Search Results (58)

High-speed train derailments can cause severe vehicle collisions with rail bridges and adjacent infrastructure; however, full-scale evidence for the collision response of trackside intrusion-protection walls and for material measures that limit concrete fragmentation remains scarce. This study addresses this safety-driven knowledge gap by reporting a full-scale collision test of a polyurea-coated reinforced concrete (RC) wall and by clarifying its governing response mechanisms and coating benefits. The inverted T-shaped RC wall was post-anchored to an existing deck and spray-coated with approximately 5 mm polyurea on the collision face and across the wall-footing junction. A 17.68 t container wagon was propelled to 34.59 km/h to reproduce the normal kinetic energy of a representative 68 t KTX car derailing at 300 km/h with a 3° collision angle. High-speed video tracking and post-test mapping captured displacements, rotations, and damage. The wall contained the container wagon without climb-over and without severe local crushing at the collision face; the response was dominated by stable wall-footing rocking, with a peak top displacement of 0.571 m, peak rotation of 19.9°, and residual inclination of approximately 15–17°. The peak collision-force estimate was approximately 1.17 MN, and most input energy (approximately 647–816 kJ) was dissipated through inelastic rocking and sliding while the anchors remained intact. The polyurea layer restrained spalling and fragment release and promoted a more global, repairable rocking-dominated damage state. These results provide rare full-scale benchmarks and mechanistic insight to support performance-based design and retrofit of derailment intrusion-protection walls for improved rail-bridge safety. Full article

Objectives: This single-arm, pre–post intervention study with a three-month follow-up aimed to determine whether a ten-day outdoor camp combining mixed-modality physical activity and time-restricted feeding elicits positive changes in multiple body-composition outcome measures and whether those changes persist at three-month follow-up. Methods: Forty healthy undergraduates (18 male, 22 female) participated in a 10-day outdoor camp that combined multi-modal physical activities (rock climbing and bouldering, swimming, hiking, applied paddling, survival skills, etc.) with a 13 h daily time-restricted feeding window. Body fat percentage, skeletal muscle percentage, body mass, total body-water percentage, visceral fat level, and skeletal muscle index were measured using the InBody 270 at baseline, immediately post-camp, and at the three-month follow-up. Results: Mixed-effects models with random intercepts for subject revealed significant reductions in body fat percentage (β = −1.63, p < 0.001) and visceral fat level (β = −0.72, p = 0.001), alongside increases in skeletal muscle percentage (β = 1.02, p < 0.001), skeletal muscle index (β = 0.30, p < 0.001), and total body-water percentage (β = 1.19, p < 0.001) from baseline to post-camp; no outcomes differed between baseline and follow-up and no time × sex interactions were observed. Conclusions: These findings indicate that a brief, intensive nature-based intervention can drive rapid, multidimensional improvements in body composition, but structured maintenance is required to sustain benefits. Full article

The shear mechanical properties of rock discontinuities with different joint wall compressive strengths are a practical basis for the stability analysis of layered rock mass. Shear tests on discontinuities possessing different joint wall strengths were carried out. The shear strength and failure characteristics were analyzed, and the influences of discontinuity morphology on its shear properties were investigated. Meanwhile, numerical tests were performed to study the shear mechanical behavior and dilation evolution of discontinuities possessing different joint wall compressive strengths. Results show that the shear process of discontinuities possessing different joint wall strengths can be divided into four stages: meshing and compacting, climbing wear of soft rock and crack formation of hard rock, shear of part of soft rock and crack expansion of hard rock, complete shearing of the rock discontinuity. Shear failure of discontinuities was mainly concentrated on the morphological structure facing the shear direction. The dilatancy evolution process of discontinuities was mainly affected by the roughness and normal stress. The magnitude of dilation, peak shear strength and residual shear strength of discontinuities possessing different joint wall strengths were between the discontinuities possessing identical joint wall strengths composed of soft and hard rock, under the same loading condition. Full article

