Constant Running Research Articles

A modeling method of sport shoes for dynamic analysis of shoe-body coupled system

The purpose of this study was to quantify the functional role of compressive characteristics of shoe sole by combining a finite-truss-element shoe sole model and the equation of whole-body motion. The equation of the shoe sole deformation was developed by modeling shoe sole as a construction of truss elements that have nonlinear spring and damper. The properties of the spring and damper were identified from impact test by using an impact device containing an accelerometer and an arm with impactor. The equation of whole-body motion was derived by modeling the human body as a system of 15-rigid linked segments. Dynamic contributions of the support leg joint torques, which were caused by the elastic and viscous forces on the shoe sole, to the generation of whole-body CG's acceleration were calculated under constant running speed condition. A fore/mid foot contact type runner participated as subject. The results in this study indicate that 1) the ankle joint torque caused by the elastic property of the forepart of shoes sole contributes to the acceleration of whole-body CG, and 2) the knee joint torque caused by the viscous property of shoe sole shows negative contribution to the body support but shows positive contribution to the propulsion.

Characteristics of transition processes in production processes in engineering

The class SH functions were used to develop a new method of the formation of smooth transition processes in the production processes in engineering in conditions such as starting up, acceleration, deceleration, reversing, constant running, and shutdown. The efficiency of the method is confirmed by the results of mathematical simulation carried out for DC drives with independent excitation in the task of controlling the feed rate in automatic and semiautomatic arc welding equipment.

High-intensity sprint fatigue does not alter constant-submaximal velocity running mechanics and spring-mass behavior

We investigated the changes in constant velocity spring-mass behavior after high intensity sprint fatigue in order to better interpret the results recently reported after ultra-long distance (ULD) exercises. Our hypothesis was that after repeated sprints (RS), subjects may likely experience losses of force such as after ULD, but the necessity to modify their running pattern to attenuate the overall impact at each step (such as after ULD) may not be present. Eleven male subjects performed four sets of five 6-s sprints with 24-s recovery between sprints and 3min between sets, on a sprint treadmill and on a bicycle ergometer. For each session, their running mechanics and spring-mass characteristics were measured at 10 and 20kmh(-1) on an instrumented treadmill before and after RS. Two-way (period and velocity) ANOVAs showed that high-intensity fatigue did not induce any change in the constant velocity running pattern at low or high velocity, after both running and cycling RS, despite significant decreases (P<0.001) in maximal power (-27.1±8.2% after running RS and -15.4±11.5 % after cycling RS) and knee extensors maximal voluntary force (-18.8±6.7 % after running RS and -15.0±7.6 % after cycling RS). These results bring indirect support to the hypothesis put forward in recent ULD studies that the changes in running mechanics observed after ULD are likely not related to the decrease in strength capabilities, but rather to the necessity for subjects to adopt a protective running pattern.

Training Load in Constant Load and Interval Running Exercises

Training load (TL) in constant velocity exercises depends on both exercise intensity and duration and in interval exercises the recovery time between the running bouts is also an important factor. Furthermore, individual training history and performance profile affect TL. Based on exercise intensity, duration and individual performance profile a new TL and TL recovery model was developed for running. PURPOSE: To test a new model to determine TL and recovery in constant velocity and interval exercises in running. METHODS: Seventeen untrained men and women performed five different constant load exercise (3.5 km at 50%, 63% and 74% of vVO2max, 7 km at 50% and 63% at vVO2max) and 13 male recreational runners performed three different constant load exercises (3 km at 60% and 85% of vVO2max and 14 km at 60% of vVO2max) and three different interval exercises (12×250m at 85% and 105% of vVO2max and 6×500m at 85% of vVO2max) on a treadmill. In order to test the validity of the new TL model, Excess Post-exercise Oxygen Consumption (EPOC), heart rate, blood lactate concentration (BLa) and rating of perceived exertion (RPE) were measured from all the exercises. Furthermore, endurance performance characteristics were measured by a graded treadmill test and a questionnaire for training history and performance profile was filled by the subjects. RESULTS: The new TL model ranked the analyzed exercises in the same order as EPOC, RPE and BLa in both untrained subjects and recreational runners. When all the subjects and exercise data were pooled, a significant correlation (P < 0.001) was observed between the calculated TL and EPOC, RPE and BLa (r = 0.56, 0.60 and 0.66, respectively). Similar correlations were also observed when untrained subjects and recreational runners were analyzed separately. Significant correlations between TL and EPOC, RPE and BLa were also observed when both constant load and interval exercises were pooled in recreational runners (r = 0.6 - 0.8, P < 0.001). CONCLUSION: The results of the present study showed that the new TL model can be used to compare training load of different constant load and interval exercises in subjects with different training history and performance profile. More study is needed to assess whether the new TL model is useful for monitoring the training in running.

