Action capability constrains visuo-motor complexity during planning and performance in on-sight climbing

Whole body coarticulation reflects expertise in sport climbing

Taking sport climbing as a testbed, we explored coarticulation in naturalistic motor-behavior at the level of whole body kinematics. Participants were instructed to execute a series of climbing routes, each composed of two initial foot-moves equal in all routes, and two subsequent hand-moves differing across routes in a set of eight possible configurations. The goal was assessing whether climbers modulate the execution of a given move depending on which moves come next in the plan. Coarticulation was assessed by training a set of classifiers and estimating how well the whole body (or single-joint) kinematics during a given stage of the climbing execution could predict its future unfolding. Results showed that most participants engage in coarticulation, with temporal and bodily patterns that depend on expertise. Nonclimbers tend to prepare the next-to-come move right before its onset and only after the end of the previous move. Rather, expert-climbers (and to a smaller extent, beginner-climbers) show early coarticulation during the execution of the previous move and engage in adjustments that involve the coordination of a larger number of joints across the body. These results demonstrate coarticulation effects in whole body naturalistic motor behavior and as a function of expertise. Furthermore, the enhanced coarticulation found in expert-climbers provides hints for experts engaging in more refined mental processes converting abstract instructions (e.g., move the right hand to a given location) into motor simulations involving whole body coordination. Overall, these results contribute to advancing our current knowledge of the rich interplay between cognition and motor control.NEW & NOTEWORTHY The current study explores the way in which having formed a plan for a sequential motor task affects its execution. We showed that climbing expertise increases the extent to which participants adjust their motor execution based on the moves that follow in a planned route. These results provide evidence of coarticulation in naturalistic motor behavior and suggest enhanced skills in mentalizing forward motor control and optimal-control strategies in expert climbers.

The interplay between motor cost and self-efficacy related to walking across terrain in gaze and walking decisions

Motor behaviours, like where to step and which path to walk, rely on gaze shifts to gather visual information necessary to decide the next action. Factors influencing both gaze and walking decisions are poorly understood. Here we had people choose between two paths to determine how a person's belief in their ability to walk across different terrains (i.e., self-efficacy) competed with the expected cost of walking different lengths in deciding how to allocate gaze and the choice of path. When paths differed in both length and terrain, participants directed gaze progressively more to the longer path as self-efficacy about it increased and the difference in rating with the shorter path grew. Participants also chose the higher-rated path more frequently regardless of path length. These results demonstrate that self-efficacy contributes to gaze and walking decisions and suggest that it may play a more dominant role versus energetic cost in both behaviours.

Vertical locomotion improves horizontal locomotion: effects of climbing on gait and other mobility aspects in Parkinson's disease. A secondary analysis from a randomized controlled trial

BACKGROUND

In the Climb Up! Head Up! trial, we showed that sport climbing reduces bradykinesia, tremor, and rigidity in mildly to moderately affected participants with Parkinson's disease. This secondary analysis aimed to evaluate the effects of sport climbing on gait and functional mobility in this cohort.

METHODS

Climb Up! Head Up! was a 1:1 randomized controlled trial. Forty-eight PD participants (Hoehn and Yahr stage 2-3) either participated in a 12-week, 90-min-per-week sport climbing course (intervention group) or were engaged in regular unsupervised physical activity (control group). Relevant outcome measures for this analysis were extracted from six inertial measurement units placed on the extremities, chest, and lower back, that were worn during supervised gait and functional mobility assessments before and after the intervention. Assessments included normal and fast walking, dual-tasking walking, Timed Up and Go test, Instrumented Stand and Walk test, and Five Times Sit to Stand test.

RESULTS

Compared to baseline, climbing improved gait speed during normal walking by 0.09 m/s (p = 0.005) and during fast walking by 0.1 m/s. Climbing also reduced the time spent in the stance phase during fast walking by 0.03 s. Climbing improved the walking speed in the 7-m- Timed Up and Go test by 0.1 m/s (p < 0.001) and the turning speed by 0.39 s (p = 0.052), the speed in the Instrumented Stand and Walk test by 0.1 m/s (p < 0.001), and the speed in the Five Times Sit to Stand test by 2.5 s (p = 0.014). There was no effect of sport climbing on gait speed or gait variables during dual-task walking.

