10-km Run Research Articles

Pain sensitivity and athletic performance.

The objective of the study is to determine whether higher pain thresholds are associated with better performance in long-distance runners. Seventy participants, divided into groups of fast and non-fast runners according to peak results in a 10km run. Main Outcome Measures, Cold pressor test. Of the 70 participants, 28 were in the fastest group (less than 39 minutes in a 10km run) and 42 in the non-fast group. The faster group was characterized with older age (34.0±8.5 vs. 29.5±5.7, P=0.01), greater mean weekly running time (5.5 [0-17]) vs. 2 [0-10], P<0.001), and more years of running (10 [1.5-34.0] vs. 7 [0-20, P=0.05]). In a multivariable analysis longer cold pressor time was associated with faster 10Km run (OR 1.01, 95% CI 1.00-1.01). It seems that higher pain thresholds play an important role in the superior ability of long distance runners.

No Benefit of Ingestion of a Ketone Monoester Supplement on 10-km Running Performance.

Preexercise ingestion of exogenous ketones alters the metabolic response to exercise, but effects on exercise performance have been equivocal. On two occasions in a double-blind, randomized crossover design, eight endurance-trained runners performed 1 h of submaximal exercise at approximately 65% V˙O2max immediately followed by a 10-km self-paced time trial (TT) on a motorized treadmill. An 8% carbohydrate-electrolyte solution was consumed before and during exercise, either alone (CHO + PLA), or with 573 mg·kg of a ketone monoester supplement (CHO + KME). Expired air, HR, and RPE were monitored during submaximal exercise. Serial venous blood samples were assayed for plasma glucose, lactate, and β-hydroxybutyrate concentrations. CHO + KME produced plasma β-hydroxybutyrate concentrations of approximately 1.0 to 1.3 mM during exercise (P < 0.001), but plasma glucose and lactate concentrations were similar during exercise in both trials. V˙O2, running economy, respiratory exchange ratio, HR, and RPE were also similar between trials. Performance in the 10-km TT was not different (P = 0.483) between CHO + KME (mean, 2402 s; 95% confidence interval, 2204-2600 s) and CHO + PLA (mean, 2422 s; 95% confidence interval, 2217-2628 s). Cognitive performance, measured by reaction time and a multitasking test, did not differ between trials. Compared with carbohydrate alone, coingestion of KME by endurance-trained athletes elevated plasma β-hydroxybutyrate concentrations, but did not improve 10-km running TT or cognitive performance.

Nitrate Supplementation Combined with a Running Training Program Improved Time-Trial Performance in Recreationally Trained Runners.

Our purpose was to verify the effects of inorganic nitrate combined to a short training program on 10-km running time-trial (TT) performance, maximum and average power on a Wingate test, and lactate concentration ([La−]) in recreational runners. Sixteen healthy participants were divided randomly into two groups: Nitrate (n = 8) and placebo (n = 8). The experimental group ingested 750 mg/day (~12 mmol) of nitrate plus 5 g of resistant starch, and the control group ingested 6 g of resistant starch, for 30 days. All variables were assessed at baseline and weekly over 30 days. Training took place 3x/week. The time on a 10-km TT decreased significantly (p < 0.001) in all timepoints compared to baseline in both groups, but only the nitrate group was faster in week 2 compared to 1. There was a significant group × time interaction (p < 0.001) with lower [La] in the nitrate group at week 2 (p = 0.032), week 3 (p = 0.002), and week 4 (p = 0.003). There was a significant group time interaction (p = 0.028) for Wingate average power and a main effect of time for maximum power (p < 0.001) and [La−] for the 60-s Wingate test. In conclusion, nitrate ingestion during a four-week running program improved 10-km TT performance and kept blood [La−] steady when compared to placebo in recreational runners.