Classification of muscle activity based on effort level during constant pace running

During running, psychologic and physiologic changes are manifested in the perception of effort, muscle properties and movement strategies. The latter two aspects are expressed as changes in electromyographic (EMG) activity. This paper tests the hypothesis that the EMG signals change in a systematic way during a run and that these changes are related to the effort level of the runner. Fifteen female recreational runners performed 1-h treadmill runs at a constant speed (95% of speed at ventilatory threshold). EMG signals were recorded from four muscles (tibialis anterior, gastrocnemius medialis, vastus lateralis, and semitendinosus). The wavelet transformed EMG data were used to discriminate between different effort phases of running using a support vector machine (SVM) approach. The effect of the penalty parameter, C, and cross validation folds, n, used were evaluated and found to have little influence on the outcome. Recognition rates of >80% were achieved for all C and n values across all muscles. Average recognition rates were: TA – 89.2, GM – 88.3%, VL – 84.6% and ST – 94.0%. These results suggest that selected lower extremity EMG signals using wavelet-based methods contained highly systematic differences that could be used by the SVM to discriminate between the low- and high-effort stages of prolonged running.

Running spectral index from inflation with modulations

We argue that a large negative running spectral index, if confirmed, might suggest that there are abundant structures in the inflaton potential, which result in a fairly large (both positive and negative) running of the spectral index at all scales. It is shown that the center value of the running spectral index suggested by the recent CMB data can be easily explained by an inflaton potential with superimposed periodic oscillations. In contrast to cases with constant running, the perturbation spectrum is enhanced at small scales, due to the repeated modulations. We mention that such features at small scales may be seen by 21 cm observations in the future.

B6 シューズ-人体連成モデルを利用したシューズの機能抽出(シューズおよびサーフェス)

The purpose of this study was to quantify the functional role of compressive characteristics of shoes sole by combining a fmite-truss-element shoes model and equation of whole-body motion. The equation of the shoes sole deformation was developed by modeling shoes sole as a construction of truss elements with nonlinear spring and damper properties. The coefficients of the properties were identified from impact test by using an impact device consisting of accelerometer and arm with impactor. The equation of whole-body motion was derived by modeling the human body as a system of 15-rigid linked segments. Dynamic contributions of the support leg joint torques, which were caused by the elastic and viscous property of the shoes sole, to the generation of whole-body CG's acceleration were calculated under constant running speed condition. The results in this study indicate that 1) the plantar flexion torque about the ankle caused by the elastic property of the forepart of shoes sole contributes to the acceleration of whole-body CG, and 2) the flexion torque of the knee caused by the viscous property of shoe sole contributes to the absorption of the vertical impact force occurred at foot contact.

Intermittent vs Continuous Graded Exercise Test for VO2max in College Soccer Athletes

