Male Amateur Runners Research Articles

Effect of Short-Term Kinesiology Taping on Knee Proprioception and Quadriceps Performance in Healthy Individuals.

Background: Kinesiology taping (KT) is well known measure for preventing musculoskeletal injuries. Our study aims to explore the actual effects of KT on healthy participants’ knee proprioception and quadriceps performance within 1 h.Methods: A total of 35 healthy male amateur runners were recruited in our study. Four taping sequences were randomly allocated to four different weeks, namely, no taping, placebo taping, KT with tension, and KT with no tension. A CON-TREX isokinetic dynamometer was used in assessing the participants’ knee proprioception and muscle strength of knee extension and flexion at 60°/s. The electromyography (EMG) signals of medial oblique muscle and vastus lateralis were collected using Myon EMG system synchronously. Two-way repeated measures ANOVA was used in exploring the difference between taping and time effects, and the significance was set to alpha <0.05.Results: Significant interaction effect was found between the taping groups and time effect [F (3.32) = 2.389, p = 0.029, η2 = 0.050] in the peak torque during the concentric contraction of quadriceps. No significant interaction and no significant differences between groups and time effects in knee proprioception and muscle activation.Conclusion: The effect of KT seems insufficiently large to impose a positive effect on healthy people within short periods. Health participants may not necessarily use KT to increase muscle activation and proprioception of knee.

Using Accelerometry for Evaluating Energy Consumption and Running Intensity Distribution Throughout a Marathon According to Sex.

The proportion of females participating in long-distance races has been increasing in the last years. Although it is well-known that there are differences in how females and males face a marathon, higher research may be done to fully understand the intrinsic and extrinsic factors affecting sex differences in endurance performance. In this work, we used triaxial accelerometer devices to monitor 74 males and 14 females, aged 30 to 45 years, who finished the Valencia Marathon in 2016. Moreover, marathon split times were provided by organizers. Several physiological traits and training habits were collected from each participant. Then, we evaluated several accelerometry- and pace-estimated parameters (pacing, average change of speed, energy consumption, oxygen uptake, running intensity distribution and running economy) in female and male amateur runners. In general, our results showed that females maintained a more stable pacing and ran at less demanding intensity throughout the marathon, limiting the decay of running pace in the last part of the race. In fact, females ran at 4.5% faster pace than males in the last kilometers. Besides, their running economy was higher than males (consumed nearly 19% less relative energy per distance) in the last section of the marathon. Our results may reflect well-known sex differences in physiology (i.e., muscle strength, fat metabolism, VO2max), and in running strategy approach (i.e., females run at a more conservative intensity level in the first part of the marathon compared to males). The use of accelerometer devices allows coaches and scientific community to constantly monitor a runner throughout the marathon, as well as during training sessions.

Myocardial Injury and Overload among Amateur Marathoners as Indicated by Changes in Concentrations of Cardiovascular Biomarkers.

Marathons continue to grow in popularity among amateurs. However, the impact of intensive exercise on the amateur’s cardiovascular system has not yet been studied. Analysis of the influence of the marathon on kinetics of biomarkers reflecting cardiac injury and overload may bring new insights into this issue. We investigated the effect of running a marathon on the concentrations of high sensitivity cardiac troponin I (hs-cTnI), heart-type fatty acid binding protein (H-FABP), N-terminal proatrial natriuretic peptide (NT-proANP), B-type natriuretic peptide (BNP), growth differentiation factor 15 (GDF-15) and galectin 3 (Gal-3) in the population of male amateur runners. The study included 35 amateur marathoners and followed 3 stages: S1—two weeks prior to the marathon, S2—at the finish line and S3—two weeks after. Blood samples were collected at each stage and analyzed for biomarkers and laboratory parameters. Concentrations of all studied biomarkers were significantly higher at S2, whereas at S3 did not differ significantly compared to S1. Running a marathon by an amateur causes an acute rise in biomarkers of cardiac injury and stress. Whether repetitive bouts of intensive exercise elicit long-term adverse cardiovascular effects in amateur marathoners needs further research.

Right Ventricular Diastolic Dysfunction after Marathon Run.

