No Sex Differences in Perceptual Responses to High-Intensity Interval Training or Sprint Interval Training.

ABSTRACT: Coe, LN and Astorino, TA. No sex differences in perceptual responses to high-intensity interval training or sprint interval training. J Strength Cond Res 36(6): 1025-1032, 2024-High-intensity interval training (HIIT) elicits similar and, in some cases, superior benefits vs. moderate-intensity continuous training (MICT). However, HIIT is typically more aversive than MICT because of the higher intensity and in turn, greater blood lactate accumulation (BLa). This study explored potential sex differences in perceptual responses to acute HIIT and sprint interval training. Fifteen men (age and V̇O2max = 29 ± 8 years and 39 ± 3 ml·kg-1·min-1) and 13 women (age and V̇O2max = 22 ± 2 years and 38 ± 5 ml·kg-1·min-1) who are healthy and recreationally active initially underwent testing of maximal oxygen uptake (V̇O2max) on a cycle ergometer. In randomized order on 3 separate occasions, they performed the 10 × 1-minute protocol at 85% of peak power output, 4 × 4-minute protocol at 85-95% maximal heart rate (%HRmax), or reduced exertion high intensity interval training consisting of 2 "all-out" 20-second sprints at a load equal to 5% body mass. Before and throughout each protocol, rating of perceived exertion (rating of perceived exertion [RPE] 6-20 scale), affective valence (+5 to -5 of the Feeling Scale), and BLa were assessed. Five minutes postexercise, enjoyment was measured using the Physical Activity Enjoyment scale survey. Results showed no difference in RPE (p = 0.17), affective valence (0.27), or enjoyment (p = 0.52) between men and women. Blood lactate accumulation increased in response to all protocols (p < 0.001), and men showed higher BLa than women (p = 0.03). Previous research suggests that interval exercise protocols are not interchangeable between men and women, yet our data reveal that men and women having similar V̇O2max exhibit no differences in perceptual responses to interval exercise.

Does Behavior Evolve First? Correlated Responses to Selection for Voluntary Wheel-Running Behavior in House Mice.

AbstractHow traits at multiple levels of biological organization evolve in a correlated fashion in response to directional selection is poorly understood, but two popular models are the very general "behavior evolves first" (BEF) hypothesis and the more specific "morphology-performance-behavior-fitness" (MPBF) paradigm. Both acknowledge that selection often acts relatively directly on behavior and that when behavior evolves, other traits will as well but most with some lag. However, this proposition is exceedingly difficult to test in nature. Therefore, we studied correlated responses in the high-runner (HR) mouse selection experiment, in which four replicate lines have been bred for voluntary wheel-running behavior and compared with four nonselected control (C) lines. We analyzed a wide range of traits measured at generations 20-24 (with a focus on new data from generation 22), coinciding with the point at which all HR lines were reaching selection limits (plateaus). Significance levels (226 P values) were compared across trait types by ANOVA, and we used the positive false discovery rate to control for multiple comparisons. This meta-analysis showed that, surprisingly, the measures of performance (including maximal oxygen consumption during forced exercise) showed no evidence of having diverged between the HR and C lines, nor did any of the life history traits (e.g., litter size), whereas body mass had responded (decreased) at least as strongly as wheel running. Overall, results suggest that the HR lines of mice had evolved primarily by changes in motivation rather than performance ability at the time they were reaching selection limits. In addition, neither the BEF model nor the MPBF model of hierarchical evolution provides a particularly good fit to the HR mouse selection experiment.

Chronic exercise and neuropsychological function in healthy young adults: a randomised controlled trial investigating a running intervention.

Despite the well-known physical and mental health benefits of regular exercise, many of the world's population, including healthy young adults, grossly undershoot recommended physical activity levels. Chronic exercise has potential to improve cognitive performance and affect in most age groups. However, there is currently a poverty of relevant research in young adults, especially randomised controlled trials. To address this, the current research investigated the effects of a running intervention on neuropsychological function (cognition and affect) in young adults. We predicted that following a running intervention, neuropsychological performance would improve alongside increases in aerobic fitness. Thirty-two healthy young adult university students were randomised (using a 3:1 ratio) into an intervention or control group, with the intervention group (n = 24) asked to run for 30 min three times a week over a 6-week period and the control group (n = 8) asked to maintain their current level of exercise over a 6-week period. We assessed fitness, cognitive performance, affect and running enjoyment at baseline and follow-up, and runners recorded the environmental conditions of their runs. Repeated measures ANCOVAs failed to find any significant effects of the running intervention on fitness or the neuropsychological measures. Anecdotal evidence supported running environment and enjoyment as potentially relevant factors. The failure to find any fitness improvements, which likely underpins the lack of neuropsychological improvements, highlights the importance of monitoring exercise sessions. Coupled with other insights gained from this trial, this article may prove useful towards future endeavours to develop exercise interventions beneficial to young adults.TRN: ACTRN12621000242820, Date of registration: 08/03/2021.

