Effects of Shoe Outsole Design and Incline on Walking Biomechanics

The purpose of the study was to examine the effects of incline at foot contact of treadmill walking between rounded outsole (ROS) and traditional outsole (TOS) shoes. A rounded outsole shoe (ROS) is specifically designed with a fulcrum under the sole so that when the mass of the body is over it, the foot is forced to roll anteriorly. Traditional ROS studies have included analyses on bipedal stance single leg standing, muscleactivity during treadmill walking, kinetics during over ground walking, and kinematics after a 6-week accommodation period. Presently, there is no research comparing a ROS and a TOS at 0% and 5% incline. The significance of this study is to expand the current body of literature relative to the biomechanical/functional understanding of a ROS. This study provides empirical data that will lend insight to kinematic and impact characteristics between a TOS and ROS at foot contact while walking on 0% and 5% incline

Examining Lower Extremity Range of Motion And Movement Variability Chages Due To Focus of Attention During Landing

Attentional focus (AF) has been explored among a variety of motor skills providing evidence that external AF promotes automaticity and enhanced performance [6]. External focus of attention is distinguished from internal focus such that external focus is directed toward movement effect rather than body movements [6]. Movement variability provides a means of assessing functional characteristics of the neuromotor system, where normal functioning is suggested to occur within optimal limits, while excessively high or low movement variability is indicative of system dysfunction [2,4,5]. Additionally, the ability of the motor system to vary, or broadly distribute, internal loads is thought to reduce the risk of injury, and increase adaptation to a wider array of stimuli [2,4,5]. Viewing movement variability as an inherent and functional element of the neuromotor system provides an avenue for investigating injury susceptibility [2,4,5]. Landing has been explored due to a high incidence of injury in athletic performance, and the ability to experimentally control task demands [3,4]. Examinations of lower extremity functioning during landing have demonstrated equivocal findings among variables, with the influence of AF instructions on injury risk remaining unexplored [3,4,5,6]. The purpose of this research was to examine the effects of AF instructions on landing kinematics, exploring strategies for reducing injury risk. Movement variability was used to assess neuromotor functioning and the ability of the motor system to vary internal loads

A Comparative Evaluation of Gait between Children with Autism and Typically Developing Matched Controls

Anecdotal reports suggest children with autism spectrum disorder (ASD) ambulate differently than peers with typical development (TD). Little empirical evidence supports these reports. Children with ASD exhibit delayed motor skills, and it is important to determine whether or not motor movement deficits exist during walking. The purpose of the study was to perform a comprehensive lower-extremity gait analysis between children (aged 5–12 years) with ASD and age- and gender-matched-samples with TD. Gait parameters were normalized to 101 data points and the gait cycle was divided into seven sub-phases. The Model Statistic procedure was used to test for statistical significance between matched-pairs throughout the entire gait cycle for each parameter. When collapsed across all participants, children with ASD exhibited large numbers of significant differences (p \u3c 0.05) throughout the gait cycle in hip, knee, and ankle joint positions as well as vertical and anterior/posterior ground reaction forces. Children with ASD exhibited unique differences throughout the gait cycle, which supports current literature on the heterogeneity of the disorder. The present work supports recent findings that motor movement differences may be a core symptom of ASD. Thus, individuals may benefit from therapeutic movement interventions that follow precision medicine guidelines by accounting for individual characteristics, given the unique movement differences observed

Effects of Backward Walking on Hamstring Flexibility and Low Back Range of Motion

