Neural and muscular contributions to the age-related differences in peak power of the knee extensors in men and women.

The mechanisms for the loss in limb muscle power output in old (60-79 yr) and very old (≥80 yr) adults and whether the mechanisms differ between men and women are not well understood. We compared maximal peak power of the knee extensor muscles between young, old, and very old men and women and identified the neural and muscular factors contributing to the age-related differences in power. Thirty-one young (22.9 ± 3.0 yr, 15 women), 82 old (70.3 ± 4.9 yr, 38 women), and 16 very old adults (85.8 ± 4.2 yr, 9 women) performed maximal isokinetic contractions at 14 different velocities (30-450°/s) to identify peak power. Voluntary activation (VA) and contractile properties were assessed with transcranial magnetic stimulation to the motor cortex and electrical stimulation of the femoral nerve. The age-related loss in peak power was ∼6.5 W·yr-1 for men (R2 = 0.62, P < 0.001), which was a greater rate of decline (P = 0.002) than the ∼4.2 W·yr-1 for women (R2 = 0.77, P < 0.001). Contractile properties were the most closely associated variables with peak power for both sexes, such as the rate of torque development of the potentiated twitch (men: R2 = 0.69, P < 0.001; women: R2 = 0.57, P < 0.001). VA was weakly associated with power in women (R2 = 0.13, P = 0.012) but not in men (P = 0.191). Similarly, neuromuscular activation [rates of electromyography (EMG) rise] during the maximal power contraction was associated with power in women (R2 = 0.07, P = 0.042) but not in men (P = 0.456). These data suggest that the age-related differences in maximal peak power of the knee extensor muscles are due primarily to factors within the muscle for both sexes, although neural factors may play a minor role in older women.NEW & NOTEWORTHY The greater age-related loss in power relative to the loss in muscle mass of the knee extensors was primarily due to factors altering the contractile properties of the muscle for both old and very old (≥80 yr) adults. The mechanisms for the decrements in power with aging appear largely similar for men and women, although neural factors may play more of a role in older women.

Sex differences in human performance.

Sex as a biological variable is an underappreciated aspect of biomedical research, with its importance emerging in more recent years. This review assesses the current understanding of sex differences in human physical performance. Males outperform females in many physical capacities because they are faster, stronger and more powerful, particularly after male puberty. This review highlights key sex differences in physiological and anatomical systems (generally conferred via sex steroids and puberty) that contribute to these sex differences in human physical performance. Specifically, we address the effects of the primary sex steroids that affect human physical development, discuss insight gained from an observational study of 'real-world data' and elite athletes, and highlight the key physiological mechanisms that contribute to sex differences in several aspects of physical performance. Physiological mechanisms discussed include those for the varying magnitude of the sex differences in performance involving: (1) absolute muscular strength and power; (2) fatigability of limb muscles as a measure of relative performance; and (3) maximal aerobic power and endurance. The profound sex-based differences in human performance involving strength, power, speed and endurance, and that are largely attributable to the direct and indirect effects of sex-steroid hormones, sex chromosomes and epigenetics, provide a scientific rationale and framework for policy decisions on sex-based categories in sports during puberty and adulthood. Finally, we highlight the sex bias and problem in human performance research of insufficient studies and information on females across many areas of biology and physiology, creating knowledge gaps and opportunities for high-impact studies.

Midlife health crisis of former competitive athletes: dissecting their experiences via qualitative study.

