Running Track Research Articles

ANALYSIS OF RELATED PHYSICAL AND MECHANICAL PROCESSES AND STATES AND SYNTHESIS METHODS OF DESIGN AND TECHNOLOGICAL SOLUTIONS OF ARMORED COMBAT VEHICLES ELEMENTS

Existing research methods of contact interaction and stress-strain state of complex structural elements are analyzed. The main elements of hydraulic transmissions in tank transmissions are ball pistons that are connected to the toroidal running surface of the stator ring. Important parameters of these elements are the ratio of the radii of the piston and the cross-section of the running track. The studied regularities indicate the optimal range of radii ratios, which ensures minimum contact pressure and stress. Taking into account the elastic-plastic deformation of the materials of the contacting parts, in particular the surface layers, is important for recommendatory decisions. Patterns of influence on the characteristics of strength and performance of the investigated structures of varied parameters have been revealed. Accordingly, in each specific case, it is possible to develop recommendations for the justification of progressive technical solutions of certain structures according to the mentioned criteria. Ball pistons in connection with the toroidal running surface of the stator ring are decisive for strength and durability of the hydraulic transmission elements of promising tank transmissions. In particular, important parameters are the radii ratio of the piston, on the one hand, and on the other, of the cross section of the treadmill. Despite the traditionally existing approaches and efforts to bring the shapes of the contacting surfaces of conjugated bodies as close as possible, the work established regularities that contradict such solutions.

Quantity of within-sport distance variety - what can pool swimmers and track runners learn from each other?

To determine the relationship between success at peak performance age and quantity of within-sport distance variety and compare the dose-time-effect between swimming and track running by determining probability of becoming an international-class female athlete based on the number of different race distances the athletes compete in each year throughout their development process. Race times of female Tier 2 to Tier 5 freestyle pool swimmers (n = 2,778) and track runners (n = 9,945) were included in the present study. All athletes were ranked according to their personal best at peak performance age. Subsequently, number of different race distances during each year were retrospectively extracted from peak performance to early junior age. Personal best performance points at peak performance age were correlated with the number of different race distances across the various age categories. Poisson distribution determined the dose-time-effect of becoming an international-class athlete based on the number of different swimming strokes. At peak performance age, correlation analysis showed a larger within-sport distance variety for higher ranked athletes, particularly for track runners (r ≤ 0.35, P < 0.001). Despite reaching statistical significance, the effects were small to moderate. While swimmers showed a generally larger within-sport distance variety than track runners, Poisson distribution revealed a dose-time-effect for the probability of becoming an international-class swimmer. Sprint and middle-distance swimmers benefit from competing in three race distances during junior age and a transition to two race distances at 17-18, 18-19, 20-21 and 25-26 years of age for 50 m, 100 m, 200 m and 400 m races, respectively. Long-distance swimmers should maintain three different race distances throughout peak performance age. Probability analysis showed a consistent benefit of competing in one or two race distances for 100 m, 200 m, 400 m and 800 m track runners. Within-sport distance variety is not a continuum but an ever-evolving process throughout the athletes' careers. While swimmers generally show larger variety than track runners, the progressive specialization towards peak performance age improves success chances to become an international-class swimmer.

Real-Time Tracking Target System Based on Kernelized Correlation Filter in Complicated Areas.

The achievement of rapid and reliable image object tracking has long been crucial and challenging for the advancement of image-guided technology. This study investigates real-time object tracking by offering an image target based on nuclear correlation tracking and detection methods to address the challenge of real-time target tracking in complicated environments. In the tracking process, the nuclear-related tracking algorithm can effectively balance the tracking performance and running speed. However, the target tracking process also faces challenges such as model drift, the inability to handle target scale transformation, and target length. In order to propose a solution, this work is organized around the following main points: this study dedicates its first part to the research on kernelized correlation filters (KCFs), encompassing model training, object identification, and a dense sampling strategy based on a circulant matrix. This work developed a scale pyramid searching approach to address the shortcoming that a KCF cannot forecast the target scale. The tracker was expanded in two stages: the first stage output the target's two-dimensional coordinate location, and the second stage created the scale pyramid to identify the optimal target scale. Experiments show that this approach is capable of resolving the target size variation problem. The second part improved the KCF in two ways to meet the demands of a long-term object tracking task. This article introduces the initial object model, which effectively suppresses model drift. Secondly, an object detection module is implemented, and if the tracking module fails, the algorithm is redirected to the object detection module. The target detection module utilizes two detectors, a variance classifier and a KCF. Finally, this work includes trials on object tracking experiments and subsequent analysis of the results. Initially, this research provides a tracking algorithm assessment system, including an assessment methodology and the collection of test videos, which helped us to determine that the suggested technique outperforms the KCF tracking method. Additionally, the implementation of an evaluation system allows for an objective comparison of the proposed algorithm with other prominent tracking methods. We found that the suggested method outperforms others in terms of its accuracy and resilience.