The purpose of this study was to determine if a 1-min active recovery between stages during a graded exercise test (GXT) would result in a higher stage intensity and maximum oxygen uptake in college soccer athletes. Eleven athletes completed two GXT protocols on separate days. Each GXT consisted of 2-min stages performed at a constant running speed and incremental increases of 2.5% grade. One GXT was performed continuously and the other was intermittent with 1-min active recovery between each stage. Tests were performed to volitional fatigue. Following the each GXT and a 10-min active recovery period, participants performed a verification stage at an intensity greater than the final stage of the GXT. All participants completed a higher intensity stage during the intermittent vs continuous GXT. As a result, VO2max and maximum heart rate (HR) were significantly higher (VO2: 57.7 ± 5.8 vs. 55.5 ± 5.7 ml•kg-1•min-1, HR: 190 ± 6 vs. 187 ± 6 bpm, p &lt; 0.02) during the intermittent GXT. Maximum ventilation and respiratory exchange ratio did not differ between intermittent and continuous protocols. Following the intermittent GXT, nine participants completed the verification stage and obtained VO2 values within the plateau criterion. We conclude that a continuous GXT underestimates VO2max in some athletes and that the intermittent protocol may provide a more accurate measure of VO2max.

Effects of high-intense stimuli on continuous running exercise at the ventilatory threshold

To verify the effects of previous interval training session on physiological and kinematic parameters during continuous running at ventilatory threshold. Ten healthy male performed initially an incremental running test, in order to determine ventilatory threshold and maximal aerobic capacity. In another session, subjects performed three tasks as follows: (1) previous five-minute run at ventilatory threshold. After ten minutes rest: (2) interval training session (8 × 1-min at maximal velocity, alternated to one-minute at 50% maximal velocity). After 15 minutes rest: (3) posterior five-minute run at ventilatory threshold. Heart rate, ventilation, blood glucose and lactate concentrations, perceived exertion, stride frequency, stance period and swing period were compared before and after the interval training session. Significant increases were found in heart rate (∼12%), ventilation (∼23%), blood glucose (∼28%), blood lactate (230%), perceived exertion (∼25%) and stride frequency (∼5%) after interval training. High-intense running stimuli affect physiological, perceptual and kinematics of a constant moderate intensity running, which could influence training session programmes, considering the impairment overall running performance. Vérifier les effets d’une séance d’entraînement par intervalles sur des paramètres physiologiques et cinématiques lors d’une course continue réalisée au seuil anaérobie. Dix sujets mâles sains ont initialement exécuté un test de course cumulatif afin de déterminer le seuil anaérobie et la vitesse aérobie maximale. Lors d’une autre séance, les sujets ont exécuté dans l’ordre les trois tâches suivantes : (1) précourse de cinq minutes au seuil anaérobie. Après dix minutes de repos, (2) séance d’entraînement par intervalles (8 × 1 minute à vélocité maximale, alternés avec une minute à 50 % de la vélocité maximale). Après 15 minutes de repos, (3) postcourse de cinq minutes au seuil anaérobie. Le rythme cardiaque, la ventilation, le taux de glucose dans le sang, la concentration d’acide lactique, la perception de l’effort, la fréquence de la marche, la phase d’appui et la phase oscillante ont été comparés avant et après la séance d’entraînement par intervalles. Des augmentations significatives ont été trouvées, après l’entraînement par intervalles, pour le taux de glucose dans le sang (∼23 %), la ventilation (∼12 %), le rythme cardiaque (∼28 %), la concentration d’acide lactique (230 %), la perception de l’effort (∼25 %), ainsi que la fréquence de la marche (∼5 %). Les stimuli induits par une course de forte intensité affectent la physiologie, la perception et la cinématique d’une course constante d’intensité modérée. Ces observations pourraient influer sur les programmes d’entraînement en considérant l’altération globale de la performance de la course.

CMB constraints on principal components of the inflaton potential

We place functional constraints on the shape of the inflaton potential from the cosmic microwave background through a variant of the generalized slow-roll approximation that allows large amplitude, rapidly changing deviations from scale-free conditions. Employing a principal component decomposition of the source function ${G}^{\ensuremath{'}}\ensuremath{\approx}3({V}^{\ensuremath{'}}/V{)}^{2}\ensuremath{-}2{V}^{\ensuremath{'}\ensuremath{'}}/V$ and keeping only those measured to better than 10% results in 5 nearly independent Gaussian constraints that may be used to test any single-field inflationary model where such deviations are expected. The first component implies $&lt;3%$ variations at the 100 Mpc scale. One component shows a 95% CL preference for deviations around the 300 Mpc scale at the $\ensuremath{\sim}10%$ level but the global significance is reduced considering the 5 components examined. This deviation also requires a change in the cold dark matter density which in a flat $\ensuremath{\Lambda}\mathrm{CDM}$ model is disfavored by current supernova and Hubble constant data and can be tested with future polarization or high multipole temperature data. Its impact resembles a local running of the tilt from multipoles 30--800 but is only marginally consistent with a constant running beyond this range. For this analysis, we have implemented a $\ensuremath{\sim}40\ifmmode\times\else\texttimes\fi{}$ faster WMAP7 likelihood method which we have made publicly available.

