THE PHYSICAL DEMANDS OF GYMNASTIC-STYLE LANDINGS: UNDERSTANDING AND ALLEVIATING INHERENT PREDISPOSITION

T he research aims to develop insight into inherent mechanisms and regulatory strategies contributing to the physical demands of gymnastic-style landings. The use of a modelling approach to examine the interaction of: 1. a performer’s physical profile and self-selected landing strategy and 2: local mass distribution and mass tuning effects on impact loading is presented. Strategy adjustments accommodating inherent physical profiles were found to be essential in ensuring effective load attenuation but were acknowledged as potentially incompatible with current constraints in gymnastic scoring systems. Mass tuning partially alleviated the loading effects of inherent local mass profiles and was considered achievable without substantial alterations in the regulatory movement patterns

AGE BASED MECHANICS OF MAXIMAL JUMP PERFORMANCE IN ENDURANCE ATHLETES

The purpose of this study was to explore age based maximal jump performance responses, and the underlying kinetic contributions of endurance athletes. Master athletes (aged 60 to 68 years) jumped significantly lower than the younger athletes (aged 26 to 32 years), which was evidenced by a lower vertical velocity at take off by 0.79 m·s-1. The significant positive correlation of lower body stiffness with age was mainly attributed to increased knee stiffness from 0.54 to 1.43 x 10-2 (o-1) for the younger to the master athletes, respectively. Exploring the knee moment associated with joint stiffness revealed that the change in knee moment in the eccentric phase was comparable between the groups and was not correlated with age. Therefore, the increased knee stiffness with age may be attributed to the restricted knee flexion in the eccentric phase

Vitamin D - what is normal according to latest research and how should we deal with it?

Vitamin D deficiency is a public health concern. Mediated by classical endocrine effects, vitamin D deficiency is causally linked with bone and calcium disorders. Non-endocrine actions of vitamin D are also widely recognised and these effects are mediated by local tissue activation of vitamin D bringing about intracrine effects in non-classical sites. Supported by large volumes of observational studies linking low circulating vitamin D with negative outcomes for many common disease states, there is growing interest that vitamin D may be central to the pathology and outcomes of many common diseases, including cardiovascular, cancer and autoimmune conditions. This article explores the quality of evidence linking vitamin D and various disease outcomes, and furthermore describes some of the cellular and molecular mechanisms of vitamin D action that may help explain some of the incongruity of data observed in observational versus interventional studies of vitamin D supplementation

INTRA-LIMB JOINT CONFIGURATION CONTRIBUTIONS TO KNEE JOINT LOADING IN A SIMULATED LANDING TASK

Causative insight into the link between important aspects of an athlete’s kinematics and knee joint loading in potentially injurious landings remains limited. The aim of this simulation study was to develop insight into the intra-limb configuration contributions to sagittal plane knee joint loading in drop (0.46m) landings. Notably accentuated (up to a 1.53 N.m.kg-1) peak knee joint extensor moments (Mek) were incurred with increased ankle, knee and hip joint flexion across the landing phase. While the peak Mek was alleviated with reduced ankle and knee joint flexion, a marginal, participant-specific effect was evident with a similarly reduced hip joint flexion. The extended use of customised simulations to understand the unique role of each lower-extremity joint in the kinematic chain was warranted to inform injury prevention strategies

SENSITIVITY OF IMPACT LOADING TO LANDING STRATEGY AND PHYSICAL PROFILES IN DROP LANDING

This study aimed to gain an insight into the sensitivity of loading in drop landings to the selected strategy and physical profile of the performer. A wobbling mass model was used to simulate landings executed by two performers. Each performer’s physical profile was used to produce simulated motions employing the performer’s self-selected strategy and in landings replicated using another performer’s strategy. Impact loads were sensitive to changes in the strategy and physical profile of the performer. Changing the strategy altered the peak vertical ground reaction force (GFz) by up to 2.55 bodyweights (BW) and modifying the physical profile similarly changed the peak GFz by 2.52 BW. The execution of a strategy customized to a performer’s physical profile is potentially beneficial for reducing loading but may not fully alleviate the effects of a predisposing physical profile

TRIAL STABILISATION OF RUNNING BIOMECHANICS WITH SHOE FAMILIARISATION IN TRAINED DISTANCE RUNNERS

Appropriate trial sizes for biomechanical studies examining running shoe functionality are important to ensure valid insights into injury prevention strategies. The study aimed to examine the influence of shoe familiarisation on trial stabilisation in trained distance runners. A sequential averaging analysis was used to define trial stabilisation of biomechanical measures obtained from two testing conditions (new shoe and familiarised shoe). Between condition group analyses suggested similar trial stabilisation irrespective of shoe familiarisation (group mean ±SD: new: 7.5 ±2.0 trials; familiarised: 7.0 ±2.0 trials). Within group analyses identified variations in trial stabilisation according to the participant, condition and measure. An eight trial protocol was advocated for participantcondition analyses in longitudinal studies examining shoe functionality

KNEE JOINT KINEMATIC VARIABILITY OF THE TOUCHDOWN LEG DURING THE MAXIMAL VELOCITY PHASE OF SPRINT RUNNING

This study aimed to develop insight into knee joint kinematic variability of the touchdown leg during the maximal velocity phase of sprint running. Joint centre coordinate data were obtained for running trials performed by seven male athletes. Between and within athlete coefficient of variations were derived for step and sagittal plane knee joint angle variables. The minimum knee joint angle produced the largest between (13.3%) and within (8.4%) athlete variability and was related to velocity by an inverted U profile. The slowest and fastest athletes produced relatively higher step velocity variability than the intermediate athletes. The discrepancy in the within athlete step and knee joint kinematic variability of performers achieving similar gait-related objectives suggested a need to consider idiosyncratic kinematic patterns in developing sprint running performance

COMPONENT INERTIA MODELLING OF FEMALE BODY SEGMENTS

A mathematical model is presented which is capable of determining subject-specific inertia parameters for female tissues. The model was evaluated for female sports participants. The model comprises segment-specific soft tissue and bone components. 57 geometric solids (40 soft tissue and 17 bone) are used to represent the tissue components. 95 anthropometric measurements were collected from five female sports participants. The overall accuracy of the model in whole body mass prediction was better than 2% with a maximum error of 5%. The success of the model is considered in relation to the accuracy reported by uniform density models. The appropriateness of the cadaver derived density values used in the model is also discussed

AN IMAGE-BASED APPROACH TO OBTAINING ANTHROPOMETRIC MEASUREMENTS FOR ATHLETE-SPECIFIC INERTIA MODELLING

This study aimed to develop and evaluate an image-based method of obtaining anthropometric measurements for athlete-specific inertia modelling. Anthropometric measurements were obtained directly from five athletic performers and indirectly from digitization of whole-body still images. The direct and image-based measurements were used in Yeadon’s (1990) inertia model. The mean absolute accuracy in predicted whole-body mass achieved using the direct and image-based approach was 2.10% and 2.87%, respectively. The presented approach provided a successful alternative to direct measurement for obtaining anthropometric measurements for inertia modelling of athletic performers. The method offers a valuable solution for obtaining measurements from elite athletic performers for whom time-consuming data collections may be undesirabl