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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Browsing School of Sport and Recreation - Te Kura Hākinakina by Subject "11 Medical and Health Sciences"
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- ItemAdolescents' Perceptions of Food Outlets in the School Neighbourhood and Their Unhealthy Snacking Behaviour on the Way to and from School(Cambridge University Press (CUP), 2024-10-07) Situmorang, ML; Mandic, S; Keall, M; Smith, M; Donnellan, N; Coppell, KJObjective: To understand the relationship between adolescents' unhealthy snacking behaviour during their school journey and their perceived and objective measures of food outlet availability in the school neighbourhood. Design: A cross-sectional survey enquired about socio-demographic information, school transport modes, perceived presence of food outlets in the school neighbourhood and unhealthy food purchase and consumption on the school journey. A geographical information system analysis of the food outlets within 500 m and 1000 m school buffers was undertaken. Data were analysed using generalised linear mixed modelling. Setting: All twelve secondary schools in Dunedin, Aotearoa New Zealand, March 2020-June 2022. Participants: Adolescents aged 13-18 years (n 725) who reported being familiar with their school neighbourhood. Results: Perceived availability of food outlets in the school neighbourhood was inversely correlated with distance to the closest food outlet from school and positively correlated with food outlet density within 500 m and 1000 m school buffers. Adolescents' purchase and consumption of unhealthy snacks and drinks during the school journey were associated with perceived availability of food outlets and with shorter distance to the closest food outlet from school. Mixed transport users, girls and those living in high-deprivation neighbourhoods had higher odds of purchasing and consuming unhealthy snacks and drinks during the school journey than active transport users, boys and those living in low-deprivation neighbourhoods, respectively. Conclusions: Adolescents perceptions of the food environment and close access to food outlets in the school neighbourhood may influence adolescents' food purchase and consumption behaviours during the school journey.
- ItemComposite Activity Type and Stride-Specific Energy Expenditure Estimation Model for Thigh-Worn Accelerometry(Springer Science and Business Media LLC, 2024-09-10) Lendt, Claas; Hansen, Niklas; Froböse, Ingo; Stewart, TomBackground Accurately measuring energy expenditure during physical activity outside of the laboratory is challenging, especially on a large scale. Thigh-worn accelerometers have gained popularity due to the possibility to accurately detect physical activity types. The use of machine learning techniques for activity classification and energy expenditure prediction may improve accuracy over current methods. Here, we developed a novel composite energy expenditure estimation model by combining an activity classification model with a stride specific energy expenditure model for walking, running, and cycling. Methods We first trained a supervised deep learning activity classification model using pooled data from available adult accelerometer datasets. The composite energy expenditure model was then developed and validated using additional data based on a sample of 69 healthy adult participants (49% female; age = 25.2 ± 5.8 years) who completed a standardised activity protocol with indirect calorimetry as the reference measure. Results The activity classification model showed an overall accuracy of 99.7% across all five activity types during validation. The composite model for estimating energy expenditure achieved a mean absolute percentage error of 10.9%. For running, walking, and cycling, the composite model achieved a mean absolute percentage error of 6.6%, 7.9% and 16.1%, respectively. Conclusions The integration of thigh-worn accelerometers with machine learning models provides a highly accurate method for classifying physical activity types and estimating energy expenditure. Our novel composite model approach improves the accuracy of energy expenditure measurements and supports better monitoring and assessment methods in non-laboratory settings.
