Limited reference values exist for visceral adipose tissue (VAT) mass measured by DXA. The objectives of this study were to provide reference values for DXA-derived VAT mass and compare the association with anthropometry measures. The study cohort comprised 677 men and 738 women aged 18–65 years from Western Australia. Whole-body scans using a GE Lunar iDXA and anthropometry measures were collected. Reference percentile data were stratified by sex and age. Correlation analysis compared DXA-derived and anthropometry variables. Specificity, sensitivity, and Youden’s Index were used to evaluate the ability of anthropometric thresholds to predict individuals with high VAT. In men, waist circumference (WC), waist-hip ratio, and waist-height ratio (WHtR) had ‘high’ correlations with VAT mass. In women, only WHtR was ‘highly’ correlated with VAT mass. Overweight thresholds for WC, along with a body mass index of 25.0 kg/m2 in women, had the highest combination of sensitivity and specificity when using anthropometry measures to identify individuals with high VAT mass. We provide the first reference data sets for DXA-derived VAT mass among Western Australians. Excessive VAT mass may be identified in men using the overweight WC threshold and in women using both the overweight BMI and WC thresholds.

No abstract

This study aims to determine if biomechanically informed injury prevention training can reduce associated factors of anterior cruciate ligament injury risk among a general female athletic population. Female community-level team sport athletes, split into intervention (n = 8) and comparison groups (n = 10), completed a sidestepping movement assessment prior to and following a 9-week training period, in which kinetic, kinematic and neuromuscular data were collected. The intervention group completed a biomechanically informed training protocol, consisting of plyometric, resistance and balance exercises, adjunct to normal training, for 15-20 min twice a week. Following the 9-week intervention, total activation of the muscles crossing the knee (n = 7) decreased for both the training (∆ -15.02%, d = 0.45) and comparison (∆ -9.68%, d = 0.47) groups. This decrease was accompanied by elevated peak knee valgus (∆ +27.78%, d = -0.36) and internal rotation moments (∆ +37.50%, d = -0.56) in the comparison group, suggesting that female community athletes are at an increased risk of injury after a season of play. Peak knee valgus and internal rotation knee moments among athletes who participated in training intervention did not change over the intervention period. Results suggest participation in a biomechanically informed training intervention may mitigate the apparent deleterious effects of community-level sport participation.

There is strong evidence linking an athlete's movement technique during sidestepping with anterior cruciate ligament (ACL) injury risk. However, it is unclear how these injurious postures are influenced by prior movement. We aim to describe preparatory trunk and thigh kinematics at toe‐off of the penultimate‐step and flight‐phase angular momenta, and explore their associations with frontal‐plane risk factors during unplanned sidestepping maneuvers. We analyzed kinematic and kinetic data of 33 male Australian Football players performing unplanned sidestepping tasks (103 trials). Linear mixed models tested for reliable associations between ACL injury risk during weight acceptance of the execution‐step, with preparatory kinematics and angular momenta of the trunk and thigh during the penultimate‐step. Multi‐planar flight‐phase trunk momenta along with hip abduction angle at penultimate‐step toe‐off were significantly associated with peak knee valgus moments during the execution‐step (R2 = .21, P < .01). Execution‐step trunk lateral flexion was significantly predicted by frontal and sagittal‐plane preparatory trunk positioning at toe‐off of the penultimate‐step (R2 = .44, P < .01). Multi‐planar flight‐phase trunk momenta as well as multi‐planar trunk and hip positioning at penultimate‐step toe‐off were associated with hip abduction during the execution‐step (R2 = .53, P < .01). Preparatory positioning of the trunk and hip, along with flight‐phase trunk momentum adjusting this positioning are linked to known ACL injury risk factors. We recommend that during the penultimate‐step athletes maintain an upright trunk, as well as minimize frontal‐plane trunk momentum and transverse‐plane trunk momentum toward the sidestep direction to reduce risk of ACL injury during unplanned sidesteps.

No abstract

Frontal plane postures during the ultimate step of sidestepping are linked to increased anterior cruciate ligament injury risk. However, there is a lack of research detailing the kinematic strategies present in the penultimate step. This study, therefore, investigated penultimate and ultimate step kinematics of planned sidestepping (pSS) and unplanned sidestepping (upSS) to further understand the effect of planning time on known ultimate step kinematic and kinetic differences.Sixty male amateur Australian Rules football players performed three trials of straight-line running (RUN), pSS, and upSS in a randomized order. Mediolateral foot placement and three-dimensional joint kinematics for the knee, pelvis, and trunk were measured at final foot contact of the penultimate step and initial foot contact of the ultimate step. Peak knee moments were measured during the weight acceptance phase of the ultimate step. In pSS, at the penultimate step final foot contact, the support foot was placed across the midline of the center of mass, in the frontal plane, contralateral to the sidestep direction. Greater trunk lateral flexion toward the sidestep direction and greater negative pelvic lateral tilt were observed in pSS compared with upSS and RUN. Differences between pSS and upSS frontal plane kinematics at penultimate step final foot contact suggest preparatory reorientation strategies are likely constrained by the amount of planning time available. As there are clear differences in preparatory kinematics, we recommend that planning time be considered when training and assessing sidestepping maneuvers and planned and unplanned maneuvers not be treated as interchangeable skills.

No abstract

Smartphone applications (SPA) now offer the ability to provide accessible in-home monitoring of relevant individual health biomarkers. Previous cross-sectional validations of similar technologies have reported acceptable accuracy with high-grade body composition assessments; this research assessed longitudinal agreement of a novel SPA across a self-managed weight loss intervention of 38 participants (21 males, 17 females). Estimations of body mass (BM), body fat percentage (BF%), fat-free mass (FFM), and waist circumference (WC) from the SPA were compared with ground-truth (GT) measures from a dual-energy x-ray absorptiometry scanner and expert technician measurement. Small mean differences (MD) and standard estimate of error (SEE) were observed between method deltas (ΔBM: MD = 0.12 kg, SEE = 2.82 kg; ΔBF%: MD = 0.06 %, SEE = 1.65 %; ΔFFM: MD = 0.17 kg, SEE = 1.65 kg; ΔWC: MD = 1.16 cm, SEE = 2.52 cm). Correlation coefficient concordance (CCC) assessed longitudinal agreement between the SPA and GT methods, with moderate concordance (CCC: 0.55 – 0.73) observed for all measures. The novel SPA may not be interchangeable with high-accuracy medical scanning methods, yet offers significant benefits in cost, accessibility, and user comfort, in conjunction with the ability to monitor body shape and composition estimates over time.