Specializing When It Counts: Comparing the Dose-Time Effect of Distance Variety between Swimming and Track Running.

To conduct a longitudinal retrospective analysis, explore the relationship between success at peak performance age and the number of different race distances athletes competed in each year (within-sport distance variety), and compare the dose-time effect of this distance variety throughout the development process between male swimmers and track runners. Male swimmers (n = 6033) and track runners (n = 19,278) still competing at peak performance age were ranked, and the number of different race distances was extracted retrospectively for each year until early junior age (13-14-year-old category) from the databases of the European Aquatics and World Athletics federations. Firstly, correlation analysis determined the relationship between ranking at peak performance age and distance variety. Secondly, Poisson distribution provided the probability and dose-time effect of distance variety for becoming an international-class athlete at peak performance age. Generally, correlation analysis revealed low coefficients (r ≤ 0.22) but significant effects (p < 0.001) for larger distance variety and success at peak performance age. Poisson distribution revealed the highest probability of becoming an international-class swimmer when competing in 2-4 race distances at junior age, depending on the primary race distance. The dose-time effect indicated a gradual reduction in the number of race distances as athletes approached peak performance age, narrowing down to 1-2, 2-3, and 3-4 distances for sprint, middle-, and long-distance races, respectively. Track runners exhibited a lower distance variety than swimmers, with a consistent optimum of 1-2 race distances across the age groups. The present findings including data of the most combined race distances for each primary race distance and a comparison between swimming and track running provide new background information to challenge traditional training regimes and help establish new strategies for long-term athlete development.

Sprinting to the top: comparing quality of distance variety and specialization between swimmers and runners.

To compare performance progression and variety in race distances of comparable lengths (timewise) between pool swimming and track running. Quality of within-sport variety was determined as the performance differences between individual athletes' main and secondary race distances across (top-) elite and (highly-) trained swimmers and runners. A total of 3,827,947 race times were used to calculate performance points (race times relative to the world record) for freestyle swimmers (n = 12,588 males and n = 7,561 females) and track runners (n = 9,230 males and n = 5,841 females). Athletes were ranked based on their personal best at peak performance age, then annual best times were retrospectively traced throughout adolescence. Performance of world-class swimmers differentiates at an earlier age from their lower ranked peers (15-16 vs. 17-20 year age categories, P < 0.05), but also plateaus earlier towards senior age compared to runners (19-20 vs. 23 + year age category, P < 0.05), respectively. Performance development of swimmers shows a logarithmic pattern, while runners develop linearly. While swimmers compete in more secondary race distances (larger within-sport variety), runners specialize in either sprint, middle- or long-distance early in their career and compete in only 2, 4 or 3 other race distances, respectively. In both sports, sprinters specialize the most (P < 0.05). Distance-variety of middle-distance swimmers covers more longer rather than sprint race distances. Therefore, at peak performance age, (top-) elite female 200 m swimmers show significantly slower sprint performances, i.e., 50 m (P < 0.001) and 100 m (P < 0.001), but not long-distance performances, i.e., 800 m (P = 0.99) and 1,500 m (P = 0.99). In contrast, (top-) elite female 800 m middle-distance runners show significantly slower performances in all their secondary race distances (P < 0.001). (Top-) elite female athletes specialize more than (highly-) trained athletes in both sports (P < 0.05). The comparison to track running and lower ranked swimmers, the early performance plateau towards senior age, and the maintenance of a large within-sport distance variety indicates that (top-) elite sprint swimmers benefit from greater within-sport specialization.

