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Helen Dixon,1 Catherine E Baker,2 Julien S Baker,3 Susan Dewhurst,4 Lawrence D Hayes4 1School of Human Sciences, London Metropolitan University, London, 2English Institute of Sport, Bisham Abbey National Sports Center, Buckinghamshire, 3Institute of Clinical Exercise and Health Science, University of the West of Scotland, Hamilton, 4Department of Medical and Sport Sciences, University of Cumbria, Lancaster, UK Abstract: This study investigated the effect of sodium bicarbonate (NaHCO3–) ingestion on the Yo-Yo intermittent recovery test 1 (IR1). We tested the hypothesis that acute ingestion of NaHCO3– would increase blood lactate concentrations [BLa], enhance performance, and reduce rating of perceived exertion (RPE) in the Yo-Yo IR1. Eight recreationally active males (N=8, age: 26±4 yr, height: 178±6 cm, body mass: 82±10 kg) participated in the Yo-Yo IR1 on two separate occasions, separated by 1 wk, in a randomized crossover design. Following familiarization, during seated rest, participants’ pretest [BLa] was taken, and participants then consumed either a placebo of 0.3 g·kg–1 body weight sodium chloride or 0.3 g·kg–1 body weight NaHCO3–. Sixty minutes postingestion, a standardized warm-up preceded the Yo-Yo IR1. Upon completion, postexercise [BLa] (mmol·L–1), RPE (arbitrary units) and Yo-Yo IR1 time to fatigue (s) were recorded. Paired t-test revealed a small but significant improvement in Yo-Yo IR1 performance under the NaHCO3– condition (610±267 sec), compared to the placebo condition (556±259 sec; p=0.01; Cohen’s d=0.20). [BLa] increased more under the NaHCO3– condition (1.6±0.7 to 17.5±5.2 mmol·L–1; p

The timing of exposure to the steroid hormone, testosterone, produces activational and organizational effects in vertebrates. These activational and organizational effects are hypothesized to relate with the number of female mating partners and reproductive success in males. We tested this hypothesis by examining 151 wild degu (Octodon degus) males across a 10-year study. We quantified the association between adult serum testosterone levels (i.e., an indirect index of adult activational effects) and anogenital distance (AGD) length (i.e., a direct index of fetal organizational effects), and their interaction on the number of female mating partners and reproductive success. We found no evidence of an association between adult male serum testosterone levels and the number of female mating partners, or between adult male serum testosterone levels and reproductive success. However, male AGD was positively associated with reproductive success, but not so with the number of female mating partners. Additionally, the positive association between male AGD and male reproductive success was mediated by the number of mates. Our findings do not support major roles of activational or organizational effects of testosterone on the number of female mating partners and its consequences on male reproductive success. Instead, our results suggest that compared with individual male attributes, the female social environment plays a more important role in driving male reproductive success., Competing Interests: Declaration of competing interest The authors have no competing interests., (Copyright © 2024. Published by Elsevier Inc.)

Background: Body composition, blood pressure, estimated maximal oxygen uptake (VO 2max ), lung function, physical activity, muscle architecture, and endothelial function had not previously been examined in people with young onset dementia. Therefore, the study measured these variables in a young onset dementia group, compared them to age-matched controls., Methods: Estimated VO 2max (via the Astrand-Rhyming test), body composition, blood pressure, lung function (via spirometry), muscle architecture (via ultrasonography) and endothelial function (via flow mediated dilation) were assessed. Physical activity was measured using ActiGraph accelerometers for 7 days., Results: We recruited 33 participants (16 young onset dementia, 17 controls). The young onset dementia group had shorter fascicle lengths of the vastus lateralis, were sedentary for longer over a seven-day period, and completed less moderate-vigorous physical activity than controls (p=0.028, d=0.81; large effect, p=0.029, d=0.54; moderate effect, and p=0.014, d=0.97; large effect, respectively for pairwise comparisons). Pairwise comparisons suggest no differences at the p<0.05 level between young onset dementia and controls for estimated VO 2max (despite a moderate effect size [d=0.66]), height, body mass, BMI, blood pressure, light physical activity, lung function, muscle thickness, pennation angle, or endothelial function., Conclusion: This study highlights differences between people with young onset dementia and controls, underscoring the need for multicomponent exercise interventions. Future interventions should target muscle architecture, increase moderate-vigorous physical activity, and reduce sedentariness, with the goal of improving quality of life and promoting functional independence., Competing Interests: Declaration of competing interest The submitted work was not carried out in the presence of any personal, professional, or financial relationships that could potentially be construed as a conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Background: Well-being and cognitive function had not previously been compared between people with long COVID and people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Therefore, this study examined well-being and cognitive function in people with long COVID (∼16 months illness duration; n = 17) and ME/CFS (∼16 years illness duration; n = 24), versus age-matched healthy controls (n = 16)., Methods: Well-being was examined using several questionnaires, namely the Health Visual Analogue Scale (VAS), Fatigue Severity Scale (FSS), post-exertional malaise (PEM), Pittsburgh Sleep Quality Index (PSQI), European Quality of Life-5 Domains (EQ-5D), MRC Dyspnoea, Self-Efficacy (SELTC), The Edinburgh Neurosymptoms Questionnaire (ENS), General Anxiety Disorder 7 (GAD-7) and Patient Health Questionnaire 9 (PHQ-9). Cognitive function was examined using Single Digit Modalities Test (SDMT), Stroop test and Trails A and B. These were delivered via a mobile application (app) built specifically for this remote data collection., Results: The main findings of the present investigation were that people with ME/CFS and people with long COVID were generally comparable on all well-being and cognitive function measures, but self-reported worse values for pain, fatigue, post-exertional malaise, sleep quality, general well-being in relation to mobility, usual activities, self-care, breathlessness, neurological symptoms, self-efficacy and other well-being such as anxiety and depression, compared to controls. There was no effect of group for cognitive function measures., Conclusions: These data suggest that both people with long COVID and people with ME/CFS have similar impairment on well-being measures examined herein. Therefore, interventions that target well-being of people with ME/CFS and long COVID are required., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