- ItemConsensus on a Netball Video Analysis Framework of Descriptors and Definitions by the Netball Video Analysis Consensus Group(BMJ, 2023-02-08) Mackay, L; Jones, B; Janse Van Rensburg, DC; Hall, F; Alexander, L; Atkinson, K; Baldrey, P; Bedford, A; Cormack, S; Clarke, J; Croft, H; Denton, K; Fox, AS; Hadley, P; Handyside, R; Hendricks, S; Kerss, J; Leota, L; Maddern, B; McErlain-Naylor, SA; Mooney, M; Pyke, D; Pistorius, D; Ramagole, DA; Ryan, D; Scott, F; Scott, T; Snow, J; Spencer, K; Thirlby, J; Viljoen, CT; Whitehead, SUsing an expert consensus-based approach, a netball video analysis consensus (NVAC) group of researchers and practitioners was formed to develop a video analysis framework of descriptors and definitions of physical, technical and contextual aspects for netball research. The framework aims to improve the consistency of language used within netball investigations. It also aims to guide injury mechanism reporting and identification of injury risk factors. The development of the framework involved a systematic review of the literature and a Delphi process. In conjunction with commercially used descriptors and definitions, 19 studies were used to create the initial framework of key descriptors and definitions in netball. In a two round Delphi method consensus, each expert rated their level of agreement with each of the descriptors and associated definition on a 5-point Likert scale (1 - strongly disagree; 2 - somewhat disagree; 3 - neither agree nor disagree; 4 - somewhat agree; 5 - strongly agree). The median (IQR) rating of agreement was 5.0 (0.0), 5.0 (0.0) and 5.0 (0.0) for physical, technical and contextual aspects, respectively. The NVAC group recommends usage of the framework when conducting video analysis research in netball. The use of descriptors and definitions will be determined by the nature of the work and can be combined to incorporate further movements and actions used in netball. The framework can be linked with additional data, such as injury surveillance and microtechnology data.
- ItemDevelopment and Evaluation of the Capability, Opportunity, and Motivation to Deliver Physical Activity in School Scale (COM-PASS)(Springer Science and Business Media LLC, 2024-08-26) Verdonschot, A; Beauchamp, MR; Brusseau, TA; Chinapaw, MJM; Christiansen, LB; Daly-Smith, A; Eather, N; Fairclough, SJ; Faulkner, G; Foweather, L; García-Hermoso, A; Ha, AS; Harris, N; Jaakkola, T; Jago, R; Kennedy, SG; Lander, NJ; Lonsdale, C; Manios, Y; Mazzoli, E; Murtagh, E; Nathan, N; Naylor, PJ; Noetel, M; O’Keeffe, B; Resaland, GK; Ridgers, ND; Ridley, K; Riley, N; Rosenkranz, RR; Rosenkranz, SK; Sääkslahti, A; Sczygiol, SM; Skovgaard, T; van Sluijs, EMF; Smith, JJ; Smith, M; Stratton, G; Vidal-Conti, J; Webster, CA; Young, ES; Lubans, DRBackground: Teachers are recognized as ‘key agents’ for the delivery of physical activity programs and policies in schools. The aim of our study was to develop and evaluate a tool to assess teachers’ capability, opportunity, and motivation to deliver school-based physical activity interventions. Methods: The development and evaluation of the Capability, Opportunity, and Motivation to deliver Physical Activity in School Scale (COM-PASS) involved three phases. In Phase 1, we invited academic experts to participate in a Delphi study to rate, provide recommendations, and achieve consensus on questionnaire items that were based on the Capability, Opportunity, and Motivation Behavior (COM-B) model. Each item was ranked on the degree to which it matched the content of the COM-B model, using a 5-point scale ranging from ‘1 = Poor match’ to ‘5 = Excellent match’. In Phase 2, we interviewed primary and secondary school teachers using a ‘think-aloud’ approach to assess their understanding of the items. In Phase 3, teachers (n = 196) completed the COM-PASS to assess structural validity using confirmatory factor analysis (CFA). Results: Thirty-eight academic experts from 14 countries completed three rounds of the Delphi study. In the first round, items had an average rating score of 4.04, in the second round 4.51, and in the third (final) round 4.78. The final tool included 14 items, which related to the six constructs of the COM-B model: physical capability, psychological capability, physical opportunity, social opportunity, reflective motivation, and automatic motivation. In Phase 2, ten teachers shared their interpretation of COM-PASS via a 20-min interview, which resulted in minor changes. In Phase 3, CFA of the 3-factor model (i.e., capability, opportunity, and motivation) revealed an adequate fit to the data (χ2 = 122.6, p <.001, CFI =.945, TLI =.924, RMSEA =.066). The internal consistencies of the three subscale scores were acceptable (i.e., capability: α =.75, opportunity: α =.75, motivation: α =.81). Conclusion: COM-PASS is a valid and reliable tool for assessing teachers’ capability, opportunity, and motivation to deliver physical activity interventions in schools. Further studies examining additional psychometric properties of the COM-PASS are warranted.
