3D Kinematics of Male and Female Soccer Players for a Variety of Game-Specific Skills.

Soccer is played by a variety of individuals with varying abilities. The complicated lower limb movements involved within the game often lead to knee and ankle injuries, with anterior cruciate ligament injuries being the most severe with regard to rehabilitation time and ongoing health risks. This research explores the biomechanical kinematics of male and female soccer players on synthetic grass to determine whether trends in lower limb biomechanics over a variety of movements could explain injury risk. Both male and female players (n = 10) aged between 19 and 24 years performed running-based and stationary-start movements. Biomechanical measurements at the hip, knee, and ankle were recorded. Observations showed that specific differences in joint angles were largely dependent on the movements performed; however, for male players, on average, across all movements, 84.6% and 72.6% of the variation in joint angles could be explained by internal/external rotation at the hip and knee, respectively. For female players, internal/external knee rotation, as well as hip abduction and adduction, accounted for 83.6% and 80.2% of the variation in joint angles, respectively, across all the tested movements. This highlights the importance of hip mechanics and knee alignment for players when performing a variety of movements.

Seated-Shot-Put Equipment in Para Athletics-A Review and Presentation of Data From the Tokyo 2020 Paralympic Games.

This research provides a review of seated shot put alongside new data from the Tokyo 2020 Paralympic Games with the aim to understand the latest trends in equipment within a recently established rule set and how key equipment variables may impact performance for athletes in different classifications. First, a review of the literature found that the throwing pole is a key equipment aid that is not well understood, in part due to limitations in testing design. New data from the 2020 Paralympic Games showed inconsistent trends for the use of the throwing pole among athletes, particularly in transitionary classes (F33-34 and F54-55). A two-way analysis of variance found a main effect of classification on performance (p < .001), as well as an interaction effect between pole use and classification on performance (p < .05). Notably, pole users are seen to perform better than non-pole users in Class F32 (p < .05).

Analysis of Movement Variability in Cycling: An Exploratory Study.

The purpose of this study was to determine the test-retest repeatability of Blue Trident inertial measurement units (IMUs) and VICON Nexus kinematic modelling in analysing the Lyapunov Exponent (LyE) during a maximal effort 4000 m cycling bout in different body segments/joints. An additional aim was to determine if changes in the LyE existed across a trial. Twelve novice cyclists completed four sessions of cycling; one was a familiarisation session to determine a bike fit and become better accustomed to the time trial position and pacing of a 4000 m effort. IMUs were attached to the head, thorax, pelvis and left and right shanks to analyse segment accelerations, respectively, and reflective markers were attached to the participant to analyse neck, thorax, pelvis, hip, knee and ankle segment/joint angular kinematics, respectively. Both the IMU and VICON Nexus test-retest repeatability ranged from poor to excellent at the different sites. In each session, the head and thorax IMU acceleration LyE increased across the bout, whilst pelvic and shank acceleration remained consistent. Differences across sessions were evident in VICON Nexus segment/joint angular kinematics, but no consistent trend existed. The improved reliability and the ability to identify a consistent trend in performance, combined with their improved portability and reduced cost, advocate for the use of IMUs in analysing movement variability in cycling. However, additional research is required to determine the applicability of analysing movement variability during cycling.

The application of the Lyapunov Exponent to analyse human performance: A systematic review.

Variability is a normal component of human movement, allowing one to adapt to environmental perturbations. It can be analysed from linear or non-linear perspectives. The Lyapunov Exponent (LyE) is a commonly used non-linear technique, which quantifies local dynamic stability. It has been applied primarily to walking gait and appears to be limited application in other movements. Therefore, this systematic review aims to summarise research methodologies applying the LyE to movements, excluding walking gait. Four databases were searched using keywords related to movement variability, dynamic stability, LyE and divergence exponent. Articles written in English, using the LyE to analyse movements, excluding walking gait were included for analysis. 31 papers were included for data extraction. Quality appraisal was conducted and information related to the movement, data capture method, data type, apparatus, sampling rate, body segment/joint, number of strides/steps, state space reconstruction, algorithm, filtering, surrogation and time normalisation were extracted. LyE values were reported in supplementary materials (Appendix 2). Running was the most prevalent non-walking gait movement assessed. Methodologies to calculate the LyE differed in various aspects resulting in different LyE values being generated. Additionally, test-retest reliability, was only conducted in one study, which should be addressed in future.

