Classification of middle- and long-distance runners based upon their performance

The scientific literature lacks consensus on classification of middle- and long-distance runners. This creates situations where the sample studied may not represent the target population and could produce misleading conclusions. Thus, we present an approach for a data-driven classification of middle- and long-distance runners according to their competition results. The best annual results of middle- and long-distance track runners participating at major (Olympics, World and European Championships) and national championships (Denmark, Sweden, Finland, Norway) were gathered for the 2012-2018 period. Overall, 1920 men's and 1808 women's performance results were gathered. The results were grouped accordingly. Quadratic discriminant analysis was applied to define the limits between the groups. Three basic categories could be proposed for classification: world class, international and national. Classification provides a realistic overview of performance standards and the number of athletes for different categories in middle- and long-distance track running in real-world settings. The performance-based classification provides data-driven and unified criteria for reporting standards on athletes' proficiency levels. It allows for more consistent reporting practices on the target population in research. In addition to scientific research, the classification could also be employed for a variety of practical purposes.

Functional network segregation is associated with higher functional connectivity in endurance runners

Neuroimaging studies have identified significant differences in brain structure, function, and connectivity between endurance runners and healthy controls. However, the topological organization of large-scale functional brain networks remains unexplored in endurance runners. Using resting-state functional magnetic resonance imaging data, this study examined the differences in the topological organization of functional networks between endurance runners (n = 22) and healthy controls (n = 20). Endurance runners had significantly higher clustering coefficients in the whole-brain functional network than healthy controls, but the two did not differ regarding the shortest path length or small-world index. Using network-based statistics, we identified one subnetwork in endurance runners with higher functional connectivity than healthy controls, and the mean functional connectivity of the subnetwork significantly correlated with the three aforementioned small-world parameters. In this subnetwork, the mean clustering coefficient of nodes associated with short-range connections was higher in endurance runners than in healthy controls, but the mean clustering coefficient of nodes associated with long-range connections did not differ between the two groups. In conclusion, using graph theoretical approaches, we revealed significant differences in the topological organization of the whole-brain functional network and functional connectivity between endurance runners and healthy controls. The relationship between these two features suggests that a more segregated network may arise from the optimization of the identified subnetwork in endurance runners. These findings are possibly the neural basis underlying the good performance of endurance runners in endurance running.

The PPARGC1A Gly482Ser polymorphism is associated with elite long-distance running performance

Success in long-distance running relies on multiple factors including oxygen utilisation and lactate metabolism, and genetic associations with athlete status suggest elite competitors are heritably predisposed to superior performance. The Gly allele of the PPARGC1A Gly482Ser rs8192678 polymorphism has been associated with endurance athlete status and favourable aerobic training adaptations. However, the association of this polymorphism with performance amongst long-distance runners remains unclear. Accordingly, this study investigated whether rs8192678 was associated with elite status and competitive performance of long-distance runners. Genomic DNA from 656 Caucasian participants including 288 long-distance runners (201 men, 87 women) and 368 non-athletes (285 men, 83 women) was analysed. Medians of the 10 best UK times (Top10) for 10 km, half-marathon and marathon races were calculated, with all included athletes having personal best (PB) performances within 20% of Top10 (this study's definition of "elite"). Genotype and allele frequencies were compared between athletes and non-athletes, and athlete PB compared between genotypes. There were no differences in genotype frequency between athletes and non-athletes, but athlete Ser allele carriers were 2.5% faster than Gly/Gly homozygotes (p = 0.030). This study demonstrates that performance differences between elite long-distance runners are associated with rs8192678 genotype, with the Ser allele appearing to enhance performance.

The effect of progressive endurance training and extract of black winter truffle on proteins levels and expression of hippocampus α-synuclein and HSF1 in the healthy and diabetic rats

Aim

The research aimed to investigate the effect of endurance running and T. Brumale extract on α-Syn and HSF1 in the brain and serum of healthy and diabetic rats.

Methods

A total of 40 Wistar rats were randomly divided into eight groups: Control (C), Exercise (E), Control-Tuber (T), Exercise-Tuber (ET), Control-Diabetes (D), Exercise-Diabetes (ED), Control-Diabetes-Tuber (CDT), and Exercise-Diabetes-Tuber (EDT). The endurance running was carried out five times per week for five weeks. The hippocampus and the serum α-Syn and HSF1 were measured using an enzyme-linked immunosorbent assay method.

