Characteristics Of Runners Research Articles

Study on vibration characteristics of pump-turbines with different runner characteristics

Abstract In terms of the problems of large vibration pendulum in some working conditions and obvious vibration sensation in local plant and water delivery system of Heimifeng pumped storage power station, test and analysis were carried out on two different runner units before and after transformation in the same flow channel, revealing the difference of pressure pulsation transmission characteristics and vibration response of different runner hydrostatic interference. The test results show that the modified runner with long and short blades is feasible and effective for reducing the pressure pulsation caused by dynamic and static interference and controlling the vibration of the plant, which can provide a reference for the vibration of the unit and the plant in the same type of pumped storage power station.

Sensitivity analysis of influencing factors in large oscillation hydraulic transient process of pumped storage power station

Abstract The calculation of large oscillation transition process is of great significance for pumped storage power station, which is beneficial for ensuring the safe of the power station and extending the lifespan of the unit. Due to the presence of inertia in water and rotating components of the unit, as well as energy imbalance in the system, hydraulic transients will cause drastic changes in water pressure in the waterway system and unit speed, resulting in a sharp increase or decrease in pressure and a sharp change in unit speed, endangering the operational safety of the power plant and affecting the lifespan of the unit. It is necessary to optimize the layout of water conveyance system, basic parameters of units, and the closing law of guide vanes through calculation and analysis of large oscillation transition processes. Relying on a pumped storage power station in Guizhou, this paper analysis the sensitivity of the factors affecting the calculation results of the large oscillation transition process, such as runner characteristics, guide vane closing law, moment of inertia GD2, surge chamber diameter and restricted orifice size, to provide reference for similar projects.

Acute effects of negative heel shoes on perceived pain and knee biomechanical characteristics of runners with patellofemoral pain.

To determine the effects of negative heel shoes on perceived pain and knee biomechanical characteristics of runners with patellofemoral pain (PFP) during running. Sixteen runners with PFP ran in negative (-11mm drops) and positive (5mm drops) heel shoes while visual analog scale (VAS) scores, retroreflective markers, and ground reaction force were acquired by applying a 10-cm VAS, infrared motion capture system, and a three-dimensional force plate. Knee moment, patellofemoral joint stress (PFJS), and other biomechanical parameters during the stance phase were calculated based on inverse dynamics and a biomechanical model of the patellofemoral joint. The foot inclination angle, peak PFJS during the stance phase, patellofemoral joint reaction force, knee extension moment, and quadriceps force at the time of peak PFJS of runners with PFP in negative heel shoes were lower than that in positive heel shoes, no significant difference was found in VAS scores, knee flexion angle, patellofemoral contact area, and quadriceps moment arm at the time of peak PFJS. Compared to positive heel shoes, running in negative heel shoes decreases peak PFJS in runners with PFP, which may decrease patellofemoral joint loading, thus reducing the possibility of further development of PFP. Sports Science Experiment Ethics Committee of Beijing Sport University. 2023095H, April 18, 2023 (prospectively registered).

Environmental Preferences and Concerns of Recreational Trail Runners.

Trail running is a fast-growing sport, linked to improvements in both physical and psychological well-being. Despite its popularity, the preferences of trail runners are not well known. The objective of this study was to examine the environmental preferences and concerns of trail runners with respect to age and gender. We conducted a cross-sectional survey of recreational trail runners. A total of 548 people responded, of which 50.1% of respondents were women and 44.2% were men. The sample was distributed relatively evenly across age groups, up to 54 years; respondents over 55 represented only 9.4% of the sample. Comparisons of runner characteristics by gender indicated significant differences (p < 0.05) according to age, distance run per week, and number of days run per week. Certain runner preferences also differed significantly by gender, including importance of running around others, the type of trail races they seek, and whether or not they like to seek "vert" or elevation in their runs. Major concerns for both genders while running included lack of cell reception (Men: 33.8%; Women: 50.8%) and getting lost (Men: 26.8%; Women: 35.5%). Comparisons of the results of this study help to strengthen our understanding of trail runners' environmental preferences and concerns and can be used to guide future design and maintenance of trail environments to encourage greater participation in the sport.