Effects of Exercise Compression Stockings on Anterior Muscle Compartment Pressure and Oxygenation During Running: A Randomized Crossover Trial Conducted in Healthy Recreational Runners

BackgroundExercise compression garments have increased in popularity among athletes at all levels during the last 10 years. However, the scientific grounds for this are unclear. The purpose of the present study was to examine the effect of wearing exercise compression stockings (CS) on the anterior compartment pressure, oxygenation of the tibialis anterior muscle, and early blood biomarkers change for muscle damage during a 10-km treadmill run in healthy subjects.MethodsTwenty healthy subjects completed two identical treadmill runs, with or without CS. The subjects were randomized regarding the order in which the sessions were performed. Intramuscular pressure (IMP) and muscle oxygenation in the one leg were continuously measured before, during, and after running sessions. Blood samples were collected just before and directly after these sessions and analyzed for myoglobin and creatine kinase concentrations.ResultsThe use of CS during running resulted in significantly higher IMP (by 22 ± 3.1 mmHg on average) and lower tissue oxygenation index (by 11 ± 1.8%) compared to running without CS (p < 0.001). In addition, the Δ change in median serum myoglobin concentration measured before and after running was significantly higher when CS were used: 58 (9‒210) µg/L as compared to 38 (0‒196) µg/L with no CS (p = 0.04). No difference in post-running early serum creatine kinase concentration was observed between using CS and not using CS.ConclusionWearing exercise CS during and following a 10-km treadmill run elevated IMP and reduced muscle tissue oxygenation in the anterior compartment of healthy runners. Furthermore, the use of exercise CS did not prevent early exercise-induced muscle damage, as measured by serum biomarkers.

Low-Carbohydrate Training Increases Protein Requirements of Endurance Athletes.

Training with low-carbohydrate (CHO) availability enhances markers of aerobic adaptation and has become popular to periodize throughout an endurance-training program. However, exercise-induced amino acid oxidation is increased with low muscle glycogen, which may limit substrate availability for postexercise protein synthesis. We aimed to determine the impact of training with low-CHO availability on estimates of dietary protein requirements. Eight endurance-trained males (27 ± 4 yr, 75 ± 10 kg, 67 ± 10 mL·kg body mass·min) completed two trials matched for energy and macronutrient composition but with differing CHO periodization. In the low-CHO availability trial (LOW), participants consumed 7.8 g CHO·kg before evening high-intensity interval training (10 × 5 min at 10-km race pace, 1 min rest) and subsequently withheld CHO postexercise (0.2 g·kg). In the high-CHO availability trial (HIGH), participants consumed 3 g CHO·kg during the day before high-intensity interval training, and consumed 5 g CHO·kg that evening to promote muscle glycogen resynthesis. A 10-km run (~80% HRmax) was performed the following morning, fasted (LOW) or 1 h after consuming 1.2 g CHO·kg (HIGH). Whole-body phenylalanine flux and oxidation were determined over 8 h of recovery via oral [C]phenylalanine ingestion, according to standard indicator amino acid oxidation methodology, while consuming sufficient energy, 7.8 g CHO·kg·d, and suboptimal protein (0.93 g·kg·d). Fat oxidation (indirect calorimetry) during the 10-km run was higher in LOW compared with HIGH (0.99 ± 0.35 g·min vs 0.60 ± 0.26 g·min, P < 0.05). phenylalanine flux during recovery was not different between trials (P > 0.05) whereas phenylalanine oxidation (reciprocal of protein synthesis) was higher in LOW compared with HIGH (8.8 ± 2.7 μmol·kg·h vs 7.9 ± 2.4 μmol·kg·h, P < 0.05), suggesting a greater amino acid requirement to support rates of whole-body protein synthesis. Our findings suggest that performing endurance exercise with low-CHO availability increases protein requirements of endurance athletes.

Massage therapy slightly decreased pain intensity after habitual running, but had no effect on fatigue, mood or physical performance: a randomised trial.

Does massage therapy reduce pain and perceived fatigue in the quadriceps, and improve the mood and physical performance of runners after habitual sporting activity (10-km run)? Randomised controlled trial with concealed allocation, intention-to-treat analysis and blinded assessment. Seventy-eight runners after sporting activity (10-km run). The experimental group received 10 minutes of massage to the quadriceps aimed at recovery following sport practice, and the control group received a sham joint mobilisation. Pain and perceived fatigue were each assessed using a 0-to-10 numerical rating scale; pain behaviour via the McGill Pain Questionnaire; mood profile via Brunel Mood Scale; quadriceps muscle flexibility using maximal knee flexion angle via inclinometer; isometric muscle strength of knee extensors via hand-held dynamometry; and vertical jump performance using jump height via My Jump 2 app. Evaluations were carried out immediately before and after the intervention, and at 24, 48 and 72 hours after the intervention. Generalised estimating equations were used to estimate a between-group difference (95% CI) using data across all time points. The experimental group had significantly lower scores than the control group on the numerical rating scale for pain by 0.7 points (95% CI 0.1 to 1.3). There were no significant between-group differences for any of the other outcome measures. Massage therapy was effective at reducing pain intensity after application to the quadriceps of runners compared to a sham technique, but the magnitude of the effect was small. There were no significant effects on perceived fatigue, flexibility, strength or jump performance. Brazilian Registry of Clinical Trials, RBR-393m7m.