The purpose of the study was to examine the effects of backward walking on hamstring flexibility and low back range of motion. Ten healthy female volunteers (29.9±10.0 yr; 165.1±8.2 cm; 68.53±18.4 kg) completed pre-post laboratory testing surrounding a 4-week intervention of backward walking. During the pretest, each participant walked forward on a treadmill at a preferred velocity for 3-5 min. A biaxial electrogoniometer was secured externally to the low back and a sit-and-reach test was performed. Each participant then walked backward at their preferred pace on a treadmill for 10 min, during which time low back motion data were obtained (1000 Hz). Following the pretest, participants completed an intervention of walking backward at a self-selected velocity for 10-15 min/day, 4 days/week. This was followed by a posttest, using the exact protocol as the pretest. Dependent variables consisted of pre-post measures of: 1) backward walking velocity (VEL), 2) flexibility of the hamstrings (HF), low back sagittal plane range of motion (sROM), and low back coronal plane range of motion (cROM). Correlated t-tests (α = 0.05) with Bonferroni correction identified significant (p \u3c 0.001) differences in VEL and HF. Low back motion parameters (sROM, cROM) were not significantly different (p \u3e 0.0125) following the intervention. Results of the study suggest that a 4-week intervention of backward walking appears to provide an appropriate stimulus for an increase in flexibility of the hamstrings. A possible interaction between VEL and sROM or cROM limited the interpretation of observed non-significant changes in low back motion

ELECTRODYNOGRAM FORCE ANALYSIS IN CROSSCOUNTRY SKIING

Effectiveness of the Langer Electrodynogram (EDG) force analysis system in the cross country ski diagonal stride was tested in a preliminary study. The objective was to utilize the EDG to investigate temporal patterns of the stride performed on level terrain

Quantifying Head Injury Severity Following Pediatric Patient Falls

The purpose of this study was to retrospectively calculate the head injury criteria (HIC) values for pediatric patient falls and correlate these values to documented injury severity (MERP) scores. A second purpose was to examine the relationship between child ages and associated HIC15 values in an attempt to scale the values obtained from pediatrics to adult values

Kinematic Effects of Stride Length Perturbations on System COM Horizontal Velocity During Locomotion

PURPOSE: To investigate the kinematic effect on the systems’ center of mass horizontal velocity in response to stride length perturbations. METHODS: Twelve healthy adults (23.1±7.71 yrs; 1.69±0.1 m; 66.82±12.6 kg; leg length 894.7±66.1 mm) performed 5 trials of preferred speed walking (PW) and running (PR)followed by 5 stride length perturbations based on percentages of leg length (60%, 80%, 100%, 120% and 140%). 3D kinematic analysis was completed using a 12-camera infrared motion capture system (Vicon, 200hz). Dependent variables computer for each condition included: center of mass horizontal velocity at the highest vertical position (COMHVhi) and at the lowest vertical position (COMHVlo). Statistical analysis included correlation matrices across levels of perturbation for each dependent variable (α=.05). RESULTS: COMHVhi demonstrated significant correlations with greater than 50% shared variance for PR vs 100% (r=.742), 60% vs 80% (r=.824), 60% vs 100% (r=.748), 60% vs 120% (r=.709), 80% vs 100% (r=.896), 100% vs 120% (r=.887), and 100% vs 140% (r=.728), and 120% vs 140% (r=.895). COMHVlo demonstrated significant correlations with greater than 50% shared variance for PR vs 100% (r=.753), PW vs 80% (r=.794), 60% vs 80% (r=.814), 60% vs 100% (r=.735), 60% vs 120% (r=.748), 80% vs 100% (r=.902), 80% vs 120% (r=.751), 100% vs 120% (r=.892), and 120% vs 140% (r=.710). DISCUSSION: Results suggest PR and PW have a greater relationship to stride length less than or equal to leg length, and thus extending stride length begins to diminish mechanical efficiency. It is a well-established mechanical relationship that horizontal velocity is a product of stride length and stride rate. Study results suggest that increases in stride length beyond 100% of leg length may be less than optimal mechanically. CONCLUSION: Stride lengths greater than 100% leg length during walking may be inefficient, perhaps owing to changes in lower extremity stiffness

The Influence of Sport-Related Concussion on Lower Extremity Injury Risk: A Review of Current Return-to-Play Practices and Clinical Implications

