The 50 most-cited articles in Medicine & Science in Sports & Exercise, 2022

ABSTRACT: This consensus statement is an update of the 2010 American College of Sports Medicine position stand on exercise and type 2 diabetes. Since then, a substantial amount of research on select topics in exercise in individuals of various ages with type 2 diabetes has been published while diabetes prevalence has continued to expand worldwide. This consensus statement provides a brief summary of the current evidence and extends and updates the prior recommendations. The document has been expanded to include physical activity, a broader, more comprehensive definition of human movement than planned exercise, and reducing sedentary time. Various types of physical activity enhance health and glycemic management in people with type 2 diabetes, including flexibility and balance exercise, and the importance of each recommended type or mode are discussed. In general, the 2018 Physical Activity Guidelines for Americans apply to all individuals with type 2 diabetes, with a few exceptions and modifications. People with type 2 diabetes should engage in physical activity regularly and be…

Skeletal muscle plays a critical role in physical function and metabolic health. Muscle is a highly adaptable tissue that responds to resistance exercise (RE; loading) by hypertrophying, or during muscle disuse, RE mitigates muscle loss. Resistance exercise training (RET)-induced skeletal muscle hypertrophy is a product of external (e.g., RE programming, diet, some supplements) and internal variables (e.g., mechanotransduction, ribosomes, gene expression, satellite cells activity). RE is undeniably the most potent nonpharmacological external variable to stimulate the activation/suppression of internal variables linked to muscular hypertrophy or countering disuse-induced muscle loss. Here, we posit that despite considerable research on the impact of external variables on RET and hypertrophy, internal variables (i.e., inherent skeletal muscle biology) are dominant in regulating the extent of hypertrophy in response to external stimuli. Thus, identifying the key internal skeletal muscle-derived variables that mediate the translation of external RE variables will be pivotal to…

INTRODUCTION: The present randomized, single-center, and single-blinded clinical trial tested the hypothesis that tele-supervised home-based exercise training (exercise) is an effective strategy for improving cardiovascular, respiratory, and functional capacity parameters in individuals who were hospitalized due to coronavirus disease 2019 (COVID-19). METHODS: Thirty-two individuals (52 ± 10 yr; 17 were female) randomly assigned to exercise ( n = 12) or control groups ( n = 20) had their anthropometric (weight, body mass index), hemodynamic (brachial and central blood pressure), vascular (arterial stiffness), ventilatory (pulmonary function and respiratory muscle strength), and functional parameters (handgrip strength, five-time sit to stand, timed up and go test, and 6-min walking test) assessed at baseline (30-45 d of hospital discharged) and after 12 wk of follow-up. RESULTS: Both groups similarly increased ( P < 0.001) forced vital capacity (absolute and percent of predicted), forced expiratory volume in the first second (absolute and percent of predicted), and handgrip strength…

PURPOSE: This study aimed to determine if a preseason field-based test battery was prospectively associated with noncontact anterior cruciate ligament (ACL) injury in elite female footballers. METHODS: In total, 322 elite senior and junior female Australian Rules Football and soccer players had their isometric hip adductor and abductor strength, eccentric knee flexor strength, countermovement jump (CMJ) kinetics, and single-leg hop kinematics assessed during the 2019 preseason. Demographic and injury history details were also collected. Footballers were subsequently followed for 18 months for ACL injury. RESULTS: Fifteen noncontact ACL injuries occurred during the follow-up period. Prior ACL injury (odds ratio [OR], 9.68; 95% confidence interval (95% CI), 2.67-31.46), a lower isometric hip adductor to abductor strength ratio (OR, 1.98; 95% CI, 1.09-3.61), greater CMJ peak take-off force (OR, 1.74; 95% CI, 1.09-3.61), and greater single-leg triple vertical hop average dynamic knee valgus (OR, 1.97; 95% CI, 1.06-3.63) and ipsilateral trunk flexion (OR, 1.60; 95% CI, 1.01-2.55) were…

PURPOSE: We aimed to study variations in strength and power performance during the menstrual cycle (MC) in eumenorrheic young women and during the pill cycle in oral contraceptives (OC) users. METHODS: Forty healthy, normal-weight women between 18 and 35 yr (n = 30 eumenorrheic women; n = 10 OC users) completed this prospective cohort study. Seven to nine times during the MC/pill-cycle, the participants completed a physical performance test series, a questionnaire about psychological well-being, blood sampling, and determination of body mass. The physical tests included isometric handgrip strength, elbow flexor strength, countermovement jump (CMJ) height, and a 10-s Wingate bike test. RESULTS: No direct correlation was observed between the variations in sex hormones and physical performance parameters. However, positive correlations were observed between physical performance outcomes and self-reported motivation, perception of own physical performance level, pleasure level, and arousal level. CMJ was 6% lower in the late luteal phase (LL) compared with the midluteal phase (ML) (P =…

PURPOSE: This study aimed to assess the effects of 20 wk resistance exercise training with or without protein supplementation on body composition, muscle mass, muscle strength, physical performance, and aerobic capacity in prostate cancer patients receiving androgen deprivation therapy (ADT). METHODS: Sixty prostate cancer patients receiving ADT were randomly assigned to perform 20 wk of resistance exercise training with supplementation of 31 g whey protein (EX + PRO, n = 30) or placebo (EX + PLA, n = 30), consumed immediately after exercise and every night before sleep. A separate control group (CON, n = 36) only received usual care. At baseline and after 20 wk, body composition (dual-energy x-ray absorptiometry), muscle mass (computed tomography scan), muscle strength (1-repetition maximum strength tests), physical performance (Timed Up and Go Test, 30-Second Chair Stand Test, and Stair Climb Test), aerobic capacity (cardiopulmonary exercise test), and habitual dietary intake (food diary) were assessed. Data were analyzed using a two-factor repeated-measures ANOVA. RESULTS: Over…