Increased Rate of Heat Storage, and No Performance Benefits, With Caffeine Ingestion Before a 10-km Run in Hot, Humid Conditions.

Although the effect of caffeine in thermoneutral or cool environmental conditions has generally shown performance benefits, its efficacy in hot, humid conditions is not as well known. The purpose of this study was to further examine the effect of caffeine ingestion on endurance running performance in the heat. Ten trained endurance runners (6 males; mean [SD] age = 26 [9]y, height = 176.7 [5.1]cm, and mass = 72.1 [8.7]kg) came to the lab for 4 visits. The first was a VO2max test to determine cardiorespiratory fitness; the final 3 visits were 10-km runs in an environmental chamber at 30.6°C and 50% relative humidity under different conditions: 3mg·kg-1 body mass (low caffeine dosage), 6mg·kg-1 (moderate caffeine dosage), and a placebo. Repeated-measures analyses of variance were used to determine the effect of condition on the 10-km time, heart rate, core temperature, rating of perceived exertion, and thermal sensation. There was no difference in the 10-km time between the placebo (53.2 [8.0]min), 3-mg·kg-1 (53.4 [8.4]), and 6-mg·kg-1 (52.7 [8.2]) conditions (P = .575, ). There was not a main effect of average heart rate (P = .406, ), rating of perceived exertion (P = .151, ), or thermal sensation (P = .286, ). There was a significant interaction for core temperature (P = .025, ); the moderate-dosage caffeine condition showed a higher rate of rise in core temperature (0.26 [0.08] °C·km-1 vs 0.20 [0.06] and 0.19 [0.10] °C·km-1 in the low-caffeine and placebo conditions, respectively). The results support previous research showing a thermogenic effect of caffeine, as the moderate-dosage condition led to a greater rate of heat storage and no performance benefits.

Effect of pre-exercise ingestion of α-lactalbumin on subsequent endurance exercise performance and mood states.

This study investigated the effect of pre-exercise α-lactalbumin ingestion on subsequent endurance exercise performance, muscle pain and mood states. In a two-stage cross-over counterbalance design, eleven male endurance runners (age: 31 (se 2) years, height: 169·5 (se 4·4) cm, weight: 63·6 (se 5·1) kg, V̇O2max: 58·8 (se 6·3) ml/kg per min) consumed two solutions (carbohydrate+α-lactalbumin, CA; carbohydrate+whey protein isolate, CW) 2 h before a self-paced 21-km run. Creatine kinase, IL-6, muscle pain, pressure pain threshold (PPT) and mood states were assessed 2 h before exercise, immediately before exercise (Pre-ex0) and immediately after exercise (Post-ex0). No difference was found in 21-km running performance between two trials (CA v. CW: 115·85 (se 5·20) v. 118·85 (se 5·51) min, P=0·48). Compared with CW, CA led to higher PPT at Pre-ex0 (41·77 (se 2·27) v. 35·56 (se 2·10) N/cm2, P&lt;0·01) and Post-ex0 (38·76 (se 3·23) v. 35·30 (se 3·55) N/cm2, P=0·047). Compared with CW, CA reduced the feeling of fatigue at Post-ex0 (P&lt;0·01); CA also reduced salivary cortisol levels at Post-ex0 (0·72 (se 0·07) v. 0·83 (se 0·13) ng/ml, P&lt;0·01). In conclusion, the ingestion of α-lactalbumin did not improve the 21-km time-trial performance. However, compared with the pre-exercise ingestion of whey protein, that of α-lactalbumin led to superior results during similar levels of endurance exercise: it elevated PPT and reduced the feeling of fatigue and the cortisol levels.

