Alternative Metabolic Strategies are Employed by Endurance Runners of Different Body Sizes; Implications for Human Evolution

Objective A suite of adaptations facilitating endurance running (ER) evolved within the hominin lineage. This may have improved our ability to reach scavenging sites before competitors, or to hunt prey over long distances. Running economy (RE) is a key determinant of endurance running performance, and depends largely on the magnitude of force required to support body mass. However, numerous environmental factors influence body mass, thereby significantly affecting RE. This study tested the hypothesis that alternative metabolic strategies may have emerged to enable ER in individuals with larger body mass and poor RE. Methods A cohort of male (n = 25) and female (n = 19) ultra-endurance runners completed submaximal and exhaustive treadmill protocols to determine RE, and V̇O2Max. Results Body mass was positively associated with sub-maximal oxygen consumption at both LT1 (male r=0.66, p<0.001; female LT1 r=0.23, p=0.177) and LT2 (male r=0.59, p=0.001; female r=0.23, p=0.183) and also with V̇O2Max (male r=0.60, p=0.001; female r=0.41, p=0.046). Additionally, sub-maximal oxygen consumption varied positively with V̇O2Max in both male (LT1 r=0.54, p=0.003; LT2 r=0.77, p<0.001) and female athletes (LT1 r=0.88, p<0.001; LT2 r=0.92, p<0.001). Conclusions The results suggest that, while individuals with low mass and good RE can glide economically as they run, larger individuals can compensate for the negative effects their mass has on RE by increasing their capacity to consume oxygen. The elevated energy expenditure of this low-economy high-energy turnover approach to ER may bring costs associated with energy diversion away from other physiological processes, however.

Endurance running during late murine adolescence results in a stronger anterior cruciate ligament and flatter posterior tibial slopes compared to controls

Background Anterior cruciate ligament (ACL) injury rates continue to rise among youth involved in recreational and competitive athletics, requiring a better understanding of how the knee structurally and mechanically responds to activity during musculoskeletal growth. Little is understood about how anatomical risk factors for ACL injury (e.g., small ACL size, narrow intercondylar notch, and steep posterior tibial slope) develop and respond to increased physical activity throughout growth. We hypothesized that the ACL-complex of mice engaged in moderate to strenuous physical activity (i.e., endurance running) throughout late adolescence and young adulthood would positively functionally adapt to repetitive load perturbations. Methods Female C57BL6/J mice (8 weeks of age) were either provided free access to a standard cage wheel with added resistance (n = 18) or normal cage activity (n = 18), for a duration of 4 weeks. Daily distance ran, weekly body and food weights, and pre- and post-study body composition measures were recorded. At study completion, muscle weights, three-dimensional knee morphology, ACL cross-sectional area, and ACL mechanical properties of runners and nonrunners were quantified. Statistical comparisons between runners and nonrunners were assessed using a two-way analysis of variance and a Tukey multiple comparisons test, with body weight included as a covariate. Results Runners had larger quadriceps (p = 0.02) and gastrocnemius (p = 0.05) muscles, but smaller hamstring (p = 0.05) muscles, compared to nonrunners. Though there was no significant difference in ACL size (p = 0.24), it was 13% stronger in runners (p = 0.03). Additionally, both the posterior medial and lateral tibial slopes were 1.2 to 2.2 degrees flatter than those of nonrunners (p < 0.01). Conclusions Positive functional adaptations of the knee joint to moderate to strenuous exercise in inbred mice offers hope that that some anatomical risk factors for ACL injury may be reduced through habitual physical activity. However, confirmation that a similar response to loading occurs in humans is needed.