Application of Piezoelectricity on Running Tracks: A Prototype for the Realization of Sustainable and Efficient Energy

Electrical energy has become a basic necessity today. As the population increases, the amount of electricity demand is also increasing. Therefore, many innovations are needed to meet these needs. One of the innovations in energy harvesting systems is the use of piezoelectricity. This research aims to create a piezoelectric-based running track prototype to produce environmentally friendly electrical energy. The arrangement of piezoelectric sensors used in this research is a parallel circuit. The research method used is the Research and Development method. The test results on the physical activities of walking, running, and jumping show that the prototype system that has been made has worked well and produces a fairly stable electric voltage even though it is still in a small amount. the difference in activity and body weight that presses the prototype produces different electric voltages. For walking activity, the prototype is able to produce a maximum voltage output of 0.83V, running activity has a maximum output of 5.83V and the maximum voltage output of jumping activity is 7.88V. The use of energy is done by storing the energy obtained from the piezoelectric in the battery, which can later be monitored directly by the voltage sensor, bluetooth module, HC-05, and RTC module the data will be sent to the cell phone so that the piezoelectric output voltage can be recorded and monitored. The electrical energy output generated by the piezoelectric is able to charge the battery and switch on the LED light at 2.5 V.

Validity of Current Smartwatches for Triathlon Training: How Accurate Are Heart Rate, Distance, and Swimming Readings?

Smartwatches are one of the most relevant fitness trends of the past two decades, and they collect increasing amounts of health and movement data. The accuracy of these data may be questionable and requires further investigation. Therefore, the aim of the present study is to validate smartwatches for use in triathlon training. Ten different smartwatches were tested for accuracy in measuring heart rates, distances (via global navigation satellite systems, GNSSs), swim stroke rates and the number of swim laps in a 50 m Olympic-size pool. The optical heart rate measurement function of each smartwatch was compared to that of a chest strap. Thirty participants (15 females, 15 males) ran five 3 min intervals on a motorised treadmill to evaluate the accuracy of the heart rate measurements. Moreover, for each smartwatch, running and cycling distance tracking was tested over six runs of 4000 m on a 400 m tartan stadium track, six hilly outdoor runs over 3.4 km, and four repetitions of a 36.8 km road bike course, respectively. Three swimming protocols ranging from 200 m to 400 m were performed in triplicate in a 50 m Olympic-size pool, evaluating the tracked distance and the detected number of strokes. The mean absolute percentage errors (MAPEs) for the average heart rate measurements varied between 3.1% and 8.3%, with the coefficient of determination ranging from 0.22 to 0.79. MAPE results ranged from 0.8% to 12.1% for the 4000 m run on the 400 m track, from 0.2% to 7.5% for the 3.4 km outdoor run, and from 0.0% to 4.2% for the 36.8 km bike ride. For the swimming tests, in contrast, the deviations from the true distance varied greatly, starting at a 0.0% MAPE for the 400 m freestyle and reaching 91.7% for the 200 m medley with style changes every 25 m. In summary, for some of the smartwatches, the measurement results deviated substantially from the true values. Measurements taken while road cycling over longer distances with only a few curves were in relative terms more accurate than those taken during outdoor runs and even more accurate than those taken on the 400 m track. In the swimming exercises, the accuracy of the measured distances was severely deteriorated by the medley changes among the majority of the smartwatches. Altogether, the results of this study should help in assessing the accuracy and thus the suitability of smartwatches for general triathlon training.

Vertical and Lateral Dynamics of 4L Freight Bogie

Freight wagons in Europe have used Y25 bogies since the 1960s. Although very cost-effective, Y25 suffers from intrinsic limitations due to its architecture and running behaviour. This study introduces an innovative lightweight bogie, named 4L bogie, aimed at removing those limitations as well as improving running dynamics and track friendliness. This task was particularly challenging as the high ratio between laden and tare weight (up to 5:1) forced us to use a non-conventional suspension system and an innovative architecture of frame, reducing the mass by about 15% and the yaw moment of inertia by about 30% with respect to the Y25 bogie. Maintenance issues were addressed by reducing the number of components and easing overhaul, while the new design was validated from both the structural and the running dynamics point of view, assessing its interaction with the track in terms of stability, curving behaviour and the vertical response of the 4L bogie. Stability was improved by about 20% even in empty conditions and high conicity at the wheel/rail contact. Vertical dynamic force on a straight track, evaluated according to the Ride Force Count metric, and wear behaviour on sharp and mild curves were considerably reduced, leading to an improved track friendliness of the bogie.