CONCLUSIONS

Sport climbing improves gait speed during normal and fast walking, as well as functional mobility in people with Parkinson's disease. Trial registration This study was registered within the U.S. National Library of Medicine (No: NCT04569981, date of registration September 30th, 2020).

Embodied planning in climbing: how pre-planning informs motor execution

Introduction

The aim of the study is to address embodied planning in climbing. Embodied planning was conceptualized as the interaction between perceptual-cognitive pre-planning and motor execution.

Methods

In an experimental study, 18 climbers were asked to pre-plan a climbing route and to perform the route afterward. During pre-planning, the visual search pattern of climbers was captured using a portable eye tracker. After previewing, they were invited to climb the wall.

Results

Results revealed that holds looked at during pre-planning were used twice as much during route execution than those not looked at. The duration of fixations was longer for holds used than those not used during route execution. The experience of climbers (training years) correlated with visual strategies and climbing performance, such that experienced participants climbed faster and fixated at the holds not used for a shorter time.

Discussion

The visual behaviors of climbers were influenced by their past sensorimotor experiences during route previewing, impacting subsequent climbing performance.

Persistent Unilateral Force Production Deficits Following Hand Injury in Experienced Climbers: A Reliability and Retrospective Injury Study

INTRODUCTION

In climbing, research is needed to guide clinical and training advice regarding strength differences between hands. The objectives of this study were to establish test-retest reliability of a field-based apparatus measuring sport-specific unilateral isometric hand strength and to investigate whether these measures detect between-hand differences in climbers with and without a history of unilateral hand injury.

METHODS

A reliability and case-control injury study was carried out. Seventeen intermediate-advanced climbers without and 15 intermediate-advanced climbers with previous unilateral hand injury participated. Unilateral isometric fingertip flexor strength was assessed during maximal voluntary contraction (MVC) and peak rate of force development (RFD) tests in full-crimp overhead position. The magnitude of within-group between-hand differences was calculated using a generalized estimating equation to evaluate if prior injury was associated with lower MVC and RFD outcomes and whether hand dominance influenced the magnitude of these effects. The control group was assessed 1 wk later to determine intraclass correlation coefficients (ICCs) for all measures.

RESULTS

The MVC (ICC 0.91-0.93) and the RFD (ICC 0.92-0.83) tests demonstrated moderate-to-high reliability. When accounting for handedness, those with prior injury showed 7% (P=0.004) reduced MVC and 13% (P=0.008) reduced RFD in the injured hand. The nondominant hand was also significantly weaker in MVC (11%, P<0.001) and RFD (12%, P=0.02) outcomes. For uninjured climbers, MVC and RFD were not significantly higher in the dominant hand (differing by 4% and 5%, respectively).

CONCLUSIONS

Previous climbing injury was associated with persistent weakness in the injured limb and exacerbated handedness effects. Therefore, recommendations for rehabilitation should be considered.

The Ecological Dynamics Framework: An Innovative Approach to Performance in Extreme Environments: A Narrative Review

(1) Background: Uncertainty in extreme sports performance environments, such as climbing, provides considerable psycho-emotional and physiological demands, notably due to the many different environments in which climbing can be performed. This variety of environments, conditions of practice and engagement would challenge the acquisition of perceptual-motor skills; (2) Methods: To better understand how perceptual-motor skills are controlled and acquired in climbing, we proposed a narrative review anchored in the ecological dynamics theoretical framework and showed how this theoretical framework would support a nonlinear pedagogy to skill acquisition and to design safe learning and training situations that are representative of extreme performance contexts; (3) Results: We explained three theoretical pillars and we provide examples for design intervention following nonlinear pedagogy, notably (i) to set a constraint-led approach (in particular task constraint), (ii) to implement conditions of practice (constant vs. variable, imposed vs. self-controlled), (iii) to promote adaptive and creative behavioral variability during practice; (4) Conclusions: The challenge for the extreme sport practitioner is how to set up conditions of practice for efficient exploration in a manner that manages the dangers of performing in uncertain environments. Representing uncertainty within the relative safety of indoor settings may be one approach for preparing climbers for performance in extreme environments.