In vertebrates, male testosterone levels vary across the year being generally higher during the mating season relative to the offspring rearing season. However, male testosterone levels may also be associated with male anogenital distance (AGD) length (a proxy of prenatal androgen exposition), and influenced by the social group environment. In social species, it has been proposed that high levels of testosterone could be incompatible with the development of an amicable social environment. Thus, in these species, it is predicted that males have relatively low levels of testosterone. Our goal was to examine the potential association between male serum testosterone levels, season, male AGD length, and the social environment in the rodent Octodon degus under natural conditions. We quantified male serum testosterone levels during the mating and offspring rearing seasons, and we determined the number of females and males in each social group, as well as the composition of groups, in terms of the AGD length of the female and male group mates, from 2009 to 2019. Our results revealed that male testosterone levels covary with season, being highest during the offspring rearing season. Additionally, male testosterone levels vary with male AGD length, and female and male social group environments. More importantly, male degus exhibit low levels of testosterone that are indistinguishable from female levels during offspring rearing season. Similar to other highly social mammals, where males and females live together year-round, male amicable behavior could be the best male mating strategy, thus leading to a reduction in circulating testosterone levels., Competing Interests: Declaration of competing interest The authors have no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Testosterone is known as a "male" hormone; however, females also synthetize testosterone, which influences female sexual and aggressive behavior. In female vertebrates, as in males, testosterone levels can vary seasonally. However, female testosterone levels may also be related with female anogenital distance (AGD) length phenotype (a proxy of prenatal androgen exposure), and the social group environment. We used data from a long-term rodent study (2009-2019) in a natural population of degus (Octodon degus) to examine the potential associations between female serum testosterone levels, season, female AGD phenotype, and social group composition. We quantified female serum testosterone levels during the mating and offspring rearing seasons, and we determined the number of females and males in social groups, as well the composition of groups, in terms of the AGD of the female and male group mates. Our results indicate that female testosterone levels vary with season, being highest during the offspring rearing season. Additionally, female testosterone levels were associated with the number of male group-members and the AGD of male group-members but were not associated with female social environment and focal female AGD phenotype. Together, our results suggest that female testosterone levels are sensitive to intersexual interactions. Our results also reveal that female and male testosterone levels do not differ between the sexes, a finding previously reported only in rock hyraxes. We discuss how the complex social system of degus could be driving this physiological similarity between the sexes., Competing Interests: Declaration of competing interest The authors have no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This investigation explored relationships between biological maturation, physical and academic performance in young male soccer players. Thirty-eight players (age: 9.79 ± 1.21 years; body mass index (BMI): 20.4 ± 2.39 kg/m2; body fat: 16.8 ± 2.21%) participated. Measures of anthropometry used for body mass, body fat percentage (%BF), and BMI as well. Postural control, 15 m sprint, squat jumps and counter-movement jumps (SJ, CMJ), and T-half test for change-of-direction (CoD) were parameters of physical performance. The grade point average (GPA) of mathematics determined academic attainment. Moore's equations were used to estimate their maturity status (PHV). Biological maturation was highly correlated with most (not 15 m sprint) physical and academic performance parameters, especially CMJ (r = -0.812) and mathematics (r = -0.781). Academic performance showed the largest relations to the jumping performance (CMJ: r = 0.771; SJ: r = 0.723). In contrast, anthropometric and fatness parameters were not relevantly (r ≥ 0.5) correlated with any other parameters. The largest correlations were calculated for sitting height vs. SJ (r = -0.408), sitting height vs. postural control (r = -0.355), leg length vs. postural control (r = -0.339). As a result, it is essential to take biological maturation inconsideration while assessing the physical and academic achievement of young soccer players. In consequence, soccer coaches and physical education (PE) teachers should be cognizant of the impact of biological maturity on physical and academic performance to assist fair and equal opportunities for achievement in young players., Competing Interests: NO authors have competing interests., (Copyright: © 2024 Hermassi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: With the rise of smartphone ownership and increasing evidence to support the suitability of smartphone usage in healthcare, the light source and smartphone camera could be utilized to perform photoplethysmography (PPG) for the assessment of vital signs, such as heart rate (HR). However, until rigorous validity assessment has been conducted, PPG will have limited use in clinical settings., Objective: We aimed to conduct a scoping review assessing the validity of resting heart rate (RHR) acquisition from PPG utilizing contact-based smartphone devices. Our four specific objectives of this scoping review were to (1) conduct a systematic search of the published literature concerning contact-based smartphone device-derived PPG, (2) map study characteristics and methodologies, (3) identify if methodological and technological advancements have been made, and (4) provide recommendations for the advancement of the investigative area., Methods: ScienceDirect, PubMed and SPORTDiscus were searched for relevant studies between January 1st, 2007, and November 6th, 2022. Filters were applied to ensure only literature written in English were included. Reference lists of included studies were manually searched for additional eligible studies., Results: In total 10 articles were included. Articles varied in terms of methodology including study characteristics, index measurement characteristics, criterion measurement characteristics, and experimental procedure. Additionally, there were variations in reporting details including primary outcome measure and measure of validity. However, all studies reached the same conclusion, with agreement ranging between good to very strong and correlations ranging from r  = .98 to 1., Conclusions: Smartphone applications measuring RHR derived from contact-based smartphone PPG appear to agree with gold standard electrocardiography (ECG) in healthy subjects. However, agreement was established under highly controlled conditions. Future research could investigate their validity and consider effective approaches that transfer these methods from laboratory conditions into the "real-world", in both healthy and clinical populations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Mather, Hayes, Mair and Sculthorpe.)

