Changes in coordination and its variability with an increase in running cadence

Alterations in joint mechanics have been associated with common overuse injuries. An increase in running cadence in healthy runners has been shown to improve several parameters that have been tied to injury, but the reorganisation of motion that produces these changes has not been examined. The purpose of this study was to determine if runners change their segment coordination and coordination variability with an acute increase in cadence. Data were collected as ten uninjured runners ran overground at their preferred cadence as well as a cadence 10% higher than preferred. Segment coordination and coordination variability were calculated for select thigh–shank and shank–foot couples and selected knee mechanics were also calculated. Paired t-tests were used to examine differences between the preferred and increased cadence conditions. With increased cadence, there was a decrease in peak knee flexion and a later occurrence of peak knee flexion and internal rotation and shank internal rotation. Segment coordination was altered with most changes occurring in mid-late stance. Coordination variability decreased with an increase in cadence across all couples and phases of gait. These results suggest examination of coordination and its variability could give insight into the risk of intervention-induced injury.     

Bringing objectivity to motor skill assessment in children

ABSTRACT

The study purpose was to use Inertial Measurement Units (IMUs) to objectively assess children’s motor competence in seven movement skills. Fourteen children aged from seven to 12 years (M = 9.64) participated. Children were asked to perform up to 10 trials of each skill. Children performed the skills, which were captured by XSENS MVN Awinda wireless motion capture, and video. Skills were assessed from video as per the criteria from the Test of Gross Motor Development 3. Initially, 17 IMU sensors were used for signal processing, but this was restricted to four sensors (wrists and ankles) to be more feasible for field assessment. Results of the signal testing against its modelled “Good” signal, showed the skip was classified correctly each time, as was the sidestep. Accuracy % rates for each skill were: kick (95.2), catch (95.0), throw (80.5), jump (78.9), and hop (76.9). Using signal processing-based methods via four sensors was a reliable and feasible way to assess seven motor skills in children. This approach means monitoring and assessment of children’s skills can be objective, which will potentially reduce the time involved in motor skill assessment and analysis for research, clinical, sport and education purposes.     

Segment coordination and variability among prospectively injured and uninjured runners

ABSTRACT

Coordinative variability (CAV) and underlying coordinative patterns are potential running-related overuse injury (RROI) mechanisms, but prospective analyses are needed. This study compared lower limb CAV and coordinative patterns between prospectively injured and uninjured runners. Knee, shank, and ankle kinematics were collected for 39 recreational runners at the beginning of a 6-month follow-up period. Subjects were classified as injured (n=21) or controls (n=18) based on RROI incidence during follow-up. CAV was quantified using modified vector coding. Time spent in each coordinative pattern category was quantified using binning frequency analysis. Coordinative patterns were classified as mechanically unsound if underlying joint/segment motions opposed anatomically allowable running motion. Wilcoxon Rank-Sum tests compared CAV and binning frequencies between groups within different stance portions for knee-shank, shank-ankle, and knee-ankle couplings (α≤0.05). During initial-stance, the injured group displayed significantly greater knee-ankle CAV (effect size (ES)=1.1), knee-shank CAV (ES=0.97), and greater frequency of mechanically unsound knee-shank (ES=0.72) and shank-ankle (ES=0.63) motion. During mid-stance, the injured group displayed lower frequency of mechanically sound knee-ankle motion (ES=0.31). In late-stance, the injured group displayed greater shank-ankle CAV (ES=0.11). Mechanically unsound coordinative patterns along with greater knee-ankle and shank-ankle CAV potentially lead to RROI.     

Coordination as a function of skill level in the gymnastics longswing

The purpose of this study was to investigate the nature of inter-joint coordination at different levels of skilled performance to: (1) distinguish learners who were successful versus unsuccessful in terms of their task performance; (2) investigate the pathways of change during the learning of a new coordination pattern and (3) examine how the learner’s coordination patterns relate to those of experts in the longswing gymnastics skill. Continuous relative phase of hip and shoulder joint motions was examined for longswings performed by two groups of novices, successful (n = 4) and unsuccessful (n = 4) over five practice sessions, and two expert gymnasts. Principal component analysis showed that during longswing positions where least continuous relative phase variability occurred for expert gymnasts, high variability distinguished the successful from the unsuccessful novice group. Continuous relative phase profiles of successful novices became more out-of-phase over practice and less similar to the closely in-phase coupling of the expert gymnasts. Collectively, the findings support the proposition that at the level in inter-joint coordination a technique emerges that facilitates successful performance but is not more like an expert’s movement coordination. This finding questions the appropriateness of inferring development towards a “gold champion” movement coordination.     