Spring-Mass Characteristics in Runners Before and After a 56-km Road Ultramarathon.

Ultramarathons are a unique model to study the effects of systemic fatigue in athletes. This investigation applied the spring-mass template to study runners before and 2days after a road ultramarathon to characterize the effects of fatigue on systemic gait patterns. Overground kinetics were captured 7days before and 2days after the event in 14 runners. Traditional kinetic and spring-mass parameters were calculated, along with nonlinear regression-derived parameters and spring-mass model fit metrics. After the ultramarathon, vertical force magnitudes and loading rates were unchanged, but impact peaks increased (1.88 ± 0.08-1.95 ± 0.10 bodyweight). Ground contact times were modestly shorter (-3 ± 1ms), resulting in increased leg stiffness (10.0 ± 0.5-10.3 ± 0.5kN/m) with equivocal vertical stiffnesses. The deviation from the modeled spring-mass kinetics also increased (171.3 ± 15.0-181.4 ± 16.5N). Overall, the systemic mechanical behaviors of the runners persisted despite the fatigue and stress induced by a road ultramarathon. These findings support previous observations that runners maintain gross mechanical behavior when fatigued with small compensatory changes in spatiotemporal and traditional spring-mass characteristics. However, these findings also suggest that the variability within that gross behavior may increase after stress, suggesting new opportunities for quantifying those deviations.

Lower-Limb Connective Tissue Morphologic Characteristics in Runners. How Do They Relate with Running Biomechanics and Tendon Pathology? A Systematic Review

Lower-Limb Connective Tissue Morphologic Characteristics in Runners. How Do They Relate with Running Biomechanics and Tendon Pathology? A Systematic Review

Characteristics of runners meeting acute kidney injury criteria following a 161‐km ultramarathon

The incidence of acute kidney injury (AKI) associated with ultramarathon running is varied partially because onsite measurement of serum creatinine concentration (Cr) is rarely performed at races due to logistical challenges. We conducted a prospective observational study using blood samples from volunteer athletes before and immediately after the Leadville Trail 100 Run in August 2014. The goals of our study were to determine the incidence of those meeting the AKI criteria immediately following the ultramarathon race and to evaluate the utility of using medical equations to back-calculate creatinine levels for runners without known baseline creatinine levels and to identify possible risk factors for developing AKI. We were able to collect pre-race and post-race blood samples on 64 and 84 volunteers, respectively. AKI was defined as a Cr increase (≥1.5 times or ≥0.3 mg/dl from baseline). Of the 37 runners for whom we had both pre- and post-race blood samples, 18 (49%) met the criteria for AKI. Using two different methods of back-calculating baseline estimated creatinine (a fixed eGFR [estimated glomerular filtration rate] and an aged-based eGFR), 6 (16%) and 22 (59%) of 37 runners met the criteria for AKI, respectively. We found that there is no accurate way to estimate baseline Cr in this population.

Genetic Polymorphisms Related to VO2max Adaptation Are Associated With Elite Rugby Union Status and Competitive Marathon Performance.

Genetic polymorphisms have been associated with the adaptation to training in maximal oxygen uptake (V˙O2max). However, the genotype distribution of selected polymorphisms in athletic cohorts is unknown, with their influence on performance characteristics also undetermined. This study investigated whether the genotype distributions of 3 polymorphisms previously associated with V˙O2max training adaptation are associated with elite athlete status and performance characteristics in runners and rugby athletes, competitors for whom aerobic metabolism is important. Genomic DNA was collected from 732 men including 165 long-distance runners, 212 elite rugby union athletes, and 355 nonathletes. Genotype and allele frequencies of PRDM1 rs10499043 C/T, GRIN3A rs1535628 G/A, and KCNH8 rs4973706 T/C were compared between athletes and nonathletes. Personal-best marathon times in runners, as well as in-game performance variables and playing position, of rugby athletes were analyzed according to genotype. Runners with PRDM1 T alleles recorded marathon times ∼3minutes faster than CC homozygotes (02:27:55 [00:07:32]h vs 02:31:03 [00:08:24]h, P = .023). Rugby athletes had 1.57 times greater odds of possessing the KCNH8 TT genotype than nonathletes (65.5% vs 54.7%, χ2 = 6.494, P = .013). No other associations were identified. This study is the first to demonstrate that polymorphisms previously associated with V˙O2max training adaptations in nonathletes are also associated with marathon performance (PRDM1) and elite rugby union status (KCNH8). The genotypes and alleles previously associated with superior endurance-training adaptation appear to be advantageous in long-distance running and achieving elite status in rugby union.