Purpose: Dexterity and bimanual coordination had not previously been compared between people with long COVID and people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Therefore, this study determined dexterity and bimanual coordination in people with long COVID (∼16-month illness duration; n = 21) and ME/CFS (∼16-year illness duration; n = 20), vs age-matched healthy controls (n = 20)., Methods: Dexterity and bimanual coordination was determined using the Purdue pegboard test., Results: The main findings of the present investigation were that people with ME/CFS and people with long COVID were generally comparable for Purdue pegboard tests (P > .556 and d < 0.36 for pairwise comparisons). It is worth noting however, that both these patient groups performed poorer in the Perdue pegboard test than healthy controls (P < .169 and d > 0.40 for pairwise comparisons)., Conclusions: These data suggest that both people with long COVID and people with ME/CFS have similarly impaired dexterity and bimanual coordination. Therefore, there is an urgent need for interventions to target dexterity and bimanual coordination in people with ME/CFS, and given the current pandemic, people with long COVID., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Prevalences of post-traumatic stress disorder (PTSD) and complex post-traumatic stress disorder (CPTSD) have not previously been compared between individuals with long coronavirus disease (COVID) and individuals with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and healthy age-matched controls. For these reasons, this study aimed to determine the prevalence of PTSD and CPTSD in individuals with long COVID (n = 21) and ME/CFS (n = 20) and age-matched controls (n = 20)., Methods: A case-case-control approach was employed; participants completed the International Trauma Questionnaire, a self-report measure of the International Classification of Diseases of PTSD and CPTSD consisting of 18 items. Scores were calculated for each PTSD and Disturbances in Self-Organization (DSO) symptom cluster and summed to produce PTSD and DSO scores. PTSD was diagnosed if the criteria for PTSD were met but not DSO, and CPTSD was diagnosed if the criteria for PTSD and DSO were met. Moreover, each cluster of PTSD and DSO were compared among individuals with long COVID, ME/CFS, and healthy controls., Results: Individuals with long COVID (PTSD = 5%, CPTSD = 33%) had more prevalence of PTSD and CPTSD than individuals with ME/CFS (PTSD = 0%, CPTSD = 20%) and healthy controls (PTSD = 0%, CPTSD = 0%). PTSD and CPTSD prevalence was greater in individuals with long COVID and ME/CFS than controls. Individuals with long COVID had greater values controls for all PTSD values. Moreover, individuals with long COVID had greater values than controls for all DSO values. Individuals with ME/CFS had greater values than controls for all DSO values. Both long COVID and ME/CFS groups differed in overall symptom scores compared with controls., Conclusion: Findings of this study demonstrated that individuals with long COVID generally had more cases of PTSD and CPTSD than individuals with ME/CFS and healthy controls., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: This meta-analysis aimed to (1) provide a comparison of peak changes in indirect markers of exercise-induced muscle damage (EIMD) in youths versus adults and (2) determine if the involved limb moderated this effect., Method: Studies were eligible for inclusion if they (1) provided a human youth versus adult comparison; (2) provided data on muscle strength, soreness, or creatine kinase markers beyond ≥24 hours; and (3) did not provide a recovery treatment. Effect sizes (ES) were presented alongside 95% confidence intervals., Results: EIMD exhibited larger effects on adults than in youths for muscle strength (ES = -2.01; P < .001), muscle soreness (ES = -1.52; P < .001), and creatine kinase (ES = -1.98; P < .001). The random effects meta-regression indicated that the effects of upper- and lower-limb exercise in youths and adults were significant for muscle soreness (coefficient estimate = 1.11; P < .001) but not for muscle strength or creatine kinase (P > .05). As such, the between-group effects for muscle soreness (ES = -2.10 vs -1.03; P < .05) were greater in the upper than lower limbs., Conclusion: The magnitude of EIMD in youths is substantially less than in their adult counterparts, and this effect is greater in upper than lower limbs for muscle soreness. These findings help guide practitioners who may be concerned about the potential impact of EIMD when training youth athletes.