Self-regulatory processes in goal striving during excellent distance-running performances: A qualitative study.

OBJECTIVE: Goal setting can improve endurance performance, yet how endurance performers maintain goal striving and bring it to a successful close has received limited attention. In this study, we investigated the self-regulatory processes employed by long-distance runners during goal striving in excellent competitive performances. METHOD: Through in-depth, event-focused interviews, we explored 21 long-distance runners' experiences of goal striving in excellent competitive performances (M = 77.43 h post-race). Furthermore, we recruited 10 additional participants with relevant experiences (runner n = 7, coach n = 2; sport psychologist n = 1) for external member-reflection interviews. FINDINGS: Through our matrix analysis, we interpreted that by contrasting their current and future goal status periodically throughout their excellent performances, using a process called mental contrasting with implementation intentions (MCII), this helped the runners to make decisions about whether to persist with a goal, or disengage from a goal and reengage with an alternative. Furthermore, our findings depict how these goal decisions unfolded when runners perceived they were behind, equalling, or exceeding their goal(s). We also illustrate how goal revision was used as an adaptive process to maximise performance, and to avert or manage action crises. CONCLUSIONS: Our findings extend theoretical understandings of goal striving and the self-regulatory processes endurance performers employ to attain and/or adapt their goals. Psychological support provided for athletes should go beyond simply setting goals, but also include training on mental frameworks such as MCII to manage goal-striving challenges and decisional conflict encountered during performances.

Temporal perception in closed-skill sports: An experimental study on expert swimmers and runners.

The cognitive benefits of closed-skill sports practice have so far been scantily investigated. Here, we thus focused on the potential impact of swimming and running - two sports that highly rely on a precise control of timing - on time processing. To investigate the impact of these closed-skill sports on time perception and estimation, three groups of participants (for a total of eighty-four young adults) took part in the present study: expert swimmers, expert runners, and non-athletes. The ability to process temporal information in the milliseconds and seconds range was assessed through a time reproduction and a finger-tapping tasks, while a motor imagery paradigm was adopted to assess temporal estimation of sport performance in a wider interval range. We also employed the Vividness of Movement Imagery Questionnaire to assess the individual's ability of motor imagery. Results showed that closed-skill sports, specifically time-related disciplines, enhance motor imagery and time perception abilities. Swimmers were more accurate and consistent in perceiving time when compared to runners, probably thanks to the sensory muffled environment that leads these athletes to be more focused on the perception of their internal rhythm.

The general interest in running and walking has increased during the COVID-19.

N/A.

Mental Toughness and Resilience in Trail Runner's Performance.

Our purpose with this study was to analyze trail runners' psychological variables of mental toughness (MT) and resilience, and their associations with runners' performances within a quantitative cross-sectional study. In total, we analyzed data from 307 Portuguese trail runners (60 female, 247 male), aged between 20 to 66 years (M age = 41.98; SD = 7.74). The results showed that the measurement model, including the factors of MT, resilience, and performance variables, exhibited an adequate fit to the data: χ2 = 150.01 (74); BS-p = .003; CFI= .953; TLI = .942; RMSEA = .058 90% (.045, .071) and SRMR= .042. Standardized direct effects revealed positive associations between these variables. More specifically: (a) MT was significantly associated with resilience; and (b) resilience was significantly associated with performance. The indirect regression paths showed that MT was positively associated with performance, with resilience considered a possible mediator (ß = .09 IC = .010, .168; p = .02). In total, considering direct and indirect effects, the model explained 21% of performance variance among trail runners.

Understanding Social Exercise: Desire and Intention to Participate in Running Crews.