Dynamic All-Red Signal Control Based on Deep Neural Network Considering Red Light Runner Characteristics

Despite recent advances in technologies for intelligent transportation systems, the safety of intersection traffic is still threatened by traffic signal violation, called the Red Light Runner (RLR). The conventional approach to ensure the intersection safety under the threat of an RLR is to extend the length of the all-red signal when an RLR is detected. Therefore, the selection of all-red signal length is an important factor for intersection safety as well as traffic efficiency. In this paper, for better safety and efficiency of intersection traffic, we propose a framework for dynamic all-red signal control that adjusts the length of all-red signal time according to the driving characteristics of the detected RLR. In this work, we define RLRs into four different classes based on the clustering results using the Dynamic Time Wrapping (DTW) and the Hierarchical Clustering Analysis (HCA). The proposed system uses a Multi-Channel Deep Convolutional Neural Network (MC-DCNN) for online detection of RLR and also classification of RLR class. For dynamic all-red signal control, the proposed system uses a multi-level regression model to estimate the necessary all-red signal extension time more accurately and hence improves the overall intersection traffic safety as well as efficiency.

Walking characteristics of runners with a transfemoral or knee-disarticulation prosthesis

BackgroundRunning with prostheses has become a common activity for amputees participating in sports and recreation. However, very few studies have characterized the kinematic and kinetic parameters of walking in individuals with amputation who are runners. Thus, this study attempts to elucidate the kinematics and kinetics of walking in runners with a unilateral transfemoral amputation or knee-disarticulation. MethodsThis study experimentally compares the prosthetic and intact limbs of runners with prostheses as well as compares the findings against the limbs of age-matched able-bodied individuals while walking. Fourteen runners with a unilateral transfemoral amputation or knee-disarticulation were recruited and 14 age-matched able-bodied individuals were prepared using gait database. Spatiotemporal, kinematic, and kinetic parameters of walking were analyzed using a 3-demensional motion capture system. ResultsThe results showed that the peak ankle positive power at pre-swing and peak hip positive power from loading response to mid stance in the intact limb were significantly larger than that in the prosthetic limb. Moreover, to compensate for missing anatomical functions on the prosthetic limb, it appeared that the intact limb of the runners generated larger peak joint power by producing more ankle plantarflexor and hip extensor moments while walking. InterpretationThis study demonstrated that the runners rely on their intact limb while walking. Training of hip extensor muscles of the intact limb may be beneficial for these individuals.

