Running with running shoes versus barefoot running: A videographical analysis

The purpose of this study was to kinematically describe the movements of the lower extremities in running with running shoes and running barefoot. Another purpose of this study was to identify and compare the anatomical and mechanical adaptations that occur. Seven college age females, members of the University of Nebraska at Omaha cross-country team, and one local competitive long-distance female runner 27 yrs old, were subjects of this study. All subjects were free of any physical disability that could have caused an impaired performance

Running With Running Shoes Versus Barefoot Running: A Videographical Analysis

The purpose of this study was to kinematically describe the movements of the lower extremities in running with running shoes and running barefoot. Another purpose of this study was to identify and compare the anatomical and mechanical adaptations that occur. Seven college age females, members of the University of Nebraska at Omaha cross-country team, and one local competitive long-distance female runner 27 yrs old, were subjects of this study. All subjects were free of any physical disability that could have caused an impaired performance. All subjects completed one testing session consisting of three acceptable trials each with and without their running shoes. A trial was defined as acceptable when the speed of the subject was 3.8 ±0.19 m/sec and a complete running stride was in the field of view of the camera. Videography (60 fields /sec) was used to film the subjects from the sagittal view. The data capture, digitizing, data calculations, and display were performed by using the Peak Performance Technology PEAK2D Software running on a Zenith 80386 computer. A SONY 1341 Trinitron monitor and a Panasonic AG 7 300 video cassette recorder controlled by the Zenith computer, were used to digitize the videography data. The results obtained from the analysis of the parameters used revealed significant differences between conditions for the vertical heel velocities before and at touchdown, and the strut length at toe off. No significant differences between conditions were found for the remaining parameters measured. From the results of this study the following conclusions were made. Removal of running shoes indicated that the human spring apparatus of the lower extremity tends to shorten at touchdown and during the support phase to diminish shock (due to a lack of cushioning). Additionally, running shoes helped the runners to exhibit sufficient forward thrust and drive in order to project their bodies more efficiently during the nonsupport phase. These changes in running mechanics could be attributed to the protection of some elements of the musculoskeletal system due to the two different loading conditions. From the findings of this study several recommendations were made concerning further research. Future studies should employ appropriate methods for a detailed determination of the internal forces. Neurophysiological or mathematical modeling could be used for such an analysis. A longitudinal study should be conducted for better evaluation of the effects of barefoot training on injuries and performance

Baseline measures are altered in biomechanical studies

The purpose of this investigation was to examine if baseline measures are altered between conditions in biomechanical studies and to determine the need for baseline measurements in biomechanics. Ten runners were asked to run at varying speeds and obstacle heights. Baseline measures were acquired between all conditions. Right lower extremity kinematic and kinetic data were collected for all baseline trials and evaluated by both a group and a single subject analysis. The group analysis revealed significant differences between baselines only for the obstacle perturbation. The single subject analysis indicated that baseline measures are altered in a greater degree for kinematics than kinetics. These findings suggested that baseline measures are altered between conditions in biomechanical studies, and they should be used when a repeated measures or a single subject experimental design is being utilized

Integer programming models for the semi-obnoxious p-median problem

The p-median problem concerns the location of facilities so that the sum of distances between the demand points and their nearest facility is minimized. We study a variant of this classic location problem where minimum distance constraints exist both between the facilities and between the facilities and the demand points. This specific type of problem can be used to model situations where the facilities to be located are semi-obnoxious. But despite its relevance to real life scenarios, it has received little attention within the vast literature on location problems. We present twelve ILP models for this problem, coupling three formulations of the p-median problem with four formulations of the distance constraints. We utilize Gurobi Optimizer v9.0.3 in order to compare these ILP models on a large dataset of problems. Experimental results demonstrate that the classic p-median model proposed by ReVelle \& Swain and the model proposed by Rosing et al. are the best performers

The relationship between subtalar and knee joint function as a possible mechanism for running injuries

The purposes of the study were: (1) to evaluate the effects of different surfaces on the relationship between subtalar and knee joint function, and (2) to examine/explore alternative approaches to the evaluation of these relationships. Five subjects ran under four different surface conditions of various hardness, while both rear and sagittal view kinematic data were collected (200 Hz). Critical parameters describing the knee angle and rearfoot motion were examined in conjunction with a curve analysis technique which incorporated slope differences and curve correlations. A repeated measure ANOVA design (surface × subject) was used along with single subject procedures. The results of the study support a strong inter-relationship between pronation and knee joint function via tibial rotation and underlined it as a possible mechanism for injury. Moreover, discrete point analysis might not be the most appropriate methodology for evaluating dynamic functions such as rearfoot motion and knee angle. Extreme methodological care must be exercised when evaluating these functions to avoid oversmoothing and/or masking correlations and differences due to differential subject responses and individual variability. The fact that increased impact force facilitated timing discrepancies between subtalar and knee joint function resulting in a transition of the pronation curve from a unimodal to bimodal configuration, is hypothesized as a possible explanation to better understand the inter-relationships among these lower extremity functions and their relationship to running injuries

Original investigation correlated joint fluctuations can influence the selection of steady state gait patterns in the elderly