The current study investigated the determinants of the desire and intention to participate in an inner-city 'running crew' among social runners using a theoretical framework of the model of goal-directed behavior (MGB). Data were obtained from 245 social runners in Korea using an online questionnaire and primarily analyzed with the structural equation modeling technique. The results indicated that the desire to participate in a running crew was influenced most by positive anticipated emotions, followed (in descending order) by attitudes, negative anticipated emotions, social norms, perceived behavioral control, and the frequency of past behaviors. Runners' behavioral intentions were predicted by desire but not directly related to perceived behavioral control and the frequency of past behavior. Overall, the study emphasized the importance of positive anticipated emotions and behavioral desire, among others, to encourage recreational runners' participation in social running activities. Given that social runners rely on mobile apps to participate in running crew activities, the current study's results have practical implications for running crew organizers, sports-branded app developers, and health promotion agencies.

The effects of different small-sided games configurations on heart rate, rating of perceived exertion, and running demands in professional soccer players.

We examined the effects of different small-sided games (SSG) configurations on heart rate (HR), rating of perceived exertion (RPE), and running demands in soccer players. Twelve male soccer players (U18) participated in this randomized cross-over study. Players performed three SSG in different "fixed" and "dynamic" pitch sizes (3v3 in large (SSGL) and small (SSGS) fixed area; or 3v3 in dynamic dimensions [SSGD]), with 4x4 minutes interspersed by 2 minutes of rest. HR measures (maximum [HRmax], average [HRavg], and percentage of maximum [%HRmax]), RPE, and running demands were collected across the SGG sessions. The following running activities were recorded: total distance covered (TD), distance covered (DC) at 6-12 km·h-1, ≥ 12-18 km·h-1, and >18 km·h-1, peak running speed, acceleration (ACC) and deceleration (DEC) at 1-2 m·s-2 and 2-3 m·s-2, player load, and high metabolic load distance (HMLD). SSGL displayed higher HRavg, %HRmax, and RPE values than SSGS (p < 0.05). SSGL resulted in higher TD, DC at 6-12 km·h-1, ≥ 12-18 km·h-1, > 18 km·h-1, and higher peak speed than SSGS and SSGD (p < 0.05). Moreover, SSGD presented higher TD and DC at 6-12 km·h-1 and ≥ 12-18 km·h-1 than SSGS (p < 0.05). In contrast, SSGD and SSGS showed higher number of ACC and DEC at 1-2 m·s-2 than SSGL (p < 0.05). In conclusion, the pitch size and playing area of the SSG can be manipulated to promote desired physiological and physical demands in young soccer players.HighlightsWe examined how fixed (small and large) or variable (dynamic) pitch sizes affected the psychophysiological and running demands of young soccer players during small-sided games.Small-sided games with larger pitch sizes and areas per player elicited greater psychophysiological and running demands than small areas.The pitch size designed in the current study does not appear to affect the number of acceleration and deceleration (> 2 m·s-2).Varying the pitch size during the small-sided games (i.e. dynamic condition) could be an interesting constraint to be considered by soccer coaches in order to enhance task variability.

A microbiome-dependent gut-brain pathway regulates motivation for exercise.

Exercise exerts a wide range of beneficial effects for healthy physiology1. However, the mechanisms regulating an individual's motivation to engage in physical activity remain incompletely understood. An important factor stimulating the engagement in both competitive and recreational exercise is the motivating pleasure derived from prolonged physical activity, which is triggered by exercise-induced neurochemical changes in the brain. Here, we report on the discovery of a gut-brain connection in mice that enhances exercise performance by augmenting dopamine signalling during physical activity. We find that microbiome-dependent production of endocannabinoid metabolites in the gut stimulates the activity of TRPV1-expressing sensory neurons and thereby elevates dopamine levels in the ventral striatum during exercise. Stimulation of this pathway improves running performance, whereas microbiome depletion, peripheral endocannabinoid receptor inhibition, ablation of spinal afferent neurons or dopamine blockade abrogate exercise capacity. These findings indicate that the rewarding properties of exercise are influenced by gut-derived interoceptive circuits and provide a microbiome-dependent explanation for interindividual variability in exercise performance. Our study also suggests that interoceptomimetic molecules that stimulate the transmission of gut-derived signals to the brain may enhance the motivation for exercise.

Recreational Running Motivations among Breast Cancer Survivors.

