The limits of endurance exercise

A macro to micro analysis to understand performance in 100-mile ultra-marathons worldwide

The purposes of this study were (i) to describe differences in participation in 100-mile ultra-marathons by continent; (ii) to investigate differences in performance between continents; and (iii) to identify the fastest runners by continent and country. Data from 148,169 athletes (119,408 men), aged 18-81 years, and finishers in a 100-miles ultra-marathon during 1870-2020 were investigated. Information about age, gender, origin, performance level (top three, top 10, top 100) was obtained. Kruskal-Wallis tests and linear regressions were performed. Athletes were mostly from America and Europe. A macro-analysis showed that the fastest men runners were from Africa, while the fastest women runners were from Europe and Africa. Women from Sweden, Hungary and Russia presented the best performances in the top three, top 10 and top 100. Men from Brazil, Russia and Lithuania were the fastest. The lowest performance and participation were observed for runners from Asia. In summary, in 100-miles ultra-marathon running, the majority of athletes were from America, but for both sexes and performance levels, the fastest runners were from Africa. On a country level, the fastest women were from Sweden, Hungary and Russia, while the fastest men were from Brazil, Russia and Lithuania.

Trends in Participation, Sex Differences and Age of Peak Performance in Time-Limited Ultramarathon Events: A Secular Analysis

Background and Objectives: Increases in the number of participants in time-limited ultra-marathons have been reported. However, no information is available regarding the trends in participation, performance and age in 12 h and 24 h time-limited events. The aim of the study was to describe the trends in runners’ participation, performance and age in 12 h and 24 h ultra-marathons for both sexes and to identify the age of peak performance, taking into account the ranking position and age categories. Materials and Methods: The sample comprised 210,455 runners in time-limited ultra-marathons (female 12 h = 23,706; female 24 h = 28,585; male 12 h = 61,594; male 24 h = 96,570) competing between 1876 and 2020 and aged 18 to 86 years. The age of peak performance was tested according to their ranking position (first−third; fourth−tenth and >tenth position) and taking into account their running speed in different age categories (<30 years; 31−40 years; 41−50 years; 51−60 years; >60 years), using the Kruskal−Wallis test, followed by the Bonferroni adjustment. Results: An increase in the number of participants and a decrease in running speed were observed across the years. For both events, the sex differences in performance decreased over time. The sex differences showed that male runners performed better than female runners, but the lowest differences in recent years were observed in the 24 h ultra-marathons. A positive trend in age across the years was found with an increase in mean age (“before 1989” = 40.33 ± 10.07 years; “1990−1999” = 44.16 ± 10.37 years; “2000−2009” = 45.99 ± 10.33 years; “2010−2020” = 45.62 ± 10.80 years). Male runners in 24 h races were the oldest (46.13 ± 10.83 years), while female runners in 12 h races were the youngest (43.46 ± 10.16 years). Athletes ranked first−third position were the youngest (female 12 h = 41.19 ± 8.87 years; female 24 h = 42.19 ± 8.50 years; male 12 h = 42.03 ± 9.40 years; male 24 h = 43.55 ± 9.03 years). When age categories were considered, the best performance was found for athletes aged between 41 and 50 years (female 12 h 6.48 ± 1.74 km/h; female 24 h 5.64 ± 1.68 km/h; male 12 h 7.19 ± 1.90 km/h; male 24 h 6.03 ± 1.78 km/h). Conclusion: A positive trend in participation in 12 h and 24 h ultra-marathons was shown across the years; however, athletes were becoming slower and older. The fastest athletes were the youngest ones, but when age intervals were considered, the age of peak performance was between 41 and 50 years.

Time courses of emotions experienced after a mountain ultra-marathon: Does emotional intelligence matter?