Measurements of roll, steering, and the far-field wake in track cycling.

A series of measurements taken with two instrumented track bicycles in a velodrome are presented. The bicycle wheel speed, cadence, roll angle, steering angle, power, and airspeed are recorded. The experimentally-measured values are compared to existing theoretical models of roll and steering angles. The accuracy of the roll angle calculations is dependent on the fidelity of the modelled cyclist path and decreases for higher riding speeds. Experimental measurements of the steering angle show a reasonable agreement to theoretical calculations, albeit with reduced steering angles on the bends at higher speeds. There is also seen an increasing steering angle oscillation within each pedal cycle with increasing bicycle velocity which may influence a cyclist's rolling resistance and the aerodynamic flow around the bicycle's front end. Observations are made of changes in the flow field ahead of the bicycle due to the presence of other riders on the track, showing an effective tailwind of up to 0.7 m/s. The measured power shows a decrease at the bend entry due to the changing roll angle. Data presented in this paper provides new insights and can help to provide a validation of values used in existing track cycling analytic models.

Prediction of Propulsion Kinematics and Performance in Wheelchair Rugby.

Prediction of propulsion kinematics and performance in wheelchair sports has the potential to improve capabilities of individual wheelchair prescription while minimizing testing requirements. While propulsion predictions have been developed for daily propulsion, these have not been extended for maximal effort in wheelchair sports. A two step-approach to predicting the effects of changing set-up in wheelchair rugby was developed, consisting of: (One) predicting propulsion kinematics during a 5 m sprint by adapting an existing linkage model; and (Two) applying partial least-squares regression to wheelchair set-up, propulsion kinematics, and performance. Eight elite wheelchair rugby players completed 5 m sprints in nine wheelchair set-ups while varying seat height, seat depth, seat angle, and tire pressure. Propulsion kinematics (contact and release angles) and performance (sprint time) were measured during each sprint and used for training and assessment for both models. Results were assessed through comparison of predicted and experimental propulsion kinematics (degree differences) for Step One and performance times (seconds differences) for Step Two. Kinematic measures, in particular contact angles, were identified with mean prediction errors less than 5 degrees for 43 of 48 predictions. Performance predictions were found to reflect on-court trends for some players, while others showed weaker prediction accuracy. More detailed modeling approaches that can account for individual athlete activity limitations would likely result in improved accuracy in propulsion and performance predictions across a range of wheelchair sports. Although this would come at an increased cost, developments would provide opportunities for more suitable set-ups earlier in an athlete's career, increasing performance and reducing injury risk.

Wheelchair Rugby chair configurations: an individual, Robust design approach.

Prescription of wheelchair rugby chairs is difficult due to the range of athlete impairment types and severities in the sport, difficulty in adjusting wheelchair settings, and assessing on-court performance. Currently, elite players rely on experiential knowledge (personal, coaches, and support staff) to select an appropriate set-up. Technological advancements, such as with inertial measurement units and processing algorithms, and representative testing approaches, has improved the potential for assessing set-ups at an individual level. An orthogonal design approach was implemented using an adjustable wheelchair to investigate the effect of seat height, seat depth, seat angle, and tyre pressure on performance, mobility, and propulsion kinematics. Six elite wheelchair rugby players completed testing in nine individually tailored wheelchair set-ups while monitoring both quantitative and qualitative measures of performance. From this testing, a recommended set-up was compared with the current set-up for each individual. A single case-study approach shows how the assessment method identifies parameter settings that can potentially improve performance. Three of six players reported a blind preference for the recommended set-up over the current set-up, whilst remaining players often displayed similar performance between their current and recommended set-ups. This approach can improve upon the current prescription process for rugby wheelchairs.

Placement effects of inertial measurement units on contact identification in wheelchair racing.