Lifestyle-associated factors play an important role in prevention of such malignancies as breast cancer (BC), prostate cancer, or colon cancer. Physical activity (PA) before, during, and after diagnosis improves outcomes for BC. People after BC live with numerous side effects and PA has potential to reduce some of them. Unfortunately, few cancer survivors exercise regularly. The aim of this study was to ascertain motivations for running among BC survivors (in comparison with the motivations of healthy women) in order to better manage their attitudes in terms of PA and active lifestyle. A total of 317 Polish women took part in the study: 152 BC women (age 46.49 ± 7.83; BMI 24.78 ± 3.50) and 165 healthy runners (control group (age 36.91 ± 9.68; BMI 23.41 ± 3.94)) using the diagnostic survey method with the Motivation for Marathoners Scale (MOMS) questionnaire. Study results show that healthy runners had higher scores for health orientation, personal goal achievement, and affiliation compared to the group of BC survivors. The scores for weight concern, recognition, psychological coping, life meaning, and self-esteem were lower than those of BC survivors. These results should be included in the management of PA attitudes among BC survivors.

Health status of recreational runners over 10-km up to ultra-marathon distance based on data of the NURMI Study Step 2.

Endurance running is well-documented to affect health beneficially. However, data are still conflicting in terms of which race distance is associated with the maximum health effects to be obtained. Therefore, the aim of this study was to compare the health status of endurance runners over different race distances. A total of 245 recreational runners (141 females, 104 males) completed an online survey. Health status was assessed by measuring eight dimensions in two clusters of health-related indicators (e.g., body weight, mental health, chronic diseases and hypersensitivity reactions, medication intake) and health-related behaviors (e.g., smoking habits, supplement intake, food choice, healthcare utilization). Each dimension consisted of analytical parameters derived to a general domain score between 0 and 1. Data analysis was performed by using non-parametric ANOVA and MANOVA. There were 89 half-marathon (HM), 65 marathon/ultra-marathon (M/UM), and 91 10-km runners. 10-km runners were leaner than both the HM and M/UM runners (p ≤ 0.05). HM runners had higher health scores for six dimensions (body weight, mental health, chronic diseases and hypersensitivity reactions, medication intake, smoking habits, and health care utilization), which contributed to an average score of 77.1% (score range 62-88%) for their overall state of health. Whereas 10-km and M/UM runners had lesser but similar average scores in the overall state of health (71.7% and 72%, respectively). Race distance had a significant association with the dimension "chronic diseases and hypersensitivity reactions" (p ≤ 0.05). Despite the null significant associations between race distance and seven (out of eight) multi-item health dimensions, a tendency towards better health status (assessed by domain scores of health) among HM runners was found compared to other distance runners. However, the optimal state of health across all race distances supported the notion that endurance running contributed to overall health and well-being.Trial registration number: ISRCTN73074080. Retrospectively registered 12th June 2015.

Estratégias de coping e motivação de praticantes de corrida de rua / Estrategias de afrontamiento y motivación de los corredores callejeros / Coping strategies and motivation of street runners

O objetivo do estufo foi analisar as estratégias de coping e a motivação de prati-cantes de corrida de rua do município de Maringá ­ PR. Trata-se de um estudo transversal, cuja mostra foi composta por 55 praticantes de corrida de rua, de ambos os sexos, com idade mínima de 20 anos de idade. Como instrumentos foram utilizados uma ficha de identificação, o Exercise Motivation Inventory (EMI-2) e o Inventário de Estratégias de Coping (IEC). A análise dos dados foi feita através de estatística descritiva e inferencial (p<0,05). Os resultados evidenciaram que os homens apresentaram um perfil mais competidor em relação às mulheres (p=0,019), além de utilizarem as estratégias rendimento máximo sob pressão (p=0,017), concentração (p=0,030) e confiança e moti-vação (p=0,021). Os indivíduos com maior tempo de prática utilizam mais da estratégia concentração (p=0,020). Os que treinavam até três vezes na semana se motivavam mais pela reabilitação da saúde. A estratégia de formulação de objetivos foi o domínio que mais obteve correlações com a motivação (p<0,05). Conclui-se que existem inúmeros motivos para a prática dos corredores de rua, assim como as estratégias de enfrentamento utilizadas.