- ItemFueling for and Recovering from Resistance Training: The Peri-Workout Nutrition Practices of Competitive Powerlifters(Elsevier BV, 2024-02-07) King, Andrew; Kwan, Kedric; Jukic, Ivan; Zinn, Caryn; Helms, EricPurpose: Nutrient timing is a concept that emphasizes the intentional ingestion of whole or fortified foods, and dietary supplements, to adequately fuel for, and recover from, acute and chronic exercise. The nutrition strategies used by powerlifters around training sessions have not, to our knowledge, been previously investigated. This study explored the self-reported periworkout (before, during, and after) nutrition practices of competitive powerlifters, including what, why, and information source that informed practice, with comparison to current sport nutrition guidelines. Methods: Actively competing male (n = 240) and female (n = 65) powerlifters completed a cross-sectional online survey of self-reported periworkout nutrition practices in the pre-, intra-, and postexercise periods, fasted training, and supplementation. Data are presented as the number (n) and percentage (%) of all powerlifters practicing a given strategy followed by a % of responses reporting various practices or beliefs within this strategy. Categorical subgroups (sex, age, and weight class; and competitive caliber) were analyzed with a chi-square test or Fisher's exact test and denoted where significant (P ≤ 0.05). Results: Most powerlifters reported paying specific attention to nutrition practices in the pre-exercise period (n = 261; 85.6%) by ingesting more carbohydrate (CHO) rich foods (n = 234; 89.6%) for the purpose of assisting in training performance (n = 222; 85.1%). Most powerlifters reported intraexercise nutrition strategies (n = 211; 69.2%), of which most included ingesting more CHO rich foods (n = 159; 74.5%) for the purpose of feeling less hungry and/or boosting energy levels during training (n = 129; 61.1%). Most powerlifters reported paying attention to postexercise nutrition (n = 244; 80%), by ingesting more protein rich foods (n = 182; 74.6%) for the purpose of recovering better for the whole day (n = 152; 62.3%) and enhancing the benefits of training (n = 149; 61.1%). Most powerlifters did not complete training sessions in the fasted state (n = 262; 85.9%). Most powerlifters reported paying attention to supplementation before training (n = 237; 77.7%), of which preworkout formulas (n = 137; 57.8%), energy drinks (n = 101; 42.6%), creatine (n = 88; 37.1%), and caffeine pills (n = 70; 29.5%) were most reported. Supplementation was used to assist in training performance (n = 197; 83.1%) and increase wakefulness/alertness (n = 183; 77.2%). Males reported more often than females that they informed multiple elements of their nutrition practices with the information they read or watched somewhere (P = 0.002–0.012). Conclusion: The periworkout nutrition practices used by competitive powerlifters followed current sport nutrition guidelines, by using CHO sources to fuel for training and ensuring the provision of protein postexercise. Competitive powerlifters may wish to exert caution with supplementation, as there is a risk of harm or inadvertent doping.