Inertial measurement units (IMUs) provide a practical solution for attaining key performance data for wheelchair sports. The effects of IMU placement position on the identification of propulsion characteristics are unknown. The aim of this study was to determine the variability in the reliability of cycle time measurements (time between hand contacts) across IMU locations on the chair frame (axle housings), and wheels (axle, push rim, outer rim), on both the left and right sides (n = 8). Contacts were defined by spikes in the resultant acceleration data, corresponding to impact between the hands and push rim, and verified against motion capture. Five elite wheelchair racing athletes propelled at racing speeds on a treadmill. Excellent inter-rater Intraclass Correlation Coefficient values indicated high reliability and repeatability for both motion capture and IMU signal analysis approaches (R = 0.997, p < 0.001 and R = 0.990, p < 0.001, respectively). The best results were (as determined by the best between method agreement) were observed for IMUs located on the frame. Detection reliability was positively associated with signal-to-noise ratio of the acceleration data. The IMU assessment approach facilitates an automated processing capability, which is an improvement to the currently used video analysis.

A practical assessment of wheelchair racing performance kinetics using accelerometers.

Due to the detrimental influence of unnecessary mass on performance, racing wheelchair instrumentation used in both competition assessment and research is currently limited. Attaining key kinetic parameters of propulsion can enhance technique and provide athletes with a competitive advantage. This research examined the plausibility of inertial measurement units (IMUs) to estimate propulsion forces, during a simulated wheelchair race start and training. Start propulsion data calculated from an IMU system was compared to reference force plate data; steady state motion data was compared with existing literature. Some agreement in kinetic parameters between IMU data was observed under steady state motion, with data from athletes following a linear force-velocity relationship. In this context, it is important to identify that this cannot be directly compared to the existing literature due to the different methods of force measurement and the lack of data for similar force measurements using IMUs. IMUs were ineffective when used with wheelchairs having spoked wheels. Performance was best for measurements in the direction of motion. Although exact agreement was not observed, the IMU can provide an effective tool in the in-field assessment of propulsion kinetics.

Estimating the Maximum Isometric Force Generating Capacity of Wheelchair Racing Athletes for Simulation Purposes.

For the wheelchair racing population, it is uncertain whether musculoskeletal models using the maximum isometric force generating capacity of non-athletic, able-bodied individuals, are appropriate, as few anthropometric parameters for wheelchair athletes are reported in the literature. In this study, a sensitivity analysis was performed in OpenSim, whereby the maximum isometric force generating capacity of muscles was adjusted in 25% increments to literature defined values between scaling factors of 0.25x to 4.0x for two elite athletes, at three speeds representative of race conditions. Convergence of the solution was used to assess the results. Artificially weakening a model presented unrealistic values, and artificially strengthening a model excessively (4.0x) demonstrated physiologically invalid muscle force values. The ideal scaling factors were 1.5x and 1.75x for each of the athletes, respectively, as was assessed through convergence of the solution. This was similar to the relative difference in limb masses between dual energy X-Ray absorptiometry (DXA) data and anthropometric data in the literature (1.49x and 1.70x), suggesting that DXA may be used to estimate the required scaling factors. The reliability of simulations for elite wheelchair racing athletes can be improved by appropriately increasing the maximum isometric force generating capacity of muscles.

The Effects of Personalized Versus Generic Scaling of Body Segment Masses on Joint Torques During Stationary Wheelchair Racing.

The anthropometries of elite wheelchair racing athletes differ from the generic, able-bodied anthropometries commonly used in computational biomechanical simulations. The impact of using able-bodied parameters on the accuracy of simulations involving wheelchair racing is currently unknown. In this study, athlete-specific mass segment inertial parameters of the head and neck, torso, upper arm, forearm, hand, thigh, shank, and feet for five elite wheelchair athletes were calculated using dual-energy X-ray absorptiometry (DXA) scans. These were compared against commonly used anthropometrics parameters of data presented in the literature. A computational biomechanical simulation of wheelchair propulsion using the upper extremity dynamic model in opensim assessed the sensitivity of athlete-specific mass parameters using Kruskal-Wallis analysis and Spearman correlations. Substantial between-athlete body mass distribution variances (thigh mass between 7.8% and 22.4% total body mass) and between-limb asymmetries (<62.4% segment mass; 3.1 kg) were observed. Compared to nonathletic able-bodied anthropometric data, wheelchair racing athletes demonstrated greater mass in the upper extremities (up to 3.8% total body mass) and less in the lower extremities (up to 9.8% total body mass). Computational simulations were sensitive to individual body mass distribution, with joint torques increasing by up to 31.5% when the scaling of segment masses (measured or generic) differed by up to 2.3% total body mass. These data suggest that nonathletic, able-bodied mass segment inertial parameters are inappropriate for analyzing elite wheelchair racing motion.