The purpose of the study was to analyze coping strategies and motivation of street runners in the city of Maringá ­ PR. This is a cross-sectional study, in which the sample consisted of 55 street runners, from both sexes, with a minimum age of 20 years old. As instruments, an identification form, the Exercise Motivation Inventory (EMI-2) and the Coping Strategies Inventory (CSI) were used. Data analysis was performed using descriptive and inferential statistics (p<0.05). The results have evinced that men had a more competitive profile than women (p=0.019), also using the following strategies: maximum performance under pressure (p=0.017), concentration (p=0.030) and confi-dence and motivation (p=0.021). Individuals with longer practice time use the concentration strategy more often (p=0.020). Individuals who used to train up to three times a week were more motivated by health rehabilitation. The strategy of formulating objectives was the domain that most correlated with motivation (p<0.05). It is concluded that there are numerous reasons for the practice of street runners, as well as the coping strategies they use.

El propósito del estudio fue analizar las estrategias de afrontamiento y la motivación de los corredores callejeros en la ciudad de Maringá - PR. Se trata de un estudio transversal, en el que la muestra estuvo compuesta por 55 corredores callejeros, de ambos los sexos, con una edad mínima de 20 años. Como instrumentos se utilizó un formulario de identificación, el Inventario de Motivación para el Ejercicio (EMI-2) y el Inventario de Estrategias de Afrontamiento (IEC). El análisis de los datos se realizó mediante estadística descriptiva e inferencial (p <0,05). Los resultados mostraron que los hombres tenían un perfil más competitivo que las mujeres (p = 0,019), además de utilizar las estrategias rendimiento máximo bajo presión (p = 0,017), concentración (p = 0,030) y confianza y motivación (p = 0,021). Las personas con mayor tiempo de práctica utilizan más la estrategia de concentración (p = 0.020). Los que entrenaron hasta tres veces por semana estaban más motivados por la rehabilitación de la salud. La estrategia de formulación de objetivos fue el dominio que más se correlacionó con la motivación (p <0,05). Se concluye que existen numerosas razones para la práctica de los corredores callejeros, así como las estrategias de afrontamiento empleadas.

Effects of involuntary treadmill running in combination with swimming on adult neurogenesis in an Alzheimer's mouse model.

Physical exercise plays a role on the prevention and treatment of Alzheimer's disease (AD), but the exercise mode and the mechanism for these positive effects is still ambiguous. Here, we investigated the effect of an aerobic interval exercise, running in combination with swimming, on behavioral dysfunction and associated adult neurogenesis in a mouse model of AD. We demonstrate that 4 weeks of the exercise could ameliorate Aß42 oligomer-induced cognitive impairment in mice utilizing Morris water maze tests. Additionally, the exercised Aß42 oligomer-induced mice exhibited a significant reduction of anxiety- and depression-like behaviors compared to the sedentary Aß42 oligomer-induced mice utilizing an Elevated zero maze and a Tail suspension test. Moreover, by utilizing 5'-bromodeoxyuridine (BrdU) as an exogenous cell tracer, we found that the exercised Aß42 oligomer-induced mice displayed a significant increase in newborn cells (BrdU+ cells), which differentiated into a majority of neurons (BrdU+ DCX+ cells or BrdU+NeuN+ cells) and a few of astrocytes (BrdU+GFAP+ cells). Likewise, the exercised Aß42 oligomer-induced mice also displayed the higher levels of NeuN, PSD95, synaptophysin, Bcl-2 and lower level of GFAP protein. Furthermore, alteration of serum metabolites in transgenic AD mice between the exercised and sedentary group were significantly associated with lipid metabolism, amino acid metabolism, and neurotransmitters. These findings suggest that combined aerobic interval exercise-mediated metabolites and proteins contributed to improving adult neurogenesis and behavioral performance after AD pathology, which might provide a promising therapeutic strategy for AD.

Relationship between Negative Running Addiction and Eating Disorder Patterns in Runners.

