Running Performance Research Articles

Biological maturation, fat mass and cardiorespiratory fitness in prepubescent girls: A mediation analysis.

The association between indicators of maturation and measures of physical fitness are not well correlated and vary according to chronological age, sex, body size, and motor characteristics. It is known that chronological age, maturation, and fat mass are significant predictors of cardiorespiratory fitness in girls, however, the contributions of fat mass to the relationship between maturation and endurance performance are still unclear. The current study aimed to examine whether the association between somatic maturation and running performance in the 20-m shuttle-run in girls is mediated by estimated fat mass. The sample comprised 67 girls, aged 8.00-8.99 years. Stature, body mass, and skinfolds were measured. Estimates of body composition and predicted mature stature (PMS) were then calculated. Current stature was expressed as a percentage of PMS and somatic maturation was given by z-scores of the percentage of PMS. Mediation analysis was performed using the bias-corrected bootstrap approach with 5000 resamples in order to obtain estimates of total, direct, and indirect effects of z-scores of the percentage of PMS on 20-m shuttle-run performance mediated by fat mass. The results show that fat mass mediated the negative effect of biological maturation on 20-m shuttle-run performance in the observed sample of prepubescent girls (Indirect effect: β = -0.177, 95%CI: -0.291 to -0.059). Although the participants were prepubescent girls, poorer aerobic running performance appeared to be partly due to increased levels of fat mass.

A review of evidence on mechanical properties of running specific prostheses and their relationship with running performance.

Although mechanical properties of running specific prostheses (RSPs) can affect running performance, manufacturers do not consistently report them. This study aimed to review existing literature on RSP mechanical and structural properties and their relationship with running performance. A comprehensive search was conducted using keywords related to mechanical properties of RSPs and running performance. Search terms included stiffness and hysteresis, as well as performance outcomes including metabolic cost and running speed. Non-peer-reviewed and non-English publications were excluded. Twenty articles were included in the review. Sixteen studies used a material testing machine to measure RSP material properties, and four articles used other techniques including 2D/3D video capture and force platforms. Both measurement techniques and reporting of outcomes were inconsistent, which limits the ability to draw broad conclusions. Additionally, several studies did not report the numerical data for material properties despite measuring them. Relatively few articles measured both material properties and running performance and assessed correlations. Several articles connected prosthesis properties to running performance. However, inconsistent measurement and reporting of mechanical properties, along with the multifactorial nature of the athlete-prosthesis system, limit the ability to draw broad conclusions regarding the relationship between material and structural properties and athlete performance. Current evidence may be useful for clinicians seeking ways to optimize RSP stiffness in a case-by-case basis; however, clinicians would benefit from more consistent and systematic comparisons of the attributes of different RSPs and their role in performance.

Fatigued or bored? Investigating the effect of different types of mental fatigue on 3 km running performance

Mental fatigue has been highly cited as having a negative impact on endurance performance. Few, however, have investigated whether different types of mental fatigue, namely active and passive fatigue, might affect endurance performance differently. This study used a repeated-measures design where 11 participants completed a 3 km run after three 32-min conditions: an actively fatiguing task (Task-load Dual-back; TloadDback); a passively fatiguing task (Mackworth Clock); and a control task (Documentary). Subjective ratings and performance on a second task (Flanker task) were taken before and after the 32-min tasks, while ratings of perceived effort, motivation and workload were taken during the 3 km run. Results showed that both fatigue conditions were mentally fatiguing, with the TloadDback rated as more demanding and the Mackworth Clock more boring and less motivating. Performance on subsequent tasks showed different effects: the TloadDback condition had the slowest responses on the post-test Flanker task, while the Mackworth Clock condition had the slowest completion time on the 3 km run, though this difference in completion times was non-significant. These results suggest that different cognitive tasks lead to different types of mental fatigue, which can lead to different outcomes on subsequent cognitive tasks but non-significant differences on subsequent physical tasks. This study highlights that to understand the influence of mental fatigue on physical performance, it is important to understand the cognitive tasks used and how different cognitive and physical tasks interact. Future work should examine whether performance outcomes in other areas commonly affected by mental fatigue, like technical and tactical sporting skills, are affected differently by active and passive fatigue.