- ItemImpacts of Digital Technologies on Child and Adolescent Health: Recommendations for Safer Screen Use in Educational Settings(Pasifika Medical Association Group, 2024-07-05) Cullen, J; Muntz, A; Marsh, S; Simmonds, L; Mayes, J; O’neill, K; Duncan, SThe use of screen-based digital technologies (such as computers and digital devices) is increasing for children and adolescents, worldwide. Digital technologies offer benefits, including educational opportunities, social connection and access to health information. Digital fluency has been recognised as an essential skill for future prosperity. However, along with these opportunities, digital technologies also present a risk of harm to young people. This issue may be particularly important for young New Zealanders, who have among the highest rates of screen use in the world. Our recently published review examined the impacts of digital technologies on the health and wellbeing of children and adolescents. Key findings revealed some positive impacts from moderate use of digital technologies; however, frequent and extended use of screen-based digital tools were associated with negative impacts on child and adolescent health in some areas, such as eye health, noise-induced hearing loss and pain syndromes. Conversely, in areas such as mental health, wellbeing and cognition, quality of screen media content and additional factors such as age may be more important than duration of use. These challenges gave us the impetus to develop pragmatic recommendations for the use of digital technologies in schools, kura kaupapa and early childhood education. Recommendations include interventions to lower risk across different ages and stages of development. Supporting young people to mitigate risk and develop safer screen behaviours will allow them to gain essential digital skills and access opportunities that will enable them to thrive.
- ItemIs Bodybuilding a Sport?(Informa UK Limited, 2023-07-23) Kind, Adrian; Helms, Eric RSince its beginnings, modern bodybuilding has been accompanied by the background issue of whether it should be considered a sport. The problem, culminating in its provisional acceptance as a sport by the International Olympic Committee, was later retracted. The uncertainty of whether bodybuilding is a sport or not seems to linger. Addressing this issue, Aranyosi (2018) provided an account to determine the status of bodybuilding as a sport that arrives at the negative answer: bodybuilding is not a sport but rather a form of artistic presentation. In this paper, we disagree with Aranyosi. We argue that by the standards he presents in his first argument, bodybuilding should be considered a sport. Further, we argue that his alternative approach on how to evaluate a discipline as more sport- or art-like on a spectrum, is not a valid basis to make such a judgment regarding bodybuilding. Further, even if his spectrum was modified to enable such a judgment, again it would result in bodybuilding being evaluated as a sport. Therefore, we conclude that everyone who accepts Aranyosi´s (or any less restrictive) requirements to decide whether bodybuilding is a sport, has to consider bodybuilding as a sport or refrain from making claims about its status.
- ItemManaging Concussion in the Real World: Stakeholder Perspectives of New Zealand Rugby’s Concussion Management Pathway(SAGE Publications, 2023-12-28) Salmon, Danielle; Walters, Simon; Brown, James; Kerr, Zachary; Clacy, Amanda; Keung, Sierra; Sullivan, S John; Mihalik, Johna Register; Whatman, Chris; Sole, Gisela; Badenhorst, MareliseThe potential adverse consequences associated with poor concussion management highlights the need to improve the translation of concussion guidelines into consistent use in real-world sport settings. To facilitate this process, New Zealand Rugby developed a community concussion management pathway to support concussion recognition, diagnosis, and management. This study adopted a pragmatic, descriptive qualitative approach to explore key stakeholders’ perceptions of the concussion management pathway, with the aim to inform policy and practice. Interviews were conducted with 123 participants, including players, parents, coaches, healthcare professionals, and school and provincial union representatives. The framework method was used to analyze data. Themes were organized according to the principles of realist process evaluation that considers contextual factors and mechanisms influencing a program's operation to produce specific outcomes. Contextual factors influencing the concussion management pathway's implementation included governing bodies’ support, existing local resources, general concussion attitudes, or concussion severity. The optimal functioning of the concussion management pathway (mechanism) was influenced by (i) pathway resources, (ii) roles and relationships, (iii) buy-in and support towards the concussion management pathway, and (iv) diligence and communication. Outcomes identified included (i) hitting the target (optimally managed and enhanced awareness) or (ii) missing the mark (dissatisfaction or management gaps). Overall, participants found the concussion management pathway valuable. However, the acceptability of certain policy-related aspects and the underlying attitudes associated with these perceptions, are some areas requiring further investigation and support. Tailoring programs according to end-users’ perceptions is crucial in developing context-sensitive interventions appropriate for a specific setting. These findings may act as a foundation for investigations of concussion management in other settings.