Age and sex influences on running mechanics and coordination variability

The purpose of this study was to examine the impact of age on running mechanics separately for male and female runners and to quantify sex differences in running mechanics and coordination variability for older runners. Kinematics and kinetics were captured for 20 younger (10 male) and 20 older (10 male) adults running overground at 3.5 m · s^?1. A modified vector coding technique was used to calculate segment coordination variability. Lower extremity joint angles, moments and segment coordination variability were compared between age and sex groups. Significant sex–age interaction effects were found for heel-strike hip flexion and ankle in/eversion angles and peak ankle dorsiflexion angle. In older adults, mid-stance knee flexion angle, ankle inversion and abduction moments and hip abduction and external rotation moments differed by sex. Older compared with younger females had reduced coordination variability in the thigh–shank transverse plane couple but greater coordination variability for the shank rotation–foot eversion couple in early stance. These results suggest there may be a non-equivalent aging process in the movement mechanics for males and females. The age and sex differences in running mechanics and coordination variability highlight the need for sex-based analyses for future studies examining injury risk with age.     

Differences in lower-limb coordination and coordination variability between novice and experienced runners during a prolonged treadmill run at anaerobic threshold speed

This study investigated differences in lower-limb coordination and coordination variability between experienced and novice runners during a prolonged run. Thirty-four participants were categorised as either experienced (n = 17) or novice runners (n = 17). All participants performed a 31-min treadmill run at their individual anaerobic threshold speed, and lower-limb kinematic data were acquired in the sagittal plane at the beginning, middle, and end of the run. Lower-limb coordination and variability during the stance phase were quantified using a vector coding technique for hip-knee, knee-ankle, pelvis-thigh, thigh-shank, and shank-foot couplings. Repeated-measure analysis of covariance revealed that running experience and time had significant interactions on the coordination patterns for hip-knee and pelvis-thigh couplings. During the midstance, experienced runners exhibited a higher percentage of in-phase motion for pelvis-thigh and knee-ankle couplings while novice runners displayed a higher percentage of distal motion for pelvis-thigh coupling and anti-phase motion for hip-knee coupling. Experienced runners displayed more variability in hip-knee and shank-foot couplings, and novice runners had more variability in hip, knee, and thigh motion. Experienced and novice runners adapted to progressive fatigue through different lower-limb coordination patterns. Throughout the prolonged run, experienced runners demonstrated greater coordination variability and novice runners displayed greater joint and segment variability.     

The feasibility of fundamental movement skill assessments for pre-school aged children

Fundamental movement skill (FMS) assessment in preschools allows for early intervention; however it is unclear what assessments are feasible. The purpose of this review is to systematically review the feasibility of FMS assessments for pre-school aged children. The search was conducted across four databases, MEDLINE, Scopus, ERIC and SportsDiscus. Search terms included synonyms of “fundamental movement skills” and “pre-school children”. Inclusion criteria were: (i) FMS assessment; (ii) feasibility data; (iii) assessment of children aged three to six years; (iv) assessment of typically developing children; and (v) peer reviewed full text publications in English. Feasibility concepts (administration time, equipment, space, assessment type, item, training, qualification) were each coded as ‘poor = 1?, ‘average = 2? and ‘good = 3?; potential total of 21. A total of 330 full text articles were considered but a quarter (n = 86) were excluded due to no feasibility data. Sixty-five studies using 13 different FMS assessments were included. The Athletic Skills Track and DEMOST-PRE assessments were most feasible (18/21) and the Test of Gross Motor Development and Movement Assessment Battery for Children were common but among the least feasible (12–14/21). This review allows pre-school staff to choose a FMS assessment based on feasibility. Future studies need to present feasibility of assessments.     

New insight for activity intensity relativity,metabolic expenditure during object projection skill performance

This study examined the metabolic cost (METs) of performing object projection skills at three practice trial intervals (6, 12, and 30 seconds). Forty adults (female n = 20) aged 18–30 (M = 23.7 ± 2.9 years) completed three, nine-minute sessions of skill trials performed at 6, 12, and 30 second intervals. Participants performed kicking, throwing and striking trials in a blocked schedule with maximal effort. Average METs during each session were measured using a COSMED K4b2. A three (interval condition) X two (sex) ANOVA was conducted to examine differences in METs across interval conditions and by sex. Results indicated a main effect for interval condition (F(5,114) = 187.02, p < .001, η² = 0.76) with decreased interval times yielding significantly higher METs [30 sec = 3.45, 12 sec = 5.68, 6 sec = 8.21]. A main effect for sex (F(5, 114) = 35.39, p < .001, η² = 0.24) also was found with men demonstrating higher METs across all intervals. At a rate of only two trials/min, participants elicited moderate physical activity, with 12 and 6-second intervals exhibiting vigorous PA. Demonstrating MVPA during the performance of object projection skill performance has potential implications for PA interventions.     

The kinematic differences between accurate and inaccurate squash forehand drives for athletes of different skill levels

ABSTRACT

To maintain the accuracy of squash shots under varying conditions, such as the oncoming ball’s velocity and trajectory, players must adjust their technique. Although differences in technique between skilled and less-skilled players have been studied, it is not yet understood how players vary their technique in a functional manner to maintain accuracy under varying conditions. This study compared 3-dimensional joint and racket kinematics and their variability between accurate and inaccurate squash forehand drives of 9 highly skilled and 9 less-skilled male athletes. During inaccurate shots, less-skilled players hit the ball with a more open racket, demonstrating a difference in this task-relevant parameter. No joint kinematic differences were found for accuracy for either group. Coordinated joint rotations at the elbow and wrist both displayed a “zeroing-in” effect, whereby movement variability was reduced from the initiation of propulsive joint rotation to a higher consistency at ball-impact; potentially highlighting the “functionality” of the variability prior to the impact that enabled consistent task-relevant parameters (racket orientation and velocity) under varying conditions. Further, highly skilled players demonstrated greater consistency of task-relevant parameters at impact than less-skilled players. These findings highlight the superior ability of highly skilled players to adjust their technique to achieve consistent task-relevant parameters and a successful shot.     