Current studies show an increase in the risk of eating disorders in runners. Since it is known that abusive exercise can be both a cause and a consequence of such developments, the main objective of the present study was to examine the risk and possible relationships between negative running addiction (NRA), as measured by the reduced and validated SAS-40 scale, and the tendency to be a compulsive eater (measured by YFAS 2.0), anorexia nervosa (AN), and/or bulimia nervosa (BN) (measured by EAT-40). This study highlights the novelty of researching the level of influence of NRA on each defined eating disorder. METHOD: A total of 167 Spanish-speaking federated runners in cross-country and track running (42% women and 58% men), with an average age of 24 years and an average BMI of 21 kg/m2, responded to an online questionnaire that asked about sociodemographic data and the Spanish versions of the SAS-40, YFAS 2, YFAS 3, and YFAS 4. Through a quantitative methodology using logistic regressions-the coefficient of determination and Pearson's correlation coefficient-we created a sample analysis that related the significant items of the DSM-V to the results of the questionnaires administered, as well as their relationship with the practice of the sport in question and various variables of the environment. RESULTS: The rates of CE, AN, and BN were 65, 11.4, and 16.2%, respectively. The tendency towards CE increased with a lower weight (r = 0.156, p < 0.05), not having been overweight in childhood (r = 0.151, p < 0.05), and being a long-distance runner (r = 0.123 p < 0.05). The risk of AN increased with the absence of menstruation for more than 3 months (r = 0.271 p < 0.01), having suffered from childhood obesity (r = 0.213 p < 0.05), and being underweight (r = 0.064 p < 0.05). The risk of BN increased with having suffered from childhood obesity (r = 0.194 p < 0.05), having a higher weight (r = 0.140, p < 0.05), and practicing athletics, especially the relay modality (r = 0.044 p < 0.05). CONCLUSIONS: A considerable number of runners are at risk of suffering from some type of eating disorder. A significant relationship was observed between long-distance runners and the risk of eating disorders (AN, BN, and CE), and the association is stronger for CE than for AN and BN. Lastly, childhood experiences (such as being obese/a healthy weight) were notorious for increasing the risk of eating disorders. Further studies are needed to research each particular parameter and the relationships between the possible levels of dependence on exercise. LEVEL OF EVIDENCE: Level III, cohort analytic study.

Social reward and support effects on exercise experiences and performance: Evidence from parkrun.

There is growing academic, civic and policy interest in the public health benefits of community-based exercise events. Shifting the emphasis from competitive sport to communal activity, these events have wide appeal. In addition to physical health benefits, regular participation can reduce social isolation and loneliness through opportunities for social connection. Taking a broad evolutionary and social psychological perspective, we suggest that social factors warrant more attention in current approaches to physical (in)activity and exercise behavior. We develop and test the hypothesis that social reward and support in exercise are associated with positive exercise experiences and greater performance outputs. Using a repeated-measures design, we examine the influence of social perceptions and behavior on subjective enjoyment, energy, fatigue, effort, and objective performance (run times) among a UK sample of parkrun participants. Social factors were associated with greater subjective enjoyment and energy. Higher subjective energy, in turn, was associated with faster run times, without any corresponding increase in perceived effort. No significant main effects of social factors on fatigue, performance or effort were detected. The role of social structural factors has long been recognized in public health approaches to physical activity. Our results indicate that there should be greater research attention on how positive and rewarding social behaviors and experiences-particularly subjective enjoyment and energy, and perceptions of community social support and belonging-influence exercise-related behavior, psychology and physiology, and promote health through collective physical activity. The research also supplements traditional emphases on social facilitation and team sport that have dominated sport and exercise psychology and offers new avenues for understanding the deep connections among psychological, social and physical function in everyday health.

What are the biopsychosocial risk factors associated with pain in postpartum runners? Development of a clinical decision tool.

BACKGROUND: In 2019, a majority of runners participating in running events were female and 49% were of childbearing age. Studies have reported that women are initiating or returning to running after childbirth with up to 35% reporting pain. There are no studies exploring running-related pain or risk factors for this pain after childbirth in runners. Postpartum runners have a variety of biomechanical, musculoskeletal, and physiologic impairments from which to recover from when returning to high impact sports like running, which could influence initiating or returning to running. Therefore, the purpose of this study was to identify risk factors associated with running-related pain in postpartum runners with and without pain. This study also aimed to understand the compounding effects of multiple associative risk factors by developing a clinical decision tool to identify postpartum runners at higher risk for pain. METHODS: Postpartum runners with at least one child ≤36 months who ran once a week and postpartum runners unable to run because of pain, but identified as runners, were surveyed. Running variables (mileage, time to first postpartum run), postpartum variables (delivery type, breastfeeding, incontinence, sleep, fatigue, depression), and demographic information were collected. Risk factors for running-related pain were analyzed in bivariate regression models. Variables meeting criteria (P<0.15) were entered into a multivariate logistic regression model to create a clinical decision tool. The tool identified compounding factors that increased the probability of having running-related pain after childbirth. RESULTS: Analyses included 538 postpartum runners; 176 (32.7%) reporting running-related pain. Eleven variables were included in the multivariate model with six retained in the clinical decision tool: runner type-novice (OR 3.51; 95% CI 1.65, 7.48), postpartum accumulated fatigue score of >19 (OR 2.48; 95% CI 1.44, 4.28), previous running injury (OR 1.95; 95% CI 1.31, 2.91), vaginal delivery (OR 1.63; 95% CI 1.06, 2.50), incontinence (OR 1.95; 95% CI 1.31, 2.84) and <6.8 hours of sleep on average per night (OR 1.89; 95% CI 1.28, 2.78). Having ≥ 4 risk factors increased the probability of having running-related pain to 61.2%. CONCLUSION: The results of this study provide a deeper understanding of the risk factors for running-related pain in postpartum runners. With this information, clinicians can monitor and educate postpartum runners initiating or returning to running. Education could include details of risk factors, combinations of factors for pain and strategies to mitigate risks. Coaches can adapt running workload accounting for fatigue and sleep fluctuations to optimize recovery and performance. Future longitudinal studies that follow asymptomatic postpartum women returning to running after childbirth over time should be performed to validate these findings.