Percentile Curves for Multiple Physical Fitness Components Among Chinese Han Children and Adolescents Aged 7–18 Years From a National Survey Based on the Total and the Normal Weight Population

Introduction: To develop sex- and age-specific percentile curves for seven physical fitness components for Chinese Han children and adolescents aged 7–18 years based on the total and the normal weight population using a nationally representative sample.Methods: A total of 214,228 Chinese Han children and adolescents aged 7–18 years old with all nutritional status and 161,999 with normal weight were examined. Seven physical fitness components [forced vital capacity (FVC), standing long jump (SLJ), 50-m dash, sit-and-reach (SR), grip strength (GS), body muscle strength (BMS), and endurance running (ER)] were measured, and percentile curves for each physical fitness component at the 20th, 40th, 60th, and 80th percentiles were calculated using the general additive model for location, scale, and shape (GAMLSS).Results: Physical fitness presents different characteristics in each subgroup of sex, age, and nutritional status among children and adolescents. Sex- and age-specific percentiles for the seven physical fitness components among the Chinese Han children and adolescents aged 7–18 years based on the total and the normal weight population were provided as curves. Boys performed better than girls in FVC, SLJ, 50-m dash, GS, and ER but worse in SR. The performances of FVC, SLJ, 50-m dash, GS, BMS, and ER increased with age, but the estimates of SR were at the bottom among boys aged 12 years and girls aged 11 years. The annual increments of all components were larger in boys than girls at the peak time, which was earlier in girls than boys. The gap of physical fitness components between sexes increased with age, especially during puberty (since after 11 years old).Conclusion: The present study described the percentile curves of seven physical fitness components among the Chinese Han children and adolescents based on the total and the normal weight population at the national level, which could help to chart the level of physical fitness across age span and identify the extreme populations with either health concerns or potential talents.

The Effects of Six-Month Subalpine Training on the Physical Functions and Athletic Performance of Elite Chinese Cross-Country Skiers

Purpose: This study investigated the changes in the blood indices, specific athletic abilities, and physical fitness of outstanding cross-country skiers, trained in the subalpine; Methods: Twenty-eight athletes (twenty males and eight females) from the National Cross-country Ski Training Team completed sub-alpine training during the 2020–2021 snow season. The athletes′ physical functions were evaluated by collecting blood from elbow veins and measuring blood biochemical indexes. To compare the treadmill roller-skiing athletic ability and physical fitness of athletes before and after subalpine; Results: Male and female athletes showed different trends in red blood cells (RBC), hemoglobin (Hb), cortisol (C), Creatine Kinase (CK) and blood urea (BU) (p < 0.05 or p < 0.01). Overall, the female athletes’ mean values of RBC, Hb, CK, and BU were lower than that of male athletes, while C was just the opposite. Comparing the athletic performance of athletes before and after the subalpine, it was found that blood lactate concentrations were significantly lower in both male and female athletes at the same load intensity (p < 0.05 or p < 0.01), whereas 10 km endurance running and 1 RM deep squat were significantly higher in both male and female athletes (p < 0.05 or p < 0.01). Conclusions: After 6 months of subalpine training, cross-country skiers improved their oxygen-carrying capacity and anabolism, and showed significant improvements in specific athletic ability, physical endurance, acid tolerance and 1 RM absolute strength for both male and female athletes.

Sustainable Food Support during an Ultra-Endurance and Mindfulness Event: A Case Study in Spain

The present industrial food-production system is not suitably ecological for the environment. Mindful nutrition in sport is a relevant emergent sub-discipline that could help reduce environmental degradation. This case study describes a sustainable support diet during an ultra-endurance running (UR) event called the “Indoor Everest Challenge”. This UR challenge involved attaining the altitude of Mount Everest (8849 m) in a simulated way, in less than 24 h, without using ultra-processed food and without wasting plastics. During this challenge, a male athlete (34 years, weight: 78 kg, and height: 173 cm) wore a SenseWear Armband® (BodyMedia Inc., Pittsburg, PA, USA) accelerometer on his right arm to estimate energy expenditure. To supply his nutritional requirements, the athlete consumed only specially prepared homemade and organic food. All consumption was weighed and recorded in real-time; we determined nutrients using two databases: a food composition software, Dial Alce Ingenieria® (Madrid, Spain), to measure energy and macro- and micro-nutrients, and Phenol Explorer Database® (INRA Institut National de Recherche pour l’Alimentation, Paris, France) precisely to determine polyphenolic content. Most energy intake (up to 96%) came from plant foods. We found that subject consumed 15.8 g/kg−1/d−1 or 1242 g of carbohydrates (CHO), (2.4 g/kg−1/d−1) or 190 g of proteins (P), and 10,692 mL of fluid. The total energy intake (7580 kcal) showed a distribution of 65% CHO, 10% P, and 25% lipids (L). Furthermore, this sustainable diet lead to a high antioxidant intake, specifically vitamin C (1079 mg), vitamin E (57 mg), and total polyphenols (1910 mg). This sustainable approach was suitable for meeting energy, CHO, and P recommendations for UR. Physical and mental training (mindfulness) were integrated from the specific preliminary phase to the day of the challenge. The athlete completed this challenge in 18 h with a low environmental impact. This sports event had an educational component, as it awakened curiosity towards food sustainability.

