Kinesiology Commons^™

Spanning Set Defines Variability In Locomotive Patterns, Max J. Kurz, Nikolaos Stergiou, Daniel Blanke

Journal Articles

The purpose of the investigation was to use the spanning set methodology to quantify variability in locomotive patterns and to compare this method with traditional measures of variability. Subjects ran on a treadmill while sagittal plane kinematic data were collected with a high-speed (180 Hz) camera. Changes in variability were evaluated as the subject ran barefoot and in shoes. Mean ensemble curves for the knee angle during the stance period were created for each condition. From these curves, traditional measures of variability were calculated using the coefficients of variation (CVs), and the mean deviation (MD). Spanning set vectors were defined …

Frequency Domain Characteristics Of Ground Reaction Forces During Walking Of Young And Elderly Females, Nikolaos Stergiou, Giannis Giakas, Jennifer E. Byrne, Valerie Pomeroy

Journal Articles

Objective. To examine the frequency domain characteristics of the ground reaction forces of young and elderly females during free walking.

Design. Independent t-tests were used to examine the frequency content of all three components of the ground reaction force.

Background. Frequency domain analysis has the potential to assist in identifying changes in gait that may be masked in the time domain. No research has been done to identify changes in gait due to age-related impairments in the frequency domain.

Methods. Ten young and ten elderly females walked at a prescribed speed while ground reaction forces were collected via a …

Effect Of Normalization And Phase Angle Calculations On Continuous Relative Phase, Max J. Kurza, Nikolaos Stergiou

Journal Articles

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 …

Comparison Of Gait Patterns Between Young And Elderly Women: An Examination Of Coordination, Jennifer E. Byrne, Nikolaos Stergiou, Daniel Blanke, Jeremy J. Houser, Max J. Kurz, Patricia A. Hageman

Journal Articles

This study investigated intralimb coordination during walking in Young and Elderly women using the theoretical model of dynamical systems. Twenty females, ten Young (M age = 24.6 yrs, SD = 3.2 yrs), and ten Elderly (M age = 73.7 yrs, SD = 4.9 yrs), were videotaped during free speed gait and gait perturbed by an ankle weight. Two parameters, one describing the phasing relationship between segments (mean absolute relative phase) and the other the variability of this relationship (deviation in phase), were calculated from the kinematics. Two-way ANOVA (age and weight) with repeated measures on weight indicated that during the …

Foot Strike Patterns After Obstacle Clearance During Running, Shane D. Scholten, Nicholas Stergiou, Alan Hreljac, Jeremy J. Houser, Daniel Blanke, L. Russell Alberts

Journal Articles

Purpose

Running over obstacles of sufficient height requires heel strike (HS) runners to make a transition in landing strategy to a forefoot (FF) strike, resulting in similar ground reaction force patterns to those observed while landing from a jump. Identification of the biomechanical variables that distinguish between the landing strategies may offer some insight into the reasons that the transition occurs. The purpose of this study was to investigate the difference in foot strike patterns and kinetic parameters of heel strike runners between level running and running over obstacles of various heights.

Methods

Ten heel strike subjects ran at their …

Intralimb Coordination Following Obstacle Clearance During Running: The Effect Of Obstacle Height, Nikolaos Stergiou, Shane D. Scholten, Jody L. Jensen, Daniel Blanke

Journal Articles

The purpose of this study was to investigate the different coordination strategies used following obstacle clearance during running. Ten subjects ran over a level surface and over obstacles of six different heights (10, 12.5, 15, 17.5, 20 and 22.5% of their standing height). Analysis based upon the dynamical systems theory (DST) was used and the phasing relationships between lower extremity segments were examined. The results demonstrated that the increasing obstacle height elicited behavioral changes. The foot and the leg became more independent in their actions, while the leg and the thigh strengthened their already stable relationship. The 15% obstacle height …

A Dynamical Systems Investigation Of Lower Extremity Coordination During Running Over Obstacles, Nikolaos Stergiou, Jody L. Jensen, Barry T. Bates, Shane D. Scholten, George Tzetzis

Journal Articles

Objective. To investigate intralimb coordination during running over a level surface and over obstacles of three different heights.

Design. The phasing relationships between the foot and leg motions in the frontal plane, and the shank and thigh motions in the sagittal plane were used to compare patterns of coordination.

Background. The coordinated actions of lower extremity segments are necessary to absorb the impact forces generated during running. The behavioral patterns of these segments can be studied under changing task demands using analysis techniques from the Dynamical Systems Theory.

Methods. Ten subjects ran at their self-selected pace …

Phase Determination During Normal Running Using Kinematic Data, Alan Hreljac, Nikolaos Stergiou

Journal Articles

Algorithms to predict heelstrike and toe-off times during normal running at subject-selected speeds, using only kinematic data, are presented. To assess the accuracy of these algorithms, results are compared with synchronised force platform recordings from ten subjects performing ten trials each. Using a single 180Hz camera, positioned in the sagittal plane, the average RMS error in predicting heelstrike times is 4.5 ms, whereas the average RMS error in predicting toe-off times is 6.9ms. Average true errors (negative for an early prediction) are +2.4 ms for heelstrike and +2.8ms for toe-off, indicating that systematic errors have not occured. The average RMS …

Asynchrony Between Subtalar And Knee Joint Function During Running, Nikolaos Stergiou, Barry T. Bates, Stanley L. James

Journal Articles

Purpose: It has been suggested that during running proper coordination between subtalar joint pronation/supination and knee joint flexion/extension via tibial rotation is important to attenuate ground reaction impact forces (GRIF). Lack of coordination may produce over time a wide range of injuries. The goal of this study was to investigate the relationship between subtalar pronation/supination and knee flexion/extension with GRIF increases during distance running.

Methods: Eight subjects ran under different speeds (a self-selected pace, 10% faster, 10% slower, and 20% faster) and over different obstacle heights (5%, 10%, and 15% of their standing height) on their self-selected pace. …

The Relationship Between Subtalar And Knee Joint Function As A Possible Mechanism For Running Injuries, Nikolaos Stergiou, Barry T. Bates

Journal Articles

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 …

Performance Accomodation To Midsole Hardness During Running, Barry T. Bates, Nikolaos Stergiou

Journal Articles

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 < 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 <0:05) 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.

Interactive Effects Between Group And Single-Subject Response Patterns, Janet S. Dufek, Barry T. Bates, Nikolaos Stergiou, C. Roger James

Journal Articles

A two-part study was undertaken to investigate the effects of movement experiences on lower extremity function during impact activities. Group and single-subject performances were evaluated for a total of 12 male volunteers during landing (Study I) and running (Study II) activities. Standard biomechanical techniques were used to obtain kinematic (200 Hz) and kinetic (1000 Hz) data during soft, normal and stiff-knee landings (Study I) and for under, normal, and over-stride running (Study II). Performance trials were tested for normality, condition differences were documented and multiple regression models were computed to predict the first (F1) and second (F2) maximum vertical forces …