The aim of the HERITAGE Family Study was to investigate individual differences in response to a standardized endurance exercise program, the role of familial aggregation, and the genetics of response levels of cardiorespiratory fitness and cardiovascular disease and diabetes risk factors. Here we summarize the findings and their potential implications for cardiometabolic health and cardiorespiratory fitness. It begins with overviews of background and planning, recruitment, testing and exercise program protocol, quality control measures, and other relevant organizational issues. A summary of findings is then provided on cardiorespiratory fitness, exercise hemodynamics, insulin and glucose metabolism, lipid and lipoprotein profiles, adiposity and abdominal visceral fat, blood levels of steroids and other hormones, markers of oxidative stress, skeletal muscle morphology and metabolic indicators, and resting metabolic rate. These summaries document the extent of the individual differences in response to a standardized and fully monitored endurance exercise program and document the…

PURPOSE: The aim of this study was to systematically review the literature on accelerometer-measured physical activity and health outcomes in adults. METHODS: Eight electronic databases were searched for relevant articles published up to March 2021. Only population-based studies of adults (age ≥18 yr) that directly compared two or more categories of physical activity (i.e., bout duration, intensity, and daily/weekly frequency) with a health outcome (e.g., mortality, cardiometabolic, healthy aging, depression, sleep, and brain structure) were included. RESULTS: Of the 15,923 publications retrieved, 52 articles were included. Twenty-eight studies directly compared the associations between physical activity accumulated in different bout durations, 31 studies directly compared the associations between physical activity accumulated in different intensities, and 9 studies directly compared the associations between the effects of varying daily and weekly frequencies of physical activity, with health outcomes. Most showed no differences in relationships with health outcomes when physical…

INTRODUCTION: The purpose of this systematic review and meta-analysis was to evaluate the effects of exercise on (i) the prevention of cancer-related lymphedema (CRL) and (ii) the treatment of CRL, lymphedema-associated symptoms, and other health outcomes among individuals with CRL. METHODS: An electronic search was undertaken for exercise studies measuring lymphedema and involving individuals at risk of developing or with CRL. The Effective Public Health Practice Project Quality scale was used to assess study quality, and overall quality of evidence was assessed using the Grading of Recommendation, Assessment, Development and Evaluation approach. Meta-analyses were performed to evaluate effects of exercise on CRL incidence, existing CRL status, lymphedema-associated symptoms, and health outcomes. RESULTS: Twelve studies ( n = 1955; 75% moderate-high quality) and 36 studies ( n = 1741; 58% moderate-high quality) were included in the prevention and treatment aim, respectively. Relative risk of developing CRL for those in the exercise group compared with the nonexercise group was 0.90…

INTRODUCTION: Plant-derived proteins have received considerable attention as an alternative to animal-based proteins and are now frequently used in both plant-based diets and sports nutrition products. However, little information is available on the anabolic properties of potato-derived protein. This study compares muscle protein synthesis rates after the ingestion of 30 g potato protein versus 30 g milk protein at rest and during recovery from a single bout of resistance exercise in healthy, young males. METHODS: In a randomized, double-blind, parallel-group design, 24 healthy young males (24 ± 4 yr) received primed continuous l -[ ring - 13 C 6 ]-phenylalanine infusions while ingesting 30 g potato-derived protein or 30 g milk protein after a single bout of unilateral resistance exercise. Blood and muscle biopsies were collected for 5 h after protein ingestion to assess postprandial plasma amino acid profiles and mixed muscle protein synthesis rates at rest and during recovery from exercise. RESULTS: Ingestion of both potato and milk protein increased mixed muscle protein synthesis…

The training of endurance athletes has been and remains a central topic of study in exercise physiology. The physiology of endurance athletes has been studied for many years (1). Their performance is widely understood in terms of the model of Joyner and Coyle (2), which integrates the sustained ability to produce ATP aerobically and convert muscular work to power/speed. Beyond the well-documented favorable effect of doing a larger volume of training, often exceeding 1000 h·yr−1 in some elite athletes, there is clear evidence of a historical trend toward more lower-intensity training and of a dose–response relationship between the training load and subsequent performance (3–6). Expressed simply, successful athletes attempt to optimize the adaptive effects (improved performance) while mitigating side effects (fatigue, injury, overreaching, overtraining syndrome) of their training regimes (7). Historical context High-volume training has been important for at least 200 yr, beginning with the era of “pedestrian competitions.” A decade-long debate persists regarding how other details of…

Aso-called polarized endurance training program is understood to mean one in which training is performed predominantly at a “low” intensity, with some training also done at a “high” intensity and with relatively little training at an intermediate (or “threshold”) intensity. It has been reported that polarized training is prevalent in elite endurance athletes (1–3), and a polarized training approach has been recommended as appropriate, or even optimal, for endurance athletes at all levels (4). Polarized training has gained traction with myriad magazine articles, blogs, podcasts, and websites presenting or promoting the concept, but has received surprisingly little scientific critique. In this article, we argue that polarized training is, in fact, rarely practiced by elite athletes, and there is limited to no evidence that it is more effective than other training models—on the contrary, there is evidence that contradicts the notion that polarized training is optimal. Hereinafter, we set out our key criticisms of the current fashion for polarized training. Inadequate definition of…

PURPOSE: The International Olympic Committee expert group on pregnancy has identified a paucity of information regarding training and performance in truly elite athletes. Thus, the purpose of this study was to quantify elite runners' training volume throughout pregnancy and postpartum competition performance outcomes. METHODS: Forty-two elite (>50% competed at the World Championships/Olympic) middle-/long-distance runners' training before, during, and after pregnancy (quality/quantity/type) data (retrospective questionnaire) and competition data (published online) were collected. RESULTS: Running volume decreased significantly ( P < 0.01) from the first trimester (63 ± 34 km·wk -1 ) to the third trimester (30 ± 30 km·wk -1 ). Participants returned to activity/exercise at ~6 wk postpartum and to 80% of prepregnancy training volumes by 3 months. Participants who intended to return to equivalent performance levels postpregnancy, there was no statistical decrease in performance in the 1 to 3 yr postpregnancy compared with prepregnancy, and ~56% improved performances postpregnancy.…