Changes in the running-related injury incidence rate ratio in a 1000-km explorative prospective cohort study involving two unspecific shoe changes

A sudden change between any types of running shoes has been suggested to affect the running-related injury incidence rate. The purpose of this project was to investigate how the running-related injury incidence rate ratio (IIRR) modulates during a 1-year explorative prospective cohort study involving two unspecific running shoe changes. Ninety-nine injury-free recreational male runners volunteered to engage in a self-structured running program. At baseline, the runners were provided with a pair of neutral running shoes and were instructed to use these shoes in each running session during the first 500 km of running. Subsequently, the runners had the possibility to switch to other running shoes. When a runner reported an injury, a sports physiotherapist or sports physician recorded it. A total of 30 of the 99 runners sustained at least one running-related injury during the 72.076 km of running with a mean covered distance of 975 (±790 km) per year. The IIRR was calculated as the ratio between the instantaneous injury incidence rate divided by the average injury incidence rate over the follow-up period. In summary, the running-related IIRR was increased above one around the time-points where the runners changed running shoes and decreased below one in the intermediate period. However, it was not possible to confirm that the increased IIRRs were caused by the running shoe changes per se because it could not be excluded that another risk factor, namely the weekly running distance and other unidentified risk factors were involved too. More large-scale studies involving alternative experimental protocols are needed to provide further insight into the association between running-related injury incidence rate and running shoe changes.

Positive Work Contribution Shifts from Distal to Proximal Joints during a Prolonged Run.

To investigate the joint-specific contributions to the total lower-extremity joint work during a prolonged fatiguing run. Recreational long-distance runners (n = 13) and competitive long-distance runners (n = 12) performed a 10-km treadmill run with near-maximal effort. A three-dimensional motion capture system synchronized with a force-instrumented treadmill was used to calculate joint kinetics and kinematics of the lower extremity in the sagittal plane during the stance phase at 13 distance points over the 10-km run. A significant (P < 0.05) decrease of positive ankle joint work as well as an increase of positive knee and hip joint work was found. These findings were associated with a redistribution of the individual contributions to total lower-extremity work away from the ankle toward the knee and hip joint which was more distinctive in the recreational runner group than in the competitive runner group. This redistribution was accomplished by significant (P < 0.05) reductions of the external ground-reaction force lever arm and joint torque at the ankle and by the significant (P < 0.05) increase of the external ground-reaction force lever arm and joint torque at the knee and hip. The redistribution of joint work from the ankle to more proximal joints might be a biomechanical mechanism that could partly explain the decreased running economy in a prolonged fatiguing run. This might be because muscle-tendon units crossing proximal joints are less equipped for energy storage and return compared with ankle plantar flexors and require greater muscle volume activation for a given force. To improve running performance, long-distance runners may benefit from an exercise-induced enhancement of ankle plantar flexor muscle-tendon unit capacities.

Prediction of running-induced Achilles tendinopathy with pain sensitivity - a 1-year prospective study.

Background and aims Achilles tendinopathy is common among runners, but the etiology remains unclear. High mechanical pain sensitivity may be a predictor of increased risk of developing Achilles tendinopathy in this group. The purpose of this study was to investigate whether local pain sensitivity could predict the development of Achilles tendinopathy in recreational male runners. The overall hypothesis was that high pain sensitivity would be related to a higher risk of developing Achilles tendinopathy among recreational male runners. Methods Ninety-nine recreational male runners were recruited and followed prospectively for 1 year. At baseline and after 500 km of running the pressure pain threshold (PPT) was assessed at the infraspinatus and at the Achilles tendon (AT-PPT). Based on the AT-PPT at baseline, a median split was used to divide the runners into two groups. The high pain sensitivity groups was defined as runners displaying a pain pressure threshold below 441 kPa on the Achilles tendon, while the low pain sensitivity group was defined as runners displaying a pain pressure threshold above 441 kPa on the Achilles tendon, respectively. Subsequently, the cumulative risk difference between the two groups was assessed by using the pseudo-observation method. Results High pain sensitivity runners sustained 5%-point (95% CI: -0.18 to 0.08) more Achilles tendinopathy episodes during the first 1,500 km. No significant group differences in risk were found at 100, 250, 500, 1,000 and 1,500 km of running. Conclusions No significant association was found between mechanical pain sensitivity in the Achilles tendon and the risk of developing Achilles tendinopathy. However, the risk difference indicated a association between a high mechanical pain sensitivity and an increased risk of developing Achilles tendinopathy. It is plausible that changes in pain sensitivity were masked by unmeasured covariates, such as the differences in progression/regression of training volume and running speed between the two groups. This study was limited in size, which limited the possibility to account for covariates, such as differences in progression/regression of running speed between runners. With the limitations in mind, future studies should control the training volume, speed and running shoes in the design or account for it in the analysis. Implications Pain sensitivity of the Achilles tendon seems not to be related to an increased risk of developing Achilles pain in relation to running.