- ItemMenstrual Cycle Characteristics, Hormonal Contraceptive Use, and Perceptions of Related Effects in Resistance-Trained Athletes(SAGE Publications, 2024-02-08) SantaBarbara, K; Helms, E; Armour, M; Harris, NThere has been an increased interest in the effects the menstrual cycle (MC) may have on sports performance. As a part of the MC, many females experience a wide range of symptoms related to hormonal fluctuations and menstrual bleeding, including physical pain and mood disturbances. Currently, there is a lack of data on the MCs of females who participate in resistance training. The dearth of information on the regular MC in female athletes may lead to poorly informed training recommendations which may be detrimental for female athletic advancement. The purpose of this survey was to determine the average MC characteristics, hormonal contraceptive (HC) use and perceived effects of the MC on training in resistance-trained athletes, and to determine if there are differences in these variables when comparing recreationally trained women to competitive-level athletes. A survey addressing questions about the MC, HC use and perceived effects of the MC was accessed by 906 participants who self-identified as resistance-trained athletes. Resistance-trained athletes, competitive or not, experience MCs similar to data on other exercising females and the general population. MC symptoms are widespread and, for some, can be quite severe and limiting. Competitive athletes were not more likely to experience MC irregularities than non-competitive females. Nearly half of the participants reported using HCs. Most participants perceived that their MC had a negative effect on their performance and that their MC caused reductions in training load or workout program adherence, although most competitive-level athletes did not withdraw from competitions due to MC symptoms.
- ItemNavigating Concussion: Community Rugby Players’ Experiences of a Concussion Management Initiative in New Zealand(Informa UK Limited, 2024-07-15) Costa, Rodrigo; Salmon, Danielle; Walters, Simon; Badenhorst, MareliseObjective: Concussion is a serious concern in sport, with the potential to cause short- and long-term health consequences. These concerns highlight the need for the translation of concussion management guidelines into use in real-world sports settings. This qualitative study explores community rugby players’ concussion experiences as part of New Zealand Rugby’s concussion management pathway. Methods: Semi-structured interviews were conducted with 36 rugby players (35 males and 1 female; 22 played at school and 14 at club-level; mean age 19.8 ± 4.8) Thematic analysis was utilized to analyze data. Results: Four themes were identified i) the symptom journey, ii) the role of a dedicated concussion management pathway in shaping players' experiences, iii) the influence of coaches and physiotherapists, and iv) rugby culture. Support received as part of the concussion management pathway, and from individuals who were part of players’ concussion journey, deeply impacted their overall experience. However, players identified insufficient guidance while returning to school/work. At times, the sport’s collective cultural values made it difficult for players to enact positive concussion management behavior. Conclusion: The findings highlight the importance of a defined management pathway to support players’ recovery. Addressing negative aspects of rugby’s collectivist culture remains critical for optimal concussion management and recovery.