Sports participation confers many health benefits yet greatly increases injury risk. Long-term health outcomes in former athletes and transition to life after competitive sports are understudied. Ending a sport may pose physical and psychosocial challenges. The purpose was to determine the lived experiences of former competitive athletes and how their sports participation impacted their long-term health and well-being. Former college varsity athletes participated in semistructured interviews focusing on their experiences, including past and current health, the impact of injuries, activity, exercise, diet and transition to life after competitive sport. Thematic analysis was completed using a collaborative, iterative process. Thirty-one (16 female, 15 male) former college athletes aged 51.3±7.4 years were interviewed. Six themes emerged: (1) lifelong athlete identity; (2) structure, support and challenges of the college athlete experience; (3) a big transition to life beyond competitive sport; (4) impact of competitive sport on long-term health; (5) facilitators and barriers to long-term health after sport and (6) transferable life skills. Continuing sports eased the transition for many but often delayed their postathlete void. Challenges included managing pain and prior injury (eg, If I didn't have my knee injury, I would definitely be more active), reducing energy needs and intake (eg, When I was an athlete, I could eat anything; and unfortunately, that's carried into my regular life), lack of accountability, changed identity and lost resources and social support. Participants suggested a programme, toolkit, mentoring or exit course to facilitate the transition. While former athletes benefit from transferrable life skills and often continue sports and exercise, they face unique challenges such as managing pain and prior injury, staying active, reducing energy intake and changing identity. Future research should develop and evaluate a toolkit, programme and other resources to facilitate life after ending competitive sports under 'normal' conditions (eg, retirement) and after a career-ending injury.

Hormonal Basis of Biological Sex Differences in Human Athletic Performance.

Biological sex is a primary determinant of athletic human performance involving strength, power, speed, and aerobic endurance and is more predictive of athletic performance than gender. This perspective article highlights 3 key medical and physiological insights related to recent evolving research into the sex differences in human physical performance: (1) sex and gender are not the same; (2) males and females exhibit profound differences in physical performance with males outperforming females in events and sports involving strength, power, speed, and aerobic endurance; (3) endogenous testosterone underpins sex differences in human physical performance with questions remaining on the roles of minipuberty in the sex differences in performance in prepubescent youth and the presence of the Y chromosome (SRY gene expression) in males, on athletic performance across all ages. Last, females are underrepresented as participants in biomedical research, which has led to a historical dearth of information on the mechanisms for sex differences in human physical performance and the capabilities of the female body. Collectively, greater effort and resources are needed to address the hormonal mechanisms for biological sex differences in human athletic performance before and after puberty.

Influence of visual feedback and cognitive challenge on the age-related changes in force steadiness.

Force steadiness can be influenced by visual feedback as well as presence of a cognitive tasks and potentially differs with age and sex. This study determined the impact of altered visual feedback on force steadiness in the presence of a difficult cognitive challenge in young and older men and women. Forty-nine young (19-30 yr; 25 women, 24 men) and 25 older (60-85 yr; 15 women; 10 men) performed low force (5% of maximum) static contractions with the elbow flexor muscles in the presence and absence of a cognitive challenge (counting backwards by 13) either with low or high visual feedback gain. The cognitive challenge reduced force steadiness (increased force fluctuation amplitude) particularly in women (cognitive challenge × sex: P < 0.05) and older individuals (cognitive challenge × age: P < 0.05). Force steadiness improved with high-gain visual feedback compared with low-gain visual feedback (P < 0.01) for all groups (all interactions: P > 0.05). Manipulation of visual feedback had no influence on the reduced force steadiness in presence of the cognitive challenge for all groups (all P > 0.05). These findings indicate that older individuals and women have greater risk of impaired motor performance of the upper extremity if steadiness is required during a low-force static contraction. Manipulation of visual feedback had minimal effects on the reduced force steadiness in presence of a difficult cognitive challenge.

Sex Differences in Track and Field Elite Youth.