Results

The brain α-Syn levels were higher in diabetic groups than in the healthy groups, but insignificantly (P ≤ 0.05). The brain α-Syn level significantly increased in the EDT group compared to the T group (P ≤ 0.05). The serum level of α-Syn in the ED group was significantly higher than in the E and D groups (P ≤ 0.05). The brain HSF1 level was significantly higher in the ED group compared to the D group (P ≤ 0.05). The gene expression of hsf1 was significantly reduced in the E group compared to the other groups and the EDT group compared to ED and CDT groups (P ≤ 0.05). Furthermore, the serum HSF1 level significantly increased in the ED group compared to the D group (P ≤ 0.05).

Conclusion

The results of this study suggest that progressive endurance running may improve neuroprotective conditions in diabetic patients by increasing HSF1 in the brain.

Prospective evaluation of cardiac effects of first-time marathon training, running, and recovery in middle-aged men: cohort study rationale and design

BACKGROUND

Several phenomena may point to potentially detrimental cardiac effects of endurance exercise, such as elevated circulating cardiac troponin levels and reductions in systolic and diastolic function directly after marathon completion. Furthermore, while myocardial abnormalities have been reported in patients who recovered from COVID-19, the cardiac impact of extensive endurance exercise in individuals who recovered from COVID-19 remains unknown. We therefore aim to investigate (potentially detrimental) cardiac effects of first-time marathon training and participation, including a subset of participants who recovered from COVID-19, in apparently healthy middle-aged men.

STUDY DESIGN

This exploratory prospective cohort study investigates cardiac effects of first-time marathon running in 24 middle-aged (35-50 years) healthy men. Primary outcomes are cardiac morphological changes from pre-training up to 1 month after marathon completion, measured with magnetic resonance imaging (MRI) at 4 time points: 1) baseline (4 months before the marathon), 2) pre-marathon (2 weeks before the marathon), 3) post-marathon (< 24 h post-marathon), and 4) recovery (4 weeks after the marathon). Secondary parameters include other cardiac or non-cardiac changes: 1) quantitative MRI myocardial mapping, including mean diffusivity and extracellular volume fraction, 2) echocardiographic morphology and function changes, 3) VO₂max, 4) electrocardiogram changes, and 5) levels of cardiac biomarkers.

DISCUSSION

This study will contribute to our understanding of cardiac adaptations and maladaptations to first-time marathon running in middle-aged men, and the interaction between extreme endurance exercise and potential detrimental cardiac effects, also in the context of COVID-19. Results will inform on future research directions while providing new clinical insights for health professionals involved in athlete care.

Sex influence on muscle synergies in a ballistic force-velocity test during the delayed recovery phase after a graded endurance run

The acute and delayed phases of the functional recovery pattern after running exercise have been studied mainly in men. However, it seems that women are less fatigable and/or recover faster than men, at least when tested in isometric condition. After a 20 km graded running race, the influence of sex on the delayed phase of recovery at 2-4 days was studied using a horizontal ballistic force-velocity test. Nine female and height male recreational runners performed maximal concentric push-offs at four load levels a week before the race (PRE), 2 and 4 days (D2 and D4) later. Ground reaction forces and surface electromyographic (EMG) activity from 8 major lower limb muscles were recorded. For each session, the mechanical force-velocity-power profile (i.e. theoretical maximal values of force ( F ¯ 0), velocity ( V ¯ 0), and power ( P ¯ max)) was computed. Mean EMG activity of each recorded muscle and muscle synergies (three for both men and women) were extracted. Independently of the testing sessions, men and women differed regarding the solicitation of the bi-articular thigh muscles (medial hamstring muscles and rectus femoris). At mid-push-off, female made use of more evenly distributed lower limb muscle activities than men. No fatigue effect was found for both sexes when looking at the mean ground reaction forces. However, the force-velocity profile varied by sex throughout the recovery: only men showed a decrease of both V ¯ 0 (p < 0.05) and P ¯ max (p < 0.01) at D2 compared to PRE. Vastus medialis activity was reduced for both men and women up to D4, but only male synergies were impacted at D2: the center of activity of the first and second synergies was reached later. This study suggests that women could recover earlier in a dynamic multi-joint task and that sex-specific organization of muscle synergies may have contributed to their different recovery times after such a race.

Changes in segment coordination variability and the impacts of the lower limb across running mileages in half marathons: Implications for running injuries

BACKGROUND

Segment coordination variability (CV) is a movement pattern associated with running-related injuries. It can also be adversely affected by a prolonged run. However, research on this topic is currently limited. The purpose of this study was to investigate the effects of a prolonged run on segment CV and vertical loading rates during a treadmill half marathon.

