Running Track Research Articles

The influence of sprint spike bending stiffness on sprinting performance and metatarsophalangeal joint function

There is evidence that increasing the longitudinal bending stiffness of sprinting footwear can lead to improved sprinting performance although this has not yet been established. This study examined the effect of four known shoe stiffness conditions on both sprinting performance and metatarsophalangeal joint (MTPJ) motion. Twelve trained sprinters performed 40 m maximal sprints along an indoor running track, two sprints in each stiffness condition, and high-speed video (600 Hz) recorded two-dimensional MTPJ motion during ground contact. To explore individual responses to the footwear manipulations, three-dimensional (1000 Hz) kinematic and kinetic data were collected during maximal sprinting for two sprinters. At the group-level, increasing shoe bending stiffness elicited no significant differences in sprinting performance or MTPJ motion, with any changes between conditions being subject-specific. In-depth individual analyses revealed that increased shoe stiffness could restrict motion about the MTPJ and there appeared to be a preferred stiffness for best performance. This notion of individual optimal sprint shoe stiffness and what factors might contribute to the optimum requires further investigation.

Comparison Of Responses Between Track And Treadmill During A One Mile Walk And Run

PURPOSE: To investigate physiological responses during a one mile walk and run at self selected pace between controlled (treadmill) and non-controlled (track) environments using stationary and portable metabolic systems. METHODS: Recreationally trained males and females (N=30, 21 ± 1.2 years) participated in four sessions: familiarization, treadmill VO2max, submaximal one mile walk and run on a track, and submaximal one mile walk and run on a treadmill. RESULTS: Comparison of track and treadmill showed higher values on treadmill walk and run for HR (p<0.0001 and p=0.012), RER (p<0.0001 and p=0.024), and RPE (p=0.001 and p=0.001). Gender comparison showed males running speed was significantly greater than females in both conditions (p=0.018). Females had a significantly higher HR while walking on the track and treadmill (p=0.003 and p<0.0001). Running energy expenditure (EE) and treadmill EE were significantly higher than walking EE and track EE, respectively (p<0.0001 and p<0.0001). EE was significantly greater in males during each of these conditions: treadmill walk (p<0.0001), treadmill run (p<0.0001), track walk (p=0.009), and track run (p<0.0001). It is worth noting that participants averaged running at 90.6% of VO2max on the treadmill and only 84.9% of VO2max on the track (average VO2max=37.73 ml/kg). Also worth noting, four participants could not complete the one mile run on the treadmill at determined self selected pace. Correlations were found between treadmill and track EE during running (r=0.953, p<0.0001) and between HR and RPE during both treadmill (r =0.426, p=0.019) and track run (r=0.408, p=0.25). Walking VO2 was significantly higher for the treadmill (p=0.041). Males’ EE was significantly higher during walking (p=0.001). Males’ running VO2 was significantly higher on the treadmill when compared to the track (p=0.002) and also higher than females on the treadmill (p=0.007). Also, males’ running EE was significantly higher on the treadmill than the track during running (p<0.0001) with no difference for females. CONCLUSION: Differences are seen in physiological and perceptual responses between the track and treadmill walk and run. This creates discrepancies for transferring information between modalities and also concern for individualized exercise prescription.

Effect Of A 6-Wk Running Training Programme Using The Self-Paced VO2max Protocol In Recreational Runners