When developing deep subsurface infrastructure in areas with intense geothermal activity, the significant temperature gradient inevitably leads to low-temperature contraction and high-temperature expansion of the rock body, resulting in changes in the rock’s mechanical properties. These thermodynamic effects can easily lead to the destabilization and subsequent collapse of the rock. There exists a pressing necessity to methodically evaluate the surrounding rock stability encountered in deep underground engineering under the action of thermal-solid coupling. This study constructed a multi-physical field coupling nonlinear calculation model based on a high-precision three-dimensional finite difference method, systematically analyzed the interdependent effects between the original rock temperature and excavation-induced disturbance, and then analyzed the dynamic changes in temperature, stress, and displacement fields along with plastic zone of surrounding rock of the deep underground engineering under thermal-solid coupling. The results indicate that the closer to the excavation contour surface, the lower the surrounding rock temperature, while the temperature gradient increased correspondingly. The farther away from the excavation contour face, the closer the temperature was to the original rock temperature. As the original rock temperature climbed from 30 °C to 90 °C, the increment of vault displacement was 2.45 times that of arch bottom displacement, and the influence of temperature change on vault deformation was more significant. The horizontal displacement magnitudes at the different original temperatures followed the following order: sidewall > spandrel > skewback, and at an original rock temperature of 90 °C, the sidewall horizontal displacement reached 15.31 cm. With the elevation of the original rock temperature, the distribution range and concentration degree of the maximum and minimum principal stresses increased obviously, and both were compression-dominated. The types of plastic zones in the surrounding rock were mainly characterized by shear stress-induced yielding and tensile stress-induced damage failure. When the original rock temperature increased to 90 °C, the rock mass extending up to 1.5 m from the excavation contour surface formed a large area of damage zone. The closer the working face was to the monitoring section, the faster the temperature dropped, and the displacement changed in the monitoring section. The findings offer a theoretical basis for engineering practice, and it is of great significance to ensure the safety of the project. Full article

Among the multiple zoomorphic and geometric images that dominate Upper Paleolithic decorated cave walls in Europe, some intriguing human hand stencils and finger flutings stand out. Dozens of these marks are attributed to toddlers and children aged 2–12. Accompanied by older group members, they entered these deep, oxygen-depleted and sensory-deprived spaces, climbing and crawling in dark, wet, difficult-to-navigate environments where one might easily get lost or separated from the group. So, why would anyone bring young children into such dangerous locations? Relevant archaeological and anthropological studies form the basis of our hypothesis that the journeys of Upper Paleolithic hunter-gatherers to the depths of deep caves along with their young children should be seen in the framework of active connection with the cosmos as practiced by many indigenous societies worldwide. Indigenous societies often view children as liminal agents with unique physical, cognitive, and mental qualities that allow them to return to the supernatural realm more easily than adults. This makes them especially adept mediators between the world of the living and that of the spirits. In this paper, we examine children’s contribution to the creation of Paleolithic cave art as active agents. Their presence in caves (liminal spaces in themselves) and their participation in the creation of rock art might thus reflect their unique role in early human cosmology and ontology. Full article

Background/Objectives: Rock climbing is a multifaceted athletic activity that requires both psychological and physiological resilience. This study aimed to examine the differences in psychological factors and fatigue predictors between novice and advanced climbers, with a focus on the interplay between experience and performance. Methods: The study included 60 participants categorized based on climbing experience (novice or advanced). Psychological and physiological assessments were conducted, including heart rate variability (HRV), grip strength, rate of force development (RFD), subjective perceived stress (SPS), and anxiety levels using validated questionnaires. Results: Advanced climbers exhibited lower anxiety levels and better sympathetic modulation compared to novices. Significant differences in HRV parameters, grip strength, and RFD were observed, reflecting the impact of experience on physiological responses. Advanced climbers demonstrated notable strength decreases post-climbing, supporting the utility of a force sensor on a 20 mm edge for assessing forearm fatigue. Correlations between cortisol levels, anxiety, and self-confidence during climbing were also identified. Conclusions: The findings highlight the importance of psychological and physiological factors in climbing performance. Forearm fatigue emerged as a critical predictor, suggesting that portable force sensors can optimize training and injury prevention. Insights from this study may enhance training protocols and improve real-time performance monitoring in climbers. Full article