It has been raised that marathon running may significantly impair cardiac performance. However, the post-race diastolic function has not been extensively analyzed. We aimed to assess whether the marathon run causes impairment of the cardiac diastole, which ventricle is mostly affected and whether the septal (IVS) function is altered. The study included 34 male amateur runners, in whom echocardiography was performed two weeks before, at the finish line and two weeks after the marathon. Biventricular diastolic function was assessed not only with conventional Doppler indices but also using the heart rate-adjusted isovolumetric relaxation time (IVRTc). After the run, IVRTc elongated dramatically at the right ventricular (RV) free wall, to a lesser extent at the IVS and remained unchanged at the left ventricular lateral wall. The post-run IVRTc_IVS correlated with IVRTc_RV (r = 0.38, p < 0.05), and IVRTc_RV was longer in subjects with IVS hypertrophy (88 vs. 51 ms; p < 0.05). Participants with measurable IVRT_RV at baseline (38% of runners) had longer post-race IVRTc_IVS (102 vs. 83 ms; p < 0.05). Marathon running influenced predominantly the RV diastolic function, and subjects with measurable IVRT_RV at baseline or those with IVS hypertrophy can experience greater post-race diastolic fatigue.

Exercise dose affects the circulating microRNA profile in response to acute endurance exercise in male amateur runners.

The systemic response to exercise is dose-dependent and involves a complex gene expression regulation and cross-talk between tissues. This context ARISES the need for analyzing the influence of exercise dose on the profile of circulating microRNAs (c-miRNAs), as emerging posttranscriptional regulators and intercellular communicators. Thus, we hypothesized that different exercise doses will determine specific c-miRNA signatures that will highlight its potential as exercise dose biomarker. Nine active middle-aged males completed a 10-km race (10K), a half-marathon (HM), and a marathon (M). Blood samples were collected immediately before and after races. Plasma RNA was extracted, and a global screening of 752 microRNAs was analyzed using RT-qPCR. Three different c-miRNA profiles were defined according to the three doses. In 10K, 14 c-miRNAs were found to be differentially expressed between pre- and post-exercise, 13 upregulated and 1 downregulated. Regarding HM, 13 c-miRNAs were found to be differentially modulated, in all the cases upregulated. A total of 28 c-miRNAs were found to be differentially expressed in M, 21 overexpressed and 7 repressed after this race. We had also found 3 common c-miRNAs between 10K and M and 2 common c-miRNAs between 10K and HM. In silico analysis supported a close association between exercise dose c-miRNA profiles and cellular pathways linked to energy metabolism and cell cycle. In conclusion, we have observed that different exercise doses induced specific c-miRNA profiles. So, our results point to c-miRNAs as emerging exercise dose biomarkers and as one of regulatory mechanisms modulating the response to endurance exercise.

Sex-specific Knee Biomechanics Associated With Patellofemoral Pain In Amateur Runners During Running

Patellofemoral Pain (PFP) is a common injury among runners. The mechanisms of sex differences associated with lower extremity biomechanics in PFP are still unclear. PURPOSE: To determine the differences in knee biomechanics between male and female amateur runners with PFP and without PFP in running task. Further, to determine the sex-specific biomechanical factors associated with the development of PFP. METHODS: 15 male and 10 female amateur runners aged 18 to 40 years with PFP were screened and enrolled in PFP group, 25 healthy amateur runners matched with the PFP group in sex, age, and running experience were recruited as control group. PFP group was tested running with and without knee pain (PFP with pain and PFP without pain groups), while control group performed one running test (running speed = 4.0 ± 0.3 m/s). Knee pain in PFP group was eliminated by decreasing the volume of running. Knee kinematics and kinetics during landing phase of running were reduced from reflective marker coordinates and ground reaction force data, as well as compared among groups and between sexes. RESULTS: Peak knee valgus angle of running in PFP group with pain (male: 3.2 ± 4.2°, female: 4.8 ± 4.9°, P = 0.001) and control group (male: 1.9 ± 2.7°, female: 3.8 ± 3.0°, P = 0.001) were significantly lower compared to PFP group without pain (male: 4.5 ± 4.3°, female: 7.9 ± 3.1°). Peak knee external rotation moment of running in PFP group with pain (male: 0.021 ± 0.008 BW × BH, female: 0.019 ± 0.006 BW × BH, P = 0.019) and control group (male: 0.020 ± 0.006 BW × BH, female: 0.017 ± 0.006 BW × BH, P = 0.001) were significantly lower compared to PFP group without pain (male: 0.024 ± 0.009 BW × BH, female: 0.022 ± 0.008 BW × BH). Peak knee flexion angle of running in PFP group without pain (48.8 ± 5.6°) was significantly greater compared to control group for male participants (46.0 ± 3.6°, P = 0.008). CONCLUSIONS: Decreased knee valgus angle and external rotation moment in running appeared to be compensations to avoid pain when amateur runners with PFP were running with pain, and increased knee valgus angle and external rotation moment might be biomechanical factors associated with the development of PFP. Increased knee flexion angle in running may be another critical biomechanical factor associated with the development of PFP for male amateur runners.