The self-paced VO2max test (SPV) has been shown to be an effective alternative to an incremental graded exercise test (GXT) in assessing maximal oxygen consumption (VO2max) in non-motorised and motorised treadmill running. However, the identification of effective training parameters has yet to be investigated. PURPOSE: This study assessed the feasibility and effectiveness of prescribing training via the SPV compared to the GXT. METHODS: Ten recreationally active males (36 ± 3 y; 1.74 ± 0.08 m; 70.0 ± 10.6 kg) and six females (26 ± 3 y; 1.66 ± 0.04 m; 58.0 ± 4.7 kg) were randomised into two training groups (GXT and SPV) and completed a 6-week training programme participating in 4 running sessions-a-week. Prior to training, participants completed 3 lab visits: SPV, GXT, and a combined Lactate Threshold (LT) and Critical Speed (CS) visit. The GXT was continuous and incremental in style, with prescribed 1 km·hr-1 increases every 2 min until the attainment of VO2max. Participants in the GXT group then completed a time-to-exhaustion (TTE) effort at velocity at VO2max (VVO2max) to determine the time for which VO2max could be maintained (Tmax). The SPV consisted of 5 x 2 min incremental stages, where running speed throughout each stage could be continuously adjusted according to five prescribed RPE levels: 11, 13, 15, 17, and maximal perception of exertion (RPE 20). The LT consisted of 1 km·hr-1 increments every 4 min until LT2 had been obtained. Participants then ran 9, 6, and 3 laps of a 400m outdoor synthetic running track to calculate CS. The training programme consisted of two interval sessions, a recovery run, and a tempo run. In the GXT group, interval training speeds were determined by Tmax, and ‘mean speed at RPE 20’ in the SPV group. VO2max, LT and CS were then retested post-training. RESULTS: In the GXT group, VO2max significantly improved following training in both the GXT (P = 0.003) and SPV (P = 0.001) tests (54.0 ± 6.0 vs. 57.5 ± 6.1 mL·kg-1·min-1 and 54.1 ± 8.3 vs. 57.4 ± 6.5 mL·kg-1·min-1, respectively). In the SPV group significant improvement was shown in the SPV (P = 0.029) (51.4 ± 5.0 vs. 55.6 ± 5.4 mL·kg-1·min-1). CONCLUSION: The present study has shown that the SPV is effective in prescribing training to improve VO2max and that ‘mean speed at RPE 20’ is an effective alternative to vVO2max as a training parameter for interval training.

The 400- and 800-m Track Running Induces Inspiratory Muscle Fatigue in Trained Female Middle-Distance Runners.

Inspiratory muscle fatigue (IMF) may limit exercise performance. A few studies have reported that IMF occurs after short-duration swimming exercise, but whether short-duration running can induce IMF remains unclear. Intra-abdominal pressure is increased during running through diaphragmatic activation to stabilize the spine during movements of the upper limbs. This occurs along with the increased inspiratory muscle effort associated with increased respirations during exercise; thus, we hypothesized that short-duration running exercise would induce IMF. To test this hypothesis, we measured maximal inspiratory pressure (MIP) before and after 400- and 800-m track running sessions. Eight female middle-distance (400, 800 m) runners performed a 400- and 800-m running test. Maximal inspiratory pressure was measured before and after each test using a portable autospirometer. The mean MIPs were significantly lower after running than before running; values obtained were 107 ± 25 vs. 97 ± 27 cmH2O (p = 0.01, effect size [ES] = 0.65) and 108 ± 26 vs. 92 ± 27 cmH2O (p = 0.01, ES = 0.74) before vs. after the 400- and 800-m tests, respectively. The mean MIP after the 800-m test was significantly lower than after the 400-m test (p = 0.04, ES = 0.48). There was no correlation between IMF value and running time (r = 0.53 and r = -0.28 for either the 400- and 800-m tests, respectively; p > 0.05). In conclusion, IMF occurs after short-duration running exercise. Coaches could consider prescribing inspiratory muscle training or warm-up in an effort to reduce the inevitable IMF associated with maximal effort running.

