Effects of Ultratrail Running on Neuromuscular Function, Muscle Damage and Hydration Status. Differences According to Training Level

Study of Blood Biomarkers in Athletes with Lower Gastrointestinal Symptoms After an Ultra-Trail Race

Background/Objectives: To investigate the value of intestinal fatty acid-binding protein (I-FABP), D-Lactate, interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-1 receptor antagonist (IL-1Ra), tumor necrosis factor-alpha (TNF-alpha), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), electrolytes and creatinine in athletes with lower gastrointestinal symptoms in a cohort of ultra-trailers. Methods: This is a prospective study set in the ultra-trail of Puy Mary Aurillac, a 105 km race. Athletes included were given two questionnaires to collect demographic data and clinical signs related to the race. Blood samples were also collected before and 1 h after the race. Biomarker results were interpreted according to the occurrence of exercise-induced lower gastrointestinal symptoms, and whether the race was completed or forfeited. Results: Of the 76 runners included, 35 (45.5%) presented lower gastrointestinal symptoms. Runners that presented these symptoms had significantly higher IL-10 concentrations (8.7 pg/mL (interquartile range (IQR): 4.2-1.6)) when compared to runners without symptoms (4.8 pg/mL (IQR: 2.4-9)) (p = 0.01). The pre/post-race amplitude of IL-1Ra variation was greater in the group of runners with lower gastrointestinal symptoms (median: +231% (IQR: 169-551)) compared to runners without symptoms (median: +172% (IQR: 91-393)) (p = 0.04). Finally, the 13 (16.9%) runners who forfeited the race displayed lower AST (p < 0.001), LDH (p = 0.002) and IL-6 (p = 0.002) concentrations, compared to runners who finished the race. These lower concentrations were independent from running time. Conclusions: IL-10 and IL-1Ra could be associated with the occurrence of lower gastrointestinal symptoms.

Impact of Ad Libitum Hydration on Muscle and Liver Damage and Electrolyte Balance in Ultra-Trail Events: A Heatmap Analysis of Biomarkers and Event Characteristics-A Pilot Study

Ultra-trail events (UTs) pose significant challenges to maintaining hydration and electrolyte balance, with risks of dehydration (DH), overhydration (OH), exercise-associated hyponatremia (EAH), and exertional rhabdomyolysis (ER). This study examined the effects of ad libitum (ADL) hydration on hydration status and muscle damage during a nine-stage UT (635 km, 40,586 m elevation gain). Four highly trained male athletes participated. Hydration was assessed via body weight loss (BWL), urine specific gravity (Usg), and serum sodium ([Na+]), while muscle damage markers included creatine kinase (CK), lactate dehydrogenase (LDH), and calcium (Ca), and liver damage biomarkers included aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Our results showed no cases of EAH or hypernatremia ([Na+] > 145 mmol·L-1), with serum [Na+] maintained above 135 mmol·L-1. BWL exceeded the 2% DH threshold in early stages (p = 0.029), and Usg remained elevated (>1.020 g·mL-1). LDH and CK significantly increased at all stages (p < 0.05), persisting for 48 h post-event. Correlations showed BWL aggravated muscle damage (r = 0.47 with CK) and hypocalcemia (r = -0.68 with Ca). Elevation gain/loss amplified fluid loss and muscle injury. While ADL hydration mitigated EAH, it did not fully address DH or muscle damage. Personalized hydration and recovery protocols are crucial to optimizing performance and health in UT events.

Body fluids and muscle changes in trail runners of various distances

Background

This study aims to investigate body fluids and muscle changes evoked by different trail races using anthropometric, bioelectrical, and creatine kinase (CK) measurements.

Methods

A total of 92 subjects (55 men, 37 women) participating in three different races of 14, 35, and 52 km were evaluated before (PRE) and after (POST) the races. Classic bioelectrical impedance vector analysis was applied at the whole-body level (WB-BIVA). Additionally, muscle-localized bioelectrical assessments (ML-BIVA) were performed in a subgroup of 11 men (in the quadriceps, hamstrings, and calves). PRE-POST differences and correlations between bioelectrical values and CK, running time and race distance were tested.

