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Background: Movement competency screens (MCSs) are commonly used by coaches and clinicians to assess injury risk. However, there is conflicting evidence regarding MCS reliability. Purpose: This study aimed to: (i) determine the inter- and intra-rater reliability of a sport specific field-based MCS in novice and expert raters using different viewing methods (single and multiple views); and (ii) ascertain whether there were familiarization effects from repeated exposure for either raters or participants. Study Design: Descriptive laboratory study. Methods: Pre-elite youth athletes (n=51) were recruited and videotaped while performing a MCS comprising nine dynamic movements in three separate trials. Performances were rated three times with a minimal four-week wash out between testing sessions, each in randomized order by 12 raters (3 expert, 9 novice), using a three-point scale. Kappa score, percentage agreement and intra-class correlation were calculated for each movement individually and for the composite score. Results: Fifty-one pre-elite youth athletes (15.0±1.6 years; n=33 athletics, n=10 BMX and n=8 surfing) were included in the study. Based on kappa score and percentage agreement, both inter- and intra-rater reliability were highly variable for individual movements but consistently high (>0.70) for the MCS composite score. The composite score did not increase with task familiarization by the athletes. Experts detected more movement errors than novices and both rating groups improved their detection of errors with repeated viewings of the same movement. Conclusions: Irrespective of experience, raters demonstrated high variability in rating single movements, yet preliminary evidence suggests the MCS composite score could reliably assess movement competency. While athletes did not display a familiarization effect after performing the novel tasks within the MCS for the first time, raters showed improved error detection on repeated viewing of the same movement. Level of Evidence: Cohort study.

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We suspected that the observed inconsistency of sex differences in drop-landing motor skills might be due to the confounding factor of prior experience. Thus, in this study, we explored the role of experience in shaping male and female surfboard riders' motor skill kinematics during drop landings while surfboard riding. We recruited 42 participants (21 females and 21 males) from three groups of surfing experience levels (competitive surfers, recreational surfers, and nonsurfers), each equally comprising seven males and seven females. Sagittal plane kinematics and vertical ground reaction force data were collected from all participants during a laboratory-based 60-cm drop-landing task. Knee flexion and ankle dorsiflexion at initial ground contact were greater among male participants, independent of experience level. In both sexes, greater range of motion at these joints was related to greater experience. Recreational female surfers landed in a more upright posture with more extended ankle and knee angles and less ankle dorsiflexion at the end of landing than participants in all other groups. We discuss our results in the context of possible remaining experience differences between male and female participants despite being grouped in the same experience levels in our study, individualized motor patterns that may still achieve similar success, and a need for continued research.

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RESUMEN

Potential sex differences in patterns of movement of recreational and competitive athletes were investigated in a systematic review of lower limb kinematics, muscle activation and stiffness during landing and hopping tasks. Little support for sex-specific lower limb kinematic patterns was found in 17 studies retrieved on landing and hopping. Ten studies retrieved on muscle activation during landing provided no support for sex-specific patterns. Four articles retrieved on leg stiffness established that absolute stiffness was lower in females, but differences in stiffness normalized to body mass were less clear. The wider literature indicates that a combination of biological, environmental and sociocultural constraints may shape movement patterns differently in females and males. Sociocultural factors differentially affect accumulated motor experience, practice opportunities and focus of attention in females, leading to differences in motor skill that confound the comparison of female and male movements. The findings of the review support the hypothesis that such sex differences in athletic performance are likely to diminish or disappear with increasing skill. In everyday movement tasks, however, where level of skill is a less meaningful dimension than in sport, differences in movement patterns observed between females and males point instead to the influence of subtle societal expectations on movement patterns.

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