This research examined the time courses of emotions in sport settings (anxiety, dejection, anger, happiness, excitement) experienced by mountain ultra-marathon (MUM) runners within the month following a demanding MUM race and the role of emotional intelligence (EI) in these time courses. A six-wave one-month longitudinal design was used with one measurement point within two days before the race to measure EI and five time points within the month following the race to assess emotions experienced among a sample of 29 runners. Results of multilevel growth curve analyses showed significant linear decreases of dejection and anxiety and a significant linear increase of anger. EI was related to the intercept (level at the end of the MUM race) of happiness, excitement and dejection. Moreover the interaction of EI with time was associated with happiness, excitement and anger. This means that high and low emotional intelligent runners exhibited distinct trajectories of emotional intelligence within the month following the MUM race. Indeed, trait-EI appeared to have a protective role against stress process leading to emotional adjustment within the recovery period following an ultra-endurance event. As such, consultants and coaches could conduct specific program over the sport season designed to enhance trait-EI of MUM runners.

Psychosocial factors as predictors of dropout in ultra-trailers

OBJECTIVE

Although research on the physiological and psychological factors of endurance performance has been extensive, the factors related to dropping out of ultra-trail races have not been well documented. The aim of this study was to examine psychosocial factors as predictors of dropout in ultra-trail runners.

METHODS

Two hundred and twenty-one volunteer athletes completed a survey that included measures of: (a) motivational variables (self-determined motivation, basic needs satisfaction, achievement goals), (b) theory of planned behavior constructs (attitudes, subjective norms, self-efficacy and intention to finish the race), and (c) coping strategies in sport.

RESULTS

The results showed that finishers had higher scores for self-efficacy and intention to finish the race than withdrawers, whereas withdrawers had higher scores for avoidance coping. Multiple logistic regression showed that the number of started and finished ultra-trail races (OR, 0.44; 95% CI 0.22-0.88; p<0.02), self-efficacy (OR, 2.03; 95% CI 1.06-3.89; p<0.04), intention to finish the race (OR, 0.34; 95% CI 0.16-0.71; p<0.004), mastery-approach goals (OR, 0.56; 95% CI 0.31-1.00; p<0.05), and coping strategies of seeking social support (OR, 0.43; 95% CI 0.26-0.71; p<0.001) were associated with a lower risk of race dropout, whereas avoidance coping strategies (OR, 2.26; 95% CI 1.46-3.52; p<0.001) were associated with an increased dropout rate.

CONCLUSION

Interventions promoting self-efficacy constructs and specific coping strategies might contribute to preventing dropout in ultra-trailers.

The role of the nervous system in neuromuscular fatigue induced by ultra-endurance exercise

Ultra-endurance events are not a recent development but they have only become very popular in the last 2 decades, particularly ultramarathons run on trails. The present paper reviews the role of the central nervous system in neuromuscular fatigue induced by ultra-endurance exercise. Large decreases in voluntary activation are systematically found in ultra-endurance running but are attenuated in ultra-endurance cycling for comparable intensity and duration. This indirectly suggests that afferent feedback, rather than neurobiological changes within the central nervous system, is determinant in the amount of central fatigue produced. Whether this is due to inhibition from type III and IV afferent fibres induced by inflammation, disfacilitation of Ia afferent fibers owing to repeated muscle stretching or other mechanisms still needs to be determined. Sleep deprivation per se does not seem to play a significant role in central fatigue although it still affects performance by elevating ratings of perceived exertion. The kinetics of central fatigue and recovery, the influence of muscle group (knee extensors vs plantar flexors) on central deficit as well as the limitations related to studies on central fatigue in ultra-endurance exercise are also discussed in the present article. To date, no study has quantified the contribution of spinal modulations to central fatigue in ultra-endurance events. Future investigations utilizing spinal stimulation (i.e., thoracic stimulation) must be conducted to assess the role of changes in motoneuronal excitability on the observed central fatigue. Recovery after ultra-endurance events and the effect of sex on neuromuscular fatigue must also be studied further.