Impairment in people with anterior cruciate ligament reconstruction in adjusting ground reaction force in running

ABSTRACTIn healthy individuals, maximum vertical ground reaction force (MVGRF) remains close to constant during constant velocity running, despite variation in stiffness of the surface underfoot. Because the anterior cruciate ligament (ACL) possesses mechanoreceptors that influence recruitment of knee muscles, it may play a role in regulation of lower limb force output. This study was designed to examine the effect of recent ACL reconstruction on MVGRF in running. Seven patients who were 5–13 weeks post-ACL reconstruction and 7 healthy participants ran for 60 seconds in shoes modified with hard and with soft 1-cm outsoles. The MVGRF during running was measured for the ACL reconstructed and nonsurgical limbs of patients and limbs of healthy participants. The difference in MVGRF between running in hard and soft shoes was significantly greater in ACL reconstructed limbs than nonsurgical limbs (p = 0.003) and compared to limbs of healthy participants (p = 0.001). In contrast, a difference in MVGRF between shoes was not found between patients' nonsurgical limbs and those of healthy participants. A lack of mechanoreceptive feedback from the ACL graft may be among the factors explaining the difference between the ACL reconstructed limbs and the other two limb conditions.

Systematically modified crash-pad reduces impact shock in running shoes

The purpose of this study was to compare the effect of (a) crash-pad thickness and (b) midsole height at the heel to reduce heel impact load during running. Twenty male runners performed heel-toe runs in four different shoe conditions. While three shoe conditions had systematic changes in crash-pad thickness without changing general heel height, a fourth shoe condition differed only in overall heel height. Kinetic and kinematic running variables were quantified by using a force platform and an electrogoniometer. Data were collected for five valid running trials at a constant running speed of 3.5 ± 0.1 m s−1. Kolmogorov–Smirnov tests, a one-way repeated measures ANOVA (P < 0.05) as well as effect sizes (η 2) were calculated for all variables. The findings of this study showed that (a) increasing crash-pad thickness resulted in reduced impact variables without influencing traditional rearfoot motion variables. Furthermore, reduced heel height (b) is influencing predominantly rearfoot stability. Consequently, crash-pad modification can be used to improve cushioning properties without influences on rearfoot stability. Furthermore, crash-pad modification allows reducing shoe weight while maintaining cushioning properties.