PURPOSE: This study aimed to investigate the effect of intensity and duration of continuous and interval exercise training on capillarization in skeletal muscle of healthy adults. METHODS: PubMed and Web of Science were searched from inception to June 2021. Eligibility criteria for studies were endurance exercise training >2 wk in healthy adults, and the capillary to fiber ratio (C:F) and/or capillary density (CD) reported. Meta-analyses were performed, and subsequent subgroup analyses were conducted by the characteristics of participants and training scheme. RESULTS: Fifty-seven trials from 38 studies were included (10%/90%, athletic/sedentary). C:F was measured in 391 subjects from 47 trials, whereas CD was measured in 428 subjects from 50 trials. Exercise training increased C:F (mean difference, 0.33 (95% confidence interval, 0.30-0.37)) with low heterogeneity ( I2 = 45.08%) and CD (mean difference, 49.8 (36.9-62.6) capillaries per millimeter squared) with moderate heterogeneity ( I2 = 68.82%). Compared with low-intensity training (<50% of maximal oxygen consumption (V̇O 2max )),…

INTRODUCTION: Loading rate (LR), the slope of the vertical ground reaction force (vGRF), is commonly used to assess running-related injury risk. However, the relationship between LR and running-related injuries, including bone stress injuries (BSI), is unclear. Inconsistent findings may result from the numerous LR calculation methods that exist and their application across different running speeds. PURPOSE: This study aimed to assess the influence of calculation method and running speed on LR values and to determine the association of LR during healthy running with subsequent injury. METHODS: Healthy preseason running data and subsequent injury records from Division I cross-country athletes ( n = 79) over four seasons (2015-2019) at 2.68 m·s -1 , preferred training pace, and 4.47 m·s -1 were collected. LR at each speed was calculated four ways: 1) maximum and 2) average slope from 20% to 80% of vGRF magnitude at impact peak (IP), 3) average slope from initial contact to IP, and 4) average slope from 3% to 12% of stance time. Linear mixed effects models and generalized estimation…

INTRODUCTION/PURPOSE: Physical activity may influence chronic disease risk, in part, through epigenetic mechanisms. Previous studies have demonstrated that an acute bout of physical activity can influence DNA methylation status. Few studies have explored the relationship between habitual, accelerometer-measured physical activity or sedentary time with epigenetic markers of aging. METHODS: We used linear regression to examine cross-sectional associations of accelerometer-measured physical activity and sedentary time with extrinsic and intrinsic epigenetic age acceleration (EEAA and IEAA) models and GrimAge measured from blood samples from Framingham Heart Study participants with accelerometry and DNA methylation data ( n = 2435; mean age, 54.9 ± 14.3; 46.0% men). Residuals of Hannum-, Horvath-, and GrimAge-predicted epigenetic age were calculated by regressing epigenetic age on chronological age. We took into account blood cell composition for EEAA, IEAA, and AdjGrimAge. Moderate to vigorous physical activity was log-transformed to normalize its distribution. Adjustment models…

PURPOSE: This study evaluated how extended match time (90 + 30 min) affected physiological responses and fatigue in male soccer players. METHODS: Twenty competitive players (mean ± SD: age, 20 ± 1 yr; maximal oxygen uptake, 59 ± 4 mL·min -1 ·kg -1 ) completed an experimental match with their activity pattern and heart rate assessed throughout the game, whereas countermovement jump performance and repeated sprint ability were tested and quadriceps muscle biopsies and venous blood samples were taken at baseline and after 90 and 120 min of match play. RESULTS: Less high-intensity running (12%) was performed in extra time in association with fewer intense accelerations and decelerations per minute compared with normal time. Peak sprint speed was 11% lower in extra time compared with normal time, and fatigue also manifested in impaired postmatch repeated sprint ability and countermovement jump performance (all P < 0.05). Muscle glycogen declined from 373 ± 59 mmol·kg -1 dry weight (dw) at baseline to 266 ± 64 mmol·kg -1 dw after 90 min, with a further decline to 186 ± 56 mmol·kg -1 dw…

PURPOSE: The aim of this audit was to assess the representation of female athletes within the literature that has led to current guidelines for carbohydrate (CHO) intake in the acute periods surrounding exercise and the quality of this research. METHODS: We conducted a standardized audit of research assessing CHO loading protocols, CHO mouth rinse, and CHO intake before, during, and after exercise. RESULTS: A total of 937 studies were identified in this audit. There were a total of 11,202 participants across these studies, with only ~11% being women. Most studies involved male-only cohorts (~79%), with a mere 38 studies (~4%) involving female-only cohorts and 14 studies (~2%) including a methodological design for comparison of sex-based responses. The frequent use of incorrect terminology surrounding menstrual status and the failure of most studies (~69%) to provide sufficient information on the menstrual status of participants suggests incomplete understanding and concern for female-specific considerations among researchers. Of the 197 studies that included women, only 13 (~7%)…

INTRODUCTION: Physical activity (PA) is recognized as one of the key lifestyle behaviors that reduces risk of developing dementia late in life. However, PA also leads to increased respiration, and in areas with high levels of air pollution, PA may increase exposure to pollutants linked with higher risk of developing dementia. Here, we investigate whether air pollution attenuates the association between PA and dementia risk. METHODS: This prospective cohort study included 35,562 adults 60 yrs and older from the UK Biobank. Average acceleration magnitude (ACCave) from wrist-worn accelerometers was used to assess PA levels. Air pollution levels (NO, NO2, PM10, PM2.5, PM2.5-10, and PM2.5 absorbance) were estimated with land use regression methods. Incident all-cause dementia was derived from inpatient hospital records and death registry data. RESULTS: In adjusted models, ACCave was associated with reduced risk of developing dementia (HR = 0.71, 95% confidence interval [CI] = 0.60-0.83), whereas air pollution variables were not associated with dementia risk. There were significant…

Medicine & Science in Sports & Exercise: May 2022 - Volume 54 - Issue 5 - p 886 doi: 10.1249/MSS.0000000000002910