Background: Controversy over treatment for people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a barrier to appropriate treatment. Energy management or pacing is a prominent coping strategy for people with ME/CFS. Whilst a definitive definition of pacing is not unanimous within the literature or healthcare providers, it typically comprises regulating activity to avoid post exertional malaise (PEM), the worsening of symptoms after an activity. Until now, characteristics of pacing, and the effects on patients' symptoms had not been systematically reviewed. This is problematic as the most common approach to pacing, pacing prescription, and the pooled efficacy of pacing was unknown. Collating evidence may help advise those suffering with similar symptoms, including long COVID, as practitioners would be better informed on methodological approaches to adopt, pacing implementation, and expected outcomes., Objectives: In this scoping review of the literature, we aggregated type of, and outcomes of, pacing in people with ME/CFS., Eligibility Criteria: Original investigations concerning pacing were considered in participants with ME/CFS., Sources of Evidence: Six electronic databases (PubMed, Scholar, ScienceDirect, Scopus, Web of Science and the Cochrane Central Register of Controlled Trials [CENTRAL]) were searched; and websites MEPedia, Action for ME, and ME Action were also searched for grey literature, to fully capture patient surveys not published in academic journals., Methods: A scoping review was conducted. Review selection and characterisation was performed by two independent reviewers using pretested forms., Results: Authors reviewed 177 titles and abstracts, resulting in 17 included studies: three randomised control trials (RCTs); one uncontrolled trial; one interventional case series; one retrospective observational study; two prospective observational studies; four cross-sectional observational studies; and five cross-sectional analytical studies. Studies included variable designs, durations, and outcome measures. In terms of pacing administration, studies used educational sessions and diaries for activity monitoring. Eleven studies reported benefits of pacing, four studies reported no effect, and two studies reported a detrimental effect in comparison to the control group., Conclusions: Highly variable study designs and outcome measures, allied to poor to fair methodological quality resulted in heterogenous findings and highlights the requirement for more research examining pacing. Looking to the long COVID pandemic, our results suggest future studies should be RCTs utilising objectively quantified digitised pacing, over a longer duration of examination (i.e. longitudinal studies), using the core outcome set for patient reported outcome measures. Until these are completed, the literature base is insufficient to inform treatment practises for people with ME/CFS and long COVID., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: This study aimed to compare flow-mediated dilation values between individuals with long COVID, individuals with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and healthy age-matched controls to assess the potential implications for clinical management and long-term health outcomes., Methods: A case-case-control approach was employed, and flow-mediated dilation measurements were obtained from 51 participants (17 long COVID patients, 17 ME/CFS patients, and 17 healthy age-matched controls). Flow-mediated dilation values were analyzed using 1-way analysis of variance for between-group comparisons., Results: Results revealed significantly impaired endothelial function in both long COVID and ME/CFS groups compared with healthy age-matched controls as determined by maximum % brachial artery diameter post-occlusion compared with pre-occlusion resting diameter (6.99 ± 4.33% and 6.60 ± 3.48% vs 11.30 ± 4.44%, respectively, both P < .05). Notably, there was no difference in flow-mediated dilation between long COVID and ME/CFS groups (P = .949), despite significantly longer illness duration in the ME/CFS group (ME/CFS: 16 ± 11.15 years vs long COVID: 1.36 ± 0.51 years, P < .0001)., Conclusion: The study demonstrates that both long COVID and ME/CFS patients exhibit similarly impaired endothelial function, indicating potential vascular involvement in the pathogenesis of these post-viral illnesses. The significant reduction in flow-mediated dilation values suggests an increased cardiovascular risk in these populations, warranting careful monitoring and the development of targeted interventions to improve endothelial function and mitigate long-term health implications., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Postural sway and physical capacity had not previously been compared between people with long COVID and people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Therefore, this study determined postural sway and physical capacity in people with long COVID (∼16-month illness duration; n = 21) and ME/CFS (∼16-year illness duration; n = 20), vs age-matched healthy controls (n = 20)., Methods: Postural sway was during a 30-s static stand test. Physical capacity was determined using the Timed Up and Go test and 5 Times Sit to Stand test. Throughout, participants wore isoinertial measurement units., Results: Postural sway was worse (ie, greater) in people with long COVID and ME/CFS than controls, but not different between long COVID and ME/CFS. Performance of the Timed Up and Go test and 5 Times Sit to Stand test were worse in long COVID and ME/CFS than controls, but not different between long COVID and ME/CFS. Of long COVID and ME/CFS participants, 87% and 13% exceeded the threshold for muscle weakness in the 5 Times Sit to Stand test and Timed Up and Go test, respectively., Conclusions: These data suggest that both people with long COVID and people with ME/CFS have similarly impaired balance and physical capacity. Therefore, there is an urgent need for interventions to target postural sway and physical capacity in people with ME/CFS, and given the current pandemic, people with long COVID., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: There has been some effort to map the prevalence, frequency, and severity of symptoms of long COVID at local and national levels. However, what is frequently