QUANTIFYING COORDINATION IN KINEMATIC DATA: A RUNNING EXAMPLE

To compare methods of quantifying coordination, one healthy male participant was filmed in three dimensions at 120 Hz whilst running at 3.8 m/s. The knee and hip angles and angular velocities of the left stride, normalised to 100 data points, were analysed using continuous relative phase (CRP) and cross correlations (CC). The phase planes were normalised to -1 and +1, and the component phase angles (I) for each segment calculated with the range O°<

THE INFLUENCE OF CLUB SHAFT CHARACTERISTICS ON THE HIP-SHOULDER SEPARATION ANGLE DURING THE GOLF DRIVE

The way in which club head speed is generated during the golf swing has often been explained using the 'double pendulum model' (e.g. Budney and Bellow, 1992). However, recent research has suggested that club head speed generation is related to the separation angle between transverse plane hip and shoulder rotations (e.g. Cheetham et aI., 2001). It is possible that the shaft characteristics of golf drivers may affect swing mechanics and alter the magnitude of the hip-shoulder separation angle. Generally, it is now recognised that single-individual designs are valuable in sports science research (Bates, 1996). The purpose of this preliminary study was to investigate the effect of club shaft characteristics on the hipshoulder separation angle during the golf drive using a single-individual desig

Development and assessment of a Microsoft Kinect based system for imaging the breast in three dimensions

Three-dimensional surface imaging technologies have been used in the planning and evaluation of breast reconstructive and cosmetic surgery. The aim of this study was to develop a 3D surface imaging system based on the Microsoft Kinect and assess the accuracy and repeatability with which the system could image the breast. A system comprising two Kinects, calibrated to provide a complete 3D image of the mannequin was developed. Digital measurements of Euclidean and surface distances between landmarks showed acceptable agreement with manual measurements. The mean differences for Euclidean and surface distances were 1.9 mm and 2.2 mm, respectively. The system also demonstrated good intra- and inter-rater reliability (ICCs > 0.999). The Kinect-based 3D surface imaging system offers a low-cost, readily accessible alternative to more expensive, commercially available systems, which have had limited clinical use

CHANGES IN COMPENSATORY VARIABILITY AS A FUNCTION OF TASK EXPERTISE AND DISTANCE DURING BASKETBALL SHOOTING

The purpose of this study was to identify how compensatory control of the shooting arm changed under the interacting constraints of task expertise and shooting distance. Expert, intermediate and novice male basketball players (n=10 in each group) performed 30 shots from three distances (4.25, 5.25 and 6.25 metres). The dependent variables included shooting performance together with variability of the wrist, elbow and shoulder joints at the instant of ball release. A significant main effect for expertise was observed for both shooting performance and shoulder joint variability at ball release. No significant main effects for expertise were found for either wrist or elbow joint variability at release. Quadratic regression analyses revealed greater compensatory control of the shooting arm for the expert participants compared to their intermediate and novice counterparts. The level of compensatory control shown also persisted with increasing shooting distance regardless of level of expertise. Findings are harmonious with existing data on movement variability during dynamic throwing tasks, specifically demonstrating how expert performers exploited variability in a functional manner to satisfy the constraints of the task

The accuracy of breast volume measurement methods: a systematic review

Breast volume is a key metric in breast surgery and there are a number of different methods which measure it. However, a lack of knowledge regarding a method’s accuracy and comparability has made it difficult to establish a clinical standard. We have performed a systematic review of the literature to examine the various techniques for measurement of breast volume and to assess their accuracy and usefulness in clinical practice. Each of the fifteen studies we identified had more than ten live participants and assessed volume measurement accuracy using a gold-standard based on the volume, or mass, of a mastectomy specimen. Many of the studies from this review report large (> 200 ml) uncertainty in breast volume and many fail to assess measurement accuracy using appropriate statistical tools. Of the methods assessed, MRI scanning consistently demonstrated the highest accuracy with three studies reporting errors lower than 10% for small (250 ml), medium (500 ml) and large (1,000 ml) breasts. However, as a high-cost, non-routine assessment other methods may be more appropriate

The relationship between peak power and leg size in mountain bike cyclists

The relationship between peak power and leg size in mountain bike cyclist

Assessment of a Microsoft Kinect-based 3D scanning system for taking body segment girth measurements : a comparison to ISAK and ISO standards