Biomechanical Investigation of Lower Limbs during Slope Transformation Running with Different Longitudinal Bending Stiffness Shoes.

During city running or marathon races, shifts in level ground and up-and-down slopes are regularly encountered, resulting in changes in lower limb biomechanics. The longitudinal bending stiffness of the running shoe affects the running performance. This research aimed to investigate the biomechanical changes in the lower limbs when transitioning from level ground to an uphill slope under different longitudinal bending stiffness (LBS) levels in running shoes. Fifteen male amateur runners were recruited and tested while wearing three different LBS running shoes. The participants were asked to pass the force platform with their right foot at a speed of 3.3 m/s ± 0.2. Kinematics data and GRFs were collected synchronously. Each participant completed and recorded ten successful experiments per pair of shoes. The range of motion in the sagittal of the knee joint was reduced with the increase in the longitudinal bending stiffness. Positive work was increased in the sagittal plane of the ankle joint and reduced in the keen joint. The negative work of the knee joint increased in the sagittal plane. The positive work of the metatarsophalangeal joint in the sagittal plane increased. Transitioning from running on a level surface to running uphill, while wearing running shoes with high LBS, could lead to improved efficiency in lower limb function. However, the higher LBS of running shoes increases the energy absorption of the knee joint, potentially increasing the risk of knee injuries. Thus, amateurs should choose running shoes with optimal stiffness when running.

Operation optimization of cement clinker production line based on neural network and genetic algorithm

The operation control plays a great role in the running performance of an industrial process. To achieve a successful control, the key point is searching for the target value of the control parameters. The relationship between operation parameters and performance parameters is usually nonlinear and complex, so it is hard to control an industrial process excellently with workers' experience. Based on a large amount of actual operation data, a bridge between control parameters and performance parameters might be built by the neural network. Prediction model is established by using neural network, genetic algorithm was then used to refine these parameters, the optimal condition can be further achieved by combining the relation bridge and genetic algorithm (GA). Paying attention to a cement clinker production process, this article established an optimizing approach based on the neural network and genetic algorithm and one-year operation data (615 sets). The feeding mass rate of raw meal and coal at the precalciner and the feeding coal mass rate at the rotary kiln are selected as the main independent variable and control parameters, and the specific standard coal consumption is determined as the key performance parameter and the optimization objective function. The mean square error and the correlation coefficient of the established neural network model are 12.84 and 0.89, respectively. The relative errors of approximately all prediction data (92.52 %) are within ±5 %. The optimal values for the raw meal feeding rate, the coal feeding rate into precalciner, and the coal feeding rate into rotary kiln are 259.57 t/h, 7.84 t/h, and 7.40 t/h, respectively. In that optimal condition, the specific standard coal consumption reaches 80.00 kgstandard coal/tclinker (This is a relative value, as there is a slight drift in zero point of the factory's instruments). A highly accurate neural network model is developed, which can significantly reduce standard coal consumption and improve industrial energy efficiency.

2024: anticipating record-breaking performances in front crawl swimming through mathematical analysis.

Introduction: This study presented a novel approach to predict future front crawl swimming world records (WRs) by employing a methodology that integrated performance data from both running and front crawl swimming. Methods: By extracting the top one running and swimming performances from 1995 to 2023 and applying a model that correlates physiological characteristics such as maximum aerobic power, anaerobic capacity, the decrement in maximum power with prolonged effort, and performance speed and duration, it was possible to project the potential record-breaking performances in 2024 across various swimming distances for both male and female athletes. Furthermore, this approach was expected to be less susceptible to the influence of the full-body swimsuit era, which may have disrupted the typical trajectory of swimming performance progression. Results: The average relative error between the top one and estimated speeds in front crawl swimming (50-1,500m, from 1995 to 2023, and for male and female) was 0.56% ± 0.17%. For male, WR in longer distances have been predicted with new WR in the 400 and 800m. A more ambitious prediction was noted among female, with twice as many WR as among male illustrated by new WR in the 50, 200, 400 and 800m. Discussion: This study illustrated that the utilization of a prediction model based on physiological parameters yielded plausible time estimates. Additionally, the research accentuated the ongoing trajectory of surpassing existing WR into 2024, illustrating the competitive zeal fueled by an emerging framework of exceptional swimmers.