Test design and individual analysis in wheelchair rugby.

OBJECTIVES: Use a task vehicle of sprint testing in wheelchair rugby (WCR) to explore the impact of small changes to test design using both group and individual analysis. DESIGN: Exploratory, repeated measures, on-court study METHOD: 25 national or international level wheelchair rugby players completed 5×5m sprints under two conditions: (i) an acceleration from standstill in their own time, and (ii) an 'active' start, simulating a key aspect of performance. Video analysis and accelerometer data were used to measure key kinematic and performance variables with a focus on the first three strokes. Each player was grouped into a high-, mid-, or low-point group based on their sport-specific classification score. Group (paired sample t-tests) and individual (meaningful differences, performance coefficients, and Cohen's d effect sizes) analysis assessed differences between the two conditions. RESULTS: The low-point classification group performed significantly slower in the active start (p<0.05). There were no differences in sprint time for the high- and mid-point groups. Mid-point players achieved greater peak accelerations for strokes two and three in the active start (p<0.05). Individual sprint performances varied substantially, ranging from 8% decrease to 14% increase in sprint time for the active start. Meaningful differences in peak accelerations were demonstrated for 23 out of the 25 players. CONCLUSIONS: Small amendments to test design can lead to significant differences in individual athlete performance. Traditional group analyses masked important individual responses to testing conditions. There is need to further consider representative test design, and individual analysis for monitoring physical and skill performance.

Overground-Propulsion Kinematics and Acceleration in Elite Wheelchair Rugby.

PURPOSE: Maximal acceleration from standstill has been identified as a key performance indicator in wheelchair rugby; however, the impact of classification and kinematic variables on performance has received limited attention. This study aimed to investigate kinematic variables during maximal acceleration, with level of activity limitation accounted for using sport-classification scores. METHODS: Based on their sporting classification scores, which reflect combined trunk, arm, and hand function, 25 elite wheelchair rugby players were analyzed in high-, mid-, and low-point groups before completing five 5-m sprints from a stationary position. Inertial measurement units and video analysis were used to monitor key kinematic variables. RESULTS: Significant differences in kinematic variables were evident across the classification groups, particularly for the first stroke-contact angle (1-way ANOVA F2,122 = 51.5, P < .05) and first stroke time (F2,124 = 18.3, P < .05). High-point players used a first stroke-contact angle that was closer to top dead center of the wheel than either other group, while also using a shorter overall stroke time than low-point players. A linear mixed-effects model was used to investigate how kinematic variables influenced performance, with results suggesting that increased release angles (ie, farther around the wheel) and decreased stroke angles resulted in larger peak accelerations. Further investigation revealed that these results are likely influenced by strong relationships for the high-point group, as there was often no clear trend evident for midpoint and low-point groups. CONCLUSION: Findings show that various propulsion approaches exist across classification groups, with this information potentially informing individual wheelchair setups and training programs.

An extra care community's perceived priorities for 'whole system' relationships: a Q-methodological study.

Health and social care settings worldwide need to sustainably improve the quality of relationships across communities or 'whole systems'. This research informs the development of a relational framework based on stakeholder perspectives. It is grounded in an action research project with practitioners, and draws on a previous literature review, to present the underpinning elements of quality relationships as statements, organised under the headings of integrity, respect, fairness, compassion and trust. Using Q methodology, 27 participants, comprising a range of stakeholders (staff, residents, family and service providers), rank-ordered 48 statements based on perceptions of the importance of differing aspects of relationships. By-person factor analysis was used to create five factors or viewpoints by comparing and contrasting using the composite rankings alongside interview data collected for each participant. The first view 'Altogether now' prioritises compassionate engagement. Second, 'Respect is a two-way street' emphasises the need for reciprocal respect and recognition of history. The factor labelled 'Free spirits' posits the dominant view of freedom. The fourth view 'Families … strengths and challenges' focuses on the necessary and complex involvement of families and finally, 'Helping hands' emphasises the role of relationships in increasing previously low expectations of social integration for previously isolated residents. The different views that exist on the composition of quality relationships can be used to help extra care communities to understand and utilise relationships as a powerful and effective resource.

