School of Sport and Recreation - Te Kura Hākinakina
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Research in the School of Sport and Recreation covers sport and activity-related areas, as well as performance, nutrition, coaching and human potential. AUT is the home of New Zealand's top sport and fitness facility, AUT Millennium, and the Sports Performance Research Institute New Zealand (SPRINZ) is New Zealand’s number one sports research institute.
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- ItemSimilar Muscle Hypertrophy Following Eight Weeks of Resistance Training to Momentary Muscular Failure or With Repetitions-in-Reserve in Resistance-Trained Individuals(Informa UK Limited, 2024-02-23) Refalo, MC; Helms, ER; Robinson, ZP; Hamilton, DL; Fyfe, JJThis study examined the influence of resistance training (RT) proximity-to-failure, determined by repetitions-in-reserve (RIR), on quadriceps hypertrophy and neuromuscular fatigue. Resistance-trained males (n = 12) and females (n = 6) completed an 8-week intervention involving two RT sessions per week. Lower limbs were randomised to perform the leg press and leg extension exercises either to i) momentary muscular failure (FAIL), or ii) a perceived 2-RIR and 1-RIR, respectively (RIR). Muscle thickness of the quadriceps [rectus femoris (RF) and vastus lateralis (VL)] and acute neuromuscular fatigue (i.e., repetition and lifting velocity loss) were assessed. Data was analysed with Bayesian linear mixed-effect models. Increases in quadriceps thickness (average of RF and VL) from pre- to post-intervention were similar for FAIL [0.181 cm (HDI: 0.119 to 0.243)] and RIR [0.182 cm (HDI: 0.115 to 0.247)]. Between-protocol differences in RF thickness slightly favoured RIR [−0.036 cm (HDI: −0.113 to 0.047)], but VL thickness slightly favoured FAIL [0.033 cm (HDI: −0.046 to 0.116)]. Mean volume was similar across the RT intervention between FAIL and RIR. Lifting velocity and repetition loss were consistently greater for FAIL versus RIR, with the magnitude of difference influenced by the exercise and the stage of the RT intervention.
- ItemLocally Applied Heat Stress During Exercise Training May Promote Adaptations to Mitochondrial Enzyme Activities in Skeletal Muscle(Springer, 2024-03-06) Maunder, Ed; King, Andrew; Rothschild, Jeffrey A; Brick, Matthew J; Leigh, Warren B; Hedges, Christopher P; Merry, Troy L; Kilding, Andrew EThere is some evidence for temperature-dependent stimulation of mitochondrial biogenesis; however, the role of elevated muscle temperature during exercise in mitochondrial adaptation to training has not been studied in humans in vivo. The purpose of this study was to determine the role of elevating muscle temperature during exercise in temperate conditions through the application of mild, local heat stress on mitochondrial adaptations to endurance training. Eight endurance-trained males undertook 3 weeks of supervised cycling training, during which mild (~ 40 °C) heat stress was applied locally to the upper-leg musculature of one leg during all training sessions (HEAT), with the contralateral leg serving as the non-heated, exercising control (CON). Vastus lateralis microbiopsies were obtained from both legs before and after the training period. Training-induced increases in complex I (fold-change, 1.24 ± 0.33 vs. 1.01 ± 0.49, P = 0.029) and II (fold-change, 1.24 ± 0.33 vs. 1.01 ± 0.49, P = 0.029) activities were significantly larger in HEAT than CON. No significant effects of training, or interactions between local heat stress application and training, were observed for complex I-V or HSP70 protein expressions. Our data provides partial evidence to support the hypothesis that elevating local muscle temperature during exercise augments training-induced adaptations to mitochondrial enzyme activity.