Use of anthropometric data to infer sporting performance is increasing in popularity, particularly within elite sport programmes. Measurement typically follows standards set by the International Society for the Advancement of Kinanthropometry (ISAK). However, such techniques are time consuming, which reduces their practicality. Schranz et al. recently suggested 3D body scanners could replace current measurement techniques; however, current systems are costly. Recent interest in natural user interaction has led to a range of low-cost depth cameras capable of producing 3D body scans, from which anthropometrics can be calculated. A scanning system comprising 4 depth cameras was used to scan 4 cylinders, representative of the body segments. Girth measurements were calculated from the 3D scans and compared to gold standard measurements. Requirements of a Level 1 ISAK practitioner were met in all 4 cylinders, and ISO standards for scan-derived girth measurements were met in the 2 larger cylinders only. A fixed measurement bias was identified that could be corrected with a simple offset factor. Further work is required to determine comparable performance across a wider range of measurements performed upon living participants. Nevertheless, findings of the study suggest such a system offers many advantages over current techniques, having a range of potential application

Effects of personal and task constraints on limb coordination during walking: a systematic review and meta-analysis

Background In human behaviour, emergence of movement patterns is shaped by different, interacting constraints and consequently, individuals with motor disorders usually display distinctive lower limb coordination modes. Objectives To review existing evidence on the effects of motor disorders and different task constraints on emergent coordination patterns during walking, and to examine the clinical significance of task constraints on gait coordination in people with motor disorders. Methods The search included CINHAL Plus, MEDLINE, HSNAE, SPORTDiscus, Scopus, Pubmed and AMED. We included studies that compared intra-limb and inter-limb coordination during gait between individuals with a motor disorder and able-bodied individuals, and under different task constraints. Two reviewers independently examined the quality of studies by using the Newcastle Ottawa Scale-cohort study. Findings From the search results, we identified1416 articles that studied gait patterns and further analysis resulted in 33 articles for systematic review and 18 articles for meta-analysis-1, and 10 articles for meta-analysis-2. In total, the gait patterns of 539 patients and 358 able-bodied participants were analysed in the sampled studies. Results of the meta-analysis for group comparisons revealed a low effect size for group differences (ES = −0.24), and a moderate effect size for task interventions (ES = −0.53), on limb coordination during gait. Interpretation Findings demonstrated that motor disorders can be considered as an individual constraint, significantly altering gait patterns. These findings suggest that gait should be interpreted as functional adaptation to changing personal constraints, rather than as an abnormality. Results imply that designing gait interventions, through modifying locomotion tasks, can facilitate the emergent re-organisation of inter-limb coordination patterns during rehabilitation

Using a wireless consumer accelerometer to measure tibial acceleration during running : agreement with a skin mounted sensor

Real-time monitoring and feedback of tibial acceleration using wireless skin mounted sensors may reduce the risk of tibial stress fractures in runners. The purpose of this study was to assess the agreement between a wireless accelerometer and a gold standard reference accelerometer, both skin mounted, in measuring peak axial tibial acceleration when treadmill running at a range of speeds. A research grade accelerometer was mounted to a wireless accelerometer and attached to the tibia. Peak positive tibial accelerations of 13 participants were compared at 2.5 m.s-1, 3.5 m.s-1 and 4.5 m.s-1. Intraclass correlation coefficients demonstrated good agreement, with limits of agreement showing accuracy to within 1.2 – 1.65 g. The wireless accelerometer has scope to be used as a tool to measure peak tibial accelerations during running for the purpose of real-time feedback in gait training systems

Validation of a single camera, spatio-temporal gait analysis system

such as tennis. However during competition, it is impracticable to instrument players. A markerless, view-independent, footsurface contact identification (FSCi) system was developed and validated. The FSCi system analysed standard colour video sequences of walking and running (barefoot and shod) from four unique camera perspectives; output data were compared to three-dimensional motion analysis. Results demonstrated that data for 99.6% of foot contacts (all camera perspectives) were identified. The calculation of gait variables, i.e. step length etc., was performed automatically for 91.3% of foot contact data; 8.7% of data required manual intervention for analysis. Resultant direction root-mean square error (RMSE) for foot contact position was 52.1 and 52.2 mm for barefoot and shod walking respectively. Resultant direction RMSE for foot contact position during running was 91.4 and 103.4 mm for barefoot and shod conditions respectively. The FSCi system measured basic gait parameters of walking and running without interfering with the activity being observed. The system represents a flexible approach which could be used for in situ gait analysis. The FSCi system could be used for gait analysis in competitive tennis however performance of the system when applied to larger filming areas, e.g. tennis courts, must be evaluated