Building a system-wide approach to community relationships with the findings of a scoping review in health and social care.

Purpose For leadership and management of Western health systems, good quality relationships are a fundamental cornerstone of organising health and social care (H&SC) delivery, delivering benefits across organisations and communities. The purpose of this paper is to explore the extant management, H&SC literature, grounded in older people care, reveal behaviours, processes and practices that if readily identified across a context will support healthy relationships across the "whole system" of stakeholders. Design/methodology/approach An academic/practitioner group designed and guided a scoping literature review of the H&SC and broader management literature to identify and extract important behaviours, processes and practices underlying the support of high-quality relationships. A search strategy was agreed and key health and management databases were interrogated and 51 papers selected for inclusion. Working with the practitioners, the selected papers were coded and then organised into emergent themes. Findings The paper outlines the relational behaviours, processes and practice elements that should be present within an older peoples care community, to support a healthy relational environment. These elements are presented under the five emergent literature themes of integrity, compassion, respect, fairness and trust. These five topics are examined in detail. A way forward for building statements using the review material, that may be applied to reveal relational patterns within older people care, is also explored and outlined. Research limitations/implications All literature reviews are subject to practical decisions around time, budget, scope and depth restraints. Therefore potentially relevant papers may have been missed in the review process. The scoping review process adapted here does not seek to make any major considerations with regards to the weighting of evidence behind the primary research. Originality/value This paper contributes to a growing need for designers of health systems to more fully understand, measure and draw on the value of relationships to help bridge the gap between diminishing resources and the expanding demand on H&SC services.

Treatment of mandibular third molars and pericoronitis in British military personnel: influence of guidelines from the National Institute for Health and Clinical Excellence.

We studied the dental records of British military personnel who were less than 20 years old on enlistment, and had at least five years' service with at least five recorded dental inspections, at three military dental centres in the UK. The median (IQR) period from first to last inspection in 720 subjects was 15 (10-19) years, and the median frequency of inspection was every 14 (13-16) months. A total of 288/1250 mandibular third molars were extracted (23%). There were significant increases in the proportion of extractions stating caries in the mandibular third molar or multi-episode pericoronitis as indications (n=13, 14%, p <0.001) (n=15, 19%, p <0.001) post-introduction of NICE guidance. The number of extractions with no documented indication was reduced by 50 (26%, p<0.001) and that for a single episode of pericoronitis by 20 (9%, p =0.02). Extractions of mandibular third molars because of caries in the adjacent second molar increased by 4 (4%, p=0.045). The median age at the time of extraction before introduction of the guidelines was 23 years compared with 25 years afterwards (p<0.001). Twenty-five of 114 (22%) extractions of mandibular third molars were in patients over the age of 30 after the introduction of guidelines compared with 1/174 (<1%) before. The introduction of the NICE guidelines on the management of third molars has significantly changed our practice. Whether or not these changes have resulted in a net benefit to patients is still a matter for debate.

Musculoskeletal Lower Limb Injury Risk in Army Populations.

Injuries are common within military populations, with high incidence rates well established in the literature. Injuries cause a substantial number of working days lost, a significant cost through compensation claims and an increased risk of attrition. In an effort to address this, a considerable amount of research has gone into identifying the most prevalent types of injury and their associated risk factors. Collective evidence suggests that training and equipment contribute to a large proportion of the injuries sustained. In particular, the large loads borne by soldiers, the high intensity training programs and the influence of footwear have been identified as significant causative factors of lower limb injury in military populations. A number of preventative strategies have been developed within military bodies around the world to address these issues. The relative success of these strategies is highly variable; however, with advancements in technology, new approaches will become available and existing strategies may become more effective.

Impaired Physical Function Associated with Childhood Obesity: How Should We Intervene?