METHODS

Fifteen healthy runners ran a half marathon on an instrumental treadmill in a biomechanical laboratory. Synchronized kinematic and kinetic data were collected every 2 km (from 2 km until 20 km), and the data were processed by musculoskeletal modeling. Segment CVs were computed from the angle-angle plots of selected pelvis-thigh, thigh-shank, and shank-rearfoot couplings using a modified vector coding technique. The loading rate of vertical ground reaction force was also calculated. A one-way MANOVA with repeated measures was performed on each of the outcome variables to examine the main effect of running mileage.

RESULTS

Significant effects of running mileage were found on segment CVs (p ≤ 0.010) but not on loading rate (p = 0.881). Notably, during the early stance phase, the CV of pelvis frontal vs. thigh frontal was significantly increased at 20 km compared with the CV at 8 km (g = 0.59, p = 0.022). The CV of shank transverse vs. rearfoot frontal decreased from 2 km to 8 km (g = 0.30, p = 0.020) but then significantly increased at both 18 km (g = 0.05, p < 0.001) and 20 km (g = 0.36, p < 0.001).

CONCLUSION

At the early stance, runners maintained stable CVs on the sagittal plane, which could explain the unchanged loading rate throughout the half marathon. However, increased CVs on the frontal/transverse plane may be an early sign of fatigue and indicative of possible injury risk. Further studies are necessary for conclusive statements in this regard.

Beetroot juice - a suitable post-marathon metabolic recovery supplement?

BACKGROUND

Red beetroot (Beta vulgaris L.) is a multifunctional functional food that reportedly exhibits potent anti-inflammatory, antioxidant, vasodilation, and cellular regulatory properties. This vegetable has gained a fair amount of scientific attention as a possible cost-effective supplement to enhance performance and expedite recovery after physical exercise. To date, no study has investigated the effects of incremental beetroot juice ingestion on the metabolic recovery of athletes after an endurance race. Considering this, as well as the beneficial glucose and insulin regulatory roles of beetroot, this study investigated the effects of beetroot juice supplementation on the metabolic recovery trend of athletes within 48 h after completing a marathon.

METHODS

By employing an untargeted two-dimensional gas chromatography time-of-flight mass spectrometry approach, serum samples (collected pre-, post-, 24 h post-, and 48 h post-marathon) of 31 marathon athletes that ingested a series (n = 7; 250 ml) of either beetroot juice (n = 15 athletes) or isocaloric placebo (n = 16 athletes) supplements within 48 h post-marathon, were analysed and statistically compared.

RESULTS

The metabolic profiles of the beetroot-ingesting cohort recovered to a pre-marathon-related state within 48 h post-marathon, mimicking the metabolic recovery trend observed in the placebo cohort. Since random inter-individual variation was observed immediately post-marathon, only metabolites with large practical significance (p-value ≤0.05 and d-value ≥0.5) within 24 h and 48 h post-marathon were considered representative of the effects of beetroot juice on metabolic recovery. These (n = 4) mainly included carbohydrates (arabitol and xylose) and odd-chain fatty acids (nonanoate and undecanoate). The majority of these were attributed to beetroot content and possible microbial fermentation thereof.

CONCLUSION

Apart from the global metabolic recovery trends of the two opposing cohorts, it appears that beetroot ingestion did not expedite metabolic recovery in athletes within 48 h post-marathon.

Training and technique choices predict self-reported running injuries: An international study

OBJECTIVES

The aim of this study was to describe the self-reported injury, training, and running technique choices of regular runners in four international regions.

DESIGN AND SETTING

756 participants began an expert derived self-report online survey in Ireland, USA, Hong Kong and Australia.

PARTICIPANTS

325 participants completed the survey (age = 38 ± 10 years; weight = 68.0 ± 13.1 kg; height = 1.70 ± 0.10 m).

MAIN OUTCOME MEASURES

Descriptive statistics are reported examining injury incidence and location; shoe and orthosis choices; and training and technique practices. A backwards logistic regression was implemented to examine associations between injury and training choices.

RESULTS

68.3% reported having an injury in the last year. 81.45% of these injuries were believed to be running related. A large variation in training and footwear choices were observed for respondents. The regression (P ≤ 0.001) explained 20% of the variance in injury selection (Nagelkerke R²) and was able to identify 73% of cases accurately. Associated injury factors included competitive running, running on more than one surface, younger age, having a lower running age, and a higher proportion of running at an easy intensity.

CONCLUSIONS

The high amount of variability in runner's choices highlights the lack of consistent information being presented to them and may be the reason for the high injury incidence.