- ItemPower Output at the Moderate-to-Heavy Intensity Transition Decreases in a Non-Linear Fashion During Prolonged Exercise(Springer Science and Business Media LLC, 2024-03-14) Gallo, Gabriele; Faelli, Emanuela Luisa; Ruggeri, Piero; Filipas, Luca; Codella, Roberto; Plews, Daniel J; Maunder, EdPurpose: The aims of this study were to: (i) describe the time course of the decrease in power output at the moderate-to-heavy intensity transition during prolonged exercise; (ii) investigate the association between durability of the moderate-to-heavy intensity transition and exercise capacity; and (iii) explore physiological correlates of durability of the moderate-to-heavy intensity transition. Methods: Twelve trained cyclists (age: 40 ± 8 y, V˙O2peak: 52.3 ± 5.2 mL·min−1·kg−1) performed an exhaustive cycling protocol involving alternating incremental exercise tests to determine power output at the moderate-to-heavy intensity transition via the first ventilatory threshold (VT1), and 30-min bouts at 90% of the power output at the previously estimated VT1 in the rested state. The individual time course of VT1 was modelled using linear and second-order polynomial functions, and time to a 5% decrease in VT1 (Δ5%VT1) was estimated using the best-fitting model. Results: Power output at VT1 decreased according to a second-order polynomial function in 11 of 12 participants. Time-to-task failure (234 ± 66 min) was correlated with Δ5%VT1 (139 ± 78 min, rs = 0.676, p = 0.016), and these were strongly correlated with absolute and relative rates of fat oxidation at specific exercise intensities measured during the incremental test performed in the rested state. Conclusions: These data: (i) identify a non-linear time course of decreases in the moderate-to-heavy intensity transition during prolonged exercise; (ii) support the importance of durability of the moderate-to-heavy intensity transition in prolonged exercise capacity; and (iii) suggest durability of the moderate-to-heavy intensity transition is related to fat oxidation rates.
- ItemUnintended Consequences: A Qualitative Exploration of Baseline Testing in Community Rugby Concussion Management(Elsevier BV, 2024-05-16) Salmon, Danielle; Badenhorst, Marelise; Clark, Brooke; Walters, Simon; Sullivan, S John; Sole, GiselaObjectives: Understanding key stakeholders' perceptions around the value of baseline testing, as well as barriers or facilitators experienced as part of the process, may assist with the decision-making process of whether to implement baseline testing in community sport. This study explored coaches', players' and physiotherapists' perceptions of the perceived value, barriers and facilitators of baseline testing as part of New Zealand Rugby's (NZR) community concussion initiative. Design: The study employed a pragmatic, qualitative descriptive design. Methods: Semi-structured interviews were used to explore participants' perceptions. In total, 73 individual interviews were conducted. The sample consisted of 36 players, 13 coaches and 24 physiotherapists involved in NZR's concussion management pathway. Interviews were audio-recorded and transcribed verbatim. Data were analysed using thematic analysis. Results: In terms of perceived value, baseline testing was reported to play a role in i) facilitating a positive concussion culture; ii) positive perceptions of rugby and player safety and iii) enhancing concussion management as part of the pathway. Barriers and facilitators of the baseline testing process included i) stakeholder buy-in as critical driver of the process and ii) contextual and operational factors. Although contextual and operational challenges exist, these participants, as key stakeholders in the process, perceived the value of baseline testing to be more important than the barriers experienced. Conclusions: The value of baseline testing extends beyond concussion assessment and management, by enhancing community concussion awareness, attitudes and player safety. The findings of this study may assist in the decision-making process around inclusion of pre-season baseline testing in community rugby.
- ItemPredicting Daily Recovery During Long-Term Endurance Training Using Machine Learning Analysis(Springer, 2024-06-20) Rothschild, Jeffrey A; Stewart, Tom; Kilding, Andrew E; Plews, Daniel JPURPOSE: The aim of this study was to determine if machine learning models could predict the perceived morning recovery status (AM PRS) and daily change in heart rate variability (HRV change) of endurance athletes based on training, dietary intake, sleep, HRV, and subjective well-being measures. METHODS: Self-selected nutrition intake, exercise training, sleep habits, HRV, and subjective well-being of 43 endurance athletes ranging from professional to recreationally trained were monitored daily for 12 weeks (3572 days of tracking). Global and individualized models were constructed using machine learning techniques, with the single best algorithm chosen for each model. The model performance was compared with a baseline intercept-only model. RESULTS: Prediction error (root mean square error [RMSE]) was lower than baseline for the group models (11.8 vs. 14.1 and 0.22 vs. 0.29 for AM PRS and HRV change, respectively). At the individual level, prediction accuracy outperformed the baseline model but varied greatly across participants (RMSE range 5.5-23.6 and 0.05-0.44 for AM PRS and HRV change, respectively). CONCLUSION: At the group level, daily recovery measures can be predicted based on commonly measured variables, with a small subset of variables providing most of the predictive power. However, at the individual level, the key variables may vary, and additional data may be needed to improve the prediction accuracy.