Vertical Jumping as a Monitoring Tool in Endurance Runners: A Brief Review

Jumping performance (e.g., countermovement jump [CMJ]), as a measure of neuromuscular performance, has been suggested as an easy-to-use tool which simultaneously provides neuromuscular and metabolic information and, thereby, allows coaches to confidently monitor the status of their athletes during a workout. This hypothesis has been satisfactorily tested with sprint athletes. However, the rationale for the use of CMJ height loss as an index to monitor the workload during an endurance running session is not sufficiently evidence-based. First, it is assumed that a CMJ height loss occurs during typical interval training for endurance runners. Second, it is also assumed that a significant relationship between metabolic stress and the neuromuscular strain induced during these endurance workouts exists. These two assumptions will be questioned in this review by critically analyzing the kinetics of CMJ performance during and after running workouts, and the relationship between neuromuscular and physiological stress induced during different protocols in endurance runners. The current evidence shows that fatigue induced by common running workouts for endurance runners does not counterbalance the potentiation effect in the CMJ height. Additionally, the findings reported among different studies are consistent regarding the lack of association between CMJ height loss and physiological stress during interval sessions in endurance runners. In practical terms, the authors suggest that this marker of neuromuscular fatigue may not be used to regulate the external training load during running workouts in endurance runners. Nevertheless, the analysis of CMJ height during running workouts may serve to monitor chronic adaptations to training in endurance runners.

Comparison and Performance Validation of Calculated and Established Anaerobic Lactate Thresholds in Running

Background and Objectives: This study aimed to compare the calculated running velocity at the anaerobic lactate threshold (cLTAn), determined by a mathematical model for metabolic simulation, with two established threshold concepts (onset of blood lactate accumulation (OBLA; 4 mmol∙L−1) and modified maximal deviation method (mDmax)). Additionally, all threshold concepts were correlated with performance in different endurance running events. Materials and Methods: Ten sub-elite runners performed a 30 s sprint test on a cycle ergometer adjusted to an isokinetic mode set to a cadence of 120 rpm to determine maximal lactate production rate (VLamax), and a graded exercise test on a treadmill to determine maximal oxygen uptake (VO2max). Running velocities at OBLA, mDmax, and cLTAn were then compared with each other, and further correlated with running performance over various distances (3000 m, 5000 m, and 10,000 m). Results: The mean difference in cLTAn was −0.13 ± 0.43 m∙s−1 and −0.32 ± 0.39 m∙s−1 compared to mDmax (p = 0.49) and OBLA (p < 0.01), respectively. cLTAn indicated moderate to good concordance with the established threshold concepts (mDmax: ICC = 0.87, OBLA: ICC = 0.74). In comparison with other threshold concepts, cLTAn exhibited comparable correlations with the assessed running performances (cLTAn: r = 0.61–0.76, mDmax: r = 0.69–0.79, OBLA: r = 0.56–0.69). Conclusion: Our data show that cLTAn can be applied for determining endurance performance during running. Due to the consideration of individual physiological profiles, cLTAn offers a physiologically justified approach to assess an athlete’s endurance performance.