PURPOSE: This study aimed to determine if durability can be predicted from laboratory measures in a professional cycling population. METHODS: Data were collected from 10 professional cyclists (age = 19.2 ± 0.8 yr, body mass = 70.4 ± 5.5 kg, height = 182.9 ± 4.0 cm, body mass index = 21.0 ± 1.3 kg·m -2 , V̇O 2max = 74.4 ± 4.8 mL·kg -1 ·min -1 , critical power [CP] = 5.6 ± 0.6 W·kg -1 , W' = 23.7 ± 5.4 kJ). Participants completed a laboratory test and a CP test on two occasions. The second occasion was preceded by a novel fatiguing protocol, which consisted of five bouts of 8-min of exercise at 105%-110% of CP. CP in a fatigued state was expressed as a percentage of the fresh CP and coined delta CP (∆CP). The Pearson product correlation analysis was conducted to determine the relationship between laboratory-based measures and ∆CP. RESULTS: Significant positive relationships were found between ∆CP and relative peak power output ( r = 0.891, P < 0.001), relative maximum oxygen uptake ( r = 0.835, P = 0.003), relative power output at the second ventilatory threshold ( r = 0.738, P =…

PURPOSE: We investigated the coupling between muscle glycogen content and localization and high-intensity exercise performance using a randomized, placebo-controlled, parallel-group design with emphasis on single-fiber subcellular glycogen concentrations and sarcoplasmic reticulum Ca 2+ kinetics. METHODS: Eighteen well-trained participants performed high-intensity intermittent glycogen-depleting exercise, followed by randomization to a high- (CHO; ~1 g CHO·kg -1 ·h -1 ; n = 9) or low-carbohydrate placebo diet (PLA, <0.1 g CHO·kg -1 ·h -1 ; n = 9) for a 5-h recovery period. At baseline, after exercise, and after the carbohydrate manipulation assessments of repeated sprint ability (5 × 6-s maximal cycling sprints with 24 s of rest), neuromuscular function and ratings of perceived exertion during standardized high-intensity cycling (~90% Wmax ) were performed, while muscle and blood samples were collected. RESULTS: The exercise and carbohydrate manipulations led to distinct muscle glycogen concentrations in CHO and PLA at the whole-muscle (291 ± 78 vs 175 ± 100 mmol·kg -1 dry weight…

INTRODUCTION: Performance fatigability is substantially greater when exercising in the severe- versus heavy-intensity domain. However, the relevance of the boundary between moderate- and heavy-intensity exercise, the gas exchange threshold (GET), to performance fatigability is unclear. This study compared alterations in neuromuscular function during work-matched exercise above and below the GET. METHODS: Seventeen male participants completed work-matched cycling for 90, 110, and 140 min at 110%, 90%, and 70% of the GET, respectively. Knee extensor isometric maximal voluntary contraction (MVC), high-frequency doublets (Db100), low- to high-frequency doublet ratio (Db10:100), and voluntary activation were measured at baseline, 25%, 50%, 75%, and 100% of task completion. During the initial baseline visit and after each constant work rate bout, ramp-incremental exercise was performed, and peak power output and oxygen uptake (V̇O 2peak ) were determined. RESULTS: After the 70% and 90% GET trials, similar reductions in MVC (-14% ± 6% and -14% ± 8%, respectively, P = 0.175) and Db100 (-7%…

PURPOSE AND METHODS: To test whether heat training performed as 5 × 50-min sessions per week for 5 wk in a heat chamber (CHAMBER) or while wearing a heat suit (SUIT), in temperate conditions, increases hemoglobin mass (Hb mass ) and endurance performance in elite cyclists, compared with a control group (CON-1). Furthermore, after the 5-wk intervention, we tested whether three sessions per week for 3 wk with heat suit (SUIT main ) would maintain Hb mass elevated compared with athletes who returned to normal training (HEAT stop ) or who continued to be the control group (CON-2). RESULTS: During the initial 5 wk, SUIT and CHAMBER increased Hb mass (2.6% and 2.4%) to a greater extent than CON-1 (-0.7%; both P < 0.01). The power output at 4 mmol·L -1 blood lactate and 1-min power output ( Wmax ) improved more in SUIT (3.6% and 7.3%, respectively) than CON-1 (-0.6%, P < 0.05; 0.2%, P < 0.01), whereas this was not the case for CHAMBER (1.4%, P = 0.24; 3.4%, P = 0.29). However, when SUIT and CHAMBER were pooled this revealed a greater improvement in a performance index (composed of power…

PURPOSE: This study aimed to examine the 12-month prevalence and 12-month prospective change in reported sexual harassment and abuse (SHA) victimization among young elite athletes, recreational athletes, and reference students in three different social settings and to identify the perpetrators. METHODS: In total, 919 adolescents responded to an online questionnaire in 12th grade (T1) and 13th grade (T2). The sample consisted of elite athletes ( n = 482) and recreational athletes ( n = 233) attending Norwegian elite sport high schools ( n = 26), and reference students ( n = 200) attending ordinary high schools with no sport specialization ( n = 6). Data were analyzed using independent-sample t -test, Pearson χ 2 for independence/Fisher's exact test, McNemar test, and logistic regression analysis. RESULTS: The total 12-month prevalence of SHA was 38.6% at T1 and 35.1% at T2. Most of the participants (74.6%-85.0%) reported no change in SHA from T1 to T2. The prevalence of SHA was higher for girls compared with boys, and elite athletes reported less SHA than recreational athletes and…

PURPOSE: This study aims to quantify heading exposure in real-life elite football at the level of individual male and female adolescents, young adults, and adults. METHODS: Heading exposure was determined by video analysis in combination with a structured electronic registration tool and observation training, to comprehensively register heading characteristics. Characteristics of heading events were registered in 116 official matches (96 male, 20 female) of Dutch national teams. RESULTS: Mean exposure for male players based on full match participation was 4.2 headers, with maximum heading exposure at 10.6 headers. Mean heading exposure was higher in adult than adolescent players ( P = 0.049), whereas maximum heading exposure was higher for adult than for young adult players ( P = 0.045). Maximum heading exposure was higher in male than in female players ( P = 0.015). Defenders had the greatest mean and maximum heading exposure ( P < 0.001). Longer flight courses of the ball had greater contribution to mean and maximum heading exposure than shorter courses ( P < 0.01). Frontal…