Structural and functional brain signatures of endurance runners

Although endurance running (ER) seems to be a simple repetitive exercise, good ER performance also requires and relies on multiple cognitive and motor control processes. Most of previous neuroimaging studies on ER were conducted using a single MRI modality, yet no multimodal study to our knowledge has been performed in this regard. In this study, we used multimodal MRI data to investigate the brain structural and functional differences between endurance runners (n = 22; age = 26.27 ± 6.07 years; endurance training = 6.23 ± 2.41 years) and healthy controls (HCs; n = 20; age = 24.60 ± 4.14 years). Compared with the HCs, the endurance runners showed greater gray matter volume (GMV) and cortical surface area in the left precentral gyrus, which at the same time had higher functional connectivity (FC) with the right postcentral and precentral gyrus. Subcortically, the endurance runners showed greater GMV in the left hippocampus and regional inflation in the right hippocampus. Using the bilateral hippocampi as seeds, further seed-based FC analyses showed higher hippocampal FC with the supplementary motor area, middle cingulate cortex, and left posterior lobe of the cerebellum. Moreover, compared with the HCs, the endurance runners also showed higher fractional anisotropy in several white matter regions, involving the corpus callosum, left internal capsule, left corona radiata, left external capsule, left posterior lobe of cerebellum and bilateral precuneus. Taken together, our findings provide several lines of evidence for the brain structural and functional differences between endurance runners and HCs. The current data suggest that these brain characteristics may have arisen as a result of regular ER training; however, whether they represent the neural correlates underlying the good ER performances of the endurance runners requires further investigations.

Development of a questionnaire to assess dietary restrictions runners use to mitigate gastrointestinal symptoms

Background

Exercise induced gastrointestinal (GI) symptoms can plague athletes, especially runners. Sport nutrition recommendations are nutrient rather than foods focused and do not adequately address strategies to reduce GI symptoms. The objective was to develop a valid and reliable questionnaire to evaluate pre-training and pre-racing voluntary food restrictions/choices, reasons for avoiding foods, and gastrointestinal symptoms in endurance runners.

Methods

Validity testing occurred through four Registered Dietitians, three of whom possess Master’s degrees, and a dietetic trainee who provided initial feedback. Additionally, one Registered Dietitian is a Board Certified Specialist in Sports Dietetics (CSSD), and another has an International Olympic Committee Diploma in Sports Nutrition. The second version was sent out to nine different experts who rated each question using a Likert scale and provided additional comments. For reliability testing, the questionnaire was administered to 39 participants in a test re-test format. Kappa statistics and the prevalence-adjusted bias-adjusted kappa (PABAK) were used to assess the reliability.

Results

All questions had an average Likert scale rating of 4/5 or greater. All test re-test results falling under basic information exhibited substantial agreement (kappa ≥0.61). All medical questions including food allergies and intolerances had moderate (kappa ≥0.41) or higher agreement. Responses were less consistent for food avoidances while training (5/28 outcomes) versus racing (0/28 outcomes) with a kappa below 0.41. All reasons for avoiding foods were deemed reliable. Regarding symptoms, side stitch while training and gas while racing were the only flagged categories.

Conclusions

Overall, the questionnaire is a valid and reliable tool to evaluate voluntary dietary restrictions among endurance runners. Future studies can use the questionnaire to assess dietary strategies runners employ to reduce GI distress and optimize performance.

Electronic supplementary material

The online version of this article (10.1186/s12970-019-0278-7) contains supplementary material, which is available to authorized users.

Hip muscular strength balance is associated with running economy in recreationally-trained endurance runners

Background

The percentage of sustained maximal oxygen uptake and the running economy are important factors that determine the running success of endurance athletes. Running economy is defined as the oxygen uptake required to run at a given speed and depends on metabolic, cardiorespiratory, biomechanical, neuromuscular, and anthropometric factors. With regard to anthropometric characteristics, total body mass seems to be a crucial factor for the running economy. Moreover, neuromuscular components, especially knee muscular strength and the strength balance ratio, also seem to be critical for the running economy. In addition to knee muscle strength, hip muscle strength is also an important contributor to running performance on level or hilly ground. However, the relationship between running economy and the hip muscles is unknown. Thus the aim of the present study was to verify whether hip flexor and extensor isokinetic peak torque, the isokinetic strength balance ratio, total body mass and fat free mass were associated with running economy in both sexes and to compare sex differences in physical fitness and isokinetic strength characteristics.