Validation of a scaled dynamic test system for simulating a high‐speed train passing bridges under seismic excitation

AbstractThis study presents the validation of a dynamic test system to simulate a high‐speed train passing bridges under seismic excitation. The system comprises scaled models of a CRH380A high‐speed train and an 11‐span simply supported bridge on a shake table array. This innovative apparatus combines seismic loading with the moving train load to replicate train‐track‐bridge interaction (TTBI) during earthquakes. It allows investigation of various train speeds and seismic excitations, providing invaluable insights into TTBI. First, the detailed similarity design principle based on the equations of motion was discussed, and its applicability to the wheel‐rail contact relationship was verified. Then, the dynamic characteristics of the scaled model were identified, and the impact of the error between the scaled model and the theoretical model on the TTBI response was assessed. Furthermore, the comparison of the dynamic test model and the numerical simulation in acceleration responses validated the accuracy of the rigid‐flexible coupling model method for the actual TTBI system. Test cases without external excitation, with simple harmonic excitation and with seismic excitation were conducted on the dynamic test system. Results showed that the influence of track irregularity and running speed on train response aligns with the classical train‐bridge interaction theory. The successful implementation of this test system marks a significant advance in understanding TTBI mechanics and has significant implications for seismic safety enhancement of railway infrastructure.

Early morning bright light therapy: its next-day effects on early morning physical performance, temperature, and mood

Many different popular sports such as swimming, rowing or team-based sports involve having to perform whether in training or competition at a high level in the early morning (Olympics.com, 2023). Various research papers in the past have shown that there is a distinct diurnal variation in physical performance. Finding ways to improve early morning performance would greatly benefit many athletes and teams in multiple disciplines. 11 active males [mean ± SD: age, 21 ± 1 years, body mass, 78 ± 8 kg and stature, 180 ± 5 cm) volunteered, completed two familiarisations. Then two experimental sessions randomly allocated in a counterbalanced order 1) bright light therapy/ 2) no bright light therapy was administered at 07:00 h for 1 h the next morning (07:00 h) participants came into the laboratory where Intra-aural temperature, mood was assessed using the Perceived Onset Mood State questionnaire and right and left grip strength using a hand grip dynamometer were taken. Finally, participants undertook a warmup, the completed 10 × 20 m repeated sprints (RS) with 30 s recoveries on an indoor running track, with heart rate, finishing time and perceived exertion measured every sprint. Blood lactate was measured at rest, after the warm-up and post RS. Data were analysed using general-linear models.

Surface Temperature Experienced and Irrigation Effects on Artificial Turf

Artificial turf has gained widespread use in sporting fields as it is considered a water-saving and maintenance-free alternative to natural turfgrass. However, the high surface temperatures that occur during the day are a potentially important unfavorable feature of artificial turfgrass. The objective of this study was to establish the temperatures experienced on an artificial turf surface and to evaluate the effect of irrigation on artificial turf surface temperature. Data was collected over five surfaces across a sports facility on the campus of the University of Thessaly in Larissa, Greece. Results showed surface temperatures on artificial turf (AT) as significantly higher than running track (RT), asphalt (AS), bare soil (BS), and natural grass (NG), with maximum surface temperatures of 72oC. Solar radiation accounted for most of the variation in surface temperature of the artificial turf (r2=0.92) as opposed to air temperature (r2=0.38), and relative humidity (r2=0.50). To lower surface temperature, four irrigation regimes were used (1x60 min, 1x30 min, 2x15 min, and 3x5 min water application). Irrigation reduced the surface temperature by as much as 30°C compared to the unirrigated surface, but these low temperatures were maintained for 90 to 120 minutes long. The most effective cooling effect occurred when water was applied in a 3-cycle, 5-minute duration, where the irrigated surface temperature remained below the unirrigated surface throughout the time after the first watering.

