SESinNZ: reconnecting Academics and Practitioners

Abstract

The analysis of human movement and performance is often complicated by the multivariate data that represent them. Analyses are further complicated by the potentially, non-linear relationships among many of the variables in the data sample. Self-organising maps (SOM), a machine learning approach, are useful for clustering and visualising multivariate data, while preserving non-linear relationships in the data distribution, which makes them attractive for studying human behaviour from many perspectives. My research groups have applied SOMs to many sub-disciplines within sport and exercise science – in particular biomechanics and performance analysis. We have used SOMs in biomechanics most recently as a method for classifying back pain, based on patients' movement patterns. The results have led to a more fine-grained distinction between pain groups than is achieved through conventional pain provocation tests. In rugby and netball performance analysis, we have clustered match data to represent 'game styles' for real-time assessment of the coupling between a team's game style and that of their opponent. Further applications of SOMs in other sub-disciplines of sport and exercise science are discussed. Pre-conditioning strategies that elevate muscle temperature when preparing for physical performance, while pre-cooling strategies are adopted in thermally challenging environments. We investigated the individual and combined effects of a passive heat maintenance strategy and the ingestion of an ice-water slurry on repeated sprint performance. In a random cross-over design, 12 performed one rectal the opposing increases in both antegrade and retrograde shear rates in response to exercise. pressure 36 20 mm Hg lower-body The influence of maturation on talent identification and development is often overlooked. The purpose of this study was to examine the relationship between maturity offset and athletic motor skills and differences between pre-PHV, circa-PHV and post-PHV males. One hundred boys age 12.9 to 14.9 with a maturity offset of -1.96 to 2.27 performed a 10 meter sprint (10m), an isometric mid-thigh pull (IMTP), a bilateral (BHJ), right leg (RHJ) and left leg (LHJ) horizontal jump and a countermovement jump (CMJ). Relative values for horizontal jumps and IMTP were obtained by dividing by leg length and weight, respectively. Maturity had a significant but small relationship with 10m, BHJ, RHJ, LHJ and CMJ (r ≈ 0.30) and a large relationship with IMTP (r = 0.70). Correlations between relative BHJ, RHJ, LHJ and IMTP were trivial (r < 0.10). When comparing between groups, effect sizes ranged from 0.11 to 1.99 for absolute measures but only 0.24 to 0.37 for relative measures. Lower body neuromuscular strength has a stronger relationship to maturity status than measures of lower body power while maturational differences are reduced with relative scores. Relative scores will reduce the influence of maturation on performance. Humans adapt powerfully to heat. Repeated bouts of clamped-or controlled-hyperthermia are deemed the ‘gold-standard’ approach to heat acclimation, and are used in research, but athletes typically self-regulate their exposures. The purpose of this study was to determine the efficacy of self-regulated intensity of heat exposures during heat acclimation. Athletes underwent a self-regulated HA regimen, whereby they cycled in a heated laboratory, manipulating their workload based on how they felt. Nine highly-trained (NZ universities) rowers (19 ± 1 y; 5 female) completed 7 days of self-regulated HA (60 min ⋅ d-1; 41 ± 1˚C; 48 ± 6% RH). On days 1 and 7, athletes cycled at 2.75 W ⋅ kg-1 for the first 7 min of their HA session. HA substantially reduced resting core temperature (-0.6 ± 0.5 ˚C), modestly expanded plasma volume (+2 ± 2%), and reduced exercising heart rate (-8 ± 7 beats ⋅ min-1). These data indicate that self-regulated HA elicits beneficial thermoregulatory and cardiovascular adaptations in well-trained individuals. Now we are comparing self-regulated HA against controlled-hyperthermia HA, assessing each regimen’s effectiveness in eliciting thermoregulatory, cardiovascular, and behavioural adaptations. increased flexibility can improve sprint performance, to evaluate the effect of an 8-week structured yoga intervention on flexibility and an experimental (EG) two a for 8 weeks and a control (CG) continued normal rugby for the 8 weeks. Data were collected during pre-season and mid-season and included hamstring flexibility (sit and reach) and sprint performance (electronic timing). The EG had a small but non-significant increase in the sit and reach test of 3.0±11.9 cm (mean ± SD) compared to the CG. Additionally, compared to CG, the 5, 10, and 30 metre sprint time EG a but improvement of -0.08 ± 0.11 s in sprint time. The changes in the flexibility from pre- to - post-test was moderately correlated with change in sprint time (r=-0.25, p <.01). Results indicate that improved hamstring a small to moderate beneficial effect on kinetics