Methods

A total of 24 male (31.0 ± 7.7 years, 176.2 ± 7.3 cm, and 70.4 ± 8.4 kg) and 15 female (31.3 ± 6.7 years, 162.9 ± 3.9 cm, and 56.0 ± 5.3 kg) recreationally-trained endurance runners were recruited. Maximal oxygen uptake, running economy, conventional (concentric flexors-to-concentric extensors) and functional (concentric flexors-to-eccentric extensors) hip isokinetic strength balance ratios, peak torque of the hip flexor and extensor muscles, total body mass, and fat-free mass were measured. Running economy was assessed on two separate days by means of the energy running cost (E_c) using a motorized treadmill at 10.0 and 12.0 km h⁻¹ (3% gradient) and 11.0 and 14.0 km h⁻¹ (1% gradient).

Results

The functional balance ratio was significantly and negatively associated with E_c at 11.0 (r =  − 0.43, P = 0.04) and 12.0 km h⁻¹ (r =  − 0.65, P = 0.04) when using a 3% gradient in male runners. Considering muscular strength, male runners only showed a significant relationship between E_c (assessed at 12 km h⁻¹ and a 3% gradient) and peak torque for extensor muscle eccentric action (r = 0.72, P = 0.04). For female runners, only peak torque relative to total body mass for extensor muscles (180° s⁻¹) was positively associated with E_c when assessed at 10 km h⁻¹ using a 3% gradient (r = 0.59, P = 0.03). No significant relationships were found between E_c and total body mass or fat-free mass.

Discussion

Given that the functional balance ratio was associated with a better E_c, coaches and athletes should consider implementing a specific strengthening program for hip flexor muscles to increase the functional ratio.

Prevalence in running events and running performance of endurance runners following a vegetarian or vegan diet compared to non-vegetarian endurance runners: the NURMI Study

Background

Beneficial and detrimental effects of various vegetarian and vegan diets on the health status are well known. Considering the growing background numbers of vegetarians and vegans, the number of vegetarian and vegan runners is likely to rise, too. Therefore, the Nutrition and Running High Mileage (NURMI) Study was designed as a comparative study to investigate the prevalence of omnivores, vegetarians, and vegans in running events and to detect potential differences in running performance comparing these three subgroups.

Methods/design

The NURMI Study will be conducted in three steps following a cross-sectional design. Step 1 will determine epidemiological aspects of endurance runners (any distance) using a short standardized questionnaire. Step 2 will investigate dietary habits and running history from eligible participants (capable of running a half-marathon at least) using an extended standardized questionnaire. Step 3 will collect data after a running event on finishing time and final ranking as well as a post-race rating of perceived exertion, mood status, nutrient and fluid intake during the race.

Discussion

Our study will provide a major contribution to overcome the lack of data on the prevalence and running performance of vegetarian and vegan runners in endurance running events. We estimate the prevalence of vegetarians and vegans participating in a running event to be less compared to the respective proportion of vegetarians and vegans to the general population. Furthermore we will validate the subject’s self-assessment of their respective diet. This comparative study may identify possible effects of dietary behavior on running performance und may detect possible differences between the respective subgroups: omnivorous, vegetarian and vegan runners.

Trial registration Current controlled trials, ISRCTN73074080

The cross-sectional area of the gluteus maximus muscle varies according to habitual exercise loading: Implications for activity-related and evolutionary studies

Greater size of the gluteus maximus muscle in humans compared to non-human primates has been considered an indication of its function in bipedal posture and gait, especially running capabilities. Our aim was to find out how the size of the gluteus maximus muscle varies according to sports while controlling for variation in muscle strength and body weight. Data on gluteus maximus muscle cross-sectional area (MCA) were acquired from magnetic resonance images of the hip region of female athletes (N=91), and physically active controls (N=20). Dynamic muscle force was measured as counter movement jump and isometric knee extension force as leg press. Five exercise loading groups were created: high impact (triple-jumpers and high-jumpers), odd impact (soccer and squash players), high magnitude (power-lifters), repetitive impact (endurance runners) and repetitive non-impact (swimmers) loadings. Individuals in high impact, odd impact or high-magnitude loading groups had greater MCA compared to those of controls, requiring powerful hip extension, trunk stabilization in rapid directional change and high explosive muscle force. Larger body size and greater muscle strength were associated with larger MCA. An increase in dynamic force was associated with larger MCA, but the strength of this relationship varied with body weight. Thus, gluteal adaptation in humans promotes powerful lower limb movements required in sprinting and rapid changes in direction, as well as maintenance and stabilization of an erect trunk which also provides a platform for powerful motions of the upper limbs. These movements have likely evolved to facilitate food acquisition, including hunting.