Match running performance preceding scoring and conceding a goal in men’s professional soccer

This study aimed to investigate the potential differences in the match running performance of professional soccer players 5 min. before scoring and conceding a goal in the Polish Ekstraklasa. The sample consisted of 278 matches with 570 goals scored during official matches of the 2022/23 Polish Ekstraklasa season. All data was collected utilising the computerised multiple-camera optical tracking system TRACAB. Total distance covered (TD), standing distance (StD; < 0.72 km h−1), walking distance (WD; 0.73–7.2 km h−1), jogging distance (JG; 7.21–14.4 km h−1), running distance (RD; 14.41–19.8 km h−1), high-speed running distance (HSR; 19.81–25.2 km h−1) and sprinting distance (SprD; > 25.2 km h−1) were analysed in 5-min intervals prior to a goal scored for both teams. The employed linear mixed models showed that all examined match-running performance metrics were higher in teams that scored a goal compared to teams that conceded a goal. Within 5 min before scoring a goal in Polish Ekstraklasa matches, the scoring team produced significantly greater TD (∆ 95%CI 256.8–300.4 m; p = 0.001), WD (∆ 95%CI 52.3–95.8 m; p = 0.001), JG (∆ 95%CI 100.5–144.1 m; p = 0.001) and RD (∆ 95%CI 16.2–59.8 m; p = 0.001) compared to the conceding team, although no differences were found for HSR and SprD. These results demonstrate the enhanced identification potential of key physical performance factors influencing goal scoring in the Polish Ekstraklasa, thereby optimising the training process and improving overall performance. To enhance the effectiveness of soccer training, coaching and performance staff should consider this study's findings, that indicate an increase in the volume of medium- and low-intensity running efforts preceding a goal.

Experimental Study on the Removal of Toluene from Water by PTFE Hydrophobic Microporous Membrane Using Air Gap Membrane Distillation Process

Toluene is used for various purposes such as a cleansing agent, paint thinner, lacquers, printing, and leather tanning process. However, it has an adverse effect on human bodies, such as skin irritation, leukemia, respiratory issues, mutagenicity, etc, when the chemical gets mixed in drinking and rainwater by the above routes. Therefore, there is a threat to the environment and society because of the presence of toluene in water bodies through industrial effluent. Henceforth, in this study, toluene is separated from water using the air gap membrane distillation (AGMD) process. The hydrophobic microporous poly-tetra- fluoro-ethylene has been employed for this purpose. Primarily, this work focussed on the study of operating parameters such as feed solution temperature and coolant temperature on the AGMD performance namely permeate flux and toluene selectivity. It was observed that the permeate flux increased exponentially from 2.07 kg/m2h to 9.23 kg/m2h, and 0.94 kg/m2h to 3.53 kg/m2h. However, it was found that the permeate flux decreased from 9.48 kg/m2h to 8.12 kg/m2h, and 3.78 kg/m2h to 2.42 kg/m2h on increasing the coolant temperature from 5°C to 25°C at 3 mm and 11 mm air gap, respectively. The membrane selectivity was found to be less than 1, which signifies the efficient toluene-water separation. In order to study the membrane performance in the long run, the permeate flux was estimated continuously till 60 h wherein the estimated flux was found to be almost constant. The membrane morphology before and after the 60 h experimental run was analysed using capture FE-SEM micrographs. The toluene concentration was estimated using a spectrophotometer at a wavelength of 264 nm.

Impact of Anaerobic Exercise Integrated Into Regular Training on Experienced Judo Athletes: Running Vs. Repetitive Throws.