PURPOSE: To understand athletic performance before and after puberty, this study determined 1) the age at which the sex difference increases among elite youth track and field athletes for running and jumping events, and 2) whether there is a sex difference in performance before ages associated with puberty among elite youth athletes. METHODS: Track and field records of elite US male and female youth (7-18 yr) across 3 yr (2019, 2021, and 2022) were collected from an online database ( athletic.net ). The top 50 performances were recorded for 100-, 200-, 400-, and 800-m track running, long jump, and high jump. RESULTS: Males ran faster than females at every age in the 100, 200, 400 and 800 m ( P < 0.001). When combining all running events, the sex difference (%) was 4.0% ± 1.7% between 7 and 12 yr and increased to 6.3% ± 1.1% at 13 yr and 12.6% ± 1.8% at 18 yr ( P < 0.001). Similarly, males jumped higher and farther than females at every age ( P < 0.001). For long jump, the sex difference was 6.8% ± 2.8% between 7 and 12 yr, increasing to 8.5% ± 1.7% at 13 yr and 22.7% ± 1.4% at 18 yr ( P < 0.001). For high jump, the sex difference was 5.3% ± 5.2% between 7 and 12 yr, increasing to 12.4% ± 2.9% at 15 yr and 18.4% ± 2.04% at 18 yr ( P < 0.001). CONCLUSIONS: Before 12 yr of age in elite youth track and field athletes, there was a consistent and significant sex difference of ~5%, such that males ran faster and jumped higher and farther than females. The magnitude of the sex difference in performance increased markedly at 12-13 yr for running and long jump and 14 yr for high jump and thus was more pronounced after ages associated with puberty.

Edward F. Adolph Distinguished Lecture. Age and sex differences in the limits of human performance: fatigability and real-world data.

High-level athletic performances may be a proxy for the trajectory of optimal function of human biology with advanced aging and the differences between males and females. Males are faster, stronger, and more powerful than females and these physical attributes decline dramatically with advanced aging for both sexes. Experimental mechanistic studies determine the physiological mechanisms for these sex and age differences in human physical performance. The assumption however, that real-world performances solely reflect the biological and physiological differences between the sexes and with advanced aging, even among elite athletes, is not complete. This review presents evidence that an integrated approach encompassing analysis of real-world data and experimental mechanistic studies is necessary to determine the biological and sociocultural factors attributed to the limits of performance with aging and between males and females. First, experimental studies are presented that focus on the sex and age differences in performance fatigability that determine the physiological mechanisms of absolute and relative exercise performance. Second, analysis of current and historical real-world data including world records, and performances of elite, collegiate, and competitive age-group athletes are highlighted. These data illustrate that the upper limits of physical performance that have changed historically, and other factors such as sociocultural influences, explain the widening of the sex and age gaps in human performance observed in real-world data even in present-day performances. These approaches have broader significance when applied to understanding the impact of the historically low representation of females and minority groups in biomedical research on health outcomes.

Heart rate variability is reduced in COVID-19 survivors and associated with physical activity and fatigue.

Reduced heart rate variability (HRV) and fatigue are common after COVID-19 infection and both are potentially influenced by physical activity (PA). We compared resting HRV, PA from accelerometers and questionnaires, and self-reported fatigue in 41 COVID-19 survivors (~8 months postinfection, 38 ± 17 years) with 41 matched controls. Differences in HRV were observed on acceleration capacity (p = 0.041), deceleration capacity (p = 0.032), high-frequency peak frequency (p = 0.019), absolute low-frequency power (p = 0.042), relative very low-frequency power (p = 0.012), SD2 (from Poincare plot; p = 0.047), and DFA2 (slope of long-term detrended fluctuation analysis; p = 0.004). Fatigue was greater in COVID-19 survivors (p < 0.001) with no differences in PA. Moderate-vigorous physical activity (MVPA) (Standardized Beta = -0.427, p = 0.003) and steps per day (Standardized Beta = -0.402, p = 0.007) were associated with DFA2 in COVID-19 survivors after controlling for age, sex, and body fat percentage. Fatigue was correlated to less MVPA (Spearman's rho = 0.342, p = 0.031) and fewer steps per day (rho = 0.329, p = 0.038) in COVID-19 survivors, and was indirectly linked to HRV through these PA mediators (Estimate = -0.20; p = 0.040). We present a model showing the complex relations between HRV, PA, and fatigue that provides the foundation for strategies to improve outcomes and rehabilitation after COVID-19 infection.

Long-term function, body composition and cardiometabolic health in midlife former athletes: a scoping review.