This investigation utilized a Markov model to investigate the relationship of correlated lower extremity joint fluctuations and the selection of a steady state gait pattern in the young and elderly. Our model simulated the neuromuscular system by predicting the behavior of the joints for the next gait cycle based on the behavior exhibited in the preceding gait cycles. Such dependencies in the joint fluctuations have been noted previously in the literature. We speculated that compared to the young model, the characteristics of the correlated fluctuations in the elderly model would result in the selection of a different steady state gait pattern. The results of our simulation support the notion that correlated fluctuations in the joint kinematics influence the selection of a steady state gait pattern. The steady state gait pattern for the elderly model was dependent the ankle and hip. Conversely, the steady state gait pattern for the young control model was dependent on the behavior of the knee and hip. Based on our model, we suggested that the altered steady state gait patterns observed in the elderly may be due to an altered neuromuscular memory of prior joint behaviors

An artificial neural network that utilizes hip joint actuations to control bifurcations and chaos in a passive dynamic bipedal walking model

Chaos is a central feature of human locomotion and has been suggested to be a window to the control mechanisms of locomotion. In this investigation, we explored how the principles of chaos can be used to control locomotion with a passive dynamic bipedal walking model that has a chaotic gait pattern. Our control scheme was based on the scientific evidence that slight perturbations to the unstable manifolds of points in a chaotic system will promote the transition to new stable behaviors embedded in the rich chaotic attractor. Here we demonstrate that hip joint actuations during the swing phase can provide such perturbations for the control of bifurcations and chaos in a locomotive pattern. Our simulations indicated that systematic alterations of the hip joint actuations resulted in rapid transitions to any stable locomotive pattern available in the chaotic locomotive attractor. Based on these insights, we further explored the benefits of having a chaotic gait with a biologically inspired artificial neural network (ANN) that employed this chaotic control scheme. Remarkably, the ANN was quite robust and capable of selecting a hip joint actuation that rapidly transitioned the passive dynamic bipedal model to a stable gait embedded in the chaotic attractor. Additionally, the ANN was capable of using hip joint actuations to accommodate unstable environments and to overcome unforeseen perturbations. Our simulations provide insight on the advantage of having a chaotic locomotive system and provide evidence as to how chaos can be used as an advantageous control scheme for the nervous system

Effect of normalization and phase angle calculations on continuous relative phase

The purpose of this investigation was to determine if phase plot normalization and phase angle definitions would have an affect on continuous relative phase calculations. A subject ran on a treadmill while sagittal plane kinematic data were collected with a high­ speed (180Hz) camera. Segmental angular displacements and velocities were used to create phase plots, and examine the coordination between the leg and thigh. Continuous relative phase was calculated with a combination of two different amplitude normalization techniques, and two different phase angle definitions. Differences between the techniques were noted with a root mean square (RMS) calculation. RMS values indicated that there were differences in the configuration of the non-normalized and normalized continuous relative phase curves. Graphically and numerically, it was noted that normalization tended to modify the continuous relative phase curve configuration. Differences in continuous relative phase curves were due to a loss in the aspect ratio of the phase plot during normalization. Normalization tended to neglect the nonlinear forces acting on the system since it did not maintain the aspect ratio of the phase plot. Normalization is not necessary because the arc tangent function accounts for differences in amplitudes between the segments. RMS values indicated that there were profound differences in the continuous relative phase curve when the phase angle was normalized and a phase angle was calculated relative to the right horizontal axi

Human Movement Variability, Nonlinear Dynamics, and Pathology: Is There A Connection?

Fields studying movement generation, including robotics, psychology, cognitive science, and neuroscience utilize concepts and tools related to the pervasiveness of variability in biological systems. The concept of variability and the measures for nonlinear dynamics used to evaluate this concept open new vistas for research in movement dysfunction of many types. This review describes innovations in the exploration of variability and their potential importance in understanding human movement. Far from being a source of error, evidence supports the presence of an optimal state of variability for healthy and functional movement. This variability has a particular organization and is characterized by a chaotic structure. Deviations from this state can lead to biological systems that are either overly rigid and robotic or noisy and unstable. Both situations result in systems that are less adaptable to perturbations, such as those associated with unhealthy pathological states or absence of skillfulness

Performance Accomodation to Midsole Hardness During Running

The effects of shoe hardness on impact force characteristics during running were elevated using both a group and single subject analysis approach. It was hypothesized that non-significant shoe effects previously reported could have resulted from the experimental design and analysis procedures employed. The present study evaluated 18 runners using a single subject procedure in addition to a group design (Shoe Condition X (Subject X Shoe Hardness)). ANOVA analyses identified significant differences (p \u3c 0.05) between mean impact forces for the soft shoe condition and mean maximum knee flexion angles for the hard shoe condition. Individual subject analyses identified no significant (p \u3c0:05) impact force differences for eight subjects while I 0 subjects exhibited significant differences. A significant correlation coefficient of -0.59 between impact force and maximum knee flexion suggested that some accommodation took place on average but the extent varied among subject. Post-hoc group analyses identified a relationship (r = 0.59) between impact tester results and impact forces for one subgroup of subjects.The results support the hypothesis that subjects can and do respond differently to the same perturbation ·and that these differential responses can compromise group analysis results