absent from such accounts is details of the impact the disease and its symptoms have had on those living with the condition. In this article, we present details of the impact on work, caring, and mental health gathered using a cross-sectional survey., Methods: Data were collected using an online survey that was available from April 21, 2022, to August 5, 2022. Included participants had either self-diagnosed or confirmed long COVID, were living in Scotland, and were aged ≥18 years. Hospitalization during initial COVID-19 infection was an exclusion criterion. Participants were asked to report on the impact of their illness on everyday activities such as working, studying, or caring. They also completed an assessment of their current mood., Results: People with long COVID were often severely impacted in their ability to work and study. Severe impact on work and study were predicted by more severe and more frequent fatigue, more severe pain, and more severe cognitive impairment. Respondents' ability to care for child dependents was also associated with more severe and more frequent fatigue, and more severe cognitive impairments. More severe pain associated with greater impact on adult care. Negative mood correlated most strongly with frequency and severity of neurological symptoms, including lack of attention, loss of smell, impaired sense of smell, loss of taste, impaired sense of taste, and loss of appetite., Conclusions: Long COVID has a significant impact on ability to work, study, and care for dependents. The severity of this impact is associated with specific symptom burden, including fatigue, pain, and cognitive impairment., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Older adults exhibit a reduced number and function of CD34 + circulating progenitor cells (CPC), a known risk factor for cardiovascular disease. Exercise promotes the mobilisation of CPCs from bone marrow, so whether ageing per se or physical inactivity in older age reduces CPCs is unknown. Thus, this study examined the effect of age on resting and exercise-induced changes in CPCs in aerobically trained adults and the effect of 8 weeks of sprint interval training (SIT) on resting and exercise-induced CPCs in older adults. Twelve young (22-34 years) and nine older (63-70 years) adults participated in the study. Blood was sampled pre and immediately post a graded exercise test to exhaustion in both groups. Older participants repeated the process after 8 weeks of SIT (3 × 20 s 'all-out' sprints, 2 × a week). Total CPCs (CD34 + ) and endothelial progenitor cells (EPCs: CD34 + KDR + ) were determined by flow cytometry. Older adults exhibited lower basal total CD34 + CPCs (828 ± 314 vs. 1186 ± 272 cells·mL -1 , p = 0.0149) and CD34 + KDR + EPCs (177 ± 128 vs. 335 ± 92 cells·mL -1 , p = 0.007) than younger adults. The maximal exercise test increased CPCs in young (CD34 + : p = 0.004; CD34 + KDR + : p = 0.017) and older adults (CD34 + : p < 0.001; CD34 + KDR + : p = 0.008), without difference between groups (p = 0.211). SIT did not alter resting or exercise-induced changes in CPCs in the older cohort (p > 0.232). This study suggests age per se does not impair exercise-induced CPC counts, but does lower resting CPC counts., (© 2023. The Author(s).)

While direct influences of the environment on population growth and resilience are well studied, indirect routes linking environmental changes to population consequences are less explored. We suggest that social behavior is key for understanding how anthropogenic environmental changes affect the resilience of animal populations. Social structures of animal groups are evolved and emergent phenotypes that often have demographic consequences for group members. Importantly, environmental drivers may directly influence the consequences of social structure or indirectly influence them through modifications to social interactions, group composition, or group size. We have developed a framework to study these demographic consequences. Estimating the strength of direct and indirect pathways will give us tools to understand, and potentially manage, the effect of human-induced rapid environmental changes., Competing Interests: Declaration of interests No interests are declared., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Introduction: This study aimed to compare 10-12-year-old Qatari male soccer players ( n = 45) regarding different dimensions (anthropometric, academic and physical performance). Methods: Anthropometric parameters (body mass, fat percentage (%BF), body mass index (BMI)) academic achievement (mathematics and science grade point average [GPA]) and physical performance [Yo-Yo Intermittent Recovery Test (level 1), squat jumps (SJ), counter-movement jumps (CMJ), stork balance test, 10 and 15 m sprint tests, T-half test for change-of-direction (CoD) ability, hand-grip strength, medicine ball throw (MBT)] were measured. Schoolchild soccer players were divided into three groups: 12-year-old players (U12; n = 16), 11-year-old players (U11; n = 14), 10-year-old players (U10; n = 15). Results: Apart from mathematics, Yo-Yo IR1 and 10 m sprint, all performance parameters showed significant age effects. The largest age-related difference was observed for 15 m sprint ( p < 0.001). Both adjacent age groups displayed significant differences for 15 sprint (U10 vs. U11: p = 0.015; U11 vs. U12: p = 0.023). Concerning academic performance, a significant age effect was found for science ( p < 0.001). There was a main age effect on academic performance difference between U10 and U11 ( p = 0.007). Academic parameters did not correlate with any physical performance parameter or anthropometric parameter. The strongest correlations were detected for body height and agility T-half test ( r = -0.686) and medicine ball throw ( r = 0.637). The biological maturity was strongly correlated with handgrip strength (r = -0.635). Discussion: Soccer coaches and physical education teachers can use these data as reference values for evaluation of school-aged soccer players, and for ascertaining specific training targets. Obviously, short sprinting ability and aerobic capacity are not functions of age and need a specific training for significant improvements., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Hermassi, Hayes, Bartels and Schwesig.)