Development of a performance assessment tool for rock climbers

Abstract

Rock climbing is a popular adventure sport for which there is a growing body of scientific knowledge. There is, however, a lack of sport-specific assessment tools to monitor performance. The aim of this study was to examine the potential of the rock-over climbing test (ROCT) as a measure of climbing performance. The ROCT was conducted on a climbaflex board and involved the climber making a rock-over move for which the height gained from lower to upper handhold was measured. Results indicated there was a significant relationship between scaled (to the height of the climber) ROCT scores and climbing ability (r=0.67, P<0.0005). Regression modelling revealed that the ROCT explained 45% of the variance in scores between climbers. The ROCT differentiated between climber ability levels. Mean ROCT scores for novice, intermediate, advanced, and elite climbers were 59.5%, 71%, 82%, and 90% of participant height respectively. Results of analysis of variance revealed that these differences were significant (F _3,42=13.38, P<0.0005). Limits of agreement and intra-class correlation indicated that the ROCT is a reliable performance measure. Our findings suggest that the ROCT is a useful measure of climbing performance.     

Multivariate analyses of individual variation in soccer skill as a tool for talent identification and development: utilising evolutionary theory in sports science

The development of a comprehensive protocol for quantifying soccer-specific skill could markedly improve both talent identification and development. Surprisingly, most protocols for talent identification in soccer still focus on the more generic athletic attributes of team sports, such as speed, strength, agility and endurance, rather than on a player’s technical skills. We used a multivariate methodology borrowed from evolutionary analyses of adaptation to develop our quantitative assessment of individual soccer-specific skill. We tested the performance of 40 individual academy-level players in eight different soccer-specific tasks across an age range of 13–18 years old. We first quantified the repeatability of each skill performance then explored the effects of age on soccer-specific skill, correlations between each of the pairs of skill tasks independent of age, and finally developed an individual metric of overall skill performance that could be easily used by coaches. All of our measured traits were highly repeatable when assessed over a short period and we found that an individual’s overall skill – as well as their performance in their best task – was strongly positively correlated with age. Most importantly, our study established a simple but comprehensive methodology for assessing skill performance in soccer players, thus allowing coaches to rapidly assess the relative abilities of their players, identify promising youths and work on eliminating skill deficits in players.     

Use of dual-task methodology for skill assessment and development: Examples from rugby league

Abstract

We assessed the attentional demands of drawing and passing in rugby league players and investigated the effects of single-task and dual-task training on the acquisition, retention, and transfer of skill in these athletes. In Study 1, high-skilled and lesser-skilled rugby league players performed a standardized 2-on-1 drill under single-task (primary skill in isolation) and dual-task (primary skill while performing a secondary verbal tone recognition task) conditions. No differences were detected in primary task performance between groups, although the performance of the high-skilled players was more resistant to skill decrement under dual-task conditions. In Study 2, high-performance rugby league players were randomly allocated to either a single-task or dual-task training group. Each group underwent 8 weeks of training between the pre- and post-test sessions. While the mean improvement for draw and pass proficiency under dual-task conditions in the dual-task training group was greater than in the single-task training group (10.0% vs. 2.3%), the differences, while providing a moderate effect size (d = 0.57), were not statistically significant. These results suggest that the attentional demands of drawing and passing are reduced in high-skilled rugby league players compared with their lesser-skilled counterparts. In addition, compared with single-task training, dual-task training appears to improve the ability to perform dual-task draw and pass tasks (possibly through an improvement in time-sharing skills). Further studies are required to verify the efficacy of dual-task training as a training stimulus.     

Especial skill vs. quiet eye duration in basketball free throw: Evidence for the inhibition of competing task solutions

Abstract

The quiet eye (QE) is a gaze phenomenon that has been studied over more than two decades. However, the underlying mechanisms of the well-known expertise effect, namely, longer QE durations in experts when compared to less-skilled athletes remain unclear. Therefore, from a functional perspective, an inhibition hypothesis was proposed that explains long QE durations in experts with increased inhibition requirements over movement parametrisation. This hypothesis was tested by making use of the especial-skill effect in basketball free throw which refers to the observation of higher actual performance than would be predicted on the basis of performance at the nearby locations. In line with the expectations, from the distance of the free-throw line, higher actual than predicted shooting accuracy and longer actual than predicted QE duration were revealed. This suggests that when performing free throws prolonged QE durations are required to shield the optimal against alternative task solutions within the very dense sub-space of this especial skill. These findings suggest an inhibition function of long QE durations in expert athletes.