Match Analysis and the Physiological Demands of Australian Football

Australian Football, the most popular football code in Australia, is a contact sport played by two teams of 18 players who contest play over four 20-minute quarters; the object of the game is to score the most points through goal kicking. Sixteen professional senior sides compete against each other in the Australian Football League (AFL) and, similar to other football codes, game demands at the elite level in the AFL have changed considerably in recent years. Early time-motion analysis studies highlighted the long periods of time players spent in low intensity activities (standing and walking). While recent studies utilizing global positioning systems (GPS) technology are somewhat in agreement with earlier findings, available evidence suggests that the game is getting faster. For example, 'playing on' after a mark (a feature of the game where players who catch the ball on the full from a kick longer than 15 m are awarded a free kick) is now much quicker. Indeed, rule changes in recent years have increased the flow and speed of the game; there has been a reduction in the time taken for umpires to restart play, and for players to kick-in (after the opposition kicks a behind) or take a set shot at goal. Nomadic players (a broad term for midfielders and ruckmen because they follow play over the entire playing field) cover slightly greater distances (12,310 m) than both forwards (11,920 m) and backs (11,880 m) in a game. Compared with players in other positions, midfielders are consistently found to spend the most time at higher intensities (running and sprint efforts with movement velocities > 4.44 m/sec), complete more high intensity efforts (approximately 98 per game), sustain them for longer and have shorter recovery periods between high intensity exercise bouts (approximately 90 seconds on average). 'Ruckmen' have similar but less intense running profiles, while forwards and backs generally have less game involvement but have a more intermittent running profile (longer recovery periods with shorter duration high intensity exercise bouts and less time spent in constant pace running). Endurance fitness remains very important for players at the elite level of competition, as does upper and lower body strength and power. In addition, given the increasing speed at which Australian Football is now played, repeated sprint ability of players is arguably more important now than it was in previous years. There are no significant differences in these measures between playing position. Similarly, speed over 10-40 m does not appear to differ between playing position. Establishing the reliability of distance and velocity-derived GPS data in highly specific game-related activities is needed; once achieved, GPS data have the potential to accurately inform coaches of the position-specific demands on their players and to drive the development of training practices that reflect the changing demands of the game.

Towards a real-time distributed computing model

This paper introduces a simple real-time distributed computing model for message-passing systems, which reconciles the distributed computing and the real-time systems perspective: By just replacing instantaneous computing steps with computing steps of non-zero duration, we obtain a model that both facilitates real-time scheduling analysis, and retains compatibility with classic distributed computing analysis techniques and results. We provide general simulations and validity conditions for transforming algorithms from the classic synchronous model to our real-time model and vice versa, and investigate whether/which properties of real systems are inaccurately or even wrongly captured when resorting to zero step-time models. We revisit the well-studied problem of deterministic drift- and failure-free internal clock synchronization for this purpose, and show that no clock synchronization algorithm with constant running time can achieve optimal precision in our real-time model. Since such an algorithm is known for the classic model, this is an instance of a problem where the standard distributed computing analysis gives too optimistic results. We prove that optimal precision is only achievable with algorithms that take Ω ( n ) time in our model, and establish several additional algorithms and lower bounds.

Running shoe sole stiffness evaluation method based on eigen vibration analysis

Running shoes have a wide range of functional requirements, such as shock attenuation, flexibility, stability and fit. These requirements vary with the conditions of the running activity, such as the runner's skill and running velocity. In the design of shoes for high speed running, sole bending and torsional moduli are important factors because excessive sole deformation can cause considerable energy loss in the contact phase. In this article, the propulsion impulse (PI) calculated by the horizontal ground reaction force in constant running velocity is proposed as a measure of running ease. In constant running speed, a reduction in PI is equivalent to a reduction in kicking power. This can help reduce runner fatigue. PI depends on sole stiffness distribution. To predict PI, a sole stiffness prediction method based on eigen vibration analysis is proposed in this article. After confirming the validity of the proposed method it is discussed further using an ASICS high speed running shoe design as an example.

Running shoe sole stiffness evaluation method based on eigen vibration analysis

Running shoes have a wide range of functional requirements, such as shock attenuation, flexibility, stability and fit. These requirements vary with the conditions of the running activity, such as the runner's skill and running velocity. In the design of shoes for high speed running, sole bending and torsional moduli are important factors because excessive sole deformation can cause considerable energy loss in the contact phase. In this article, the propulsion impulse (PI) calculated by the horizontal ground reaction force in constant running velocity is proposed as a measure of running ease. In constant running speed, a reduction in PI is equivalent to a reduction in kicking power. This can help reduce runner fatigue. PI depends on sole stiffness distribution. To predict PI, a sole stiffness prediction method based on eigen vibration analysis is proposed in this article. After confirming the validity of the proposed method it is discussed further using an ASICS high speed running shoe design as an example.