While sports medicine has traditionally focused on recovering from injury and returning athletes to sport safely after injury, there is a growing interest in the long-term health of athletes. The purpose of this scoping review was to (1) summarise the literature (methodologies and findings) on physical function, body composition and cardiometabolic health in midlife (age 40-65 years) former competitive athletes compared with non-athlete controls, (2) identify areas for future study in long-term health in athletes and (3) determine outcomes that could be evaluated in a future systematic review(s). We searched PubMed, CINAHL, Web of Science and SPORTDiscus for studies published between 2000 and 2022 evaluating former athletes and controls on physical function, body composition and/or cardiometabolic measures using MeSH terms. We identified 20 articles that met our criteria. Outcomes varied considerably across studies, most of which were cross-sectional and evaluated only males. Limited data suggest that former endurance athletes have leaner body compositions, higher aerobic capacity and better cardiometabolic indicators than controls; former athletes who maintain higher physical activity (ie, self-reported exercise) are healthier than those who do not; and former team sport athletes, who have higher injury prevalence, may have poorer functional performance than controls who were recreationally active in college. Studies rarely evaluated functional performance, did not control for prior injury or diet and seldom assessed current physical activity levels. Future research should include females and evaluate sex differences, control for prior sports-related injury(ies), quantify physical activity, use standardised outcome measures including performance-based functional assessments and incorporate longitudinal designs.

Neural and muscular contributions to the age-related loss in power of the knee extensors in men and women.

The mechanisms for the loss in limb muscle power in old (60-79 years) and very old (≥80 years) adults and whether the mechanisms differ between men and women are not well-understood. We compared maximal power of the knee extensor muscles between young, old, and very old men and women and identified the neural and muscular factors contributing to the age-related loss of power. 31 young (22.9±3.0 years, 15 women), 83 old (70.4±4.9 years, 39 women), and 16 very old adults (85.8±4.2 years, 9 women) performed maximal isokinetic contractions at 14 different velocities (30-450°/s) to identify peak power. Voluntary activation (VA) and contractile properties were assessed with transcranial magnetic stimulation to the motor cortex and electrical stimulation of the femoral nerve. The age-related loss in power was ~6.5 W·year-1 for men (R2=0.62, p<0.001), which was a greater rate of decline (p=0.002) than the ~4.2 W·year-1 for women (R2=0.77, p<0.001). Contractile properties were the most closely associated variables with power output for both sexes, such as the rate of torque development of the potentiated twitch (men: R2=0.69, p<0.001; women: R2=0.57, p<0.001). VA was weakly associated with power in women (R2=0.13, p=0.012) but not men (p=0.191), whereas neuromuscular activation (EMG amplitude) during the maximal power contraction was not associated with power in men (p=0.347) or women (p=0.106). These data suggest that the age-related loss in power of the knee extensor muscles is due primarily to factors within the muscle for both sexes, although neural factors may play a minor role in older women.

The Biological Basis of Sex Differences in Athletic Performance: Consensus Statement for the American College of Sports Medicine.

ABSTRACT: Biological sex is a primary determinant of athletic performance because of fundamental sex differences in anatomy and physiology dictated by sex chromosomes and sex hormones. Adult men are typically stronger, more powerful, and faster than women of similar age and training status. Thus, for athletic events and sports relying on endurance, muscle strength, speed, and power, males typically outperform females by 10%-30% depending on the requirements of the event. These sex differences in performance emerge with the onset of puberty and coincide with the increase in endogenous sex steroid hormones, in particular testosterone in males, which increases 30-fold by adulthood, but remains low in females. The primary goal of this consensus statement is to provide the latest scientific knowledge and mechanisms for the sex differences in athletic performance. This review highlights the differences in anatomy and physiology between males and females that are primary determinants of the sex differences in athletic performance and in response to exercise training, and the role of sex steroid hormones (particularly testosterone and estradiol). We also identify historical and nonphysiological factors that influence the sex differences in performance. Finally, we identify gaps in the knowledge of sex differences in athletic performance and the underlying mechanisms, providing substantial opportunities for high-impact studies. A major step toward closing the knowledge gap is to include more and equitable numbers of women to that of men in mechanistic studies that determine any of the sex differences in response to an acute bout of exercise, exercise training, and athletic performance.