PURPOSE: This study aimed to investigate whether a reduction in daily sedentary behavior (SB) improves insulin sensitivity in adults with metabolic syndrome in 6 months, without adding intentional exercise training. METHODS: Sixty-four sedentary inactive middle-age adults with overweight and metabolic syndrome (mean (SD) age, 58 (7) yr; mean (SD) body mass index, 31.6 (4.3) kg·m -2 ; 27 men) were randomized into intervention and control groups. The 6-month individualized behavioral intervention supported by an interactive accelerometer and a mobile application aimed at reducing daily SB by 1 h compared with baseline. Insulin sensitivity by hyperinsulinemic euglycemic clamp, body composition by air displacement plethysmography, and fasting blood samples were analyzed before and after the intervention. SB and physical activity were measured with hip-worn accelerometers throughout the intervention. RESULTS: SB decreased by 40 (95% confidence interval, 17-65) min·d -1 , and moderate-to-vigorous physical activity increased by 20 (95% confidence interval, 11-28) min·d -1 on average in the…

PURPOSE: This study aimed to describe longitudinal trends in children's moderate-to-vigorous physical activity (MVPA) and to investigate associations with individual, familial, and school characteristics. METHODS: A sample of 341 Portuguese children age 5-10 yr (173 girls) from six age cohorts was followed over 3 yr using a mixed-longitudinal design. Physical activity, body mass index (BMI), gross motor coordination, and musculoskeletal fitness were assessed annually. Information on socioeconomic status and school characteristics was collected and analyzed with mixed models. RESULTS: MVPA shows a similar declining trend in both sexes, but on average, boys exceeded the World Health Organization recommendations of 60 min·d -1 . The best model showed that boys spend, on average, more time in MVPA than girls. Children with lower BMI are less prone to the decline in MVPA, whereas higher levels of musculoskeletal fitness were associated with lower declines in MVPA. Of all school characteristics, only playground dimension was related to MVPA decreasing trajectories. CONCLUSIONS: MVPA…

PURPOSE: Physical activity levels (PAL) are associated with mortality risk and were instrumental in estimating national energy requirements, but we are unaware of population-based estimates of PAL in US adults. Thus, we conducted a nationwide survey using a validated previous-day recall method to estimate PAL and the behavioral determinants of low and higher PAL. METHODS: Participants from the AmeriSpeak panel 20-75 yr of age ( N = 2640) completed Activities Completed over Time in 24-hours previous-day recalls. PAL values were estimated as the average metabolic equivalent value over 24 h. Recalls were conducted on randomly selected days in October and November 2019. Survey sample design weights were applied to reflect the US population. RESULTS: Mean age was 45.3 yr, 51% were female, 67% were non-Hispanic White, and 37% had a body mass index of ≥30 kg·m -2 . US adults reported a mean PAL of 1.63 (95% confidence interval, 1.60-1.65), and 39% (37%-42%) of adults reported PAL ≥1.6 on a given day. Men reported higher PAL than women (1.67 vs 1.59), and older adults reported lower PAL.…

PURPOSE: Quadriceps weakness is common after anterior cruciate ligament (ACL) reconstruction, resulting in prolonged disability and increased risk for reinjury and osteoarthritis. Functional resistance training (FRT) combines resistance training with task-specific training and may prove beneficial in restoring quadriceps strength. The primary purpose of this study was to determine if a walking-specific FRT program (e.g., resisted walking) improves knee strength in individuals after ACL reconstruction. METHODS: Thirty participants were randomized into one of three groups: 1) FRT with a customized knee BRACE applied to the ACL leg, 2) FRT with elastic BAND tethered to the ankle of the ACL leg, or 3) a TARGET MATCH condition where no resistance was externally applied. Participants in all groups received training while walking on a treadmill 2-3 times per week for 8 wk. Isometric knee extension and flexion strength were measured before the start of the intervention, after the intervention (POST), and 8 wk after intervention completion (POST-2). RESULTS: The BRACE group had greater knee…

PURPOSE: There is growing evidence that subsymptom threshold aerobic exercise speeds recovery from sport-related concussion (SRC). It is not known whether there is a direct relationship between adherence to a personalized exercise prescription and recovery or if initial symptom burden affects adherence to the prescription. METHODS: This study was a planned secondary analysis of one arm of a randomized controlled trial. Male and female adolescent athletes (age 13-18 yr) presenting within 10 d of SRC were given aerobic exercise prescriptions based on their heart rate threshold at the point of exercise intolerance on a graded treadmill test. Adherence was determined objectively with HR monitors and compared against time to recovery. Participants who completed at least two-thirds of their aerobic exercise prescription were considered to be adherent. RESULTS: Sixty-one percent of adolescents met the adherence criterion. Those who were adherent were more symptomatic and were more exercise intolerant at their initial visit, yet they recovered faster than those who were not adherent (median…

PURPOSE: This study aimed to test the hypothesis that a novel nutritional blend composed of tryptophan, glycine, magnesium, tart cherry powder, and l -theanine enhances subjective and objective measures of sleep during free living conditions. METHODS: In a randomized, repeated-measures crossover and double-blind deception design, participants ( n = 9 males and 7 females, age = 24 ± 3 yr, body mass = 69.8 ± 11.6 kg, stature = 170.8 ± 9.1 cm) completed a 3-d familiarization period, followed by 3-d intervention and placebo trials. Subjective Pittsburgh Quality Sleep Index, Core Consensus Sleep Diary, and Karolinska Sleepiness Scale survey tools, alongside objective actigraphy measures of sleep, were assessed, with daily nutritional intake, activity, and light exposure standardized between trials. Participants provided daily urine samples for assessment of targeted and untargeted metabolomes. RESULTS: The intervention trial reduced sleep onset latency (-24 ± 25 min; P = 0.002), increased total sleep time (22 ± 32 min; P = 0.01), and increased sleep efficiency (2.4% ± 3.9%; P = 0.03),…