The Optimal Span Length of the Overhead Catenary System for the Gemas-Johor Bahru Electrified Double Track Project

The span term in the Overhead Catenary System (OCS) refers to the distance between two subsequent supports in the running track direction. Longer spans are preferable for economic reasons because they reduce the number of supporting structures. The maximum span along the track was suggested by OCS designers using a structure spacing table and chart with varying wind speeds and radius of curvature. The structure spacing chart is a logarithmic curve that is plotted based on the specifications of the project and design constraints. According to the current design, the maximum span length for the Gemas-Johor Bahru Electrified Double Track Project is 72 metres (GJBEDTP). The current OCS design can be upgraded to provide a greater maximum span. This study looked at the economic benefits of increasing the maximum span length of the GJBEDTP in terms of reducing the total number of supporting structures. The track is separated into many equal-length track sections, and their individual spans are selected using the wind study assessment report and the structure spacing chart. Divide the total track length by the average span to get the estimated total number of supporting structures. In this study, a graph showing the percentage of cost savings and the maximum allowable span is plotted. In this optimization issue, the Elbow approach is used to select a point where diminishing returns are no longer worth the extra expense of going for a longer span. According to the results, the maximum span of 72 m is the ideal span for the GJBEDTP.

Experimental installation for wear tests of materials and coatings

On the basis of the analysis of existing tribological testing methodologies, which includes the selection of controlled wear parameters, the influence of the type of friction, contact geometry, surface roughness, the scheme of tribological research, the choice of a machine 2168UМТ for friction testing of materials is substantiated. The friction machine allows you to install three samples at the same time, change the pressure in the contact zone in a wide range, control the moment of friction, the rotation frequency of the counterbody, the number of revolutions (friction path), change the rotation frequency, respectively, the sliding speed, automatically limit the distance traveled and other functions. The method of wear is adopted according to the finger-ring scheme, linear wear is monitored using an indicator rack with a value of divisions of the measuring device of 0.001 mm. To fix the samples on the machine caliper, holders were designed and manufactured, which ensure the self-fixation of the sample on the counterbody - a spherical joint made of the rolling body of the bearing. due to the fact that the samples were pressed against the counterbody with a force corresponding to the nominal contact pressure, they were self-aligned. After the sample was self-assembled, the whole structure was fixed by tightening the nuts. The counterbody is made of a rolling bearing ring, the material is steel SHX15, the hardness of the base is HRC 61. Three devices are mounted on the caliper for permanent lubrication of the running track immediately before the approaching sample. Thus, at certain values of pressure and speed, the mode of marginal friction can be reached, which was marked by a low coefficient of friction.

Sex Differences in Track and Field Elite Youth.

To understand athletic performance before and after puberty, this study determined 1) the age at which the sex difference increases among elite youth track and field athletes for running and jumping events, and 2) whether there is a sex difference in performance before ages associated with puberty among elite youth athletes. Track and field records of elite US male and female youth (7-18 yr) across 3 yr (2019, 2021, and 2022) were collected from an online database ( athletic.net ). The top 50 performances were recorded for 100-, 200-, 400-, and 800-m track running, long jump, and high jump. Males ran faster than females at every age in the 100, 200, 400 and 800 m ( P < 0.001). When combining all running events, the sex difference (%) was 4.0% ± 1.7% between 7 and 12 yr and increased to 6.3% ± 1.1% at 13 yr and 12.6% ± 1.8% at 18 yr ( P < 0.001). Similarly, males jumped higher and farther than females at every age ( P < 0.001). For long jump, the sex difference was 6.8% ± 2.8% between 7 and 12 yr, increasing to 8.5% ± 1.7% at 13 yr and 22.7% ± 1.4% at 18 yr ( P < 0.001). For high jump, the sex difference was 5.3% ± 5.2% between 7 and 12 yr, increasing to 12.4% ± 2.9% at 15 yr and 18.4% ± 2.04% at 18 yr ( P < 0.001). Before 12 yr of age in elite youth track and field athletes, there was a consistent and significant sex difference of ~5%, such that males ran faster and jumped higher and farther than females. The magnitude of the sex difference in performance increased markedly at 12-13 yr for running and long jump and 14 yr for high jump and thus was more pronounced after ages associated with puberty.