Lived experiences of American adults who survive COVID-19: Implications for physical activity and interpersonal stress.

INTRODUCTION: The cumulative number of COVID-19 cases has surpassed 579 million globally. Symptoms during and after COVID-19 infection vary from mild cold symptoms to severe multisystem illness. Given the wide range of symptom presentations and complications post-COVID-19, the purpose of this study was to describe the lived experience of American adults surviving COVID-19. METHOD: This study employed an exploratory qualitative description design. Semi-structured interviews were conducted with a sample of 35 individuals (White [94%], female [71%], Mage = 43.7 years), with proximity to a university in an urban Midwest American city. Interviews occurred between May and August 2021, 3 or more months after participants tested positive for COVID-19. RESULTS: Forty percent of the 35 participants experienced prolonged COVID-19 symptoms impacting their lifestyle. Four themes characterized the impacts of the post-COVID-19 condition on the lives of the participants within the context of a global pandemic: (a) disruptions in health and well-being, (b) persistent uncertainty, (c) disruptions in interpersonal relationships, (d) beneficent outcomes and adaptation. DISCUSSION: This study of COVID-19 has identified important implications for physical activity and interpersonal stress. Prolonged COVID-19 symptoms led to disruptions in the health, well-being, and interpersonal relationships of participants. Health care professionals need to attend to symptoms post-COVID-19, assess interpersonal functioning, and provide guidance on physical activity. Future studies are recommended to track consequences of COVID-19's impact on long-term health and well-being. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Underrepresentation of women in exercise science and physiology research is associated with authorship gender.

Historically, low representation of women participants in exercise science and physiology studies has led to a lack of understanding in the response of women to exercise and therapeutic interventions. We hypothesized that 1) the number of women authors, participants, and editorial board members increased over 30 years (1991-2021) and 2) larger representation of women as editors and authors is associated with more women participants. Gender (man/woman) of editorial board members (n = 394), authors (n = 5,735), and participants (n = 2,984,883) of 972 original research articles with human participants published in 1991 and 2021 was analyzed from three journals: Journal of Applied Physiology, Medicine and Science in Sports and Exercise, and British Journal of Sports Medicine. Between 1991 to 2021, the average percent women per article as participants (21.9 ± 31.7% vs. 36.3 ± 30.3%, respectively, P < 0.001), authors (16.4 ± 22.4% vs. 30.9 ± 24.0%, P < 0.001), and editorial board members (13.3 ± 5.4% vs. 41.5 ± 7.3%, P = 0.006) increased. In 2021, the gender proportion of participants in large datasets was similar (50.2 ± 20.2% women). However, studies with smaller datasets (i.e., <∼3,000 participants) included less women (35.6 ± 30.6%). Women participants (%) were less when the last author was a man rather than a woman in 1991 (19.9 ± 29.5% vs. 34.3 ± 42.2%) and 2021 (31.6 ± 27.7% vs. 51.7 ± 33.4%). In 2021, there was a positive correlation between author and participant gender (% women) (r = 0.42, P < 0.001). Our data suggest that the low representation of women in exercise science and physiology research could be resolved with equitable numbers of women authors and editors and by encouraging men authors to study both women and men participants.NEW & NOTEWORTHY Analysis of human applied physiology studies revealed that the representation of women authors, participants, and editorial board members increased over 30 years but remained lower than men in 2021. Larger representation of women editors and authors was associated with more women participants. Women authors assessed similar numbers of women and men participants, whereas men authors included less women. Equitable representation of women participants may be achieved by closing the gender gap in authorship and editorial board membership.

Sex differences in fatigability and recovery following a 5†km running time trial in recreationally active adults.