PURPOSE: This study aimed to identify and characterize joint profiles of sedentary time and physical activity among adults and to investigate how these profiles are associated with markers of cardiometabolic health. METHODS: The participants included 3702 of the Northern Finland Birth Cohort 1966 at age 46 yr, who wore a hip-worn accelerometer during waking hours and provided seven consecutive days of valid data. Sedentary time, light-intensity physical activity, and moderate- to vigorous-intensity physical activity on each valid day were obtained, and a data-driven clustering approach ("KmL3D") was used to characterize distinct joint profiles of sedentary time and physical activity intensities. Participants self-reported their sleep duration and performed a submaximal step test with continuous heart rate measurement to estimate their cardiorespiratory fitness (peak heart rate). Linear regression was used to determine the association between joint profiles of sedentary time and physical activities with cardiometabolic health markers, including adiposity markers and blood lipid,…

INTRODUCTION: High-intensity interval training and sprint interval training significantly increase maximal oxygen uptake (V̇O 2max ), which enhances endurance performance and health status. Whether this response is due to increases in central cardiovascular function (cardiac output (CO) and blood volume) or peripheral factors is unknown. PURPOSE: This study aimed to conduct a systematic review and meta-analysis to assess the effects of high-intensity interval training and sprint interval training (referred to as intense interval training) on changes in central cardiovascular function. METHODS: We performed a systematic search of eight databases for studies denoting increases in V̇O 2max in which CO, stroke volume (SV), blood volume, plasma volume, end-diastolic/systolic volume, or hematocrit were measured. RESULTS: Forty-five studies were included in this analysis, comprising 946 men and women of various health status (age and V̇O 2max , 20-76 yr and 13-61 mL·kg -1 ·min -1 ) who performed 6-96 sessions of interval training. Results showed an increase in V̇O 2max with intense…

PURPOSE: Long-term development of endurance performance requires a proper balance between strain and recovery. Because responses and adaptations to training are highly individual, this study examined whether individually adjusted endurance training based on recovery and training status would lead to greater adaptations compared with a predefined program. METHODS: Recreational runners were divided into predefined (PD; n = 14) or individualized (IND; n = 16) training groups. In IND, the training load was decreased, maintained, or increased twice a week based on nocturnal heart rate variability, perceived recovery, and heart rate-running speed index. Both groups performed 3-wk preparatory, 6-wk volume, and 6-wk interval periods. Incremental treadmill tests and 10-km running tests were performed before the preparatory period ( T0 ) and after the preparatory ( T1 ), volume ( T2 ), and interval ( T3 ) periods. The magnitude of training adaptations was defined based on the coefficient of variation between T0 and T1 tests (high >2×, low <0.5×). RESULTS: Both groups improved ( P < 0.01)…

PURPOSE: This study investigates the effects of normobaric hypoxia on repeated sprint exercise (RSE) with different balance between oxidative (phosphocreatine and oxidative pathway) and glycolytic contributions. Therefore, performance and psychophysiological responses were compared during RSE to exhaustion with the same exercise-to-rest ratio (1:2) but different sprint durations (5, 10, or 20 s) either in normoxic (RSN) or hypoxic (RSH; F io2 = 0.13) conditions. METHODS: On separate visits, 10 active participants completed in random order three cycling RSN (5:10; 10:20 and 20:40) and three similar RSH sessions to exhaustion. Vastus lateralis muscle oxygenation was recorded by near-infrared spectroscopy. Blood lactate concentration, limb and breathing discomfort, and ratings of perceived exertion were measured. RESULTS: Total sprint number was smaller in hypoxia than in normoxia for 5:10 (20.8 ± 8.6 vs 14.7 ± 3.4; P = 0.014) and 10:20 (13.7 ± 6.3 vs 8.8 ± 2.5; P = 0.018) but not 20:40 (5.6 ± 1.9 vs 5.6 ± 2.5). The fatigue index was larger in hypoxia only for 5:10 (-43.5%, P < 0.001).…

PURPOSE: Greater articular cartilage T1ρ magnetic resonance imaging relaxation times indicate less proteoglycan density and are linked to posttraumatic osteoarthritis development after anterior cruciate ligament reconstruction (ACLR). Although changes in T1ρ relaxation times are associated with gait biomechanics, it is unclear if excessive or insufficient knee joint loading is linked to greater T1ρ relaxation times 12 months post-ACLR. The purpose of this study was to compare external knee adduction (KAM) and flexion (KFM) moments in individuals after ACLR with high versus low tibiofemoral T1ρ relaxation profiles and uninjured controls. METHODS: Gait biomechanics were collected in 26 uninjured controls (50% females; age, 22 ± 4 yr; body mass index, 23.9 ± 2.8 kg·m -2 ) and 26 individuals after ACLR (50% females; age, 22 ± 4 yr; body mass index, 24.2 ± 3.5 kg·m -2 ) at 6 and 12 months post-ACLR. ACLR-T1ρ High ( n = 9) and ACLR-T1ρ Low ( n = 17) groups were created based on 12-month post-ACLR T1ρ relaxation times using a k-means cluster analysis. Functional analyses of variance were…

PURPOSE: The purpose of this study was to examine the physiological responses resulting from an acute blood flow restriction resistance exercise bout with two different cuff pressures in young, healthy men and women. METHODS: Thirty adults (18-30 yr) completed a bilateral leg extension blood flow restriction bout consisting of four sets (30-15-15-15 repetitions), with cuffs applied at pressures corresponding to 40% and 60% of the minimum arterial occlusion pressure (AOP) needed to completely collapse the femoral arteries. During each of these conditions (40% and 60% AOP), physiological measures of near-infrared spectroscopy (NIRS) and EMG amplitude (EMG AMP) were collected from the dominant or nondominant vastus lateralis. After each set, ratings of perceived exertion (RPE) were collected, whereas only at baseline and at the end of the bout, mean arterial pressure (MAP) was assessed. Separate mixed-factorial ANOVA models were used to examine mean differences in the change in EMG AMP and NIRS parameters during each set. The absolute RPE and MAP values were also examined with separate…