The 400- And 800-m Track Running Induces Inspiratory Muscle Fatigue In Trained Female Middle-distance Runners

Inspiratory muscle fatigue (IMF) may limit exercise performance. A few studies have reported that IMF occurs after short-duration swimming exercise, but whether short-duration running can induce IMF remains unclear. Intra-abdominal pressure is increased during running through diaphragmatic activation to stabilize the spine during movements of the upper limbs. This occurs along with the increased inspiratory muscle effort associated with increased respirations during exercise; thus, we hypothesized that short-duration running exercise would induce IMF. PURPOSE: This study was designed to investigate short-duration running-induced IMF. To test this hypothesis we measured maximal inspiratory pressure (MIP) before and after 400-m and 800-m track running sessions. METHODS: Eight female middle-distance (400-m, 800-m) runners performed a 400-m and an 800-m running test on an outdoor 400-m tartan athletic track. All the participants were members of a collegiate athletic club and had participated in interscholastic and/or intercollegiate athletic competitions at least once. MIP was measured before whole-body warm-up, and within 2 min after completion of the 400-m and 800-m running tests, using a portable autospirometer. The percentage decrease in MIP from pre-warm up to post-test was considered to represent the IMF associated with each test. RESULTS: The mean MIPs were significantly lower after running than before running; values obtained were 107 ± 25 vs. 97 ± 27 cmH2O (P = 0.01, ES = 0.65) and 108 ± 26 vs. 92 ± 27 cmH2O (P = 0.01, ES = 0.74) before vs. after the 400-m and 800-m tests, respectively. The mean MIP after the 800-m test was significantly lower than after the 400-m test (P = 0.04, ES = 0.48). There was no correlation between IMF value and running time (r = 0.53 and r = –0.28 for either the 400-m and 800-m tests, respectively; P > 0.05). CONCLUSION: IMF occurs after short-duration running exercise. Coaches could consider prescribing inspiratory muscle training or warm-up in an effort to reduce the inevitable IMF associated with maximal effort running.

Effects of Arc/Arg3.1 gene deletion on rhythmic synchronization of hippocampal CA1 neurons during locomotor activity and sleep

The activity-regulated cytoskeletal-associated protein/activity regulated gene (Arc/Arg3.1) is crucial for long-term synaptic plasticity and memory formation. However, the neurophysiological substrates of memory deficits occurring in the absence of Arc/Arg3.1 are unknown. We compared hippocampal CA1 single-unit and local field potential (LFP) activity in Arc/Arg3.1 knockout and wild-type mice during track running and flanking sleep periods. Locomotor activity, basic firing and spatial coding properties of CA1 cells in knockout mice were not different from wild-type mice. During active behavior, however, knockout animals showed a significantly shifted balance in LFP power, with a relative loss in high-frequency (beta-2 and gamma) bands compared to low-frequency bands. Moreover, during track-running, knockout mice showed a decrease in phase locking of spiking activity to LFP oscillations in theta, beta and gamma bands. Sleep architecture in knockout mice was not grossly abnormal. Sharp-wave ripples, which have been associated with memory consolidation and replay, showed only minor differences in dynamics and amplitude. Altogether, these findings suggest that Arc/Arg3.1 effects on memory formation are not only manifested at the level of molecular pathways regulating synaptic plasticity, but also at the systems level. The disrupted power balance in theta, beta and gamma rhythmicity and concomitant loss of spike-field phase locking may affect memory encoding during initial storage and memory consolidation stages.

Comprehensive thermal preference phenotyping in mice using a novel automated circular gradient assay

ABSTRACTCurrently available behavioral assays to quantify normal cold sensitivity, cold hypersensitivity and cold hyperalgesia in mice have betimes created conflicting results in the literature. Some only capture a limited spectrum of thermal experiences, others are prone to experimenter bias or are not sensitive enough to detect the contribution of ion channels to cold sensing because in mice smaller alterations in cold nociception do not manifest as frank behavioral changes. To overcome current limitations we have designed a novel device that is automated, provides a high degree of freedom, i.e. thermal choice, and eliminates experimenter bias. The device represents a thermal gradient assay designed as a circular running track. It allows discerning exploratory behavior from thermal selection behavior and provides increased accuracy by providing measured values in duplicate and by removing edge artifacts. Our custom-designed automated offline analysis by a blob detection algorithm is devoid of movement artifacts, removes light reflection artifacts and provides an internal quality control parameter which we validated. The assay delivers discrete information on a large range of parameters extracted from the occupancy of thermally defined zones such as preference temperature and skew of the distribution. We demonstrate that the assay allows increasingly accurate phenotyping of thermal sensitivity in transgenic mice by disclosing yet unrecognized details on the phenotypes of TRPM8-, TRPA1- and TRPM8/A1-deficient mice.