Around 5.5-6.5 months of age, infants first attend to object size and perceive its mass cues in simple collision events. Infants attend to the size of the moving object and expect a greater displacement following a collision with a large object and stationary object, and lesser displacement following a collision with a small object and stationary object. It has been proposed that infants of 6-to-7 months of age can differentiate between sizes of moving objects but do not perceive the size and mass relationships in simple collision events. The present two investigations aimed to investigate whether infants 10-to-11 months of age (N = 16) could perceive this relationship (experiment 1) and the reverse of this relationship (experiment 2) utilising the looking time paradigm. The reverse of this relationship entailed the circumstances in which the moving object size was kept constant, but the stationary object size varied (small or large). Results from these experiments revealed that infants did not differ in their looking times for size congruent and size incongruent distances in both conditions. Infants did not look longer at the incongruent test events that violated expectation. For that reason, we conclude infants of 10-to-11 months of age were unable to perceive size and mass associations in collision events in either direction (moving object or stationary object size).

The present study aimed to determine the effect of high intensity interval training (HIIT) in hypoxia on maximal oxygen uptake (VO 2max ) compared with HIIT in normoxia with a Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)-accordant meta-analysis and meta-regression. Studies which measured VO 2max following a minimum of 2 weeks intervention featuring HIIT in hypoxia versus HIIT in normoxia were included. From 119 originally identified titles, nine studies were included ( n = 194 participants). Meta-analysis was conducted on change in (∆) VO 2max using standardised mean difference (SMD) and a random effects model. Meta-regression examined the relationship between the extent of environmental hypoxia (fractional inspired oxygen [FiO 2 ]) and ∆VO 2max and intervention duration and ∆VO 2max . The overall SMD for ∆VO 2max following HIIT in hypoxia was 1.14 (95% CI = 0.56-1.72; p < 0.001). Meta-regressions identified no significant relationship between FiO 2 (coefficient estimate = 0.074, p = 0.852) or intervention duration (coefficient estimate = 0.071, p = 0.423) and ∆VO 2max . In conclusion, HIIT in hypoxia improved VO 2max compared to HIIT in normoxia. Neither extent of hypoxia, nor training duration modified this effect, however the range in FiO 2 was small, which limits interpretation of this meta-regression. Moreover, training duration is not the only training variable known to influence ∆VO 2max , and does not appropriately capture total training stress or load. This meta-analysis provides pooled evidence that HIIT in hypoxia may be more efficacious at improving VO 2max than HIIT in normoxia. The application of these data suggest adding a hypoxic stimuli to a period of HIIT may be more effective at improving VO 2max than HIIT alone. Therefore, coaches and athletes with access to altitude (either natural or simulated) should consider implementing HIIT in hypoxia, rather than HIIT in normoxia where possible, assuming no negative side effects.

Aims: Aerobic exercise is well recognised as an effective treatment for people with type 2 diabetes but the optimal amount of aerobic exercise to improve glycaemic control remains to be determined. Thus, the aim of this meta-analysis and meta-regression was to assess the impact of volume and intensity of aerobic exercise on glycaemic control., Methods: Medline, Cochrane, Embase, and Web of Science databases were searched up until 15 December 2020 for the terms "aerobic exercise AND glycaemic control", "type 2 diabetes AND exercise", and "exercise AND glycaemic control AND Type 2 diabetes AND randomised control trial". We included (i) randomised control trials of ≥ 12 weeks, (ii) trials where participants had type 2 diabetes and were aged 18 or over, and (iii) the trial reported HbA1c concentrations pre- and post-intervention. Two reviewers selected studies and extracted data. Data are reported as standardised mean difference (SMD) and publication bias was assessed using funnel plots., Results: A total of 5364 original titles were identified. Sixteen studies were included in the meta-analysis. Aerobic exercise reduced HbA1c versus control (SMD = 0.56 (95% CI 0.3-0.82), p < 0.001). There were also significant reductions in BMI (SMD = 0.76 (95% CI 0.25-1.27), p < 0.05). There was no dose-response relationship between improvement in HbA1c and the intensity and volume of the intervention (p > 0.05)., Conclusions: Twelve-week or longer aerobic exercise programmes improve glycaemic control and BMI in adults with type 2 diabetes. Longer or more intense interventions appear to confer no additional benefit on HbA1c., (© 2022. The Author(s).)