PURPOSE: We investigated whether hepcidin and erythroferrone (ERFE) could complement the athlete biological passport (ABP) in indirectly detecting a 130-mL packed red blood cells (RBC) autologous blood transfusion. Endurance performance was evaluated. METHODS: Forty-eight healthy men ( n = 24) and women ( n = 24) participated. Baseline samples were collected weekly followed by randomization to a blood transfusion (BT, n = 24) or control group (CON, n = 24). Only the BT group donated 450 mL whole blood from which 130 mL red blood cell was reinfused 4 wk later. Blood samples were collected 3, 7, 14, 21, and 28 d after donation, and 3, 6, and 24 h and 2, 3, and 6 d after reinfusion. In the CON group samples were collected with the same frequency. Endurance performance was evaluated by a 650-kCal time trial ( n = 13) before and 1 and 6 d after reinfusion. RESULTS: A time-treatment effect existed ( P < 0.05) for hepcidin and ERFE. Hepcidin was increased ( P < 0.01) ~110 and 89% 6 and 24 h after reinfusion. Using an individual approach (99% specificity, e.g., allowing 1:100…

ABSTRACT Purpose Muscle anatomical cross-sectional area (ACSA) can be assessed using ultrasound and images are usually evaluated manually. Here, we present DeepACSA, a deep learning approach to automatically segment ACSA in panoramic ultrasound images of the human rectus femoris (RF), vastus lateralis (VL), gastrocnemius medialis (GM) and lateralis (GL) muscles. Methods We trained three muscle-specific convolutional neural networks (CNN) using 1772 ultrasound images from 153 participants (age = 38.2 yr, range = 13–78). Images were acquired in 10% increments from 30% to 70% of femur length for RF and VL and at 30% and 50% of muscle length for GM and GL. During training, CNN performance was evaluated using intersection-over-union scores. We compared the performance of DeepACSA to manual analysis and a semiautomated algorithm using an unseen test set. Results Comparing DeepACSA analysis of the RF to manual analysis with erroneous predictions removed (3.3%) resulted in intraclass correlation (ICC) of 0.989 (95% confidence interval = 0.983–0.992), mean difference of 0.20 cm 2…

PURPOSE: The aim of our study was to compare maximal force, force steadiness, and discharge characteristics of motor units in tibialis anterior during contractions with the dorsiflexors of the dominant and nondominant legs at low-to-moderate target forces and three ankle angles. METHODS: Twenty young adults performed maximal and submaximal isometric contractions (5%, 10%, 20%, 40%, and 60% of maximal voluntary contraction (MVC)) with the dorsiflexors of the dominant and nondominant legs at three ankle angles (75°, short length; 90°, intermediate length; 105°, long length). High-density EMG signals from the tibialis anterior muscle of each leg were recorded. RESULTS: Maximal force (average dominant, 182.9 ± 64.5 N; nondominant, 179.0 ± 58.8 N) and the fluctuations in force, quantified as absolute (SD) and normalized amplitudes (coefficient of variation (CoV)), were similar between the two legs across the three ankle angles (average CoV for dominant, 1.5% ± 1.0%; nondominant, 1.7% ± 1.3%). The CoV for force for both legs decreased from 5% to 20% MVC force, and then it plateaued at 40%…

PURPOSE: This study aimed to evaluate a 10-month neuromuscular training (NMT) intervention on isometric and dynamic kinetics, standing long jump (SLJ) distance, speed, and sport-specific performance. METHODS: Forty-three prepubertal female gymnasts were allocated into either a gymnastics + NMT (gNMT; n = 16), gymnastics only (GYM, n = 15), or maturity-matched control (CON; n = 12) group. The gNMT followed a 10-month, twice-weekly NMT program that targeted movement competency, strength, power, and speed. Vaulting vertical take-off velocity, speed, SLJ distance, and kinetics during an isometric mid-thigh pull (IMTP), countermovement jump (CMJ), and drop jump (DJ) were measured at baseline and thereafter at 4, 7, and 10 months. Within-group differences were calculated using 3 × 4 repeated-measures ANCOVA. RESULTS: Interaction effects were observed for SLJ distance and various IMTP, DJ, and vaulting variables. The gNMT showed significant improvements in IMTP absolute force and SLJ distance after 4 months and each subsequent testing session. IMTP relative force and various CMJ and DJ…

PURPOSE: Joint deafferentation after post-ankle sprain ligament healing can disrupt sensory input from the ankle and induce maladaptive neuroplasticity, especially in the cerebellum. This study aimed to determine whether the regional homogeneity of intrinsic cerebellar activity differs between patients with ankle instability and healthy controls without a history of ankle injury. METHODS: The current study used a primary data set of 18 patients and 22 healthy controls and an external UK Biobank data set of 16 patients with ankle instability and 69 healthy controls for a cross-database, cross-sectional investigation. All participants underwent resting-state functional magnetic resonance imaging to calculate their regional homogeneity (ReHo) value. Between-group comparisons of the sensorimotor-related subregions of the cerebellum were first performed in the primary data set to identify low cerebellar ReHo in patients with multiple comparison corrections, and the surviving subregions were then externally validated in the UK Biobank data set. Correlation analyses between the ReHo values…

PURPOSE: The aim of this study was to examine the cross-sectional and longitudinal associations of 24-h movement behaviors (sleep, sedentary behavior (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA)) with body composition and cardiometabolic health in i) early and ii) late pregnancy (gestational weeks 14 and 37). METHODS: This observational study utilized cross-sectional ( n = 273) and longitudinal data ( n = 242) from the HealthyMoms trial. Time spent in movement behaviors over seven consecutive 24-h periods (ActiGraph wGT3x-BT accelerometer), body composition (Bod Pod), and cardiometabolic health indicators (glucose levels, homeostatic model for insulin resistance (HOMA-IR), systolic and diastolic blood pressure, metabolic syndrome (MetS) score) were measured in early and late pregnancy. RESULTS: In early pregnancy, reallocating time to MVPA from LPA, SB, and sleep was associated with lower MetS score (adjusted γ = -0.343, P = 0.002). Correspondingly, reallocating time to LPA from SB and sleep in early pregnancy was associated with lower body…