The Influence of Train Running Direction and Track Supports Position on the Behaviour of Transition Zones

Different types of track infrastructure can be found along railway lines. Separation zones between these different types of structures are the source of a lot of problems. Transition zones on a railway line represent a gradual solution for the problems between conventional railway structure and singular structures located at different points along the line. The different nature, positioning and geometry used with the materials generate changes in the stiffness on both sides of these singular zones leading to an increase in wear and a loss of geometry, with the associated maintenance costs.This article describes the use of mathematical modelling to represent the behaviour of these zones as a function of train running direction and track supports. Available research into transition zones has not studied these separation points where high increases in load are generated for very short periods of time.Finite elements are used to model two types of track (conventional ballasted track and slab track), using a vehicle to dynamically simulate the behaviour in these zones as a function of train running direction and the position of track supports.The magnitudes analysed were the vertical stresses and the vertical displacements under the sleepers and the supports in both types of structure.The results show increased stresses at the separation zone between both structures which varied in magnitude and position depending most of track supports’ location than the train running direction.

الشيخ علي بن محمد بن يونس البياضي وأثره العلمي والأدبي

The history of the JabalAmel that mired in mystery was witnessed the scientific- literatural revival since the eighth century A.H. / fourteenth century A.D. made it take the running track and become the Imamiyyah Scientific center and that was manifested in the efforts of the pioneer thought in it: Mohammed bin MakkiAljizzyni (d. 786 AH / 1374 AD) based on the foundational era back it's originality to the middle of the fourth century A.H. / tenth century A.D. where grew up cultural and scientific links between the JabalAmel and the science centers in Iraq until JabalAmel became illuminates it's way with science torches represented in it's Endowed scholars. Here in this research I highlighted on the Amili unique character had was an important scientifically and literary impact on the scientific arena so he was one of notables scholars in the ninth century AH / fifteenth century the whole between science and literature and he has been known by his authored in the field of «Al-Kalaam» and his famous book in this section is: «Al-Sirat Al-Mustagheem li-Mostahaghi Al-Taghdeem», that it has been known in the issues of the Imamate, as he has the other works in this area in the folds that we know its in the pages of this research.

A 3D Numerical Model for the Optimization of Running Tracks Performance

In previous works, a finite element model of the shock absorbing characteristics of athletics tracks was developed, able to give sufficiently reliable predictions from laboratory tests performed on suitable material samples. The model proved to be effective in discriminating the effects of geometry (i.e. thickness) and material properties (essentially the elastic characteristics) on force reduction, thus allowing a first optimization of the tracks in view of their approval by the International Association of Athletics Federations (IAAF).This simplified 2D model neglected the real track structure, considering it as a single layer of material having homogenized properties. In the present study, a new 3D model was developed to accurately describe the structure of multi-layered tracks, with properties and geometrical construction (e.g. solid or honeycomb) differing from one layer to another.Several tracks having different combinations of top/bottom layers varying in both material formulation (i.e. chemical composition) and geometry were thus considered. Mechanical properties of the individual elements constituting the track were measured with small-scale laboratory tests, taking into account their strain-rate dependence.The 3D model allowed a complete representation of the loads acting on the track and it gave results which are in very good agreement with the experiments. This proves it to be a valuable tool for the purpose of optimizing the track in terms of material formulation as well as layer geometrical construction and arrangement: as an example, the effect of changing the cell size of the honeycomb pattern was investigated.