Set in a wide open plain, the monolith of Uluṟu (‘Ayers Rock’) has become an internationally recognizable symbol for the Australian outback, currently attracting hundreds of thousands of tourists each year. Promoted since the 1950s as an exotic tourist destination, one of the major activities has been the ‘conquest’ of Uluṟu by completing the steep climb to the top. Always disapproved by the Aṉangu, the Indigenous Australian community of the area, and actively discouraged since 1990, the climb became an extremely contentious issue in the final two years before it was permanently closed to tourists on 26 October 2019. Given that climbing Uluṟu as a tourist activity has become an event of the past, this paper will examine the nature, materiality, and potential heritage value of the portable material culture associated with the climb. The background to the history of climbing Uluṟu in the context of European invasion (‘exploration’), the nature of tourism at Uluṟu and the role climbing played in this, as well as the management decisions that led to the closure of the climb can be grouped into four thematic periods: the beginnings of settler colonialist ascents (1873–1950), the ‘heroic’ age of Uluṟu tourism (1950–1958), lodges in a National Park (1958–1985), and joint management and the eventual closure of the climb (1985–2019). Based on a description of the material culture associated with the climb, particularly badges, patches and certificates, and drawing on the methodologies of historic and material culture studies, this paper will discuss the various interpretations of climbing Uluṟu and how the portable material culture reflects or exemplifies climbing as a conquest and heroic deed, as a spiritual ritual, and as a violation of cultural rights. After examining the materiality of the wearable material culture, we conclude by exploring which of these portable items are culturally significant and which, if any, should be curated in public collections. Full article

This manuscript presents a multidisciplinary study that proposes a methodology for delineating and categorizing vulnerability at rockfall risk areas to avoid human injuries and infrastructure damage caused by rockfalls. The presented workflow includes (i) classical geological mapping, (ii) the interpretation of high-resolution satellite data for observing the spatial distribution of fallen boulders, (iii) analytical hierarchy processing of spatial information within a Geographical Information System (GIS) platform, (iv) close-range remote sensing campaigns with Unmanned Aerial Systems (UASs), and (v) integrated simulation of rockfall events. This methodology was applied to Kalymnos Island, which belongs to the Dodecanese Islands complex of the southeastern Aegean Sea in Greece. It is characterized by unique geomorphological features, including extensive vertical limestone cliffs that span the island. These cliffs make it one of the world’s most densely concentrated areas for sport climbing. The results highlighted the areas that the local authorities need to focus on and suggested measures for increasing the safety of climbers and infrastructure. Full article

Shear-dominated hazards, such as induced earthquakes, pose an escalating threat to the sustainability and safety of the geothermal exploitation. Variations in fault orientations and compression–shear stress ratios exert a profound influence on the failure processes underlying these disasters. To better understand these effects on the shear failure mechanisms of hot dry rocks, mode-II fracturing tests on granites were conducted at varying loading angles (specifically, 55°, 60°, 65°, and 70°). These tests were accompanied by a comprehensive analysis of the mechanical properties, energy dissipation behavior, acoustic emission (AE) responses, and digital image correlation (DIC)-extracted displacement fields. The tensile–shear properties of stress-induced microcracks were discerned via AE characteristic parameter analysis and DIC displacement decomposition, and the mode-II fracture energy release rate was quantitatively characterized. The results reveal that with increasing compression–shear loading angles, the mechanical properties of granites are weakened, and the elastic strain energy at peak stress gradually decreases, while the slip-related dissipated energy increases. Throughout the fracturing process, the AE count progressively climbs and reaches a peak near catastrophic failure, with an upsurge in low-frequency and high-amplitude AE events. Microcrack distribution concentrates aggregation along the shear plane, reflecting the emergent displacement discontinuities evident in DIC contours. Both the AE characteristic parameter analysis and DIC displacement decomposition demonstrate that shear-sliding constitutes the paramount mechanism, and the fraction of shear-oriented microcracks and the ratio of tangential versus normal displacement escalate with increases in shear stress. This analysis is supported by the heightened propensity for transgranular microcracking events observed through scanning electron microscopy. As the shear-to-compression stress increases, the energy concentration along the shear band intensifies, with the gradient of the fitting line between cumulative AE energy and slip displacement steepening, indicative of a heightened mode-II energy release rate. These results contribute to a deeper understanding of the mode-II fracture mechanism of rocks, thereby providing a foundational basis for early warnings of shear-dominant geomechanical disasters, and improving the safety and sustainability of subsurface rock engineering. Full article