Effects of a 75-km mountain ultra-marathon on heart rate variability in amateur runners.

This study examined the effects of a mountain ultra-marathon (MUM) on the activity of the autonomous nervous system through heart rate variability (HRV) monitoring and determined whether this variable related to final performance. Heart rate and HRV were measured in eight male amateur runners (aged 37-60 years). Measurements were recorded before and after the event, in resting conditions, as well as continuously throughout the whole MUM. In addition, percentage (%) of heart rate reserve (HR<inf>res</inf>) and partial and total times during the race were analyzed. Average heart rate (HR<inf>avg</inf>) measured at rest was increased after the event (+37%). Standard deviation of successive differences (SDSD) and the square root of the mean squared differences of successive NN intervals (RMSSD) were reduced after the MUM (-56% and -59%, respectively). There was a positive relationship between the frequency-domain index normalized low frequency power (PLFn) measured at rest before the event and race time (0.79) while there was a negative relationship between race time and the difference in HR<inf>avg</inf> before and after the event. In the last half of the event, there was a high correlation (Spearman coefficient of correlation >0.9) between race time and the standard deviation of the NN intervals (SDNN) registered during the race. Autonomous cardiac regulation can be related to the performance in a mountain ultra-marathon. HRV monitoring could represent a practical tool for the evaluation of the relationship between the autonomous nervous system activity and performance in a mountain ultra-marathon.

The Effect of Prolonged Running on the Symmetry of Biomechanical Variables of the Lower Limb Joints

The aim of this study was to examine whether there are kinematic and kinetic differences in the lower limb and whether the symmetry of the lower extremities is different after prolonged-running. Fifteen healthy male amateur runners (age: 22 ± 1 years, height: 173 ± 8 cm, mass: 65 ± 7 kg, BMI: 21.62 ± 2 kg/m2) were recruited as participants for this study. A Vicon eight-camera motion capture system and Kistler force plate were used to collect kinematic and kinetic parameters. A motorized treadmill, 15-point Borg scale and heart rate bands were used to monitor fatigue during a running-induced fatigue protocol. Paired sample T tests were used to check statistical difference (p = 0.05) between the lower limbs and the symmetry changes in pre-fatigue and post-fatigue running sessions. The symmetry angle (SA) of the knee flexion angle, hip flexion angle and hip extension angle in post-fatigue was significantly greater than in pre-fatigue, increasing by 4.32%, 10.71%, and 23.12%, respectively. Moreover, the SA of hip flexion moment increased by 2.61%. However, the knee extension velocity and hip flexion velocity became more symmetrical than in pre-fatigue (p &lt; 0.05), the SA decreased by 5.91% and 5.45%, respectively. Differences in limb function during post-fatigue may lead to changes of symmetry in the lower limbs. The variables of asymmetry may be used as a compensation mechanism to maintain gait stability. Physical therapy assessment of fatigue injuries and long-distance running training programs may want to consider the changes in symmetry due to limb dominance.

Effects of endurance exercise on serum concentration of calcitonin gene-related peptide (CGRP): a potential link between exercise intensity and headache.