BACKGROUND: This study examined relationships between adiposity, physical functioning, and physical activity. METHODS: Obese (N = 107) and healthy-weight (N = 132) children aged 10-13 years underwent assessments of percent body fat (%BF, dual energy X-ray absorptiometry); knee extensor strength (KE, isokinetic dynamometry); cardiorespiratory fitness (CRF, peak oxygen uptake by cycle ergometry); physical health-related quality of life (HRQOL); and worst pain intensity and walking capacity [six-minute walk (6MWT)]. Structural equation modelling was used to assess relationships between variables. RESULTS: Moderate relationships were observed between %BF and (1) 6MWT, (2) KE strength corrected for mass, and (3) CRF relative to mass (r -0.36 to -0.69, p ≤ 0.007). Weak relationships were found between %BF and physical HRQOL (r -0.27, p = 0.008); CRF relative to mass and physical HRQOL (r -0.24, p = 0.003); physical activity and 6MWT (r 0.17, p = 0.004). Squared multiple correlations showed that 29.6% variance in physical HRQOL was explained by %BF, pain, and CRF relative to mass; while 28.0% variance in 6MWT was explained by %BF and physical activity. CONCLUSIONS: It appears that children with a higher body fat percentage have poorer KE strength, CRF, and overall physical functioning. Reducing percent fat appears to be the best target to improve functioning. However, a combined approach to intervention, targeting reductions in body fat percentage, reductions in pain, and improvements in physical activity and CRF may assist physical functioning.

The Biomechanics of the Modern Golf Swing: Implications for Lower Back Injuries.

The modern golf swing is a complex and asymmetrical movement that places an emphasis on restricting pelvic turn while increasing thorax rotation during the backswing to generate higher clubhead speeds at impact. Increasing thorax rotation relative to pelvic rotation preloads the trunk muscles by accentuating their length and allowing them to use the energy stored in their elastic elements to produce more power. As the thorax and pelvis turn back towards the ball during the downswing, more skilled golfers are known to laterally slide their pelvis toward the target, which further contributes to final clubhead speed. However, despite the apparent performance benefits associated with these sequences, it has been argued that the lumbar spine is incapable of safely accommodating the forces they produce. This notion supports a link between the repeated performance of the golf swing and the development of golf-related low back injuries. Of the complaints reported by golfers, low back injuries continue to be the most prevalent, but the mechanism of these injuries is still poorly understood. This review highlights that there is a paucity of research directly evaluating the apparent link between the modern golf swing and golf-related low back pain. Furthermore, there has been a general lack of consensus within the literature with respect to the methods used to objectively assess the golf swing and the methods used to derived common outcome measures. Future research would benefit from a clear set of guidelines to help reduce the variability between studies.

The crunch factor's role in golf-related low back pain.

BACKGROUND CONTEXT: The golf swing exposes the spine to complex torsional, compressive, and shearing loads that increase a player's risk of injury. The crunch factor (CF) has been described as a measure to evaluate the risk of low back injuries in golfers and is based on the notion that lateral flexion and axial trunk rotation jointly contribute to spinal degeneration. However, few studies have evaluated the appropriateness of this measure in golfers with low back pain (LBP). PURPOSE: To objectively examine the usefulness of the CF as a measure for assessing the risk of low back injury in golfers. STUDY DESIGN: Field-based research using a cross-sectional design. METHODS: This research used three-dimensional motion analysis to assess the golf swings of 12 golfers with LBP and 15 asymptomatic controls. Three-dimensional kinematics were derived using Vicon Motus, and the CF was calculated as the instantaneous product of axial trunk rotation velocity and lateral trunk flexion angle. RESULTS: Maximum CFs and their timings were not significantly different between the symptomatic and asymptomatic groups. Furthermore, for those golfers who produced higher CFs (irrespective of the group), the increased magnitude could not be attributed to an increased axial angular trunk velocity or lateral flexion angle, but rather to a concomitant increase in both of these variables. CONCLUSIONS: The findings suggested that although the fundamental concepts that underpin the CF seem sensible, this measure does not appear to be sensitive enough to distinguish golfers with LBP from the asymptomatic players.