Toward responsive visualization services for scatter/gather browsing

AbstractAs a type of relevance feedback, Scatter/Gather demonstrates an interactive approach to relevance mapping and reinforcement. The Scatter/Gather model, proposed by Cutting, Karger, Pedersen, and Tukey (1992), is well known for its effectiveness in situations where it is difficult to precisely specify a query. However, online clustering on a large data corpus is computationally complex and extremely time consuming. This has prohibited the method's real world application for responsive services. In this paper, we proposed and evaluated a new clustering algorithm called LAIR2, which has linear worst‐case time complexity and constant running time average for Scatter/Gather browsing. Our experiment showed when running on a single processor, the LAIR2 online clustering algorithm is several hundred times faster than a classic parallel algorithm running on multiple processors. The efficiency of the LAIR2 algorithm promises real‐time Scatter/Gather browsing services. We have implemented an online visualization prototype, namely, LAIR2 Scatter/Gather browser, to demonstrate its utility and usability.

Limits on primordial power spectrum resolution: an inflationary flow analysis

We investigate the ability of current cosmic microwave background data to reliablyconstrain the form of the primordial power spectrum generated during inflation. Weattempt to identify more exotic power spectra that yield equally good fits to the data assimple power-law spectra. In order to test a wide variety of spectral shapes, we combine theflow formalism, which is a method of stochastic model generation, with a numericalintegration of the mode equations of quantum fluctuations. This allows us to handleinflation models that yield spectra that are not well described by the standard spectralparameterization. Using the latest WMAP data set, we find a high degree of variation inpossible spectral shapes. In particular, we find strongly running spectra arising fromfast-rolling inflaton fields providing equally good fits to the data as power-law spectraarising from slowly rolling fields. Current data poorly constrains the spectrum on scalesk<0.01h Mpc−1, where the error due to cosmic variance is large. Among the statistically degeneratemodels, we identify spectra with strong running on these larger scales, but with reducedrunning at smaller scales. These models predict values for the tensor-to-scalar ratio,r, that lieoutside the 2-σ confidence interval obtained from SDSS + WMAP (Sloan Digital Sky Survey plusWilkinson Microwave Anisotropy Probe) data for spectra that are parameterized as powerlaws or spectra with constant running. By considering more generalized powerspectra, we therefore open up regions of parameter space excluded for simplermodels.

Minimum weight pseudo-triangulations

We consider the problem of computing a minimum weight pseudo-triangulation of a set S of n points in the plane. We first present an O ( n log n ) -time algorithm that produces a pseudo-triangulation of weight O ( log n ⋅ wt ( M ( S ) ) ) which is shown to be asymptotically worst-case optimal, i.e., there exists a point set S for which every pseudo-triangulation has weight Ω ( log n ⋅ wt ( M ( S ) ) ) , where wt ( M ( S ) ) is the weight of a minimum weight spanning tree of S . We also present a constant factor approximation algorithm running in cubic time. In the process we give an algorithm that produces a minimum weight pseudo-triangulation of a simple polygon.

Scale dependence of the primordial spectrum from combining the three-year WMAP,galaxy clustering, supernovae, and Lyman-alpha forests

We probe the scale dependence of the primordial spectrum in the light ofthe three-year WMAP (WMAP3) alone and WMAP3 in combination withthe other cosmological observations such as galaxy clustering and type Iasupernova (SNIa). We pay particular attention to the combination with theLyman-α (Lyα) forest. In contrast to the first-year WMAP (WMAP1), WMAP3’s preference for therunning of the scalar spectral index on large scales is now fairly independent of the lowCMB multipoles . A combination with the galaxy power spectrum from the SloanDigital Sky Survey (SDSS) prefers a negative running to larger than2σ, regardless of the presence of the low- CMB () or not. On the other hand, if we focus on the power lawΛCDM cosmology with only six parameters (matter densityΩmh2, baryon densityΩbh2, Hubble constantH0, optical depthτ, the spectralindex, ns, andthe amplitude, As, of the scalar perturbation spectrum) when we drop the low- CMB contributions WMAP3 is consistent with the Harrison–Zel’dovich–Peebles scale-invariant spectrum(ns = 1 and no tensorcontributions) at ∼1σ. When assuming a simple power-law primordial spectral index or a constant running, inthe case when one drops the low- contributions () WMAP3 is more consistent with the other observations, such as the inferred value ofσ8.