International Journal of Exercise Science 13(3): 873-889, 2020. Sport-related concussions (SRCs) are now classified as a major health concern affecting athletes across all sporting levels, with recent evidence suggesting upwards of 3.8 million SRCs occur each year. Multiple injury surveillance datasets have recently determined that athletes post-SRC, compared to non-concussed counterparts, are at greater risk for lower extremity (LE) injury beyond the resolution of traditional SRC assessment batteries. However, it is presently uncertain if common clinical practices (symptom reporting, neuropsychological (NP) examination, and static postural control analysis) can determine athletes at risk for LE injury following an SRC. A comprehensive review of the literature determined that these tools may not reveal subtle cognitive and neuromuscular deficits that lead to subsequent LE injury during dynamic sporting tasks. Current return-to-play (RTP) protocols should consider clarifying the addition of specific objective locomotor analysis, such as gait tasks and sport-specific maneuvers, to determine the risk of LE injury after an athlete has sustained an SRC

Step Length Perturbations Alter Variations in Center of Mass Horizontal Velocity

PURPOSE: The purpose of the study was to investigate the effects of SL perturbations on system COM forward velocity (vx) during walking gait. METHODS: Eight healthy adults (23.5±3.6 yrs; 1.72±0.18 m; 73.11±15.29 kg) performed 5 trials of preferred speed walking (PW) and running (PR) followed by 5 stride length perturbations based on percentages of leg length (LL: 60%, 80%, 100%, 120% and 140%). 3D kinematic analysis was completed using a 12-camera infrared motion capture system (Vicon MX T40-S, 200Hz). Data filtering and interpolation included a low pass, 4th order Butterworth filter (cutoff frequency 15Hz) and cubic (3rd order spline). Maximum and minimum system COMvx comparisons were made independently among stride conditions using one-way repeated measures ANOVA and Bonferroni post-hoc contrasts. Change in system COMvx across gait stride were evaluated using one-way repeated measures ANOVA and Bonferroni post-hoc contrasts (α=0.05). RESULTS: Differences in maximum COMvx were detected among stride conditions (F[1.847,59.105]=339.458, pdetected among stride conditions (F[2.118,65.666] =130.951, pdetected significantly greater ΔCOMvx at 140% LL, and significantly less ΔCOMvx at 60% LL (p≤.005). DISCUSSION: Differences in maximum COMvx were detected among stride conditions (F[1.847,59.105]=339.458,

The Relationship Between Concussion History and Sex on Lower Extremity Biomechanics During a Cutting Task

Athletes with a history of sports related concussion (SRC) have been shown to exhibit lower extremity (LE) mechanics during high impact landing tasks that are conducive to increased injury risk. The underlying cause, and extent of this phenomena is currently unknown. PURPOSE: The purpose of this study was to analyze the relationship between SRC history and sex on LE biomechanics during a land-and-cut task. METHODS: College athletes with a history of SRC and a control group of healthy athletes matched by sport, position, sex, and age were recruited for this study. Both groups were comprised of 9 males and 11 females. Athletes performed an unanticipated land-and-cut task. The task consisted of each athlete standing on a 60 cm box with a visual stimulus positioned three meters away from the athlete. Various colors (green, pink, blue, and red) were presented as the visual stimulus. Athletes were instructed to only respond to a green or red light. When a red or green light was shown, athletes were instructed to step off the box, land on both limbs and perform a 45-degree cutting movement to the left or right, respectively. Two separate point biserial correlations were conducted (one for each sex) correlating group (0 = control, 1 = SRC) with the following dependent variables: vertical ground reaction force (vGRF), peak knee extensor moment (pKEM), peak knee abduction moment (pKAM), peak ankle dorsiflexion angle (pDF), peak knee flexion angle (pKFA), and peak knee abduction angle (pKA). A linear regression equation was obtained for significant correlations. RESULTS: There was a significant negative moderate correlation between group and KF in males (r = -.69, p \u3c .01). There were no other significant correlations between group and LE biomechanical variables in either males or females (p \u3e .05). A linear regression analysis showed SRC history was a significant predictor of KF (KF = 63.71 – 12.43(group); R2 = .473, p = .002) CONCLUSION: Males in the SRC group were associated with lower KF. Specifically, the regression analysis indicated that males with an SRC history had a predicted 12.4 degree decrease in KF during the land-and-cut task. This suggests previously concussed males may be at increased risk for LE injury