Kamandulis, S, Dudėnienė, L, Snieckus, A, Kniubaite, A, Mickevicius, M, Lukonaitiene, I, Venckunas, T, Stasiule, L, and Stasiulis, A. Impact of anaerobic exercise integrated into regular training on experienced judo athletes: running vs. repetitive throws. J Strength Cond Res 38(9): e489-e495, 2024-Anaerobic training in high-level athletes is of considerable interest to practitioners aiming to optimize performance. This study compared the impact of interval anaerobic training (IAT) sessions consisting of either high-intensity running or throwing that were performed twice a week together with regular judo training on the anaerobic and aerobic performance of experienced judo athletes. Employing a repeated-measures, counterbalancing, research design, 12 national team judo athletes (7 women and 5 men; mean age, 20.4 ± 0.95 years; mean judo training experience, 13.4 ± 1.4 years; competitive level, black belt first and second Dan) performed each IAT modality for 6 weeks, for a full training cycle of 12 weeks. Assessments of their anaerobic fitness (Cunningham and Faulkner Anaerobic Treadmill Test), sport-specific anaerobic fitness (Special Judo Fitness Test [SJFT]), and aerobic capacity (maximal incremental treadmill running test) were performed before, after 6 weeks, and after 12 weeks of training. The uphill running performance improved by 13.1% over the 12-week period ( p = 0.047). Simultaneously, there was a 9.0% improvement in the SJFT index and a 6.9% increase in the number of throws ( p = 0.011 and p = 0.017, respectively). Although a trend for throwing drills being more effective than interval sprint running was observed, the interaction effect lacked statistical significance ( p = 0.074). Moreover, no substantial changes were noted in aerobic endurance markers. In conclusion, this study suggests that incorporating specific and nonspecific high-intensity drills into a routine training regimen may enhance anaerobic capacity among well-trained judo athletes, potentially leading to favorable competitive outcomes.

Role of midsole hollow structure in energy storage and return in running shoes

Understanding the relationship between footwear features and their potential influence on running performance can inform the ongoing innovation of running footwear, aimed at pushing the limits of humans. A notable shoe feature is hollow structures, where an empty space is created in the midsole. Presently, the potential biomechanical effect of the hollow structures on running performance remains unknown. We investigated the role of hollow structures through quantifying the magnitude and timing of foot and footwear work. Sixteen male rearfoot runners participated in an overground running study in three shoe conditions: (a) a shoe with a hollow structure in the forefoot midsole (FFHS), (b) the same shoe without any hollow structure (Filled-FFHS) and (c) a shoe with a hollow structure in the midfoot midsole (MFHS). Distal rearfoot power was used to quantify the net power generated by foot and footwear together. The magnitude and timing of distal rearfoot work and ankle joint work were compared across shoe conditions. The results indicated that MFHS can significantly (p = 0.024) delay distal rearfoot energy return (3.4 % of stance) when compared to Filled-FFHS. Additionally, FFHS had the greatest positive (0.425 J/kg) and negative (−0.383 J/kg) distal rearfoot work, and the smallest positive (0.503 J/kg) and negative (−0.477 J/kg) ankle joint work among the three conditions. This showed that the size and location of the midsole hollow structure can affect timing and magnitude of energy storage and return. The forefoot hollow shoe feature can effectively increase distal rearfoot work and reduce ankle joint work during running.

Validity of simple field tests as indicators of elite female field hockey match performance.

Due to the change in field hockey match format, the need exits for research to determine whether current fitness test are still valid indicators of match performance. This study aimed to determine the direct validity of the 5-m multistage shuttle test (5-m MST) and Yo-Yo Intermittent recovery level 1 test (Yo-Yo IR1) by correlating their results with external load measures in international field hockey matches. Nineteen female field hockey players completed the 5-m MST and Yo-Yo IR1 before nine matches. Players covered mean distances of 750.3 m±19.6 m (5-m MST) and 1649.7 m±277.6 m (Yo-Yo IR1). Average relative distance, relative player load, and high-intensity activity during matches were 107.8±16.3 m/min, 10.3±1.4 AU/min, and 10.0±3.0%, respectively. The 5-m MST showed small to moderate significant (P<0.05; r=0.21-0.5) correlations with relative distance and high-intensity activity, while the Yo-Yo IR1 only had a small negative significant (P<0.05; r=-0.27) correlation with high-intensity activity. Strong correlations (r>0.51) were found between the 5-m MST and Yo-Yo IR1. The tests demonstrated low direct validity for current field hockey matches due to weak relationships with relative load and running performance. Additionally, the strong correlation between the Yo-Yo IR1 and 5-m MST suggests that both tests may not be necessary to assess match readiness. Coaches should consider using better-validated fitness tests for this population and sport.