- ItemThe Effect of a Bodybuilding Carbohydrate-Loading Protocol on Anthropometry: Preliminary Findings from a Randomised Crossover Trial(Elsevier BV, 2024-07-09) Homer, Kai A; Jukic, Ivan; Cross, Matt R; Helms, Eric RTo acutely enhance muscle size and definition, carbohydrate (CHO)-loading protocols are commonly implemented by bodybuilders in the week before competition. This study sought to evaluate the effects of a bodybuilding CHO-loading protocol on anthropometry. Four dieting males engaging in resistance training (RT) with very low body fat participated in this randomised crossover trial. Each experimental period consisted of data collection on days one, four, and five corresponding to baseline, post-depletion, and post-loading phases, respectively. During depletion, a standardised RT regimen and diet was followed. This diet was maintained on day 4 with the addition of placebo (PLA) or CHO drinks which contained 9g/kg BM CHO for post-loading data collection on day 5. Body mass (BM), skinfold thickness (SF), and ultrasound muscle thickness (MT) was obtained with descriptive data at both group and individual level calculated. From baseline, BM, SF, and MT mostly decreased in both conditions following depletion. All outcomes then increased from post-depletion following CHO-loading (BM: +0.8%, SF: +1.1%, MT: +2.9%) but not with PLA. Comparing to baseline, post-loading changes were greater with CHO (BM: +0.3%, SF: -2.3%, MT: +2.1%) than PLA (BM: -0.9%, SF: -0.5%, MT: -0.8%). Individual differences in response to each phase were also observed. Group level changes seemingly favour CHO-loading; however, it is difficult to judge these changes practically meaningful as they may not be large enough to exceed measurement error and daily biological fluctuations. Before implementation, coaches and competitors should consider individualising protocols through pre-competition testing and visually assessing changes in physique.
- ItemThe Effects of Regional Quadriceps Architecture on Angle-Specific Rapid Force Expression(Canadian Science Publishing, 2023-06-30) Oranchuk, Dustin J; Hopkins, William G; Cronin, John B; Storey, Adam G; Nelson, André REvaluating anatomical contributions to performance can increase understanding of muscle mechanics and guide physical preparation. While the impact of anatomy on muscular performance is well studied, the effects of regional quadriceps architecture on rapid torque or force expression are less clear. Regional (proximal, middle, distal) quadriceps (vastus lateralis, rectus femoris, and vastus intermedius) thickness (MT), pennation angle (PA), and fascicle length (FL) of 24 males (48 limbs) were assessed via ultrasonography. Participants performed maximal isometric knee extensions at 40º, 70º, and 100º of knee flexion to evaluate rate of force development from 0-200 ms (RFD0-200). Measurements were repeated on three occasions with the greatest RFD0-200 and mean muscle architecture measures used for analysis. Linear regression models predicting angle-specific RFD0-200 from regional anatomy provided adjusted correlations (√adjR2) with bootstrapped compatibility limits. Mid-rectus femoris MT (√adjR2=0.41-0.51) and proximal-vastus lateralis FL (√adjR2=0.42-0.48) were the best single predictors of RFD0-200, and the only measures to reach precision with 99% compatibility limits. Small simple correlations were found across all regions and joint angles between RFD0-200 and vastus lateralis MT (√adjR2=0.28±0.13; mean±SD), vastus lateralis FL (√adjR2=0.33±0.10), rectus femoris MT (√adjR2=0.38±0.10), and lateral vastus intermedius MT (√adjR2=0.24±0.10). Between-correlation comparisons are reported within the article. Researchers should measure mid-region rectus femoris MT and vastus lateralis FL to efficiently and robustly evaluate potential anatomical contributions to rapid knee extension force changes, with distal and proximal measurements providing little additional value. However, correlations were generally small to moderate, suggesting that neurological factors may be critical in rapid force expression.