Psychological changes arising from an Antarctic stay: systematic overview

Long-term stays in extreme environments, such as Polar Regions, may cause significant changes in the health and well-being of individuals. A systematic overview aimed to map studies about the psychological effects on Antarctic expeditioners. The reviewed data were categorized and divided into two thematic axes: Negative Effects, resulting from harmful psychophysiological variations caused by exposure to the polar stressors, which may present seasonal symptom patterns, altering cognitive performance, mood and interpersonal relationships; and Positive Effects, such as salutogenic results arising from successful adaption to environmental adversities. Due to the great deal of evidence, it is suggested that protection factors should be promoted through preventive approaches, such as psychological training and support in order to reduce symptoms and generate satisfactory adaptation to Antarctica.

Energy expenditure during the LANY Footrace 2011 – a case study

We reported results obtained in estimating the energy expenditure (EE) of an active adult subject participating in LANY Footrace 2011 (5129 km, 70 consecutive days). At each stage EE was calculated from literature metabolic cost equations and GPS-measured speeds–inclines. The subject’s average speed was 7.41 ± 0.51 km·h–1. Race expenditure amounted to 87% of EE (31.3 MJ·day–1) (47.8%–37.1% of measured maximal oxygen uptake). These results provide data about EE for future stage-type ultra-endurance competitors.

Ultramarathon is an outstanding model for the study of adaptive responses to extreme load and stress

Ultramarathons comprise any sporting event involving running longer than the traditional marathon length of 42.195 km (26.2 miles). Studies on ultramarathon participants can investigate the acute consequences of ultra-endurance exercise on inflammation and cardiovascular or renal consequences, as well as endocrine/energetic aspects, and examine the tissue recovery process over several days of extreme physical load. In a study published in BMC Medicine, Schütz et al. followed 44 ultramarathon runners over 4,487 km from South Italy to North Cape, Norway (the Trans Europe Foot Race 2009) and recorded daily sets of data from magnetic resonance imaging, psychometric, body composition and biological measurements. The findings will allow us to better understand the timecourse of degeneration/regeneration of some lower leg tissues such as knee joint cartilage, to differentiate running-induced from age-induced pathologies (for example, retropatelar arthritis) and finally to assess the interindividual susceptibility to injuries. Moreover, it will also provide new information about the complex interplay between cerebral adaptations/alterations and hormonal influences resulting from endurance exercise and provide data on the dose-response relationship between exercise and brain structure/function. Overall, this study represents a unique attempt to investigate the limits of the adaptive response of human bodies.Please see related article: http://www.biomedcentral.com/1741-7015/10/78.

100 Years Since Scott Reached the Pole: A Century of Learning About the Physiological Demands of Antarctica

The 1910–1913 Terra Nova Expedition to the Antarctic, led by Captain Robert Falcon Scott, was a venture of science and discovery. It is also a well-known story of heroism and tragedy since his quest to reach the South Pole and conduct research en route, while successful was also fateful. Although Scott and his four companions hauled their sledges to the Pole, they died on their return journey either directly or indirectly from the extreme physiological stresses they experienced. One hundred years on, our understanding of such stresses caused by Antarctic extremes and how the body reacts to severe exercise, malnutrition, hypothermia, high altitude, and sleep deprivation has greatly advanced. On the centenary of Scott's expedition to the bottom of the Earth, there is still controversy surrounding whether the deaths of those five men could have, or should have, been avoided. This paper reviews present-day knowledge related to the physiology of sustained man-hauling in Antarctica and contrasts this with the comparative ignorance about these issues around the turn of the 20th century. It closes by considering whether, with modern understanding about the effects of such a scenario on the human condition, Scott could have prepared and managed his team differently and so survived the epic 1,600-mile journey. The conclusion is that by carrying rations with a different composition of macromolecules, enabling greater calorific intake at similar overall weight, Scott might have secured the lives of some of the party, and it is also possible that enhanced levels of vitamin C in his rations, albeit difficult to achieve in 1911, could have significantly improved their survival chances. Nevertheless, even with today's knowledge, a repeat attempt at his expedition would by no means be bound to succeed.