Does Environmental, Social and Governance Have an Impact on Stock Performance? A Panel Study of Indian Companies

The present study investigates the impact of environmental, social, and governance (ESG) on firms' profitability in the Indian setting on a sample of 23 firms. The bootstrap corrected fixed effects estimation and inference in the dynamic panel method is employed to investigate the relationship. The dynamic panel results show that the relationship between ESG score and firms' profitability is inconclusive in the short run. However, governance conditions affect firms' investment decisions and the nexus between ESG and firm financial performance in the long run. Therefore, institutional reforms are warranted to stabilise property rights and check parent-client politics for the long-run effects of sustainable environmental governance on firms' profitability.

Study on bridge tower-induced sudden wind and its impact on running performance of high-speed train

Study on bridge tower-induced sudden wind and its impact on running performance of high-speed train

Acute dose-response effect of photobiomodulation therapy on 5-km running performance in trained runners: a randomized, double-blind, placebo-controlled, crossover study.

Photobiomodulation therapy (PBMT) has been advocated as a potential intervention to improve muscle performance and recovery in the health and sports context. However, the short- and long-term effects of PBMT on endurance running performance remain under-researched and controversial. The purpose of this study was to investigate the acute dose-response effect of PBMT with light-emitting diodes (LEDs) on endurance performance and rating of perceived exertion (RPE; 6-20 Borg) during a 5-km running trial in recreational runners. In a crossover design, eighteen young adult runners (28.7 ± 7.8 years) were randomized to receive 1 of 4 PBMT conditions (placebo, 300, 900, and 1260 Joules [J]) 60min before the 5-km running trial on four occasions, separated by a 2-wk washout period. The treatments were applied to the quadriceps, hamstrings, and gastrocnemius muscles of both legs using a device containing 200 LEDs (100 red and 100 infrared). The following variables were assessed: endurance performance (i.e. total time, mean velocity, and velocity in the split distances at the initial 200m and every 400m lap) and RPE in the split distances at the initial 200m and every 400m lap. Data normality and homogeneity were tested using Shapiro-Wilk's and Levene's tests, respectively. Differences between treatment conditions were assessed using the analysis of variance tests (one- or two-way ANOVA, depending on the comparisons), complemented by the Bonferroni post hoc test. There were significant time effects for the running velocity and RPE in the split distances (p < 0.0001), with no significant treatment-by-time interaction (running velocity, p = 0.59; RPE, p = 0.95). The mean velocity (p = 0.997), total time (p = 0.998), and total mean of the RPE (p = 0.91) were similar between treatment conditions. In conclusion, acute PBMT with LEDs at doses of 300, 900, and 1260J is not recommended for improving endurance performance and RPE in the 5-km running trial in recreational runners.

The effect of forward postural lean on running economy, kinematics, and muscle activation.

Running economy, commonly defined as the metabolic energy demand for a given submaximal running speed, is strongly associated with distance running performance. It is commonly believed among running coaches and runners that running with increased forward postural lean either from the ankle or waist improves running economy. However, recent biomechanical research suggests using a large forward postural lean during running may impair running economy due to increased demand on the leg muscles. This study tests the effect of altering forward postural lean and lean strategy on running economy, kinematics, and muscle activity. 16 healthy young adult runners (23±5 years, 8M/8F) ran on a motorized treadmill at 3.58m/s using three postural lean angles [upright, moderate lean (50% of maximal lean angle), and maximal lean] and two strategies (lean from ankle and lean from waist [trunk lean]). Metabolic energy consumption, leg kinematics, and muscle activation data were recorded for all trials. Regardless of lean strategy, running with an increased forward postural lean (up to 8±2 degrees) increased metabolic cost (worsened economy) by 8% (p < .001), increased hip flexion (p < .001), and increased gluteus maximus (p = .016) and biceps femoris (p = .02) muscle activation during the stance phase. This relation between running economy and postural lean angle was similar between the ankle and trunk lean strategies (p = .743). Running with a large forward postural lean reduced running economy and increased reliance on less efficient extensor leg muscles. In contrast, running with a more upright or moderate forward postural lean may be more energetically optimal, and lead to improved running performance.