Background Calcitonin gene-related peptide (CGRP) is a powerful neuropeptide that is strongly involved in headache pain pathogenesis by triggering vasodilation, mast cell degranulation and neurogenic inflammation. This evidence has prompted us to investigate the acute influence of endurance exercise on CGRP concentration in blood. Methods The study population consisted of 48 male amateur runners, who ran a half-marathon distance at 75%-85% of maximal oxygen uptake. Blood was drawn before the run (pre-run) and immediately after each runner ended his trial (post-run). The serum concentration of CGRP was measured with a commercial enzyme-linked immunosorbent assay (ELISA) technique. Results Overall, 22/48 subjects (45.8%) reported suffering from headache, three of whom (6.2%) had an exertional headache, whilst 26/48 (54.2%) subjects did not report at least one headache episode during the previous 6 months (i.e. headache-free). All 48 athletes successfully covered the 21.1 km distance. Serum concentration of CGRP significantly increased by 1.5-fold in the entire group, as well as in the headache-positive and headache-free cohorts. Univariate Spearman's correlation revealed that post-run variation of serum CGRP was significantly and inversely associated with running time (r = -0.30; p = 0.036). Conclusions The serum concentration of CGRP is significantly enhanced by medium-distance endurance exercise and the post-exercise increase is dependent on running intensity. Accordingly, high-exercise intensity might be directly related to triggering both exertional headache and/or migraine episodes.

Plantar load characteristics among runners with different strike patterns during preferred speed

ObjectivesThis study aimed to compare the plantar loads between habitual rearfoot strike (RFS) and non-RFS (NRFS) during running under the participant’s preferred speed. MethodsA total of 66 (36 RFS, 30 NRFS) healthy amateur male runners were included in our study. In-shoe pressure sensors were utilised to the test plantar loads when participants were running using their preferred foot strike pattern and running speed (RFS: 3.2 ± 0.3 m/s; NRFS: 3.4 ± 0.4 m/s). ResultsResults indicated that running speed has a significant effect on the total contact area [F (1, 64) = 7.061, P = 0.01, η2 = 0.101], which also affects midfoot and forefoot regions. No significant difference was found on the total maximum force, force-time-integral, peak pressure (PP) and pressure-time-integral (PTI), but the total contact area of RFS was higher than that of NRFS runners [F (1, 64) = 77.406, P < 0.001, η2 = 0.551]. Plantar loads were mainly focused on the heel and midfoot for RFS runners in all variables, and NRFS runners experienced increased PP and PTI in medial forefoot regions. ConclusionHabitual runners tend to adjust their contact area according to the running speed through midfoot and forefoot regions. RFS runners remain susceptible to high impact force on the heel and midfoot, and NRFS runners experience high impact force in the first metatarsal regions. Therefore, runners should note this situation to avoid running-related injuries.

Factors influencing post-exercise proteinuria after marathon and ultramarathon races.

Post-exercise proteinuria is one of the most common findings observed after short and intensive physical activity, but is observed also after long runs with low intensity. The aim of this study was to analyze factors influencing proteinuria after marathon runs. Two groups of male amateur runners were studied. The results of 20 marathon finishers (42.195 m), with a mean age of 49.3 ± 6.85 years; and 17 finishers of a 100-km ultramarathon with a mean age of 40.18±4.57 years were studied. Urine albumin to creatinine ratio (ACR) was calculated before and after both races. The relationship between ACR and run pace, metabolites (lactate, beta hydroxybutyrate), markers of inflammation (CRP, IL-6) and insulin was studied. The significant increase in ACR was observed after both marathon races. ACR increased from 6.41 to 21.96 mg/g after the marathon and from 5.37 to 49.64 mg/g after the ultramarathon (p<0.05). The increase in ACR was higher after the ultramarathon that after the marathon. There was no correlation between run pace and proteinuria. There was no correlation between ACR and glucose, free fatty acids, lactate, beta-hydroxybutyrate and insulin levels. There was significant negative correlation between ACR and interleukin 6 (IL-6) (r =-0.59, p< 0.05) after ultramarathon. Proteinuria is a common finding after physical exercise. After very long exercises it is related to duration but not to intensity. There is no association between metabolic and hormonal changes and ACR after marathon runs. The role on inflammatory cytokines in albuminuria is unclear.

Physical Exercise Modulates miR-21-5p, miR-129-5p, miR-378-5p, and miR-188-5p Expression in Progenitor Cells Promoting Osteogenesis.

