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Alisa Nana, Gary J. Slater, Will G. Hopkins, Shona L. Halson, David T. Martin, Nicholas P. West and Louise M. Burke

Purpose:

The implications of undertaking DXA scans using best practice protocols (subjects fasted and rested) or a less precise but more practical protocol in assessing chronic changes in body composition following training and a specialized recovery technique were investigated.

Methods:

Twenty-one male cyclists completed an overload training program, in which they were randomized to four sessions per week of either cold water immersion therapy or control groups. Whole-body DXA scans were undertaken with best practice protocol (Best) or random activity protocol (Random) at baseline, after 3 weeks of overload training, and after a 2-week taper. Magnitudes of changes in total, lean and fat mass from baseline-overload, overload-taper and baseline-taper were assessed by standardization (Δmean/SD).

Results:

The standard deviations of change scores for total and fat-free soft tissue mass (FFST) from Random scans (2–3%) were approximately double those observed in the Best (1–2%), owing to extra random errors associated with Random scans at baseline. There was little difference in change scores for fat mass. The effect of cold water immersion therapy on baseline-taper changes in FFST was possibly harmful (-0.7%; 90% confidence limits ±1.2%) with Best scans but unclear with Random scans (0.9%; ±2.0%). Both protocols gave similar possibly harmful effects of cold water immersion therapy on changes in fat mass (6.9%; ±13.5% and 5.5%; ±14.3%, respectively).

Conclusions:

An interesting effect of cold water immersion therapy on training-induced changes in body composition might have been missed with a less precise scanning protocol. DXA scans should be undertaken with Best.

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Jeremy M. Sheppard, Sophia Nimphius, Greg G. Haff, Tai T. Tran, Tania Spiteri, Hedda Brooks, Gary Slater and Robert U. Newton

Purpose:

Appropriate and valid testing protocols for evaluating the physical performances of surfing athletes are not well refined. The purpose of this project was to develop, refine, and evaluate a testing protocol for use with elite surfers, including measures of anthropometry, strength and power, and endurance.

Methods:

After pilot testing and consultation with athletes, coaches, and sport scientists, a specific suite of tests was developed. Forty-four competitive junior surfers (16.2 ± 1.3 y, 166.3 ± 7.3 cm, 57.9 ± 8.5 kg) participated in this study involving a within-day repeated-measures analysis, using an elite junior group of 22 international competitors (EJG), to establish reliability of the measures. To reflect validity of the testing measures, a comparison of performance results was then undertaken between the EJG and an age-matched competitive junior group of 22 nationally competitive surfers (CJG).

Results:

Percent typical error of measurement (%TEM) for primary variables gained from the assessments ranged from 1.1% to 3.0%, with intraclass correlation coefficients ranging from .96 to .99. One-way analysis of variance revealed that the EJG had lower skinfolds (P = .005, d = 0.9) than the CJG, despite no difference in stature (P = .102) or body mass (P = .827). The EJG were faster in 15-m sprint-paddle velocity (P < .001, d = 1.3) and had higher lower-body isometric peak force (P = .04, d = 0.7) and superior endurance-paddling velocity (P = .008, d = 0.9).

Conclusions:

The relatively low %TEM of these tests in this population allows for high sensitivity to detect change. The results of this study suggest that competitively superior junior surfers are leaner and possess superior strength, paddling power, and paddling endurance.

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Jessica M. Stephens, Shona L. Halson, Joanna Miller, Gary J. Slater, Dale W. Chapman and Christopher D. Askew

Purpose: To explore the influence of body composition on thermal responses to cold-water immersion (CWI) and the recovery of exercise performance. Methods: Male subjects were stratified into 2 groups: low fat (LF; n = 10) or high fat (HF; n = 10). Subjects completed a high-intensity interval test (HIIT) on a cycle ergometer followed by a 15-min recovery intervention (control [CON] or CWI). Core temperature (Tc), skin temperature, and heart rate were recorded continuously. Performance was assessed at baseline, immediately post-HIIT, and 40 min postrecovery using a 4-min cycling time trial (TT), countermovement jump (CMJ), and isometric midthigh pull (IMTP). Perceptual measures (thermal sensation [TS], total quality of recovery [TQR], soreness, and fatigue) were also assessed. Results: Tc and TS were significantly lower in LF than in HF from 10 min (Tc, LF 36.5°C ± 0.5°C, HF 37.2°C ± 0.6°C; TS, LF 2.3 ± 0.5 arbitrary units [a.u.], HF 3.0 ± 0.7 a.u.) to 40 min (Tc, LF 36.1°C ± 0.6°C, HF 36.8°C ±0.7°C; TS, LF 2.3 ± 0.6 a.u., HF 3.2 ± 0.7 a.u.) after CWI (P < .05). Recovery of TT performance was significantly enhanced after CWI in HF (10.3 ± 6.1%) compared with LF (3.1 ± 5.6%, P = .01); however, no differences were observed between HF (6.9% ±5.7%) and LF (5.4% ± 5.2%) with CON. No significant differences were observed between groups for CMJ, IMTP, TQR, soreness, or fatigue in either condition. Conclusion: Body composition influences the magnitude of Tc change during and after CWI. In addition, CWI enhanced performance recovery in the HF group only. Therefore, body composition should be considered when planning CWI protocols to avoid overcooling and maximize performance recovery.

