Biomechanics Commons^™

The Effects Of Two Different Fatigue Protocols On Lower Extremity Kinematics And Kinetics During An Unanticipated Running Stop-Jump, David L. Quammen

Human Movement Studies & Special Education Theses & Dissertations

Altered neuromuscular control strategies and biomechanical movement risk factors are most likely to contribute to the increased incidence of non-contact ACL injury for female athletes. Neuromuscular control strategies and movement patterns are further altered when the effects of fatigue are present. The purpose of this study was to determine neuromechanical differences between two fatigue protocols [Slow Linear Oxidative Fatigue Protocol (SLO-FP) and Functional Agility Short-Term Fatigue Protocol (FASTFP)] when performing a running stop-jump task (RS). A sample of convenience of fifteen Division I female soccer players (age= 19.2 ± 0.8 years; height= 1.67 ± 0.05 m; mass= 61.7 ± 8.1 …

High Intensity Running Results In An Impaired Neuromuscular Response In Acl Reconstructed Individuals, Kostas Patras, Giorgos Ziogas, Stavros Ristanis, Elias Tsepis, Nikolaos Stergiou, Anastasios D. Georgoulis

Journal Articles

Anterior cruciate ligament (ACL) reconstruction reestablishes electromyographic activity during moderate activities such as walking but is unclear if this is also the case in sports activities such as high intensity running that results in accumulation of metabolic fatigue. Nine bone-patella tendon-bone ACL reconstructed athletes were evaluated 19.2 (5.7) months post-operatively using a telemetric electromyographic system. The neuromuscular response of vastus lateralis and biceps femoris muscles was tested bilaterally on separate occasions during 10 min running at moderate intensity (20% below the lactate threshold) and 10 min running at high intensity (40% above the lactate threshold). During moderate intensity running, electromyographic …

Joint Kinetics Of The Ankle And Knee When Running Over Obstacles, Alan Hreljac, Nikolaos Stergiou, Shane D. Scholten

Journal Articles

When running over obstacles of increasing height, heelstrike runners switch to a forefoot landing pattern once a critical obstacle height is reached. The primary purpose of this study was to determine whether ankle or knee joint kinetic variables trigger the gait change from a heelstrike to a forefoot striking pattern as obstacle height increases. Ten subjects were filmed from the sagittal plane as they ran at their preferred running speed over a force platform during six obstacle height conditions ranging from 10% to 22.5% of standing height, as well as an additional baseline condition with no obstacle (0%). An inverse …

The Effect Of Anterior Cruciate Ligament Recontruction On Lower Extremity Relative Phase Dynamics During Walking And Running, Max J. Kurz, Nikolaos Stergiou, Ugo H. Buzzi, Anastasios D. Georgoulis

Journal Articles

The purpose of this investigation was to use relative phase dynamics to evaluate gait in individuals with a reconstructed anterior cruciate ligament (ACL) during walking and running. Relative phase dynamics can describe the coordination strategies between the interacting segments at the lower extremity. Ten subjects who had undergone ACL reconstruction using the central third of their patellar tendon and ten healthy controls walked and ran on a treadmill at a self-selected pace. Relative phase dynamics were calculated for the foot–shank and shank–thigh coordinative relation- ships. Statistical differences between the groups were noted for the foot– shank relationship (p<0.05) during both walking and running and for the shank–thigh relationship (p<0.05) during walking. Our results indicate that current ACL reconstructive techniques may result in altered relative phase dynamics. These changes in relative phase dynamics could be related to a loss of sensory information about joint position and velocity that is typically provided by the intact ACL. Additionally, relative phase adaptations could be a learned response from the early stages of postsurgical rehabilitation. Relative phase dynamics provide quantitative information about the dynamic status of the ACL-reconstructed knee that cannot be gained from the conventional time-series evaluation of gait analysis data. Relative phase dynamics measures should supplement the conventional gait analysis measures that are used today for the clinical evaluation of the functional dynamic stability of the reconstructed knee. The examination of relative phase dynamics could be clinically important for the quantification of new ACL surgical interventions and of patient performance at various stages of rehabilitation. Further research should incorporate relative phase dynamics to understand the influence of ACL reconstruction on coordination and functional patient outcomes.

Walking And Running In The Red-Legged Running Frog, Kassina Maculata, Anna N. Ahn, E Furrow, Andrew A. Biewener

All HMC Faculty Publications and Research

Although most frog species are specialized for jumping or swimming, Kassina maculata (red-legged running frog) primarily uses a third type of locomotion during which the hindlimbs alternate. In the present study, we examined Kassina's distinct locomotory mode to determine whether these frogs walk or run and how their gait may change with speed. We used multiple methods to distinguish between terrestrial gaits: the existence or absence of an aerial phase, duty factor, relative footfall patterns and the mechanics of the animal's center of mass (COM). To measure kinematic and kinetic variables, we recorded digital video as the animals moved …

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 …

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 …

Energy Absorption During Running By Leg Muscles In A Cockroach, Robert J. Full, Darrell R. Stokes, Anna N. Ahn, Robert K. Josephson

All HMC Faculty Publications and Research

Biologists have traditionally focused on a muscle's ability to generate power. By determining muscle length, strain and activation pattern in the cockroach Blaberus discoidalis, we discovered leg extensor muscles that operate as active dampers that only absorb energy during running. Data from running animals were compared with measurements of force and power production of isolated muscles studied over a range of stimulus conditions and muscle length changes. We studied the trochanter-femoral extensor muscles 137 and 179, homologous leg muscles of the mesothoracic and metathoracic legs, respectively. Because each of these muscles is innervated by a single excitatory motor axon, …

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 …