ABSTRACTFemales demonstrate greater fatigue resistance compared to males in tasks ranging from single-limb contractions to whole-body exercise, including running. Many of the studies investigating sex differences in fatigability following running, however, occur after long duration, low-intensity tasks and it is unknown whether there is a sex difference in fatigability following high-intensity running. This study compared fatigability and recovery following a 5 km running time trial in young males and females. Sixteen recreationally active participants (8 males, 8 females, age: 23 ± 4 years) completed a familiarisation and experimental trial. Knee-extensor maximal voluntary contractions (MVCs) were performed before and up to 30 min after a 5 km time trial on a treadmill. Heart rate and rating of perceived exertion (RPE) were recorded after every kilometre during the time trial. Although not significantly different, males completed the 5 km time trial 15% faster than females (p = 0.095). Heart rate (p = 0.843) and RPE (p = 0.784) were similar between the sexes during the trial. Prior to running, males had larger MVCs (p = 0.014). The relative decrease in MVC force was less in females than males immediately post-exercise (-4.6 ± 2.4% vs. -15.1 ± 3.0%, p < 0.001) and at 10-minutes post-exercise (p = 0.018). At 20- and 30-minutes recovery, however, relative MVC force was not different between the sexes (p ≥ 0.129). These data demonstrate that females experienced less fatigability of the knee extensors than males following a high-intensity 5 km running time trial. The findings highlight the need to understand responses to exercise in both sexes and have implications for recovery from training and exercise prescription.Highlights Data regarding sex differences in fatigability following high-intensity running is relatively sparse.Therefore, this study quantified the decrease in knee-extensor maximum voluntary contraction force (MVC) following a 5-km self-paced running time trial.Despite similar heart rates and ratings of perceived exertion, the percentage decrease in MVC was three times greater in males compared to females.Relative MVCs remained greater in females compared to males until 20 min post-exercise.

Cognitive challenge as a probe to expose sex- and age-related differences during static contractions.

Despite activities of daily living being frequently performed simultaneously with a cognitive task, motor function is often investigated in isolation, which can hinder the applicability of findings. This brief review presents evidence that 1) performing a cognitive challenge simultaneously with a motor task can negatively impact force steadiness and fatigability of limb muscles during a static contraction, 2) the negative impact on old adults (>65 years old), particularly older women is greater than young when a cognitive challenge is simultaneously performed with a static motor task, 3) age-related mechanisms potentially explain impairments in motor performance in the presence of a cognitive challenge, and 4) the mechanisms for the age-related decrements in motor performance can be distinct between men and women. These observations are highly relevant to the older adults, given the increased risk of accidents and injury when a motor task is performed with a high cognitive-demand task, especially in light of the expanding reliance on an aging workforce.

Localized Pain and Fatigue During Recovery From Submaximal Resistance Exercise in People With Fibromyalgia.

OBJECTIVE: Exercise is recommended as a main treatment in fibromyalgia. However, many people have limited exercise tolerance and report exacerbated pain and fatigue during and following a bout of exercise. This study examined the local and systemic changes in perceived pain and fatigue during exercise and through the 3-day recovery following isometric and concentric exercises in people with and without fibromyalgia. METHODS: Forty-seven participants with a physician diagnosis of fibromyalgia (44 women; mean age [SD] = 51.3 [12.3] years; mean body mass index [SD] = 30.2 [6.9]) and 47 controls (44 women; mean age [SD] = 52.5 [14.7] years; mean body mass index [SD] = 27.7 [5.6]) completed this prospective, observational cohort study. A bout of submaximal resistance exercise (isometric and concentric) was performed localized to the right elbow flexors on 2 separate days. Baseline attributes (pain, fatigue, physical function, physical activity, and body composition) were assessed prior to exercise. Primary outcomes were: change in perceived pain and fatigue (0 to 10 on the visual analog scale) in the exercising limb and whole body during recovery with movement (immediately, 1 day following exercise, and 3 days following exercise). Secondary outcomes were perceived pain and exertion during exercise performance and pain and fatigue at rest during recovery. RESULTS: Following a single bout of isometric or concentric exercise, there was increased perceived pain (ηp2 = 0.315) and fatigue (ηp2 = 0.426) in the exercising limb, which was greater in people with fibromyalgia (pain: ηp2 = 0.198; fatigue: ηp2 = 0.211). Clinically, relevant increases in pain and fatigue during exercise and through the 3-day recovery occurred in individuals with fibromyalgia only. Concentric contractions led to greater perceived pain, exertion, and fatigue during exercise compared with isometric exercise for both groups. CONCLUSIONS: People with fibromyalgia experienced significant pain and fatigue in the exercising muscle during recovery from low-intensity and short-duration resistance exercise, with greater pain during concentric contractions. IMPACT: These findings highlight a critical need to assess and manage pain and fatigue in the exercising muscles of people with fibromyalgia up to 3 days following a single bout of submaximal resistance exercise. LAY SUMMARY: If you have fibromyalgia, you might have significant pain and fatigue up to 3 days following an exercise bout, with the pain and fatigue localized to the exercising muscles and no changes in whole-body pain.