- ItemValidation of Actigraphy Sleep Metrics in Children Aged 8 to 16 Years: Considerations for Device Type, Placement and Algorithms(Springer Science and Business Media LLC, 2024-04-16) Meredith-Jones, KA; Haszard, JJ; Graham-DeMello, A; Campbell, A; Stewart, T; Galland, BC; Cox, A; Kennedy, G; Duncan, S; Taylor, RWBackground: Actigraphy is often used to measure sleep in pediatric populations, despite little confirmatory evidence of the accuracy of existing sleep/wake algorithms. The aim of this study was to determine the performance of 11 sleep algorithms in relation to overnight polysomnography in children and adolescents. Methods: One hundred thirty-seven participants aged 8–16 years wore two Actigraph wGT3X-BT (wrist, waist) and three Axivity AX3 (wrist, back, thigh) accelerometers over 24-h. Gold standard measures of sleep were obtained using polysomnography (PSG; Embletta MPRPG, ST + Proxy and TX Proxy) in the home environment, overnight. Epoch by epoch comparisons of the Sadeh (two algorithms), Cole-Kripke (three algorithms), Tudor-Locke (four algorithms), Count-Scaled (CS), and HDCZA algorithms were undertaken. Mean differences from PSG values were calculated for various sleep outcomes. Results: Overall, sensitivities were high (mean ± SD: 91.8%, ± 5.6%) and specificities moderate (63.8% ± 13.8%), with the HDCZA algorithm performing the best overall in terms of specificity (87.5% ± 1.3%) and accuracy (86.4% ± 0.9%). Sleep outcome measures were more accurately measured by devices worn at the wrist than the hip, thigh or lower back, with the exception of sleep efficiency where the reverse was true. The CS algorithm provided consistently accurate measures of sleep onset: the mean (95%CI) difference at the wrist with Axivity was 2 min (-6; -14,) and the offset was 10 min (5, -19). Several algorithms provided accurate measures of sleep quantity at the wrist, showing differences with PSG of just 1–18 min a night for sleep period time and 5–22 min for total sleep time. Accuracy was generally higher for sleep efficiency than for frequency of night wakings or wake after sleep onset. The CS algorithm was more accurate at assessing sleep period time, with narrower 95% limits of agreement compared to the HDCZA (CS:-165 to 172 min; HDCZA: -212 to 250 min). Conclusion: Although the performance of existing count-based sleep algorithms varies markedly, wrist-worn devices provide more accurate measures of most sleep measures compared to other sites. Overall, the HDZCA algorithm showed the greatest accuracy, although the most appropriate algorithm depends on the sleep measure of focus.
- ItemWeight Loss Induces Changes in Adaptive Thermogenesis in Female and Male Physique Athletes(Canadian Science Publishing, 2023-01-16) Isola, Ville; Hulmi, Juha J; Petäjä, Pirita; Helms, Eric R; Karppinen, Jari E; Ahtiainen, Juha PPhysique athletes lose substantial weight preparing for competitions, potentially altering systemic metabolism. We investigated sex differences in body composition, resting energy expenditure (REE), and appetite-regulating and thyroid hormone changes during a competition preparation among drug-free physique athletes. The participants were female (10 competing (COMP) and 10 non-dieting controls (CTRL)) and male (13 COMP) and 10 CTRL)) physique athletes. COMP were tested before they started their diet 23 weeks before competing (PRE), during their diet one week before competing (MID), and 23 weeks after competing (POST) whereas CTRL were tested at similar intervals but did not diet. Measurements included body composition by DXA, muscle size, and subcutaneous fat thickness (SFA) by ultrasound, REE by indirect calorimetry, circulating ghrelin, leptin T3, and T4 hormone analysis. Fat mass (FM) and SFA decreased in both sexes (p<0.001), while males (p<0.001) lost more lean mass (LM) than females (p<0.05). Weight loss, decreased energy intake, and increased aerobic exercise (p<0.05) led to decreased LM and FM-adjusted REE (p<0.05), reflecting metabolic adaptation. Absolute leptin levels decreased in both sexes (p<0.001) but more among females (p<0.001) due to higher baseline leptin levels. These changes occurred with similar decreases in T3 (p<0.001) and resting heart rate (p<0.01) in both sexes. CTRL, who were former or upcoming physique athletes, showed no systematic changes in any measured variables. In conclusion, while dieting, female and male physique athletes experience REE and hormonal changes leading to adaptive thermogenesis. However, responses seemed temporary as they returned toward baseline after the recovery phase. ClinicalTrials.gov (NCT04392752).