Influence of On-Sight and Flash Climbing Styles on Advanced Climbers' Route Completion for Bouldering

Route previewing has been established as a critical parameter in indoor climbing performance, as it could determine the success or failure in ascending the route. We addressed the effect of different types of previews on output climbing performance. Twenty-one advanced climbers (7b and 7c+ climbing grade) were required to complete 18 routes, rated at 6c, according to the French Rating Scale of Difficulty. Each climber previewed the route under three conditions: “No-previewing”, “video-model previewing”, and “real-model previewing”. Output climbing performance was assessed in terms of route completion. The results showed differences on output climbing performance between types of preview. Specifically, the climbers achieved more successful attempts at climbing to the “Top” of the wall when inspecting the route with the “real-model previewing” condition, compared to the other conditions of preview. On the contrary, the climbers displayed more failed attempts in climbing the route with the “on-sight” condition, compared to the “flash” styles (“video-model” and “real-model”). The preview of the route, including performance of a real/video-projected model manipulating climbing holds, seems to increase the opportunities to climb the boulder successfully, attuning climbers to information specifying ascending actions. Climbing coaches should reinforce the design of representative training, using flash styles, to promote movement solutions for route completion.

The influence of skill and task complexity on perception of nested affordances

This study investigated how skill level and task complexity influence the calibration of perception–action and particularly how close an individual acts relative to his or her maximal action capabilities. Complexity was manipulated between two (Touch, Grasp) and more than two (Removing, Moving Up) nested affordance conditions. For all conditions, we examined whether advanced climbers had greater maximal action capabilities than intermediate climbers or whether they better scaled their action (i.e., acted nearer to their maximal action capabilities) or both. Eleven intermediate and 11 advanced male climbers were first asked to estimate the maximum distance that they could reach a climbing hold. The hold was moved along a slide and fixed once requested by the participant; subsequently, the distance to the starting hold was measured. After each estimation, the participant was required to execute the climbing action. After four estimation-action trials in each of the four conditions, the maximal action capability (i.e., actual maximal reaching distance) was determined. Advanced climbers demonstrated greater actual maximal reaching distances than intermediate climbers for all conditions, but they only estimated greater maximal reaching distances for the more complex conditions, which featured more than two nested affordances. When estimated maximal reaching distances were scaled to actual maximal reaching distances, advanced climbers did not differ from intermediate climbers for any condition, and there were no differences between conditions. Our findings indicate that expertise was a function of greater action capabilities, but not due to the accuracy of calibration.

Movement Matters! Understanding the Developmental Trajectory of Embodied Planning

Human motor skills are exceptional compared to other species, no less than their cognitive skills. In this perspective paper, we suggest that "movement matters!," implying that motor development is a crucial driving force of cognitive development, much more impactful than previously acknowledged. Thus, we argue that to fully understand and explain developmental changes, it is necessary to consider the interaction of motor and cognitive skills. We exemplify this argument by introducing the concept of "embodied planning," which takes an embodied cognition perspective on planning development throughout childhood. From this integrated, comprehensive framework, we present a novel climbing paradigm as the ideal testbed to explore the development of embodied planning in childhood and across the lifespan. Finally, we outline future research directions and discuss practical applications of the work on developmental embodied planning for robotics, sports, and education.

Action capability constrains visuo-motor complexity during planning and performance in on-sight climbing

The capability to adapt to changing conditions is crucial for safe and successful performance in physical activities and sports. According to the affordance‐based control perspective, individuals act in such a way as to take into account the limits of their capability to act. However, it is not clear how strength interacts with skill in shaping performer‐environment interactions. We, therefore, determined whether fingertip strength influences patterns of gaze and climbing behavior on new routes of ever‐increasing difficulty. We expected that comparatively weaker climbers would show less complex behavior because of an inability to perceive and act. Stronger climbers would show more complex visuo‐motor behavior because more opportunities for action remain, even as route difficulty increases. For very strong climbers the route would not be challenging enough, and less complex patterns suffice. Twenty climbers, ranging from lower grade to elite level participated. Maximum fingertip strength was obtained. Participants previewed and then climbed two separate 3 m long traverses, gradually decreasing in edge depth. Gaze and hip positions were collected for subsequent computation of gaze transition entropy (during preview) and hip displacement entropy (during climbing). Data revealed statistically significant curvilinear relationships between both fingertip strength and gaze transition entropy, and fingertip strength, and hip displacement entropy. Visuo‐motor complexity is scaled by how close the individual must act relative to boundaries of what the environment affords and does not afford for action given the individual constraints. Future research should examine in greater detail relationships between action capabilities and functional movement variability.