PURPOSE: In the present study, we tested the hypothesis that caffeine would increase endurance performance via attenuation of neural and muscular determinants of performance fatigability during high-intensity, whole-body exercise. METHODS: Ten healthy males cycled until exhaustion (89% ± 2% of V̇O2max) after the ingestion of caffeine or placebo. During another four visits, the same exercise was performed after either caffeine or placebo ingestion but with exercise discontinued after completing either 50% or 75% of the duration of placebo trial. An additional trial with caffeine ingestion was also performed with interruption at the placebo time to exhaustion (isotime). Performance fatigability was measured via changes in maximal voluntary contraction, whereas neural and muscular determinants of performance fatigability were quantified via preexercise to postexercise decrease in quadriceps voluntary activation (VA) and potentiated twitch force, respectively. RESULTS: Compared with the placebo, caffeine increased time to exhaustion (+14.4 ± 1.6%, P = 0.017, 314.4 ± 47.9 vs 354.9 ± 40.8…

INTRODUCTION: This study characterized a sample of the first women to complete elite United States (US) military training. METHODS: Twelve female graduates of the US Army Ranger Course and one of the first Marine Corps Infantry Officers Course graduates participated in 3 d of laboratory testing including serum endocrine profiles, aerobic capacity, standing broad jump, common soldiering tasks, Army Combat Fitness Test, and body composition (dual-energy x-ray absorptiometry, three-dimensional body surface scans, and anthropometry). RESULTS: The women were 6 months to 4 yr postcourse graduation, 30 ± 6 yr (mean ± SD); height, 1.67 ± 0.07 m; body mass, 69.4 ± 8.2 kg; body mass index, 25.0 ± 2.3 kg·m -2 . Dual-energy x-ray absorptiometry relative fat was 20.0% ± 2.0%; fat-free mass, 53.0 ± 5.9 kg; fat-free mass index, 20.0 ± 1.7 kg·m -2 ; bone mineral content, 2.75 ± 0.28 kg; bone mineral density, 1.24 ± 0.07 g·cm -2 ; aerobic capacity, 48.2 ± 4.8 mL·kg -1 ·min -1 ; total Army Combat Fitness Test score 505 ± 27; standing broad jump 2.0 ± 0.2 m; 123 kg casualty drag 0.70 ± 0.20 m·s -1 ,…

ABSTRACT Introduction Individual differences in brain structure and function in older adults are potential proxies of brain reserve or maintenance and may provide mechanistic predictions of adherence to exercise. We hypothesized that multimodal neuroimaging features would predict adherence to a 6-month randomized controlled trial of exercise in 131 older adults (age, 65.79 ± 4.65 yr, 63% female), alone and in combination with psychosocial, cognitive, and health measures. Methods Regularized elastic net regression within a nested cross-validation framework was applied to predict adherence to the intervention in three separate models (brain structure and function only; psychosocial, health, and demographic data only; and a multimodal model). Results Higher cortical thickness in somatosensory and inferior frontal regions and less surface area in primary visual and inferior frontal regions predicted adherence. Higher nodal functional connectivity (degree count) in default, frontoparietal, and attentional networks and less nodal strength in primary visual and temporoparietal networks…

PURPOSE: The hamstrings (HS) muscle group plays a fundamental role in maintaining knee stability, thus contributing to the prevention and rehabilitation of lower limb musculoskeletal injuries. However, little is known about HS structural and functional adaptations after periods of prolonged inactivity. Our purpose was to investigate the HS morphological and contractile properties changes during 10 d of bed rest (BR). METHODS: Ten young healthy males underwent a 10-d BR. HS cross-sectional area (CSA) (at 30%, 50%, and 70% of femur length) and biceps femoris long head (BFlh) architecture were assessed by ultrasound imaging after 0 d (BR0), 2 d (BR2), 4 d (BR4), 6 d (BR6), and 10 d (BR10) of BR, whereas BFlh contractile properties (radial twitch displacement [Dm] and contraction time [Tc]) were evaluated at the same time points by tensiomyography. HS muscle volume was assessed by magnetic resonance imaging at BR0 and BR10. RESULTS: A reduction in muscle volume was observed in BFlh ( P = 0.002; Δ = -3.53%), biceps femoris short head ( P = 0.002; Δ = -3.54%), semitendinosus ( P = 0.002;…

INTRODUCTION: Running and cycling represent two of the most common forms of endurance exercise. However, a direct comparison of the neuromuscular consequences of these two modalities after prolonged exercise has never been made. The aim of this study was to compare the alterations in neuromuscular function induced by matched-intensity and duration cycling and running exercise. METHODS: During separate visits, 17 endurance-trained male participants performed 3 h of cycling and running at 105% of the gas exchange threshold. Neuromuscular assessments were taken are preexercise, midexercise, and postexercise, including knee extensor maximal voluntary contractions (MVC), voluntary activation (VA), high- and low-frequency doublets (Db100 and Db10, respectively), potentiated twitches (Qtw,pot), motor evoked potentials (MEP), and thoracic motor evoked potentials (TMEP). RESULTS: After exercise, MVC was similarly reduced by ~25% after both running and cycling. However, reductions in VA were greater after running (-16% ± 10%) than cycling (-10% ± 5%; P < 0.05). Similarly, reductions in TMEP…

PURPOSE: This study aimed to investigate hamstring architectural, strength, and morphological adaptations after an eccentric or isometric hip extension exercise intervention. METHODS: Twenty-four recreationally active males performed either an eccentric ( n = 12) or an isometric hip extension ( n = 12) exercise intervention, twice per week for 6 wk, followed by a 4-wk detraining period. Biceps femoris long head (BFlh) architecture was assessed pre-intervention, mid-intervention, post-intervention, and post-detraining via two-dimensional ultrasound. Strength was assessed pre-intervention, post-intervention, and post-detraining during an isokinetic knee flexion, an isometric hip extension, a Nordic hamstring exercise, and a single-leg hamstring bridge repetition to fatigue test. Hamstring muscle morphology was assessed via magnetic resonance imaging before strength testing sessions. RESULTS: The eccentric hip extension exercise intervention significantly lengthened BFlh fascicles (+19.7%, P < 0.001, d = 1.57), increased eccentric knee flexion torque (ECC 60°·s -1 , +12%, P < 0.005, d…