The Expressway Traffic Sign Information Volume Threshold and AGS Position Based on Driving Behaviour

Reasonable traffic signs are important for ensuring operation safety and efficiency of expressways. The overloaded information of the traffic signs and improper distance ahead of the signs present serious problems, for they may raise the driver's visual cognition burden, reduce expressway operation efficiency and cause potential safety hazards. This paper aims at developing design criteria of traffic sign information volume and reasonable AGS positions with regard to driving behavior and traffic safety. The relationship among driving behavior, traffic sign information and AGS positions has been studied based upon driving simulation tests in this paper. The information of traffic signs is processed and quantified with the method of information entropy under the framework of information theory. According to traffic flow theory and a mathematical model of vehicle lane change, AGS positions are analyzed and reasonable positions are recommended in relation to the operation conditions on multi-lane expressways. During the simulation tests, drivers aged 20-40 with 2-10 year driving experience were invited for the tests and asked to drive along the designed expressway scenes. The driver's visual behavior was monitored with an eye tracking system and data of driving behavior and the vehicle running tracks were also collected during the simulation tests. The relationship model between traffic sign information volume, AGS position and driving behavior parameters was developed as a result of further data mining, analysis and synthesis. Eventually, a multidimensional indicator of expressway sign information volume threshold has been proposed and reasonable AGS positions on multi-lane expressways are determined.

Do light sport facilities foster sports participation? A case study on the use of bark running tracks

ABSTRACTAn increasing share of light sports participants (e.g. self-organised runners) challenge traditional ‘Sport for All’ policy systems to target a more diversified array of people participating in sport and physical activity. The main aim of this article is to analyse whether light sport facilities, as a distinct local level policy intervention, can contribute to the goals of attracting ‘light’ and/or new sports participants with public means. The study is carried out in the context of a particular case of running facilities (i.e. bark running tracks, BRTs) in Flanders. The use of BRTs is investigated by structured face-to-face interviews with runners at the location of the BRT (n = 546; RR = 98.8%). The profile of users of BRTs is elaborated based on users’ characteristics (whether or not one started to run due to the provision of a BRT, the frequency and intensity of using the BRT) in bivariate logistic regression analysis. Next, reasons for using BRTs are investigated. It is concluded that BRTs mainly serve as a facility of the fragmented individualised society by reaching a large share of light sports participants (86%). However, it has the ability to reach runners at different levels, who show different patterns of using BRTs. It is suggested that so-called silent expectations in light facilities may function differently for different types of users. In this view, findings are discussed in order to identify policy implications related to Sport for All.

Acute Physiological and Thermoregulatory Responses to Extended Interval Training in Endurance Runners: Influence of Athletic Performance and Age.

This study aimed to describe the acute impact of extended interval training (EIT) on physiological and thermoregulatory levels, as well as to determine the influence of athletic performance and age effect on the aforementioned response in endurance runners. Thirty-one experienced recreational male endurance runners voluntarily participated in this study. Subjects performed EIT on an outdoor running track, which consisted of 12 runs of 400 m. The rate of perceived exertion, physiological response through the peak and recovery heart rate, blood lactate, and thermoregulatory response through tympanic temperature, were controlled. A repeated measures analysis revealed significant differences throughout EIT in examined variables. Cluster analysis grouped according to the average performance in 400 m runs led to distinguish between athletes with a higher and lower sports level. Cluster analysis was also performed according to age, obtaining an older group and a younger group. The one-way analysis of variance between groups revealed no significant differences (p≥0.05) in the response to EIT. The results provide a detailed description of physiological and thermoregulatory responses to EIT in experienced endurance runners. This allows a better understanding of the impact of a common training stimulus on the physiological level inducing greater accuracy in the training prescription. Moreover, despite the differences in athletic performance or age, the acute physiological and thermoregulatory responses in endurance runners were similar, as long as EIT was performed at similar relative intensity.