Physical exercise is known to promote beneficial effects on overall health, counteracting risks related to degenerative diseases. MicroRNAs (miRNAs), short non-coding RNAs affecting the expression of a cell’s transcriptome, can be modulated by different stimuli. Yet, the molecular effects on osteogenic differentiation triggered by miRNAs upon physical exercise are not completely understood. In this study, we recruited 20 male amateur runners participating in a half marathon. Runners’ sera, collected before (PRE RUN) and after (POST RUN) the run, were added to cultured human mesenchymal stromal cells. We then investigated their effects on the modulation of selected miRNAs and the consequential effects on osteogenic differentiation. Our results showed an increased expression of miRNAs promoting osteogenic differentiation (miR-21-5p, miR-129-5p, and miR-378-5p) and a reduced expression of miRNAs involved in the adipogenic differentiation of progenitor cells (miR-188-5p). In addition, we observed the downregulation of PTEN and SMAD7 expression along with increased AKT/pAKT and SMAD4 protein levels in MSCs treated with POST RUN sera. The consequent upregulation of RUNX2 expression was also proven, highlighting the molecular mechanisms by which miR-21-5p promotes osteogenic differentiation. In conclusion, our work proposes novel data, which demonstrate how miRNAs may regulate the osteogenic commitment of progenitor cells in response to physical exercise.

Comparison of plasma lipids changes after middle-distance running in euglycemic and diabetic subjects

Background: Although regular performance of aerobic physical exercise is pivotal for preserving or improving health and fitness, scarce information is available on plasma lipids changes after middle-distance running in euglycemic and diabetic subjects. Methods: Eleven male euglycemic amateur runners (mean age 41±6 years) and 9 male diabetic amateur runners (4 with type 1 and 5 with type 2 diabetes; mean age 55±14 years) participated to a 21.1-km running trial. All subjects belonged to an amateur running team, regularly engaged in amateur running. Blood was collected before the start of the trial and immediately after. The lipid profile, encompassing measurement of total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), was assayed with Roche Cobas 6000. Results: All athletes successfully completed the 21.1-km running trial, with running pace comprised between 9.6–12.8 km/h. In both categories of subjects the values of LDL-C significantly decreased by approximately 6% after the run, whilst HDL-C and triglycerides significantly increased by 6–9% and 30–36%, respectively. The post-run variations of all lipoprotein fractions after the running trial were virtually identical in diabetic and euglycemic subjects. Conclusions: The results of this study show for the first time that middle-distance running elicits acute favorable changes of lipid profile both in euglycemic and diabetic subjects. This form of endurance exercise shall hence be further fostered for purposes of public health promotion and improvement.

Cardiovascular stress biomarker assessment of middle-aged non-athlete marathon runners.

Cardiovascular safety of marathon running in recreational runners remains unclear. We set up this study to comprehensively evaluate the effects of a marathon run on the profile of cardiovascular stress biomarkers in connection with transthoracic echocardiography. Thirty-three healthy male amateur runners, aged ≥50 years (mean age 57 ± 7) were enrolled. Venous blood samples were obtained before the marathon, just after the race, 2-4 and seven days after the marathon. Using novel single molecule counting technology we measured: plasma concentrations of high-sensitivity cardiac troponin I (hs-cTnI) and endothelin-1. N-terminal pro B-type natriuretic peptide was measured using electrochemiluminescence. Each participant had transthoracic echocardiography before and immediately after the race. We observed a sharp rise in the levels of all biomarkers after the race (all p < 0.01), which subsequently normalized after 2-4 days and stayed within normal range after seven days. Runners with intensive training programmes (>169 km/month, a median for the studied group) had lower hs-cTnI leak after the race (median 15.11 ng/ml and 31.2 ng/ml, respectively; p < 0.05). Neither transthoracic echocardiography measures of ventricles nor strain rates changed after the run. We observed a decrease in the left atrial volume index and increase in the maximal right atrial volumes (all p < 0.05). Changes in Doppler indices of diastolic function suggestive of alteration in left ventricular relaxation were observed. Marathon run is associated with sharp and significant rises in the biomarkers of cardiovascular stress. The profile of these changes, however, along with echocardiographic parameters, does not suggest irreversible myocardial damage.

Neuromuscular Fatigue Does Not Impair the Rate of Force Development in Ballistic Contractions of Submaximal Amplitudes.