Running Injury According To Training And Performance Related Data

PURPOSE: A runners training and performance history over the previous 12 months is rarely considered in data related to running injury and participation level. The purpose of this on-line questionnaire was to gather self-reported history of exposure, performance and injury over the preceding 12 months in runners of different abilities. Self-reported history of barefoot running and injuries was also collected. METHODS: An on-line questionnaire (QualtricsXM software) was developed by the investigators and then distributed to a sample of runners recruited via social media and running clubs. Runners declared their participation level as; Non-competitive/recreational (NCR), represent club (RC) and represent county (RCOUN). RESULTS: There were 224 respondents (59% = NCR, 35% = RC and 6% = RCOUN). Respondents reported (mean + SD): fastest 5km run time (minutes) = NCR 24.4 ± 6.6, RC 21.05 ± 4.06 RCOUN 16.53 ± 1.61; ‘on average’ kilometres ran per week = NCR 28.8 ± 18.50, RC 43.52 ± 20.44, RCOUN 82.35 ± 36.0; ‘on average’ minutes ran per week = NCR 190.36 ± 142.28, RC 268.10 ± 126.21, RCOUN 428.21 ± 157.92. There were 175 respondents (78%) reporting at least one injury over the previous 12 months (total injuries = 348). Injury rates were; 10.99 injuries/1000hrs for NCR, 4.52 injuries/1000hrs for RC and 2.48 injuries/1000hrs for RCOUN. The most common injury sites were; knee for NCR (17%, 30/176), Achilles (19%, 21/109) for RC and calf (21%, 5/24) and/or shin (21%, 5/24) for RCOUN. There were 31 respondents (14%) that reported participating in barefoot running at least once per week, of which 20 (65%) reported having at least one injury with a relative risk of 0.803 (95% CI, 0.613-1.053), and an odds ratio of 0.613 (95% CI, 0.197-1.009). The Achilles was the most common site of injury (30%, 9/30). CONCLUSIONS: These findings offer insights to the injury characteristics of runners from different participation levels. The findings should serve to catalyse prospective studies, including exploration of the risk of barefoot running on injury.

Acute changes in sagittal plane kinematics while wearing a novel belt device during treadmill running

ABSTRACT Somatosensory feedback is used in walking retraining; however, its utility in running is less feasible due to the greater associated speeds. The purpose of this study was to examine the acute effects of wearing a novel running belt device on sagittal plane running kinematics. Ten healthy runners ran on a treadmill with and without the use of a running belt device within a repeated measures study design. Temporal-spatial characteristics and sagittal plane knee and ankle kinematics were recorded with three-dimensional motion analysis. Wilcoxon Signed-Rank Tests revealed significant decreases in centre of mass vertical displacement (z = −2.083, p = 0.003), tibial inclination at initial contact (z = −2.803, p = 0.003), and stance phase knee joint excursion (z = −2.701, p = 0.003), and greater knee flexion at initial contact (z = −2.803, p = 0.003) when the belt was donned. No differences were observed in step rate (z = −0.351, p = 0.363), foot inclination angle at initial contact (z = −2.090, p = 0.018), or peak knee flexion during stance (z = −1.172, p = 0.121). Findings suggest that donning a running belt can minimise specific high-risk biomechanical characteristics in runners with particular kinematic profiles.

An Assessment of Training Characteristics Associated with Atrial Fibrillation in Masters Runners.

A growing body of literature supports an association between long-term endurance exercise and the development of atrial fibrillation (AF). Given the benefits of lifelong exercise, a better understanding of this association is critical to allow healthcare providers to counsel aging exercisers on the proper “dose” of exercise to maximize health benefits but minimize AF risk. The current study examines the relationship between specific aspects of training volume and intensity and the occurrence of AF among older runners in order to better understand what aspects of endurance exercise may contribute to the development of AF. The study was an Internet-based survey of endurance training and health characteristics of runners 35 years of age and older. A total 2819 runners participated and 69 (2.4%) reported a current or prior diagnosis of AF. Among “traditional” risk factors, runners reporting AF were older, more likely to be male, and had higher rates of hypertension and diabetes. Among training characteristics, only accumulated years of training was associated with AF. In contrast, average weekly mileage, training pace, and days of training per week were not associated with AF. In a multivariable analysis that included chronologic age, sex, diabetes, and hypertension, accumulated years of training remained significantly associated with the report of AF. These findings suggest that the relationship between chronic endurance exercise and AF is dependent on the accumulated training duration but does not appear to be influenced by specific training characteristics such as frequency or intensity of endurance exercise. Further confirmation of these relationships may help healthcare providers counsel exercisers on optimal training habits and identify endurance athletes who are at risk for the development of AF.