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Louise Capling, Janelle A. Gifford, Kathryn L. Beck, Victoria M. Flood, Gary J. Slater, Gareth S. Denyer and Helen T. O’Connor

Food-based diet indices provide a practical, rapid, and inexpensive way of evaluating dietary intake. Rather than nutrients, diet indices assess the intake of whole foods and dietary patterns, and compare these with nutrition guidelines. An athlete-specific diet index would offer an efficient and practical way to assess the quality of athletes’ diets, guide nutrition interventions, and focus sport nutrition support. This study describes the development and validation of an Athlete Diet Index (ADI). Item development was informed by a review of existing diet indices, relevant literature, and in-depth focus groups with 20 sports nutritionists (median of 11 years’ professional experience) from four elite athlete sporting institutes. Focus group data were analyzed (NVivo 11 Pro; QSR International Pty. Ltd., 2017, Melbourne, Australia), and key themes were identified to guide the development of athlete-relevant items. A modified Delphi survey in a subgroup of sports nutritionists (n = 9) supported item content validation. Pilot testing with athletes (n = 15) subsequently informed face validity. The final ADI (n = 68 items) was categorized into three sections. Section A (n = 45 items) evaluated usual intake, special diets or intolerances, dietary habits, and culinary skills. Section B (n = 15 items) assessed training load, nutrition supporting training, and sports supplement use. Section C (n = 8 items) captured the demographic details, sporting type, and caliber. All of the athletes reported the ADI as easy (40%) or very easy (60% of participants) to use and rated the tool as relevant (37%) or very relevant (63% of participants) to athletes. Further evaluation of the ADI, including the development of a scoring matrix and validation compared with established dietary methodology, is warranted.

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Jessica M. Stephens, Ken Sharpe, Christopher Gore, Joanna Miller, Gary J. Slater, Nathan Versey, Jeremiah Peiffer, Rob Duffield, Geoffrey M. Minett, David Crampton, Alan Dunne, Christopher D. Askew and Shona L. Halson

Purpose: To examine the effect of postexercise cold-water immersion (CWI) protocols, compared with control (CON), on the magnitude and time course of core temperature (T c) responses. Methods: Pooled-data analyses were used to examine the T c responses of 157 subjects from previous postexercise CWI trials in the authors’ laboratories. CWI protocols varied with different combinations of temperature, duration, immersion depth, and mode (continuous vs intermittent). T c was examined as a double difference (ΔΔT c), calculated as the change in T c in CWI condition minus the corresponding change in CON. The effect of CWI on ΔΔT c was assessed using separate linear mixed models across 2 time components (component 1, immersion; component 2, postintervention). Results: Intermittent CWI resulted in a mean decrease in ΔΔT c that was 0.25°C (0.10°C) (estimate [SE]) greater than continuous CWI during the immersion component (P = .02). There was a significant effect of CWI temperature during the immersion component (P = .05), where reductions in water temperature of 1°C resulted in decreases in ΔΔT c of 0.03°C (0.01°C). Similarly, the effect of CWI duration was significant during the immersion component (P = .01), where every 1 min of immersion resulted in a decrease in ΔΔT c of 0.02°C (0.01°C). The peak difference in T c between the CWI and CON interventions during the postimmersion component occurred at 60 min postintervention. Conclusions: Variations in CWI mode, duration, and temperature may have a significant effect on the extent of change in T c. Careful consideration should be given to determine the optimal amount of core cooling before deciding which combination of protocol factors to prescribe.

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Louise M. Burke, Linda M. Castell, Douglas J. Casa, Graeme L. Close, Ricardo J. S. Costa, Ben Desbrow, Shona L. Halson, Dana M. Lis, Anna K. Melin, Peter Peeling, Philo U. Saunders, Gary J. Slater, Jennifer Sygo, Oliver C. Witard, Stéphane Bermon and Trent Stellingwerff

The International Association of Athletics Federations recognizes the importance of nutritional practices in optimizing an Athlete’s well-being and performance. Although Athletics encompasses a diverse range of track-and-field events with different performance determinants, there are common goals around nutritional support for adaptation to training, optimal performance for key events, and reducing the risk of injury and illness. Periodized guidelines can be provided for the appropriate type, amount, and timing of intake of food and fluids to promote optimal health and performance across different scenarios of training and competition. Some Athletes are at risk of relative energy deficiency in sport arising from a mismatch between energy intake and exercise energy expenditure. Competition nutrition strategies may involve pre-event, within-event, and between-event eating to address requirements for carbohydrate and fluid replacement. Although a “food first” policy should underpin an Athlete’s nutrition plan, there may be occasions for the judicious use of medical supplements to address nutrient deficiencies or sports foods that help the athlete to meet nutritional goals when it is impractical to eat food. Evidence-based supplements include caffeine, bicarbonate, beta-alanine, nitrate, and creatine; however, their value is specific to the characteristics of the event. Special considerations are needed for travel, challenging environments (e.g., heat and altitude); special populations (e.g., females, young and masters athletes); and restricted dietary choice (e.g., vegetarian). Ideally, each Athlete should develop a personalized, periodized, and practical nutrition plan via collaboration with their coach and accredited sports nutrition experts, to optimize their performance.