Running performance of substitutes in the FIFA World Cup after the change in substitution rule: influence of match outcome, playing position and sex

ABSTRACT This study intended to investigate the impact of substitution rule change on the physical performance in World Cup tournaments. Running data from the 2022 and 2023 FIFA World Cups were used for analysis. The results show that substitutes have much more sprinting, high-speed running and moderate speed running per minute than starters (p < 0.05), with similar magnitudes of differences for the men’s (28.4–47.6%) and women’s World Cup (23.4–59.5%). Substitutes in winning vs losing teams had higher sprint distance (3.7 vs 2.8 m· min−1) and number of high-speed running (1.70 vs 1.58 times· min−1) in men’s World Cup and higher sprint distance (3.3 vs 2.5 m· min−1) in women’s World Cup. In the men’s World Cup, substituted midfielders had a higher frequency and greater distance covered with high-speed running (1.85 vs 1.57 and 1.44 times· min−1; 10.1 vs 8.9 and 7.8 m· min−1) and higher sprint frequency (0.74 vs 0.71 and 0.62 times· min−1) compared to forwards and defenders, which was not the case for the Women’s World Cup. Together, this study underlines the importance of substitutions for the team running performance in modern elite football under the new substitution rules, and practitioners need to pay attention to the use of substitute players under the new rules.

“Run Forrest Run!”: Measuring the Impact of App-Enabled Performance and Social Feedback on Athletic and Usage Outcomes

Exercise-tracking apps are digital tools for delivering personalized behavioral interventions. Despite the growing usage of exercise applications, the efficacy of in-exercise app features in driving usage and athletic outcomes remains poorly understood. To remain competitive, sports organizations now need to leverage tracking tools to efficiently allocate resources and streamline training regimens and interventions for their core assets (i.e., athletes). In response to these operational needs, we examine two specific forms of such in-exercise interventions, namely performance feedback and social feedback. We conducted an 18-month-long field study with 1,037 uniformed group servicemen to assess the effect of these feedback types on running and usage outcomes. Results from the field study provided evidence that these two app features improved the servicemen’s running times and frequency of application usage, on average. Contrary to the common belief that more features are better, the joint usage of two feedback features does not produce additive effects. Tests at more granular levels suggest that users who received both feedback types in exercise episodes exhibit overconfidence behavior by participating in fewer subsequent exercises. The receipt of both feedback may be redundant and can cause user annoyance. Heterogeneity tests revealed that while performance feedback benefited most runners, social features were effective only for already stronger runners. Also, only positive social feedback had a significant impact on running performance. The results further indicate that performance feedback generated a slow but sustained increase in usage frequency, while social feedback spurred quick initial growth in usage but dwindled in effectiveness over time. Implications for theory and practice, as well as directions for further research, are discussed.

Streamflow prediction in ungauged basins: How dissimilar are drainage basins?

Hydrological processes leading to flow in river channels are extremely complex, which is why we cannot use any fundamental law to fully explain river flow dynamics at basin scale. The general approach for hydrological modelling considers that every catchment’s response to precipitation input is unique, which means different catchments respond differently to the same precipitation input. In other words, river basins are sufficiently dissimilar to warrant having hydrological models with multiple free-parameters for predicting discharge. It is assumed that free-parameters are related to static catchment characteristics. However, past efforts to relate model parameters with observable catchment characteristics have not been very successful. We thus need a framework to quantify catchment dissimilarities exhibited by catchment characteristics because there is no need of free-parameters if we decide to ignore dissimilarities. Thus, the relative roles of climate and catchment characteristics in the streamflow response of the basin needs to be quantified. In this study, we have considered daily data from 3534 gauging stations spread across the globe to compare HBV, a widely used hydrological model, with Dynamic Budyko (DB) model, a recently proposed calibration-free model. The HBV model assumes that both climate and catchment characteristics are important in modeling streamflow response, whereas a calibration-free DB model essentially assumes that streamflow response is largely governed by climate. The performance of HBV run with regionalized parameters and DB in terms of median coefficient of determination (R2) and weighted R2 (WR2) are (0.43, 0.45) and (0.24, 0.27), respectively. The corresponding values of R2 and WR2 from quantile-quantile comparison are (0.94, 0.94) and (0.60, 0.59). The results here seem to support the idea of developing calibration-free models by appreciating similarities between basins, particularly if the objectives are prediction in ungauged basins and assessment of climate change impact on streamflow.