Running Recession: A Trend Analysis of Running Involvement and Runner Characteristics to Understand Declining Participation

Market trends indicate the distance running event industry is facing a running recession. Since 2013, consumer demand has declined annually while supply increased. The current research provides insight into why running as a recreational activity is declining and implications for organized events’ utility. Based on seven years of participants’ postevent surveys from a long-distance running event, the value placed on hedonic, symbolic, and lifestyle features of running (i.e., running involvement) is gradually declining, which corresponds to a decline in annual event participation. Results are based on analyses of both a time series of cross-sections (N = 23,790) and a panel of multiyear respondents (n = 461). Also, there are gender differences in the rates at which running involvement declined. These results shed light onto a sociopsychographic explanation for the declining levels of running event participation and general interest in running.

Vulnerability to exercise addiction, socio-demographic, behavioral and psychological characteristics of runners at risk for eating disorders

BackgroundExcessive exercise is frequently associated with eating disorders and may degenerate into exercise addiction. We still don't know whether runners at risk for eating disorders are at risk for exercise addiction. Our aim is to assess: 1) risk for exercise addiction in runners at risk for eating disorders and 2) socio-demographic, behavioral and psychological characteristics distinguishing runners at-risk from not-at-risk for eating disorders. MethodsWe assessed risk for eating disorders and exercise addiction using the SCOFF questionnaire and the Exercise Addiction Inventory personality traits with the Big-Five Inventory Test, socio-demographic data, eating and training habits in a sample of 154 healthy runners. ResultsTwenty five subjects had a score of ≥2 at the SCOFF and were included in the group “at risk for eating disorders”. In this group, we found a higher percentage of subjects at risk for exercise addiction (p=0.01) and higher average scores at the Exercise Addiction Inventory (p=0.01) than runners not at risk (N=136). Runners at risk were statistically younger (p=0.03), women (p=0.001), started running to lose weight more often (p=0.03), lost more kilos since affiliation in their running club (p=0.04), and were characterized by neurotic traits using the Big-Five-Inventory Test (p=3.10−6). ConclusionsScreening for exercise addiction and mood disorders could lead to a more accurate management of runners at risk for eating disorders. Identifying vulnerable individuals will facilitate the prevention of eating disorders and preserve the benefits of sport practice.

Ultrasound characteristics of the mid-portion of the Achilles tendon in runners: a systematic review protocol

BackgroundAchilles tendinopathy is one of the most common overuse injuries in recreational and competitive runners, yet the clinical significance and frequency of abnormal sonographic characteristics in runners remains unclear. This paper presents a protocol for a systematic review which aims to assess existing literature which has employed ultrasonography to evaluate characteristics of the mid-portion of the Achilles tendon in runners.MethodsAn electronic literature search will be conducted using the following electronic databases: MEDLINE, CINAHL and SPORTDiscus. Studies published in English will be included if they evaluate ultrasound characteristics associated with mid-portion Achilles tendinopathy in runners. Methodological quality will be assessed using a scale adapted from the Newcastle-Ottawa Scale.DiscussionThis will be the first systematic review to summarise the existing evidence on ultrasound characteristics of the mid-portion of the Achilles tendon in recreational runners.Systematic review registrationPROSPERO CRD42016050509

Design and Velocity Distribution of Runner Blade of Kaplan Turbine Using CFD (Computer Fluid Dynamic) for Small Hydroelectric Power Plant

Procedures for designing runner of Kaplan water turbine based on the specific conditions in the water potential of the area to be placed, and assessed on the terms of the theoretical analysis and engineering. The main objective of this study was to determine the main characteristics of runners, namely suction head, water flow, and the hydraulic forces that occur when the turbine operates. Modern software for engineering such as computational fulid dynamics (CFD) is used to predict the flow of fluid passing through the runner and Computer Aided Engineering (CAE) to verify the design with Finite Element Analisys (FEA). Kaplan turbine runner is designed to place the suction head low and as an option for power generation in Galih Pakuan isolated from Ciwidey area and has not been electricity. The available head and flow rate for turbine are 8 m and 0,3 m3/sec in this site. The output power is 20kW estimated and turbine speed is 900 rpm, In designing blade, blade element theories are the main theories of blade parameter calculation. This paper selecting airfoil shape of the blade from Gottingen (GOE) series and modelling the exact airfoil geometry by using Airfoil.com software.