Participation and Performance Trends in the ITU Duathlon World Championship From 2003 to 2017.

Nikolaidis, PT, Villiger, E, and Knechtle, B. Participation and performance trends in the ITU Duathlon World Championship from 2003 to 2017. J Strength Cond Res 35(4): 1127-1133, 2021-Participation and performance across years have been studied extensively in various endurance and ultra-endurance sports; however, less information exists with regards to duathlon (i.e., Run 1, Bike, and Run 2). The aim of this study was to examine performance and participation trends of duathletes competing either to short (10-km Run 1, 50-km Bike, and 5-km Run 2) or to long distance (10-km Run 1, 150-km Bike, and 30-km Run 2) in the Powerman World Championship "Powerman Zofingen." We analyzed 7,951 finishers (women, n = 1,236, age 36.7 ± 9.1 years; men, n = 6,715, 40.1 ± 10.1 years) competing in "Powerman Zofingen" from 2003 to 2017. Men were faster than women by 8.2% (171 ± 21 minutes vs. 186 ± 21 minutes, p < 0.001, η2 = 0.068) and 7.5% (502 ± 57 minutes vs. 543 ± 64 minutes, p < 0.001, η2 = 0.068) in the short and long distances, respectively. Women were younger than men by 4.6 years (35.0 ± 9.0 years vs. 39.6 ± 10.5 years, p < 0.001, η2 = 0.026) and 1.8 years (38.8 ± 8.7 years vs. 40.6 ± 9.5 years, p < 0.001, η2 = 0.005) in the short and long distances, respectively. An increase of women finishers across years in the long distance was observed (e.g., n = 19 in 2003 and n = 58 in 2017; p < 0.001), whereas no change was shown in short distance and men finishers. The men-to-women ratio (MWR) decreased across years in the long, but not in the short distance. No change of race time across years was observed. The sex difference in race time increased in long distance (p = 0.014), whereas it did not change in the short. Age increased across years in both sexes and distances (p < 0.001). The sex difference in age decreased in the long (p = 0.007), but not in the short distance. In summary, the number of women finishers increased and the MWR decreased in the long distance. The age of the finishers increased across years, and their performance remained unchanged. The increase of the sex difference in race time in the long distance might be attributed to the increased number of women finishers.

Beta-Alanine Supplementation Improved 10-km Running Time Trial in Physically Active Adults.

The purpose of this study was to investigate the effects of β-alanine supplementation on a 10 km running time trial and lactate concentration in physically active adults. Sixteen healthy subjects were divided randomly into two groups: β-alanine (n = 8) and placebo group (n = 8). The experimental group ingested 5 g/day of β-alanine plus 1 g of resistant starch, and control group ingested 6 g of resistant starch, both for 23 days. Time to complete a 10-km running time trial and lactate concentration following the test were assessed at baseline and post 23 days. The running training program was performed three times per week on non-consecutive days (day 1: running 7 km; day 2: six sprints of 500 m at maximum speed with 2 min of recovery; day 3: running 12 km). The time to complete a 10-km running time trial decreased significantly only for the β-alanine group (Pre = 3441 ± 326.7, Post = 3209 ± 270.5 s, p < 0.05). When analyzing the delta (Time post minus Time at baseline value) there was a statistically significant difference between the β-alanine vs placebo group (-168.8 ± 156.6 vs. -53.60 ± 78.81 s, p = 0.007), respectively. In addition, the β-alanine group presented lower blood lactate concentration after the 10-km test (β-alanine: Pre = 8.45 ± 1.94 vs. Post = 6.95 ± 2.44 mmol/L; Placebo: Pre = 8.7 ± 3.0 vs. Post = 10.8 ± 2.5 mmol/L, p = 0.03). In conclusion, β-alanine supplementation improved the 10-km running time trial and reduced lactate concentration in physically active adults.