Differences in pacing behaviour between global championship medal performances and world records in men’s and women’s middle- and long-distance running track events

ABSTRACT The differences in pacing demands between track distance-running championship and meet (e.g., World Record [WR]) races have not been specified yet in the current literature. Therefore, the aim of this study was to determine pacing behaviour differences between WRs and global championship (i.e., World Championships and Olympic Games) medal performances (GCMs) in middle- and long-distance running events. Percentages of mean race section speeds were compared through analysis of variance between men’s and women’s 169 WRs and 189 GCMs over 800 m, 1500 m, 3000 m steeplechase, 5000 m and 10,000 m. U-shaped and negative pacing approaches are observed during men’s and women’s 1500 m WRs and GCMs, respectively. The first and third 400 m of men’s and women’s 1500 m GCMs were relatively slower and faster, respectively (p ≤ 0.05, 1.31 ≤ d ≤ 1.69). Even profiles are followed during women’s 3000 m steeplechase WRs and GCMs, whereas positive approaches were adopted in men’s GCMs. Finally, whereas 5000 m and 10,000 m GCMs were finished with a fast endspurt, WRs had a U-shaped profile in men, with differences between the initial and last race stages (p ≤ 0.01, 1.20 ≤ d ≤ 3.66), and an even profile in women. Coaches should consider the different pacing demands existing among meet and global championship races to specifically implement training characteristics targeting either goal type.

Investigations on wagon–track interaction and running safety with unsupported sleepers

Unsupported sleeper defects are not rare for the ballasted track. Based on the status quo of the railway in Kosovo, this paper presents a study on the wagon–track interaction and running safety risk with unsupported sleepers. A three-dimensional wagon–track dynamic model is first developed and validated through a full-scale field experiment. The dynamic response features of wagon and track components are respectively presented and analysed under the sleeper hanging condition. Parameter studies and safety analysis are then conducted with different wagon speeds, including gap height, unsupported quantity, wagon load, and asymmetric effects of the unsupported sleeper. The results indicate that unsupported sleepers will induce wheel–rail impact and significantly exacerbate the vibrations of the wagon and track. The wavelength corresponding to the dominant frequency for the wagon vertical acceleration (ACC) is equal to the wheelbase. Moreover, adjacent ballasts of the unsupported zone exhibit maximal displacements and ACCs, which could be the compelling evidence to explain the extension of the unsupported zone. The derailment risk is typically higher when the unsupported sleepers are asymmetrically distributed compared to the scenarios with symmetrically unsupported sleepers. Additionally, the combined effects of unsupported sleepers and wheel flat will further deteriorate the wagon running safety. The presented results can provide a significant reference for the wagon speed increase and track maintenance in Kosovo and other countries with deficient railway infrastructure.

Sex‐based differences in track running distances of 100, 200, 400, 800, and 1500m in the 8 and under and 9–10‐year‐old age groups

AbstractThere are contradictory claims regarding sex‐based differences in athletic performance before puberty, but there has been minimal evaluation of sex‐based differences in competitive running performance before puberty. The purpose of this project was to determine if there are prepubertal sex‐based differences in track running performance. Finalist times from the USA Track and Field National Youth Outdoor Championships and National Junior Olympic Championships during the years 2016–2023 for running distances of 100, 200, 400, 800, and 1500m in the 8 and under and 9–10‐year‐old age groups were analyzed for sex‐based differences. In the 8 and under age group, the males were, on average, faster (p = 0.000, Hedges' g = 0.632–0.834) than females by 4.0% in the distance of 100m, 4.7% in 200m, 5.3% in 400m, 6.7% in 800m, and 6.1% in 1500m. In the 9–10‐year‐old age group, the males were, on average, faster (p = 0.000, Hedges' g = 0.584–1.089) than females by 2.9% in the distance of 100m, 4.6% in 200m, 4.0% in 400m, 4.0% in 800m, and 5.9% in 1500m. In each distance and age group between 2016 and 2023, the individual fastest male was faster than the individual fastest female by 3.7 ± 2.3%. The present data indicate that, in elite competition, males in the 8 and under and 9–10‐year‐old age groups typically run faster than females of the same age by 2.9%–6.7% for running distances of 100, 200, 400, 800, and 1500m. These findings are of particular importance as government agencies and sports organizations consider policies regarding single sex sports competition for youth.

Constant low-to-moderate mechanical asymmetries during 800-m track running.