Rock climbing has propelled from niche sport to mainstream free-time activity and Olympic sport. Moreover, climbing can be studied as an example of a high-stakes perception-action task. However, understanding what constitutes an expert climber is not simple or straightforward. As a dynamic and high-risk activity, climbing requires a precise interplay between cognition, perception, and precise action execution. While prior research has predominantly focused on the movement aspect of climbing (i.e., skeletal posture and individual limb movements), recent studies have also examined the climber’s visual attention and its links to their performance. To associate the climber’s attention with their actions, however, has traditionally required frame-by-frame manual coding of the recorded eye-tracking videos. To overcome this challenge and automatically contextualize the analysis of eye movements in indoor climbing, we present deep learning-driven (YOLOv5) hold detection that facilitates automatic grasp recognition. To demonstrate the framework, we examined the expert climber’s eye movements and egocentric perspective acquired from eye-tracking glasses (SMI and Tobii Glasses 2). Using the framework, we observed that the expert climber’s grasping duration was positively correlated with total fixation duration (r = 0.807) and fixation count (r = 0.864); however, it was negatively correlated with the fixation rate (r = −0.402) and saccade rate (r = −0.344). The findings indicate the moments of cognitive processing and visual search that occurred during decision making and route prospecting. Our work contributes to research on eye–body performance and coordination in high-stakes contexts, and informs the sport science and expands the applications, e.g., in training optimization, injury prevention, and coaching. Full article

Background/Objectives: Rock climbing is becoming more popular, leading to an increased focus on diagnosing and treating related injuries. Finger pulley and flexor tendon injuries are common among climbers, with the A2 pulley being the most frequently affected. High-resolution ultrasound (US) is the preferred method for detecting pulley injuries. This study aimed to determine the reliability and validity of US in identifying anatomical landmarks for diagnosing A2 pulley ruptures. Methods: This study was cross-sectional, involving 36 fingers from 4 cadaver arms. A Canon Aplio i800 US machine was used to measure two anatomical landmarks: the midpoint of the proximal phalanx and the distal edge of the A2 pulley. For the first anatomical landmark, the length of the proximal phalanx (PP distance), and for the second landmark, the distance between the distal edges of the proximal phalanx and the A2 pulley (“A” distance), were measured. Measurements were performed by two sonographers and compared to a digital caliper measurement taken post-cadaver dissection. Observers were blinded during measurements to ensure unbiased results. Results: Overall PP distance measured by US (O1: 37.5 ± 5.3 mm, O2: 37.8 ± 5.4 mm) tended to be shorter than caliper measurements (O3: 39.5 ± 5.5 mm). The differences between sonographers were minimal, but larger when compared to caliper measurements. High reliability for PP distance measurement was observed, especially between sonographers, with an ICC average of 0.99 (0.98, 1.00). However, reliability was lower for the “A” distance, with significant differences between US and caliper measurements. Regarding validity, US measurements were valid when compared to caliper measurements for PP distance, but not as reliable for the “A” due to wider confidence intervals. While US can substitute caliper measurements for PP distance (LR, Y:O2, X:O3, −0.70 (−3.28–1.38), 0.98 (0.93 ± 1.04)), its validity for “A” distance is lower (LR, Y:O2, X:O3, −2.37 (−13.53–4.83), 1.02 (0.62–1.75)). Conclusions: US is a reliable and valid tool in identifying anatomical landmarks for diagnosing A2 pulley ruptures, particularly for detecting the midpoint of the proximal phalanx. This is important to differentiate between complete and partial A2 pulley tears. However, the measurement of the “A” distance requires further refinement. These findings support efforts to standardize US examination protocols and promote consensus in diagnostic methodology, though further research is needed to address the remaining challenges. Full article

Background: The ability to hang for a long time before forearm muscle fatigue is a crucial element of successful rock climbing. Electromyography (EMG) and near-infrared spectroscopy (NIRS) are also useful for measuring hemoglobin oxygenation for determining muscle endurance. In the present study, we aimed to evaluate the reliability and validity of muscle endurance indices derived using EMG and NIRS during a hanging task. Methods: A bilateral hanging task was designed to compare rock climbers and non-climbers in terms of the slopes of changes in the median frequency (MDF) and tissue oxygenation index (TOI) of forearm muscles. Results: A total of 17 participants were included in each of the two groups. The intraclass correlation coefficient (3,1) values derived for the MDF slope, TOI slope, ΔTOI, percentage change in oxygen concentration, and ΔHbt were 0.85, 0.73, 0.65, 0.75, and 0.65, respectively. The MDF slope, TOI slope, and ΔHbt differed significantly between the groups (p < 0.05). The MDF slope, TOI slopes, and ΔHbt were significantly correlated with V-scale levels for climbing (p < 0.05). Conclusions: The satisfactory reliability and observed distinctions between climbers and non-climbers imply that these indices are a valuable tool for assessing muscle endurance. Full article