Background: Ageing is accompanied by decreases in physical capacity and physiological regulatory mechanisms including altered hormonal regulation compared with age-matched sedentary people. The potential benefits of exercise in restoring such altered hormone production and secretion compared to age-matched physically inactive individuals who are ageing remains unclear., Objectives: The aim of this systematic review was to summarise the findings of exercise training in modulating levels of ostensibly anabolic and catabolic hormones in adults aged > 40 years., Methods: We searched the following electronic databases (to July 2021) without a period limit: Cochrane Library, PubMed, Science Direct, Scopus, SPORTDiscus and Web of Science. Additionally, a manual search for published studies in Google Scholar was conducted for analysis of the 'grey literature' (information produced outside of traditional commercial or academic publishing and distribution channels). The initial search used the terms 'ageing' OR 'advanced age' OR 'old people' OR 'older' OR elderly' AND 'anabolic hormones' OR 'catabolic hormones' OR 'steroid hormones' OR 'sex hormones' OR 'testosterone' OR 'cortisol' OR 'insulin' OR 'insulin-like growth factor-1' OR 'IGF-1' OR 'sex hormone-binding globulin' OR 'SHBG' OR 'growth hormone' OR 'hGH' OR 'dehydroepiandrosterone' OR 'DHEA' OR 'dehydroepiandrosterone sulfate (DHEA-S)' AND 'exercise training' OR 'endurance training' OR 'resistance training' OR ' strength training' OR 'weight-lifting' OR 'high-intensity interval training' OR 'high-intensity interval exercise' OR 'high-intensity intermittent training' OR 'high-intensity intermittent exercise' OR 'interval aerobic training' OR 'interval aerobic exercise' OR 'intermittent aerobic training' OR 'intermittent aerobic exercise' OR 'high-intensity training' OR 'high-intensity exercise' OR 'sprint interval training' OR 'sprint interval exercise' OR 'combined exercise training' OR 'anaerobic training'. Only eligible full texts in English or French were considered for analysis., Results: Our search identified 484 records, which led to 33 studies for inclusion in the analysis. Different exercise training programs were used with nine studies using endurance training programs, ten studies examining the effects of high-intensity interval training, and 14 studies investigating the effects of resistance training. Most training programs lasted ≥ 2 weeks. Studies, regardless of the design, duration or intensity of exercise training, reported increases in testosterone, sex hormone-binding globulin (SHBG), insulin-like growth factor-1 (IGF-1), human growth hormone (hGH) or dehydroepiandrosterone (DHEA) (effect size: 0.19 < d < 3.37, small to very large) in both older males and females. However, there was no consensus on the effects of exercise on changes in cortisol and insulin in older adults., Conclusion: In conclusion, findings from this systematic review suggest that exercise training increases basal levels of testosterone, IGF-1, SHBG, hGH and DHEA in both male and females over 40 years of age. The increases in blood levels of these hormones were independent of the mode, duration and intensity of the training programs. However, the effects of long-term exercise training on cortisol and insulin levels in elderly people are less clear., (© 2021. Crown.)

Background: Just-in-time adaptive interventions (JITAIs) provide real time in-the-moment behavior change support to people when they need it most. JITAIs could be a viable way to provide personalized physical activity (PA) support to older adults in the community. However, it is unclear how feasible it is to remotely deliver a PA intervention through a smartphone to older adults or how acceptable they would find a JITAI targeting PA in everyday life., Objective: The aims of this study are to describe the development of JitaBug, a personalized smartphone-delivered JITAI designed to support older adults to increase or maintain their PA level, assess the feasibility of conducting an effectiveness trial of the JitaBug intervention, and explore the acceptability of JitaBug among older adults in a free-living setting., Methods: The intervention was developed using the Behavior Change Wheel and consisted of a wearable activity tracker (Fitbit) and a companion smartphone app (JitaBug) that delivered goal-setting, planning, reminders, and JITAI messages to encourage achievement of personalized PA goals. Message delivery was tailored based on time of day, real time PA tracker data, and weather conditions. We tested the feasibility of remotely delivering the intervention with older adults in a 6-week trial. Data collection involved assessment of PA through accelerometery and activity tracker, self-reported mood and mental well-being through ecological momentary assessment, and contextual information on PA through voice memos. Feasibility outcomes included recruitment capability and adherence to the intervention, intervention delivery in the wild, appropriateness of data collection methodology, adverse events, and participant satisfaction., Results: Of the 46 recruited older adults (aged 56-72 years), 31 (67%) completed the intervention. The intervention was successfully delivered as intended; 87% (27/31) of the participants completed the intervention independently; 94% (2247/2390) of the PA messages were successfully delivered; 99% (2239/2261) of the Fitbit and 100% (2261/2261) of the weather data calls were successful. Valid and usable wrist-worn accelerometer data were obtained from 90% (28/31) of the participants at baseline and follow-up. On average, the participants recorded 50% (7.9/16, SD 7.3) of the voice memos, 38% (3.3/8, SD 4.2) of the mood assessments, and 50% (2.1/4, SD 1.6) of the well-being assessments through the app. Overall acceptability of the intervention was very good (23/30, 77% expressed satisfaction). Participant feedback suggested that more diverse and tailored PA messages, app use reminders, technical refinements, and an improved user interface could improve the intervention and make it more appealing., Conclusions: This study suggests that a smartphone-delivered JITAI is an acceptable way to support PA in older adults in the community. Overall, the intervention is feasible; however, based on user feedback, the JitaBug app requires further technical refinements that may enhance use, engagement, and user satisfaction before moving to effectiveness trials., (©Jacqueline Louise Mair, Lawrence D Hayes, Amy K Campbell, Duncan S Buchan, Chris Easton, Nicholas Sculthorpe. Originally published in JMIR Formative Research (https://formative.jmir.org), 07.04.2022.)