Genetically determined exercise capacity affects systemic glucose response to insulin in rats.

Aerobic exercise capacity is inversely related to morbidity and mortality as well as to insulin resistance. However, exercising in patients has led to conflicting results, presumably because aerobic exercise capacity consists of intrinsic (genetically determined) and extrinsic (environmentally determined) parts. The contribution of both parts to insulin sensitivity is also not clear. We investigated sedentary and exercised (aerobic interval training) high-capacity runners (HCR) and low-capacity runners (LCR) differing in their genetically determined aerobic exercise capacity to determine the contribution of both parts to insulin sensitivity. LCR and HCR differed in their untrained exercise capacity and body weight. Sedentary LCR displayed a diabetic phenotype with higher random glucose, lower glucose infusion rate during hyperinsulinemic euglycemic clamping than HCR. Echocardiography showed equal morphological and functional parameters and no change with exercise. Four week of exercise caused significant improvements in aerobic exercise capacity, which was more pronounced in LCR. However, with respect to glucose use, exercise affected HCR only. In these animals, exercise increased 2-deoxyglucose uptake in gastrocnemius (+58.5%, P = 0.1) and in epididymal fat (+106%; P < 0.05). Citrate synthase activity also increased in these tissues (gastrocnemius 69% epididymal fat 63%). In our model of HCR and LCR, genetic predisposition for low exercise capacity is associated with impaired insulin sensitivity and impedes exercise-induced improvements in insulin response. Our results suggest that genetic predisposition for low aerobic exercise capacity impairs insulin response, which may not be overcome by exercise.

Disordered Eating, Development of Menstrual Irregularity, and Reduced Bone Mass Change After a 3-Year Follow-Up In Female Adolescent Endurance Runners.

This prospective study evaluated the 3-year change in menstrual function and bone mass among 40 female adolescent endurance runners (age 15.9 ± 1.0 years) according to baseline disordered eating status. Three years after initial data collection, runners underwent follow-up measures including the Eating Disorder Examination Questionnaire and a survey evaluating menstrual function, running training, injury history, and prior sports participation. Dual-energy X-ray absorptiometry was used to measure bone mineral density and body composition. Runners with a weight concern, shape concern, or global score ≥4.0 or reporting >1 pathologic behavior in the past 28 days were classified with disordered eating. Compared with runners with normal Eating Disorder Examination Questionnaire scores at baseline, runners with disordered eating at baseline reported fewer menstrual cycles/year (6.4 ± 4.5 vs. 10.5 ± 2.8, p = .005), more years of amenorrhea (1.6 ± 1.4 vs. 0.3 ± 0.5, p = .03), and a higher proportion of menstrual irregularity (75.0% vs. 31.3%, p = .02) and failed to increase lumbar spine or total hip bone mineral density at the 3-year follow-up. In a multivariate model including body mass index and menstrual cycles in the past year at baseline, baseline shape concern score (B = -0.57, p value = .001) was inversely related to the annual number of menstrual cycles between assessments. Weight concern score (B = -0.40, p value = .005) was inversely associated with lumbar spine bone mineral density Z-score change between assessments according to a multivariate model adjusting for age and body mass index. These finding support associations between disordered eating at baseline and future menstrual irregularities or reduced accrual of lumbar spine bone mass in female adolescent endurance runners.