The effect of muscle fatigue on rate of force development (RFD) is usually assessed during tasks that require participants to reach as quickly as possible maximal or near-maximal force. However, endurance sports require athletes to quickly produce force of submaximal, rather than maximal, amplitudes. Thus, this study investigated the effect of muscle fatigue induced by long-distance running on the capacity to quickly produce submaximal levels of force. Twenty-one male amateur runners were evaluated before and shortly after a half-marathon race. Knee extensors force was recorded under maximal voluntary and electrically evoked contractions. Moreover, a series of ballistic contractions at different submaximal amplitudes (from 20 to 100% of maximal voluntary force) was obtained, by asking the participants to reach submaximal forces as fast as possible. The RFD was calculated for each contraction. After the race, maximal voluntary activation, resting doublet twitch, maximal force, and RFD during maximal contraction decreased (-12, -12, -21, and -19%, respectively, all P-values < 0.0001). Nevertheless, the RFD values measured during ballistic contractions up to 60% of maximal force were unaffected (all P-values > 0.4). Long-distance running impaired the capacity to quickly produce force in ballistic contractions of maximal, but not of submaximal, amplitudes. Overall, these findings suggest that central and peripheral fatigue do not affect the quickness to which muscle contracts across a wide range of submaximal forces. This is a relevant finding for running and other daily life activities that rely on the production of rapid submaximal contractions rather than maximal force levels.

Fatigue-induced dissociation between rate of force development and maximal force across repeated rapid contractions

We examined whether the presence of fatigue induced by prolonged running influenced the time courses of force generating capacities throughout a series of intermittent rapid contractions. Thirteen male amateur runners performed a set of 15 intermittent isometric rapid contractions of the knee extensor muscles, (3s/5s on/off) the day before (PRE) and immediately after (POST) a half marathon. The maximal voluntary contraction force, rate of force development (RFDpeak), and their ratio (relative RFDpeak) were calculated. At POST, considering the first (out of 15) repetition, the maximal force and RFDpeak decreased (p<0.0001) at the same extent (by 22±6% and 24±22%, respectively), resulting in unchanged relative RFDpeak (p=0.6). Conversely, the decline of RFDpeak throughout the repetitions was more pronounced at POST (p=0.02), thus the decline of relative RFDpeak was more pronounced (p=0.007) at POST (−25±13%) than at PRE (−3±13%). The main finding of this study was that the fatigue induced by a half-marathon caused a more pronounced impairment of rapid compared to maximal force in the subsequent intermittent protocol. Thus, the fatigue-induced impairment in rapid muscle contractions may have a greater effect on repeated, rather than on single, attempts of maximal force production.

Biochemical, physiological, and performance response of a functional watermelon juice enriched in L-citrulline during a half-marathon race

ABSTRACTBackground: Watermelon is a rich natural source of l-citrulline. This non-essential amino acid increases exercise performance.Objective: Evaluate the effect of Fashion watermelon juice enriched in l-citrulline (CWJ) (3.45 g per 500 mL) in physical performance and biochemical markers after a half-marathon race.Design: A randomised, double blind, crossover design where 2 h after drinking 500 mL of CWJ or placebo (PLA, beverage without l-citrulline) amateur male runners performed two half-marathon races. Jump height, heart rate and rating of perceived exertion were evaluated before and after the races. Moreover, muscle soreness and plasma markers of muscle damage and metabolism were evaluated for 72 h after the races.Results: Muscle soreness perception was significantly lower from 24 to 72 h after the race with CWJ beverage. Immediately after the races, runners under CWJ condition showed plasma lactate and glucose concentrations significantly lower and higher lactate dehydrogenase and l-arginine concentration than runners under PLA. A maintenance of jump heights after the races under CWJ supplementation was found, decreasing significantly with PLA.Conclusion: A single Fashion watermelon juice enriched in l-citrulline dose diminished muscle soreness perception from 24 to 72 h after the race and maintained lower concentrations of plasma lactate after an exhausting exercise.