Case Studies in Physiology: Male to female transgender swimmer in college athletics.

There is current scientific and legal controversy about sports competition eligibility regulations for transgender athletes. In this case study, we quantified performances by an elite, transgender woman (male sex, female gender identity) college swimmer who competed in both the men's and women's National Collegiate Athletic Association (NCAA) categories. We also contextualized her performances with respect to world-record performances and contemporary elite college swimmers. These data demonstrate that the declines in freestyle swimming performances of a transgender woman after about 2 yr of reported feminizing gender-affirming hormone treatment (0.5% for the 100 to 7.3% for the 1,650 yard distance) are smaller than the observed sex-related differences in performance of top 200 world record performances in metric distances of similar durations (11.4% for the 100 m to 9.3% for the 1,500 m distance). Despite slower performances, the transgender woman swimmer experienced improvements in performance for each freestyle event (100 to 1,650 yards) relative to sex-specific NCAA rankings, including producing the best swimming time in the NCAA for the 500-yard distance (65th in the men's category in 2018-2019 to 1st in the women's, 2022). Similarly, NCAA-ranked male swimmers had no improvements in rank in the men's category during the same time frame. Our findings suggest that the performance times of the transgender woman swimmer in the women's NCAA category were outliers for each event distance and suggest that the transgender woman swimmer had superior performances relative to rank-matched swimmers. Our analysis may be useful as a framework for regulators considering participation guidelines, which promote fair competition for all athletes-irrespective of gender identity.NEW & NOTEWORTHY This case study, longitudinal analysis of freestyle swimming performances before and after 2 yr of feminizing gender-affirming hormone therapy of an elite transgender woman (male sex, female gender identity), demonstrates superior performance relative to rank-matched female swimmers and a lower performance gap than previously observed between elite male and female swimmers.

Sex Differences in the Speed-Duration Relationship of Elite Runners across the Lifespan.

PURPOSE: To determine if the speed-duration relationship is altered with age and sex of elite Master's runners. METHODS: The world's top 10 performances for men and women in three events (800, 1500, and 5000 m) across six age groups (18-34 yr, 40-49 yr, 50-59 yr, 60-69 yr, 70-79 yr, and 80-89 yr) were analyzed from public data to establish theoretical models of the speed-duration relationship. Critical speed (CS) and the curvature constant ( D ') were estimated by fitting the average speeds and performance times with a two-parameter hyperbolic model. RESULTS: Critical speed expressed relative to the 18- to 34-yr-olds, declined with age (92.2% [40-49] to 55.2% [80-89]; P < 0.001), and absolute CS was higher in men than women within each age group ( P < 0.001). The percent difference in CS between the men and women progressively increased across age groups (10.8% [18-34] to 15.5% [80-89]). D ' was lower in women than men in the 60-69 yr, 70-79 yr, and 80-89 yr age groups ( P < 0.001), but did not differ in the 18-34 yr, 40-49 yr, or 50-59 yr age groups. CONCLUSIONS: Critical speed progressively decreased with age, likely due to age-related decrements in several physiological systems that cause reduced aerobic capacity. The mechanism for the larger sex difference in CS in the older age groups is unknown but may indicate physiological differences that occur with aging and/or historical sociological factors that have reduced participation opportunities of older female runners resulting in a more limited talent pool.