Identifying physiological determinants of 800 m running performance using post-exercise blood lactate kinetics

PurposeThe aims of the present study were to investigate blood lactate kinetics following high intensity exercise and identify the physiological determinants of 800 m running performance.MethodsFourteen competitive 800 m runners performed two running tests. First, participants performed a multistage graded exercise test to determine physiological indicators related to endurance performance. Second, participants performed four to six 30-s high intensity running bouts to determine post-exercise blood lactate kinetics. Using a biexponential time function, lactate exchange ability (γ1), lactate removal ability (γ2), and the quantity of lactate accumulated (QLaA) were calculated from individual blood lactate recovery data.Results800 m running performance was significantly correlated with peak oxygen consumption (r = −0.794), γ1 and γ2 at 800 m race pace (r = −0.604 and −0.845, respectively), and QLaA at maximal running speed (r = −0.657). V˙\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\dot{\ ext{V}}}$$\\end{document}O2peak and γ2 at 800 m race pace explained 83% of the variance in 800 m running performance.ConclusionOur results indicate that (1) a high capacity to exchange and remove lactate, (2) a high capacity for short-term lactate accumulation and, (3) peak oxygen consumption, are critical elements of 800 m running performance. Accordingly, while lactate has primarily been utilized as a performance indicator for long-distance running, post-exercise lactate kinetics may also prove valuable as a performance determinant in middle-distance running.

The effect of caffeine on running performance in performance triathletes

Background and purpose In an endurance sport such as triathlon, coaches at the elite level strive to select an appropriate nutritional strategy prior to performance in addition to optimizing the training process. Based on this, the research in question was designed with the aim to verify the effect of caffeine on the running performance of performance triathletes during the preparation period. Purpose is to determine the effect of caffeine on running performance in triathletes. Material and methods The study sample consisted of 8 performance triathletes from the TRIAN club of ŠK UMB Banská Bystrica, whose age was 16.7 ± 0.67 years. Diagnostics were run on InSPORTline Condi T6000i treadmill with the aim of detecting lactate and blood sugar levels (mmol/l) before the performance and within 10 seconds after the performance. The blood lactate level was detected with the portable device Lactate Scout+ and the blood glucose level was measured with the Wellion CALLA light glucose meter. The running pace at which the participants performed the test was at anaerobic threshold and they attempted to cover a distance of 1,500 m at a constant incline of 3%. The testing took place 1 time per week in the morning hours (08:00-08:30). On the second day after the initial testing from 01.03.2023 to 14.03.2023, the participants started taking placebo (magnesii lactas) on a daily basis in form of capsules. The participants took 2 capsules (200 mg magnesium) which they consumed with 200 mL of water 45 to 60 minutes before each morning workout/test. This was followed by the administration of caffeine capsules, which they consumed for an additional 2 weeks from 03.15.2023 to 03.28.2023. The participants consumed caffeine capsules at 5 mg/kg body weight 45 to 60 minutes before each morning workout/test. The intervention programme lasted 5 weeks. Results When administering caffeine capsules at a dose of 5 mg/kg body weight, there was a significant reduction of approximately 26% in the average blood lactate level of the participants after the 1,500 m run. The participants' mean blood glucose levels increased by approximately 4.9% after the 1500 m run. Conclusions Based on the results we can claim that for ergogenic effects on performance we recommend supplementing with 5mg/kg body weight of caffeine approximately 45 to 60 minutes before training.