Effect of beetroot juice supplementation on 10-km performance in recreational runners.

The purpose of this study was to investigate the effects of chronic beetroot juice (BRJ) supplementation on 10-km running performance in recreational runners. In a double-blind, placebo-controlled, crossover-designed study, 14 male recreational runners (age, 27.8 ± 3.4 years) performed three 10-km running tests, at baseline and under the conditions of BRJ supplementation and placebo (PLA). Supplementation was administered for 3 days, and on the days of the assessments, the ingestion occurred 2 h before the test and consisted of a dose of 420 mL of BRJ in natura (8.4 mmol inorganic nitrate (NO3-)·day-1) or PLA with depleted NO3- (0.01 mmol NO3-·day-1). The mean velocity (MV) was calculated, and the following variables were determined: maximal heart rate, maximal rating of perceived exertion, blood glucose concentration (analyzed before and after the test), and lactate peak. There was no main effect between conditions regarding 10-km running time performance (BRJ: 50.1 ± 5.3 min; PLA: 51.0 ± 5.1 min; P = 0.391) and total MV (BRJ: 12.1 ± 1.3 km·h-1; PLA: 11.9 ± 1.2 km·h-1; P = 0.321) or in the other analyzed variables. The time to complete the first half of the test (5 km) was statistically lower in the BRJ group than in the PLA group (P = 0.027). In conclusion, chronic supplementation with BRJ increased MV in the first half of the test and improved the final test times of 10 of the 14 runners, although we did not find a statistically significant difference in the performance of the 10-km run.

Perception of running shoe cushioning: wear test vs. controlled experiment

Footwear developers employ feedback from human wear testers to assess the functionality and acceptability of their products. However, there is often poor correspondence between perceptions reported in wear tests and in vitro measurements of running shoe characteristics. This study evaluated runners’ ability to perceive differences in running shoe cushioning under controlled conditions and compared those results with wear test outcomes. Five running shoe conditions were chosen based on the ASTM F1976 impact test results (g-max) to span a typical range of cushioning scores with g-max differences among shoes distributed between 0.9 and 6.5 g. Samples of each shoe condition were used by an independent group of wear testers for about one month and 160 km of running. They provided ratings of various shoe attributes, including ‘heel cushioning’ and ‘forefoot cushioning’, using a 1–7 Likert-type scale. In a laboratory study, 50 healthy runners evaluated the same five shoe conditions and ranked them from ‘least cushioned’ to ‘most cushioned’. For each of the 10 possible pair-wise shoe comparisons, the probability that subjects would rank the shoes consistently with g-max scores was calculated as a function of the difference in g-max between shoes. There were no significant differences in wear test cushioning ratings among the four most cushioned shoes. However, using the ranking protocol, subjects were able to detect differences in cushioning with a ‘least noticeable difference’ of 1.4 g and demonstrated increasing sensitivity with larger difference magnitudes. In contrast to a typical wear test protocol, the laboratory test demonstrated that runners are able to perceive cushioning differences of sufficient magnitude, consistent with mechanical test results, under appropriately controlled conditions.

Resting sympatho-vagal balance is related to 10 km running performance in master endurance athletes.

Relationships between heart rate recovery after exercise (HRR, baseline heart rate variability measures (HRV), and time to perform a 10Km running trial (t10Km) were evaluated in "master" athletes of endurance to assess whether the measured indexes may be useful for monitoring the training status of the athletes. Ten “master” athletes of endurance, aged 40-60 years, were recruited. After baseline measures of HRV, the athletes performed a graded maximal test on treadmill and HRR was measured at 1 and 2 minutes from recovery. Subsequently they performed a 10Km running trial and t10Km was related to HRV and HRR indexes. The time to perform a 10Km running trial was significantly correlated with baseline HRV indexes. No correlation was found between t10Km and HRR. Baseline HRV measures, but not HRR, were significantly correlated with the time of performance on 10km running in “master” athletes. The enhanced parasympathetic function at rest appears to be a condition to a better performance on 10km running. HRV can be simple and useful measurements for monitoring the training stratus of athletes and their physical condition in proximity of a competition.