Physiological adaptation of a mature adult walking the Alps

Research on endurance locomotion has mainly focused on elite athletes rather than common middle-aged subjects. Our report describes the physiological and hematological adaptation of a healthy, active 62-year-old man who trekked alone along a 1300 km/3 month course of Alpine paths (Via Alpina). The following procedures were conducted: pre- and post-trekking and fortnightly field anthropometry (total and lean body mass), functional tests (isometric maximal voluntary force, spontaneous walking speed, relative metabolic cost, and peak oxygen consumption) and clinical chemistry/hematological measurements with laboratory instruments; daily self-administered effort measurements using portable devices along the route (walked distance, ascent, descent, time, metabolic consumption, and cost). Despite the tough trekking route, the subject completed the trek without any worsening of his performance, or any significant health or functional problems. In addition, his peak oxygen consumption increased by 13.2%. His successful adaptation may be attributed to his constant, repeated middle-intensity and extensive exercise and lengthy exposure to high altitude. The clinical chemistry/hematological measurements documented his physiological adaptation. In conclusion, we show how an active, middle-aged man can successfully face endurance trekking, not only without any harm to his health or functions but also with an increase in his capacity to support specific effort.

Can neuromuscular fatigue explain running strategies and performance in ultra-marathons?: the flush model

While the industrialized world adopts a largely sedentary lifestyle, ultra-marathon running races have become increasingly popular in the last few years in many countries. The ability to run long distances is also considered to have played a role in human evolution. This makes the issue of ultra-long distance physiology important. In the ability to run multiples of 10 km (up to 1000 km in one stage), fatigue resistance is critical. Fatigue is generally defined as strength loss (i.e. a decrease in maximal voluntary contraction [MVC]), which is known to be dependent on the type of exercise. Critical task variables include the intensity and duration of the activity, both of which are very specific to ultra-endurance sports. They also include the muscle groups involved and the type of muscle contraction, two variables that depend on the sport under consideration. The first part of this article focuses on the central and peripheral causes of the alterations to neuromuscular function that occur in ultra-marathon running. Neuromuscular function evaluation requires measurements of MVCs and maximal electrical/magnetic stimulations; these provide an insight into the factors in the CNS and the muscles implicated in fatigue. However, such measurements do not necessarily predict how muscle function may influence ultra-endurance running and whether this has an effect on speed regulation during a real competition (i.e. when pacing strategies are involved). In other words, the nature of the relationship between fatigue as measured using maximal contractions/stimulation and submaximal performance limitation/regulation is questionable. To investigate this issue, we are suggesting a holistic model in the second part of this article. This model can be applied to all endurance activities, but is specifically adapted to ultra-endurance running: the flush model. This model has the following four components: (i) the ball-cock (or buoy), which can be compared with the rate of perceived exertion, and can increase or decrease based on (ii) the filling rate and (iii) the water evacuated through the waste pipe, and (iv) a security reserve that allows the subject to prevent physiological damage. We are suggesting that central regulation is not only based on afferent signals arising from the muscles and peripheral organs, but is also dependent on peripheral fatigue and spinal/supraspinal inhibition (or disfacilitation) since these alterations imply a higher central drive for a given power output. This holistic model also explains how environmental conditions, sleep deprivation/mental fatigue, pain-killers or psychostimulants, cognitive or nutritional strategies may affect ultra-running performance.

The biochemical, physiological and psychological consequences of a "1,000 miles in 1,000 hours" walking challenge

The combined effects of 42 days of chronic sleep disruption and repeated hourly bouts of physical exertion have not been described. This case study reports the physiological and psychological demands placed on one individual who walked 1 mile in each consecutive hour for a period of 1,000 h (42 days), covering a total distance of 1,000 miles. The participant walked at a mean speed of 1.75 m/s completing each mile in approximately 15 min. Over the course of the challenge, the individual lost 1.6 kg in body weight. Markers of skeletal muscle damage, increased gradually whilst free testosterone levels decreased over the course of the challenge. Stress hormones increased whilst inflammatory markers (CRP) initially rose but then returned towards baseline over the course of the study. Cognitive motor performance measured via reaction time was maintained throughout the 42 days. The participant also displayed mood states typical of an elite athlete at baseline and throughout the challenge. Participation in this novel '1,000 mile 1,000 h' walking challenge evoked considerable physiological stress in a fit, healthy middle-aged participant but did not markedly alter cognitive performance or mood over the 42-day period.