Modeling of Women's 100-m Dash World Record: Wind-Aided or Not?

On July 16, 1988, Florence Griffith Joyner (FGJ) shattered the women's 100-m dash world record (WR) with a time of 10.49 s, breaking the previous mark by an astonishing 0.27 s. By all accounts FGJ dominated the race that day, securing her place as the premiere female sprinter of that era, and possibly all time. In the aftermath of such an extraordinary performance, track officials immediately assumed that her posted time was wind aided—that is, attained under tailwind conditions beyond the legal limit of 2.0 m/s for world records. However, wind-measuring devices at the track site showed zero wind conditions during her WR performance. Before and during FGJ's race, other wind-measuring devices indicated speeds exceeding 4.0 m/s at the site of the triple jump runway, located on the same field as the running track. Video clips of flags placed near the starting line of FGJ's race also revealed tailwind conditions. Using available data from that era, the study here incorporates modeling techniques to compute velocity and position as functions of time for no wind and tailwind conditions. Modeling under no wind conditions produces a 100-m time of 10.70 s, a performance clearly attainable by FGJ during this stage of her sprinting career. Incorporating tailwinds of 4.0 m/s into the computations reduces this time by approximately 0.20 s, in close agreement with FGJ's record-breaking performance. These results strongly suggest that tailwinds of order 4 m/s were present during FGJ's world record race even though wind-measuring devices at the track site did not register these speeds. In spite of such strong evidence to support a wind-aided race on July 16, 1988, FGJ remains one of the top female sprinters in history and would likely hold the WR even today, given that she attained a non-wind-aided 100-m time of 10.61 s on the day following her WR performance.

A Functional Polymer Cement Mortar for Repair of Partially Damaged Asphalt Pavement

A newly polymer cement mortar to repair the rutting and bump of the pavement was developed and studied. In order to satisfy the required performance of the asphalt pavement as repair material, the polymer cement ratio of this mortar went up more than fifty percent. The basic properties such as workability, mechanical properties and adhesion durability of the polymer cement mortar was firstly investigated. Subsequently, the dynamic stability of the composite specimens repaired by the polymer cement mortar was clarified by wheel tracking tests. Finally, the availability of this mortar applied for the repair of the pavement was confirmed by the track running test more than two years.

Technique determinants of knee abduction moments during pivoting in female soccer players

BackgroundNo previous studies have investigated the optimal technique for pivoting with regard to reducing peak knee abduction moments and potential knee injury risk. The aim of this study was to investigate the relationships between technique characteristics and peak knee abduction moments during pivoting. MethodsTwenty-seven female soccer players [mean (SD); age: 21 (3.8) years, height: 1.67 (0.07) m, and mass: 60.0 (7.2) kg] participated in the study. Three dimensional motion analyses of pivots on the right leg were performed using 10 Qualysis ‘Pro reflex’ infrared cameras (240Hz). Ground reaction forces were collected from two AMTI force platforms (1200Hz) embedded into the running track to examine penultimate and final contact. Pearson's correlation coefficients, co-efficients of determination and stepwise multiple regression were used to explore relationships between a range of technique parameters and peak knee abduction moments. Significance was set at P<0.05. FindingsStepwise multiple regression found that initial foot progression and initial knee abduction angles together could explain 35% (30% adjusted) of the variation in peak knee abduction moments (F(2,26)=6.499, P=0.006). InterpretationThe results of the present study suggest that initial-foot progression and knee abduction angles are potential technique factors to lower knee abduction moments during pivoting.

How should I regulate my emotions if I want to run faster?