0136: Impact of a multi-stage ultra-long duration exercise on left ventricular contractility indexes: an echocardiographic study using multilayer speckle-tracking imaging

some controversy still exists about the reality and mechanics of exercise-induced cardiac fatigue. Little is known about the kinetics of the impact of ultra-long duration exercise (ULDE) on the left ventricular (LV) function. We studied evolution of LV contractility indexes by serial examinations during a multistage ULDE race. successive echocardiographic assessment was performed on 20 well-trained amateur male runners (42.8±3.5 year-old) participating in a 236 km 5-stage foot race in the Sahara desert. An echocardiograhic study was performed the day before the race (T1), following the completion of the second (41 km, T2) and the fifth (42.2 km, T3) stages, then within the second day of recovery (T4). Contractility indexes included biplan ejection fraction (EF), LV global longitudinal (GL) peak-strain (PS) and strain-rate (SR), subendocardial layer (ENDO) and sub-epicardial layer (EPI) longitudinal strain. LV preload was evaluated by LV End Diastolic Biplan Volume (LVEDV) and afterload by LV Meridional Wall Stress. no change of EF was observed during the study period. LV GLPS significantly decreased at T2 (from – 20.8±2 to –19±2.9%, p<0.05) while GLSR did not change (from –1.19±0.17 to –1.19±0.17). GLPS returned to initial values at T3 and T4; evolution of ENDO and EPI longitudinal PS strictly followed modifications of GLPS. Afterload did not change. There was a tendancy to a transient drop in preload at T2 (111±20 to 104±16mL); preload then increased in T3 (115±25mL, p<0.05 versus T2) and T4 (121±20mL, p<0.05 versus T1 and T2). transient drop in LV GLPS occured at early stage of the race but returned to pre-race value when exercise was repeated and remained stable 2 days after this race. Impact seemed to be of same magnitude in different layers of LV myocardium. Whether preload conditions influenced contractility indexes cannot be ruled out.

Impact of different running distances on muscle and lymphocyte DNA damage in amateur marathon runners.

[Purpose] The aim of this study was to investigate the impact of different marathon running distances (10 km, 21 km, and 42.195 km) on muscle and lymphocyte DNA damage in amateur marathon runners. [Subjects and Methods] Thirty male amateur runners were randomly assigned to 10 km, 21 km, and 42 km groups, with 10 subjects in each group. Blood samples were collected before and after the races and on the 3rd day of recovery to examine levels of muscle damage (creatine kinase and lactate dehydrogenase) and lymphocyte DNA damage (DNA in the tail, tail length, and tail moment). [Results] Serum creatine kinase, serum lactate dehydrogenase, and tail moment were significantly higher after the races compared with before the races in all groups. In addition, the 42 km group showed significantly higher levels of creatine kinase, lactate dehydrogenase, and tail moment than the 10 km and 21 km groups after the races. [Conclusion] Strenuous endurance exercise can cause muscle and lymphocyte DNA damage, and the extent of such damage can increase as running distance increases.

Echocardiographic and biochemical analysis of cardiac function and injury among female amateur runners post-marathon.

Numerous studies with male amateur runners have determined negative changes in their cardiac function/of their myocard following long endurance loads. This study aims to examine such potential changes in women, specifically, after running a marathon. A total of 18 female amateur runners (39.5 ± 10.5 years) were examined before (T1), immediately after (T2) and 24 h post-marathon (T3). An echocardiography was performed using Tissue Doppler (TD) imaging. In addition, the concentration of cardiac troponin T (cTnT) and the activity of the myocardial muscle creatine kinase (CK-MB) were determined at T1 and T2. The echocardiographic parameters revealed impairment of the diastolic function, without, however, documenting a diastolic dysfunction (in accordance with the classification of Nagueh (J Am Soc Echocardiogr, 22:107-33, 2009)). The ratio of blood flow velocity through the mitral valve during early versus late diastole (MV E/A ratio), for example, decreased. The values measured at T3 were similar to those measured at T1. The ratio of early transmitral diastolic filling velocity and of the transmitral diastolic filling velocity by TD imaging (MV E/E') did not indicate any change from T1 to T2, but a significant increase at T3 (in comparison with T1). The systolic function (measured by the left ventricular ejection fraction) did not change significantly. The cTnT concentration and CK-MB activity were significantly higher in T2 than in T1. The data collected does not provide any solid evidence of pathological changes in the cardiac function of female amateur runners post-marathon, although the lab values indicate a strongly increased myocardial stimulation.