This study examined the differences in the level of physical fitness and academic performance among male middle-school children based on different body status categories. A total of 69 male children [age: 12.4 ± 0.7 years; body mass: 58.5 ± 7.2 kg; height: 1.62 ± 0.09 m; and body mass index (BMI): 22.4 ± 3.3 kg/m 2 ] participated and were divided into BMI age-adjusted groups (i.e., lowest, middle, and highest BMI). Height, mass, BMI, stork test of static balance, 10 and 15 m sprint as an indicator for speed, hand-grip strength test, agility T-half test, medicine ball throw (MBT), and the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1) were assessed. School records were retrieved for grade point averages (GPA) of mathematics, science, and Arabic. We found significant group differences regarding anthropometric (height: η p 2 = 0.24, mass: η p 2 = 0.33, and BMI: η p 2 = 0.66), physical (sprint 10 m: η p 2 = 0.26), and academic (mathematics: η p 2 = 0.19 and science: η p 2 = 0.15) performance parameters. The largest difference ( p < 0.001) was observed between the lowest and highest group for the 10 m sprint. All pairwise differences were between the lowest and highest BMI group or the lowest and middle BMI group. No relevant ( r > 0.5) correlation between parameters of different dimensions (e.g., anthropometric vs. physical performance parameters) was found. In conclusion, the highest BMI group exhibited similar physical and academic performances than the lowest group. Thus, these data emphasize the importance and appropriateness to engage young Qatari schoolchildren in physical activity as it associates with superior academic performance., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hermassi, Hayes, Sanal-Hayes and Schwesig.)

This investigation explored the association between anthropometric measures, fitness, and academic attainment (mathematics and science grade point average [GPA]) in male schoolchildren from a soccer academy. Thirty-one males (age: 10.3 ± 1.19 years; body mass: 41.7 ± 6.5 kg; height: 1.43 ± 0.07 m; body mass index (BMI): 20.2 ± 2.8 kg/m2) participated. Body mass, body fat percentage (%BF), and BMI were used as measures of anthropometry. The Yo-Yo Intermittent Recovery Test (level 1), squat and counter-movement jumps (SJ and CMJ), static balance, 10 and 15 m sprint, and a T-half test for change-of-direction (CoD) performance were used to measure fitness parameters. The GPA of mathematics and science determined academic attainment. All physical performance tests showed excellent relative reliability. ICC was between 0.87 (10 m sprint) and 1.00 (15 m sprint, CMJ). Regarding correlations between fatness and academic attainment, we found three correlations of practical value (r > 0.5), but only for mathematics (BMI: r = 0.540, subscapular skinfold: r = 0.589, body fat: r = 0.560). Mathematics was relevantly correlated with 15 m sprint (r = 0.574) and Yo-Yo IR1 test (r = 0.770). Only static balance (r = 0.428) did not reach the relevance criteria (r > 0.5). Science only showed large correlations with static balance (r = 0.620) and Yo-Yo IR1 test (r = 0.730). In conclusion, fatness and fitness are related to academic attainment in schoolchildren. In addition, except for static balance, all physical performance parameters were relevantly (r > 0.5) correlated with mathematics.

This study examined the effect of 8 weeks of biweekly combined plyometric and short sprint training into the typical within-season training schedule of youth male soccer players. Participants were allocated at random to an experimental group (EG; n = 17, age: 14.6 ± 0.5 years, body mass: 60.5 ± 7.1 kg, height: 1.64 ± 0.08 m, body fat: 11.3 ± 1.4%) and a control group (CG; n = 17, age: 14.6 ± 0.4 years, body mass: 61.0 ± 3.9 kg, height: 1.67 ± 0.05 m, body fat: 11.8 ± 1.4%). Measures obtained pre- and post-intervention included vertical and horizontal jump performances (i.e., squat jump (SJ), countermovement jump with aimed arms (CMJA), and five-jump test (FJT)) and sprint performances (i.e., 10 and 30 m sprint). In addition, change-of-direction ability (sprint with 90° Turns (S90°) and sprint 9-3-6-3-9 m with backward and forward running (SBF)), repeated shuttle sprint ability (RSSA), and dynamic balance performance (Y balance test) were measured pre- and post-intervention. The EG experienced higher jump (all p < 0.05; d ≥ 0.71), sprint (all p < 0.05; d ≥ 0.64), change-of-direction ability (all p < 0.05; d ≥ 0.66), RSSA (all parameters except the fatigue index p < 0.01; d ≥ 0.71), and dynamic balance (all p ≤ 0.05; d ≥ 0.50) improvement compared to the CG. Adding biweekly combined plyometric and short sprint training to standard training improves the athletic performance of youth male soccer players (under 15 (U15))., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Aloui, Hermassi, Bartels, Hayes, Bouhafs, Chelly and Schwesig.)