Results

Changes in whole-body vectors and phase angles disclosed an inclination towards dehydration among men in the 14, 35, and 52 km groups (p < 0.001), as well as among women in the 35 and 52 km groups (p < 0.001). PRE Z/H was negatively correlated with running time in the 35 km men group and 14 km women group (r = -0.377, p = 0.048; r = -0.751, p = 0.001; respectively). POST Z/H was negatively correlated with running time in the 14 km women group (r = -0.593, p = 0.02). CK was positively correlated with distance in men and women (p < 0.001) and negatively correlated with reactance and vector length in the 14 km men group (p < 0.05). ML-BIVA echoed the same tendency as the WB-BIVA in the 35 and 52 km runners, with the most notable changes occurring in the calves (p < 0.001).

Conclusions

WB-BIVA and CK measurements underscored a conspicuous trend towards post-race dehydration and muscle damage, displaying a weak association with performance. Notably, ML-BIVA detected substantial alterations primarily in the calves. The study underscores the utility of BIVA as a technique to assess athlete's body composition changes.

Acute Kidney Injury and Hyponatremia in Ultra-Trail Racing: A Systematic Review

Background and objectives: Ultra-trail races can cause episodes of acute kidney injury (AKI) and exercise-associated hyponatremia (EAH) in healthy subjects without previous renal pathology. This systematic review aims to review the incidence of these two syndromes together and separately taking into account the length and elevation of the ultra-trail race examined. Materials and Methods: A systematic review was conducted through electronic search in four electronic databases (PubMed, EBSCO, Web of Science and Alcorze). Results: A total of 1127 articles published between January 2006 and December 31, 2021 were included, 28 of which met the inclusion criteria. The studies were categorized according to the length and stages of the race in four categories: medium (42 to 69 km), long (70 to 99 km), extra (>100 km) and multi-stage if they included various stages. A total of 2950 runners (666 females and 2284 males) were extracted from 28 publications. The AKI incidence found was 42.04% (468 cases of 1113), and 195 of 2065 were diagnosed with EAH, accounting for 9.11%. The concurrence of both pathologies together reached 11.84% (27 individuals) from a total of 228 runners with AKI and EAH simultaneously analyzed. Sorted by race category, the AKI+EAH cases were distributed as follows: 18 of 27 in the extra (13.63% and n = 132), 4 in the large (5.79% and n = 69) and 5 in the medium category (18.15% and n = 27). Conclusions: According to these results, extra and medium races showed a similar incidence of AKI+EAH. These findings underline the importance of the duration and intensity of the race and may make them responsible for the etiology of these medical conditions. Due to their variable incidence, EAH and AKI are often underdiagnosed, leading to poorer prognosis, increased condition seriousness and hindered treatment. The results of this review urge participants, coaches and race organizers to take measures to improve the early diagnosis and urgent treatment of possible EAH and AKI cases.

768-km Multi-Stage Ultra-Trail Case Study-Muscle Damage, Biochemical Alterations and Strength Loss on Lower Limbs

A series of case studies aimed to evaluate muscular fatigue in running a 768-km ultra-trail race in 11 days. Four non-professional athletes (four males) were enrolled. Muscle damage blood biomarkers (creatine kinase (CK), lactodeshydrogenase (LDH), aspartate transaminase (AST) and alanine aminotransferase (ALT) and lower limb strength were evaluated by using Bosco jumps test; squat jump (SJ), countermovement jump (CMJ) and Abalakov jump (ABA) were assessed before (pre), after the race (post) and for two and nine days during the recovery period (rec2 and rec9), respectively. Results showed: pre-post SJ = −28%, CMJ = −36% and ABA = −21%. Values returned to basal during rec9: SJ = −1%, CMJ = −2% or even exceeded pre-values ABA = +3%. On the contrary, muscle damage blood biomarkers values increased at post; CK = +888%, LDH = +172%, AST = +167% and ALT = +159% and the values returned gradually to baseline at rec9 except for AST = +226% and ALT = +103% which remained higher. Nonparametric bivariate Spearman’s test showed strong correlations (Rs ≥ 0.8) between some jumps and muscle damage biomarkers at post (SJ-LDH Rs = 0.80, SJ-AST Rs = 0.8, ABA-LD H Rs = 0.80 and ABA-AST Rs = 0.80), at rec2 (SJ-CK Rs = 0.80 and SJ-ALT Rs = 0.80) and even during rec9 (ABA-CK). Similarly, some parameters such as accumulated elevation and training volume showed a strong correlation with LDH values after finishing the ultra-trail race. The alteration induced by completing an ultra-trail event in the muscle affects lower limb strength and may in some circumstances result in serious medical conditions including post- exertional rhabdomyolysis.