Incidence of exercise-associated hyponatremia during a high-altitude 161-km ultramarathon

[Purpose] Exercise-associated hyponatremia (EAH) is a well-known condition among endurance athletes at low altitudes. The incidence of EAH during ultramarathons at high altitudes warrants further investigation. This prospective observational study was conducted on the participants of the Leadville Trail 100 run, a 161- km race held at a high altitude (2,800 m-3,840 m).[Methods] Venous blood samples were collected before and immediately after the race. The participants completed an electronic survey after the race. Our main outcome measure was the post-race serum sodium ([Na+]) level.[Results] Of the 672 athletes who started the race, 351 (52%) successfully completed the event within the 30- hour cut-off. Post-race blood samples were collected from 84 runners (66 finishers). Both pre- and post-race blood samples were collected from 37 participants. Twenty percent of the post-race participants had EAH. Only one post-race participant had a [Na+] level of <130 mmol/L. All participants with EAH were asymptomatic. One participant had an abnormal pre-race [Na+] level (134 mmol/L). Female participants had a significantly higher rate of EAH than male participants (40% vs. 16%; p=0.039). Age, body mass index, weight changes, race completion status, nonsteroidal anti-inflammatory drug use, and urine specific gravity were not associated with the development of EAH. Lower postrace [Na+] levels were associated with higher serum creatine kinase values (R2=0.1, p<0.005).[Conclusion] High altitude (3,840 m peak) does not appear to enhance the incidence of EAH after an ultramarathon footrace. This suggests that ambient temperature (low temperatures reduce risk), sex (female predilection), endurance running, and overhydration are more prominent risk factors for EAH than high altitude.

Motivations for the training effort of Romanian masters athletes

The aim of this study was to investigate the motivations of Romanian Masters athletes to train for endurance running in order to participate in half-marathon competitions. The research method used was the survey. This tool consisted of a questionnaire that was purposely developed for the present research. Out of the 111 experienced respondents practising running for 13 years on average, 61.8% are men and 38.2% are women. The results are different and are mainly focused on reaching a state of well-being (67%) for both men (67.2%) and women (66.7%); there are significant differences between the 35-44 and 55+ age categories (t = 2.776, p < 0.01). This motivation has contributed to maintaining and improving physical performance with aging. Women are more motivated than men to run for health benefits. In conclusion, we believe that paying attention tomotivation is important in terms of encouraging people of all ages to play outdoor sports, promoting a healthy lifestyle based on exercise and managing grassroots sport. The Masters athlete is a rich source of information regarding a person’s ability to maintain maximum physical performance and physiological function as they get older. The impressive capacity for physical performance and physiological functioning makes Masters athletes a model for society.

Characterizing Marathon-Induced Metabolic Changes Using 1H-NMR Metabolomics

Although physical activity is a health-promoting, popular global pastime, regular engagement in strenuous exercises, such as long-distance endurance running races, has been associated with a variety of detrimental physiological and immunological health effects. The resulting altered physiological state has previously been associated with fluctuations in various key metabolite concentrations; however, limited literature exists pertaining to the global/holistic metabolic changes that are induced by such. This investigation subsequently aims at elucidating the metabolic changes induced by a marathon by employing an untargeted proton nuclear magnetic resonance (1H-NMR) spectrometry metabolomics approach. A principal component analysis (PCA) plot revealed a natural differentiation between pre- and post-marathon metabolic profiles of the 30-athlete cohort, where 17 metabolite fluctuations were deemed to be statistically significant. These included reduced concentrations of various amino acids (AA) along with elevated concentrations of ketone bodies, glycolysis, tricarboxylic acid (TCA) cycle, and AA catabolism intermediates. Moreover, elevated concentrations of creatinine and creatine in the post-marathon group supports previous findings of marathon-induced muscle damage. Collectively, the results of this investigation characterize the strenuous metabolic load induced by a marathon and the consequential regulation of main energy-producing pathways to accommodate this, and a better description of the cause of the physiological changes seen after the completion of a marathon.