Can the endurance training change the pacing strategy during 10 km running performance?

The aim of this study was to verify the effect of endurance training on the pacing strategy and analyse the risk of premature fatigue during the 10-km performance in moderately trained runners. Study participants were 14 runners (18–35 years) who had training prescribed with peak velocity (Vpeak) and its time limit (tlim). Three tests were performed on a treadmill: two maximum incrementals for VO2max and Vpeak and one for tlim. The 10-km running performance was evaluated on a 400-m track. The mean velocity, heart rate (HR) and rate of perceived exertion (RPE) were monitored at each trial of 10-km running performance. Evaluations were collected pre and after 4 weeks of endurance training. The RPE and HR increased linearly throughout the test, and the risk of fatigue decreased after 3 km. The pacing strategy used by the participants was the “U” running pace in pre- and post-training. There was improvement in the 10-km run after training (40.8 ± 2.8 vs. 39.6 ± 2.7 min). The study showed that 4 weeks of endurance training does not change the pacing strategy and the risk of premature fatigue. However, the training was responsible for improving the 10-km running performance.

Method of forming a fleet of transport and technological machines for road construction

Abstract Trucks are one of the main transport and technological machines in road construction. Trucks are used at all stages of road construction and define its rate. The need to develop a method of forming a fleet of trucks is caused by the need of transport companies to increase the efficiency of their activity in complicated economic conditions (Decree No. 548 of the Government of the Russian Federation, 2017). One of the ways to increase the efficiency is purchasing of pre-owned trucks, since using a specific volume of capital investments, it is possible to purchase more vehicles. Therefore, the purpose of the study is to increase the efficiency of transport companies by forming vehicle fleets with consideration for purchasing pre-owned vehicles. The main task of the study is to develop an engineering method for vehicle fleet formation with consideration of purchasing of pre-owned vehicles. In this article, the vehicle serves as the object of the study. The subject of the study is methods for control over the performance of vehicles being operated. The article methodology includes statistical methods for collection and processing of operational information. The suggested method of forming a fleet of transport and technological machines through the example of trucks is based on an analysis of the relationship between the dynamics of reduction in the market price of trucks and resource consumption during the life cycle. The method suggests calculating the cost of one km of run including the costs for owning and operation. The method results in recommendations for purchasing trucks with various service life. Key conclusions are the following: one of the ways to increase the efficiency of transport companies is purchasing of pre-owned vehicles, since their cost of one km of run is significantly lower (up to 20%) as compared to that when purchasing new vehicles. The analysis of the difference between the relative remaining life and relative cost of one km of run (with regard to trucks) depending on the service life allows selecting the most efficient option to purchase a pre-owned vehicle (POV).

The Study of Blood metabolic Variation on 10Km Horseback Riding and Running

The Study of Blood metabolic Variation on 10Km Horseback Riding and Running

MRI Cartilage Assessment of the Subtalar and Midtarsal Joints During a Transcontinental Ultramarathon - New Insights into Human Locomotion.

MR measurements can be accurately performed during 4486 km of running, opening a window into in vivo assessment of hindfoot articular cartilage under extreme ultra-endurance loading. This observational cross-sectional study included 22 randomized participants of TransEurope FootRace between Italy and the North Cape, which was accompanied by a trailer-mounted 1.5T MRI scanner over 9 weeks. Four follow up MR examinations of subtalar and midtarsal joints were performed. Statistics of cartilage T2* and thickness were obtained. Nearly all observed joints showed an initial significant mean T2* increase of 20.9% and 26.3% for the left and right side, followed by a relative decrease of 28.5% and 16.0% during the second half, respectively. It could be demonstrated that mobile MRI field studies allow in vivo functional tissue observations under extreme loading. Elevated T2* values recovered during the second half of the ultramarathon supported the evidence that this response is a physiological adaptive mechanism of chondrocyte function via upregulation of de novo synthesis of proteoglycans and collagen. These changes occurred in a distinct asymmetric pattern leaving a "biochemical signature" of articular cartilage that allows in vivo insight into joint loading. In conclusion, the normal articular cartilage of the hindfoot is resilient and adaptive, leaving extreme endurance activities up to limitless human ambition.