechanics of the foot an increased stress load is applied to the fore-foot. Thus chronic conditions as subungual hematoma, callosity and pain resolve. Also a high incidence of hallux valgus and hallux rigidus is described.

Hand osteoarthritis and bone loss: is there an inverse relationship?

An inverse relationship between osteoarthritis (OA) and bone loss has been supported in clinical research, but there has been little research on bioarchaeological skeletal remains. The current study examines 115 adults from a prehistoric hunter-gatherer population to aid in determining whether hand OA and bone loss are negatively correlated. OA lipping is scored on a four-point scale on left and right trapezia, MC1s, and MC2s and then analyzed with regard to their relationships with sex, age, right MC2 cortical index, and left and right MC1 robusticity, midshaft circumference, and midshaft diameter values. With sexes and ages combined, higher OA scores are found in individuals with greater midshaft diameters. However, lower cortical indices were found in individuals with higher right MC2 OA scores. The data presented tenuously support that bone loss is lower in individuals with more severe osteoarthritis, but age-related changes in bone deposition may make cortical index and other external shaft dimensions an unsuitable variable to examine this relationship.

Comparisons of bone mineral density and bone quality in adult rock climbers, resistance-trained men, and untrained men

The nature of muscular contractions and episodes of impact loading during technical rock climbing are often varied and complex, and the resulting effects on bone health are unclear. The purpose of this study was to compare total body, lumbar spine, proximal femur, and forearm areal bone mineral density (aBMD) and tibia and forearm bone quality in male rock climbers (RC) (n = 15), resistance trained men (RT) (n = 16), and untrained male controls (CTR) (n = 16). Total body, anteroposterior (AP) lumbar spine, proximal femur, and forearm aBMD and body composition were measured using dual-energy X-ray absorptiometry (DXA) (Lunar Prodigy, v. 10.50.086; GE Healthcare, Waukesha, Wisconsin, U.S.A.). Volumetric BMD (vBMD), bone content, bone area, and muscle cross-sectional area (MCSA) of the tibia and forearm were measured using pQCT (peripheral quantitative computed tomography; Stratec XCT 3000, Pforzheim, Germany). No significant group differences were seen in bone-free lean body mass. CTR had significantly (p < 0.05) greater body fat % than RC and RT and significantly (p < 0.05) greater fat mass than RC. Lumbar spine and femoral neck aBMD were significantly (p < 0.05) greater in RT compared to both RC and CTR. RC had significantly (p < 0.05) lower aBMD at the 33% radius site than CTR. Forearm MCSA was significantly (p < 0.05) lower in CTR than in the other groups. No significant differences were seen between groups for vBMD or bone area of the tibia and forearm. In conclusion, resistance-trained men had higher bone density at the central skeletal sites than rock climbers; however, bone quality variables of the peripheral limbs were similar in rock climber and resistance-trained groups.

Interindividual variation in functionally adapted trait sets is established during postnatal growth and predictable based on bone robustness

Adults acquire unique sets of morphological and tissue-quality bone traits that are predictable based on robustness and deterministic of strength and fragility. How and when individual trait sets arise during growth has not been established. Longitudinal structural changes of the metacarpal diaphysis were measured for boys and girls from 3 mo to 8 yr of age using hand radiographs obtained from the Bolton-Brush collection. Robustness varied approximately 2-fold among boys and girls, and individual values were established by 2 yr of age, indicating that genetic and environmental factors controlling the relationship between growth in width and growth in length were established early during postnatal growth. Significant negative correlations between robustness and relative cortical area and a significant positive correlation between robustness and a novel measure capturing the efficiency of growth indicated that coordination of the subperiosteal and endocortical surfaces was responsible for this population acquiring a narrow range of trait sets that was predictable based on robustness. Boys and girls with robust diaphyses had proportionally thinner cortices to minimize mass, whereas children with slender diaphyses had proportionally thicker cortices to maximize stiffness. Girls had more slender metacarpals with proportionally thicker cortices compared with boys at all prepubertal ages. Although postnatal growth patterns varied in fundamentally different ways with sex and robustness, the dependence of trait sets on robustness indicated that children sustained variants affecting subperiosteal growth because they shared a common biological factor regulating functional adaptation. Considering the natural variation in acquired trait sets may help identify determinants of fracture risk, because age-related bone loss and gain will affect slender and robust structures differently.

Middle and ring fingers are more exposed to pulley rupture than index and little during sport-climbing: a biomechanical explanation

BACKGROUND

Finger pulley injury is a common incident observed during sport-climbing. The total rupture of one or several pulleys is highly debilitating and requires surgical reconstruction and/or rehabilitation programs. Literature reports show that fingers are not equally exposed to this injury. The ring and middle fingers are usually injured while the index and little fingers are less exposed. The objective of this study was to determine the biomechanical factors leading to the enhanced exposure of ring and middle finger pulleys.

METHOD

Eight subjects were required to exert maximal four-finger force in a specific sport-climbing finger posture. External fingertip forces and finger joint postures were used as input data of a specifically developed biomechanical model of the four fingers (i.e., index, middle, ring and little). This model was based on classical Newton static laws and used an optimization process to quantify the flexor tendon tensions and the pulley forces in each finger. Passive participation of ligaments was also considered into mechanical equations.

FINDINGS

Results showed that two main factors could explain the enhanced exposure of ring and middle fingers. Firstly, the fingertip force intensities applied by these two fingers were higher than those observed for the index and little fingers. Secondly, results show that the pulley forces of the ring and middle fingers were close to their rupture thresholds, while it was not the case for the two other fingers. This could be explained by a specific localisation of the finger pulleys of the ring and middle fingers leading to enhanced pulley forces.

INTERPRETATION

These results are relevant and could help clinicians to understand finger pulley pathologies and adapt the surgical interventions to reconstruct the fingers pulleys.

Physiological responses to rock climbing in young climbers

Key questions regarding the training and physiological qualities required to produce an elite rock climber remain inadequately defined. Little research has been done on young climbers. The aim of this paper was to review literature on climbing alongside relevant literature characterising physiological adaptations in young athletes. Evidence-based recommendations were sought to inform the training of young climbers. Of 200 studies on climbing, 50 were selected as being appropriate to this review, and were interpreted alongside physiological studies highlighting specific common development growth variables in young climbers. Based on injury data, climbers younger than 16 years should not participate in international bouldering competitions and intensive finger strength training is not recommended. The majority of climbing foot injuries result from wearing too small or unnaturally shaped climbing shoes. Isometric and explosive strength improvements are strongly associated with the latter stages of sexual maturation and specific ontogenetic development, while improvement in motor abilities declines. Somatotyping that might identify common physical attributes in elite climbers of any age is incomplete. Accomplished adolescent climbers can now climb identical grades and compete against elite adult climbers aged up to and >40 years. High-intensity sports training requiring leanness in a youngster can result in altered and delayed pubertal and skeletal development, metabolic and neuroendocrine aberrations and trigger eating disorders. This should be sensitively and regularly monitored. Training should reflect efficacious exercises for a given sex and biological age.