Why marathon migrants get away with high metabolic ceilings: towards an ecology of physiological restraint

Animals usually are not willing to perform at levels, or for lengths of time, of which they should be maximally capable. In stating this, exercise performance and inferred capacity are gauged with respect to body size and the duration of particular levels of energy expenditure. In such relative terms, the long-term metabolic ceiling of ca. 7 times basal metabolic rate in challenged but energy-balanced individuals may be real and general, because greater performance over long periods requires larger metabolic machinery that is ever more expensive to maintain. Avian marathon migrants relying on stored fuel (and therefore not in energy balance) that work for 9 consecutive days at levels of 9-10 times basal metabolic rate are exceptional performers in terms of the 'relative expenditure' on 'duration of a particular activity' curve nevertheless. Here I argue that metabolic ceilings in all situations (energy balanced or not) have their origin in the fitness costs of high performance levels due to subsequently reduced survival, which then precludes the possibility of future reproduction. The limits to performance should therefore be studied relative to ecological context (which includes aspects such as pathogen pressure and risk of overheating), which determines the severity of the survival punishment of over-exertion. I conclude that many dimensions of ecology have determined at which performance levels (accounting for time) individual animals, including human athletes, begin to show physiological restraint. Using modern molecular techniques to assay wear and tear, in combination with manipulated work levels in different ecological contexts, might enable experimental verification of these ideas.

Age-dependent endothelial dysfunction is associated with failure to increase plasma nitrite in response to exercise

Age-dependent alterations of the vessel wall may predispose older individuals to increased cardiovascular pathology. Aging is associated with an impaired bioactivity of nitric oxide (NO). Plasma nitrite reflects NO-synthase activity under fasting conditions and is an important storage pool of NO. To test the hypothesis that aging is associated with an impaired capacity of the vasculature to increase plasma nitrite during exercise, 29 young and 28 old healthy individuals (25 +/- 1 years and 58 +/- 2 years; P < 0.001) without major cardiovascular risk factors were enrolled. Exercise stress was similar in both groups. Baseline nitrite did not differ (107 +/- 8 vs. 82 +/- 10 nmol/l, young vs. old; n.s.) although a trend toward higher nitrite levels in young individuals was seen. In young subjects, exercise increased plasma nitrite by 38 +/- 7% (P < 0.001) compared to only 13 +/- 8% (P = n.s.) in older subjects. L-NMMA blocked increases of nitrite. Endothelial function, as defined by flow-mediated-dilation (FMD) of the brachial artery via ultrasound, was impaired in older subjects (5.4 +/- 0.4% vs. 6.7 +/- 0.3%; P < 0.01). Multivariate analysis showed that age (P = 0.007), BMI (P = 0.010), and LDL (P = 0.021) were independent predictors of nitrite increase. The fact that aging is associated with an impaired capacity of the vasculature to adequately increase nitrite to physiological stimuli may contribute to attenuated maintenance and further deterioration of vascular homeostasis with aging.

Mind and muscle: the cognitive-affective neuroscience of exercise

There is growing basic-science interest in the mechanisms underpinning the positive effects of exercise on brain function and cognitive-affective performance. There is also increasing clinical evidence that exercise may prevent and treat various neuropsychiatric disorders. At the same time, there is growing awareness that athletic performance is mediated in crucial ways by central nervous system mechanisms. The relevant mechanisms in all these cases requires further exploration, but likely includes neurotrophic, neuroendocrine, and neurotransmitter systems, which in turn are crucial mediators of psychopathology and resilience. The hypothesis that Homo sapiens evolved as a specialist endurance runner provides an intriguing context against which to research the proximal mechanisms relevant to a cognitive-affective neuroscience of exercise.