Climbing is an Olympic discipline in full development and multidisciplinary in nature, where the influences of body composition and nutritional status on performance have not yet been clarified despite the quest for a low weight in anti-gravity disciplines such as climbing. The present cross-sectional study aimed to conduct nutritional (3-day dietary diaries) and body composition (ISAK profile) assessments on sport climbing athletes by gender and climbing level during the months of February and March 2024. The t-test for independent samples and the Mann–Whitney U-test, as well as an ANOVA and the Kruskal–Wallis H-test, were used to compare the distributions of two or more groups, respectively, and Pearson’s and Spearman’s correlation coefficients were used to estimate the correlations between the different variables. The mean age of the 46 Spanish climbers (22 men and 24 women) was 30 years (SD: 9) with 7.66 years of experience (SD: 6.63). The mean somatotype of the athletes was classified as balanced mesomorph. Negative correlations were observed between fat mass variables and climbing level (p < 0.010), and positive correlations were observed with forearm circumference (p < 0.050). The mean energy availability (EA) was 33.01 kcal-kg FFM⁻¹d⁻¹ (SD: 9.02), with 55.6% of athletes having a suboptimal EA status and 35.6% having low energy availability (LEA). The carbohydrate and protein intakes were below the recommendations in 57.8% and 31.1% of athletes, respectively. There were deficient intakes of all micronutrients except phosphorus in males. These findings suggest that climbing athletes are at a high risk of developing low energy availability states and concomitant problems. Optimal nutritional monitoring may be advisable in this type of athlete to try to reduce the risk of LEA. Full article

Competitive ice climbing involves ascending ice and natural rock/manmade features using specialized equipment. Despite its growing popularity, there is limited knowledge regarding the relationship between ice climbers’ biomechanics and performance. The purpose of this study was to analyze spatiotemporal variables and upper-extremity joint kinematics during an elite lead ice-climbing competition. A total of 24 (16 male, 8 female) competitors participated. Video data was recorded during the ice climbing competition, and biomechanical analysis software was used to measure kinematic variables (shoulder and elbow angles) and spatiotemporal (time climbing/resting and number of moves/rests) throughout a section of the competition route. Independent t-tests examined differences between the top and bottom 50% of competitors, and correlations assessed the strength of the relationship between the measured variables and competition rank. We found a strong correlation between elbow and shoulder angles at weight bearing on the ice tool, indicating that ice climbers rely on more extended arm positions, which may decrease muscle fatigue, maintain optimal muscle fiber lengths, and keep the trunk close to the wall with lower contact forces. Additionally, we found that higher-performing ice climbers moved faster with fewer moves, which is likely due to their ability to identify specific holds as affordances to guide their movement. Full article

Climbing performance is greatly dependent on the endurance of the finger flexors which, in turn, depends on the ability to deliver and use oxygen within the muscle. Near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) have provided new possibilities to explore these phenomena in the microvascular environment. The aim of the present study was to explore climbing-related microvascular adaptations through the comparison of the oxygen concentration and hemodynamics of the forearm between climbers and non-climber active individuals during a vascular occlusion test (VOT). Seventeen climbers and fifteen non-climbers joined the study. Through NIRS and DCS, the oxyhemoglobin (O₂Hb) and deoxyhemoglobin (HHb) concentrations, tissue saturation index (TSI), and blood flow index (BFI) were obtained from the flexor digitorum profundus during the VOT. During the reactive hyperemia, climbers presented greater blood flow slopes (p = 0.043, d = 0.573), as well as greater O₂Hb maximum values (p = 0.001, d = 1.263) and HHb minimum values (p = 0.009, d = 0.998), than non-climbers. The superior hemodynamics presented by climbers could indicate potential training-induced structural and functional adaptations that could enhance oxygen transportation to the muscle, and thus enhance muscle endurance and climbing performance. Full article