Modifications in asymmetry in response to self-paced efforts have not been thoroughly documented, particularly regarding horizontally-derived ground reaction force variables. We determined the magnitude and range of gait asymmetries during 800 m track running. Eighteen physical education students completed an 800 m self-paced run on a 200 m indoor track. During the run, vertical and horizontal ground reaction forces were measured at a sampling frequency of 500 Hz using a 5 m-long force platform system, with data collected once per lap. The following mechanical variables were determined for two consecutive steps: contact time and duration of braking/push-off phases along with vertical/braking/push-off peak forces and impulses. The group mean asymmetry scores were evaluated using the "symmetry angle" (SA) formula, where scores of 0% and 100% correspond to perfect symmetry and perfect asymmetry, respectively. There was no influence of distance interval on SA scores for any of the nine biomechanical variables (P ≥ 0.095). The SA scores were ∼1%-2% for contact time (1.3 ± 0.5%), peak vertical forces (1.8 ± 0.9%), and vertical impulse (1.7 ± 1.0%). The SA scores were ∼3%-8% for duration of braking (3.6 ± 1.1%) and push-off (3.2 ± 1.4%) phases, peak braking (5.0 ± 2.1%) and push-off (6.9 ± 3.1%) forces as well as braking (7.6 ± 2.3%) and push-off (7.7 ± 3.3%) impulses. The running velocity progressively decreased at 300 m and 500 m compared to that at 100 m but levelled off at 700 m (P < 0.001). There were no modifications in gait asymmetries, as measured at 200-m distance intervals during 800-m track running in physical education students. The 800 m self-paced run did not impose greater mechanical constraints on one side of the body. Experimental procedures for characterizing the gait pattern during 800 m track running could be simplified by collecting leg mechanical data from only one side.

A Comparison of Critical Speed and Critical Power in Runners Using Stryd Running Power.

Although running traditionally relies on critical speed (CS) as an indicator of critical intensity, portable inertial measurement units offer a potential solution for estimating running mechanical power to assess critical power (CP) in runners. The purpose of this study was to determine whether CS and CP differ when assessed using the Stryd device, a portable inertial measurement unit, and if 2 running bouts are sufficient to determine CS and CP. On an outdoor running track, 10 trained runners (V˙O2max, 59.0 [4.2]mL·kg-1·min-1) performed 3 running time trials (TT) between 1200 and 4400m on separate days. CS and CP were derived from 2-parameter hyperbolic speed-time and power-time models, respectively, using 2 (CS2TT and CP2TT) and 3 (CS3TT and CP3TT) TTs. Subsequently, runners performed constant-intensity running for 800m at their calculated CS3TT and CP3TT. Running at the calculated CS3TT speed (3.88 [0.44]m·s-1) elicited an average Stryd running power (271 [28]W) not different from the calculated CP3TT (270 [28]; P = .940; d = 0.02), with excellent agreement between the 2 values (intraclass correlation coefficient = .980). The CS2TT (3.97 [0.42]m·s-1) was not higher than CS3TT (3.89 [0.44]m·s-1; P = .178; d = 0.46); however, CP2TT (278 [29] W) was greater than CP3TT (P = .041; d = 0.75). The running intensities at CS and CP were similar, supporting the use of running power (Stryd) as a metric of aerobic fitness and exercise prescription, and 2 trials provided a reasonable, albeit higher, estimate of CS and CP.

THE EFFECT OF MINERAL WATER AND RUNNING 400 METERS 3×3 ON PULSE RATE

This study aims to investigate the effect of mineral water consumption and physical activity in the form of running 400 meters (3 rounds 3 times) on a person's pulse rate and the difference in pulse rate for each set. The implementation of the test was carried out in the running track of the SSA pontianak stadium, this study checked the pulse before carrying out the test for 10 seconds, after which a light jogging warm-up for 10 minutes and continued by doing the test that had been determined. The research was conducted by measuring the subject's pulse before and after consuming mineral water, as well as before and after undergoing physical activity in the form of running 400 meters for 3 rounds 3 times. With a data collection method of one shot case study, the sample taken was 10 people, 6 men and 4 women from students of Sports Coaching Education (PKO) Tanjungpura University Pontianak. The data obtained was analyzed using the ANOVA test using the SPSS application. The results analyzed by the ANOVA test showed that there was no significant difference, the results showed a significance value of 0.357&gt; 0.05, therefore it can be concluded that 240ml mineral water does not have a significant effect on pulse performance when doing more effort than usual. This study provides insight into how mineral water consumption and physical activity can affect a person's pulse rate, which is important for further understanding of cardiovascular health