The present study investigated the effects of emotion regulation strategies on self-reported emotions and 1600 m track running performance. In stage 1 of a three-stage study, participants (N = 15) reported emotional states associated with best, worst and ideal performance. Results indicated that a best and ideal emotional state for performance composed of feeling happy, calm, energetic and moderately anxious whereas the worst emotional state for performance composed of feeling downhearted, sluggish and highly anxious. In stage 2, emotion regulation interventions were developed using online material and supported by electronic feedback. One intervention motivated participants to increase the intensity of unpleasant emotions (e.g. feel more angry and anxious). A second intervention motivated participants to reduce the intensity of unpleasant emotions (e.g. feel less angry and anxious). In stage 3, using a repeated measures design, participants used each intervention before running a 1600 m time trial. Data were compared with a no treatment control condition. The intervention designed to increase the intensity of unpleasant emotions resulted in higher anxiety and lower calmness scores but no significant effects on 1600 m running time. The intervention designed to reduce the intensity of unpleasant emotions was associated with significantly slower times for the first 400 m. We suggest future research should investigate emotion regulation, emotion and performance using quasi-experimental methods with performance measures that are meaningful to participants.

Predictive value of ventilatory inflection points determined under field conditions

ABSTRACTThe aim of this study was to evaluate the predictive potential provided by two ventilatory inflection points (VIP1 and VIP2) examined in field without using gas analysis systems and uncomfortable facemasks. A calibrated respiratory inductance plethysmograph (RIP) and a computerised routine were utilised, respectively, to derive ventilation and to detect VIP1 and VIP2 during a standardised field ramp test on a 400 m running track on 81 participants. In addition, average running speed of a competitive 1000 m run (S1k) was observed as criterion. The predictive value of running speed at VIP1 (SVIP1) and the speed range between VIP1 and VIP2 in relation to VIP2 (VIPSPAN) was analysed via regression analysis. VIPSPAN rather than running speed at VIP2 (SVIP2) was operationalised as a predictor to consider the covariance between SVIP1 and SVIP2. SVIP1 and VIPSPAN, respectively, provided 58.9% and 22.9% of explained variance in regard to S1k. Considering covariance, the timing of two ventilatory inflection points provides predictive value in regard to a competitive 1000 m run. This is the first study to apply computerised detection of ventilatory inflection points in a field setting independent on measurements of the respiratory gas exchange and without using any facemasks.

Technique determinants of knee joint loads during cutting in female soccer players

The aim of this study was to investigate the relationships between technique characteristics and knee abduction moments during 90° cuts. A cross sectional design involving 26 elite and sub-elite female soccer players (mean±SD; age: 21±3.2years, height: 1.68±0.07m, and mass: 59.1±6.8kg) was used to explore relationships between pre-determined technical factors on knee abduction moments during cutting. Three dimensional motion analyses of 90° cuts on the right leg were performed using ‘Qualisys Pro Reflex’ infrared cameras (240Hz). Ground reaction forces were collected from two AMTI force platforms (1200Hz) embedded into the running track to examine 2nd last and last footfalls. Pearson’s correlation coefficients, co-efficients of determination and hierarchical multiple regression were used to explore relationships between a range of technique parameters and peak knee abduction moments. Significance was set at p<.05. Hierarchical multiple regression revealed that initial knee abduction angle, lateral leg plant distance and initial lateral trunk lean could explain 67% (62% adjusted) of the variation in peak knee abduction moments (F(1,22)=8.869, p=.007). These findings reveal potential modifiable technical factors to lower peak knee abduction moments during cutting.

Reprodutibilidade do desempenho em provas de corrida de 5 e 10 km em pista de atletismo

We examined the reproducibility of performance in running events of 5 and 10km in running track. Thirty‐one recreational, male, runners performed two tests of 5 and two tests of 10km in an official running track. There was no significant difference in time between the test‐retest for both tests using the paired t test (P>0.05). The intraclass coefficient of correlation and the coefficient of variation were 0.94/3.44% (5km) and 0.97/2.43% (10km), respectively. The reproducibility of both running events in running track was similar to that reported in the literature for laboratory tests. In addition, the 10km test was more reproducible than the 5km test for this studied sample, requiring approximately half the sample needed to detect significant increases during test‐retest in running events of 5km.