Ankle and toe muscle strength characteristics in runners with a history of medial tibial stress syndrome

BackgroundA high proportion of flexor digitorum longus attachment is found at the posteromedial border of the tibia, which is the most common location of medial tibial stress syndrome (MTSS). Therefore, plantar flexion strength of the lesser toes could be related to MTSS; however, the relationship between MTSS and muscle strength of the hallux and lesser toes is not yet evaluated due to the lack of quantitative methods. This study investigated the muscle strength characteristics in runners with a history of MTSS by using a newly developed device to measure the muscle strength of the hallux, lesser toes, and ankle.MethodsThis study comprised 27 collegiate male runner participants (20.0 ± 1.6 years, 172.1 ± 5.1 cm, 57.5 ± 4.0 kg). Maximal voluntary isometric contraction (MVIC) torque of the plantar flexion, dorsiflexion, inversion, and eversion of the ankle were measured by using an electric dynamometer. MVIC torque of the 1st metatarsophalangeal joint (MTPJ) and 2nd–5th MTPJ were measured by using a custom-made torque-measuring device. MVIC torques were compared between runners with and without a history of MTSS.ResultsMVIC torque of the 1st MTPJ plantar flexion was significantly higher in runners with a history of MTSS than in those without it. In contrast, there were no significant differences in the MVIC torque values of the 2nd–5th MTPJ plantar flexion and each MVIC torque of the ankle between runners with and without a history of MTSS.ConclusionA history of MTSS increased the isometric FHL strength.

Analysis of Sudden Cardiac Arrest during Marathon Races in Japan

Objective: Increased number of runners in Japan has been one reason for increasing the risk of cardiac arrest during marathon races. The purpose of the study was to examine 1) the incidence of cardiac arrest during marathon races held in the past in Japan, 2) the characteristics of runners with cardiac arrest, 3) the effectiveness of public access defibrillation (PAD) use for cardiac arrest cases. Methods: We examined the incidence of the cardiac arrest during marathon races in Japan from the medical records of marathon races that Kokushikan University provided in the past five years. Also, we analyzed cardiac arrests occurred in Japan in the past 15 years between 1999 and 2013. Results: The incidence rate of cardiac arrest was 2.18 per 100,000 participants. As shown in Table 1, the incidence rates were 2.00 per 100,000 participants in full marathon and 2.50 per 100,000 participants in half-marathon. A total of 63 cardiac arrests occurred in the past 15 years, and the number of incidents has been increasing every year. Among 63 cardiac arrest cases, the mean age was 45.3 ± 14.9 years old and 93.7% (59/63 cases) were in males. Eighty-three percentage of cardiac arrest cases applied AED (20/24 cases) were the shockable rhythm. In terms of the survival rate, there was a statistically significant difference between the cases where both bystander CPR and PAD were delivered and the cases where the only bystander CPR took place without PAD (95.0% vs. 47.1%; p < 0.05). In Japan, the case of the PAD use during marathon races has been increasing since the use of AED was permitted for public citizens in 2004. Conclusions: Performing PAD on the scene during marathon races could be expected to be higher in the survival rate. Creating a medical support system is needed to handle sudden cardiac arrest rapidly in order to perform early bystander CPR and PAD.

The effect of cushioning system on impact attenuation of athletic footwear

Several studies sought to determine impact attenuation of shoes through the evaluation of force platform or accelerometer measurements. Recent literature however points out methodological flaws of “subject inclusive” experimentation, as this approach is unable to evaluate neither the foot/ground interface nor the absorbed energy allocation. This study provides a holistic evaluation of the biomechanical response of athletic footwear to individual runner characteristics through advanced mechanical testing.