The purpose of this paper is to discuss the role of variability in human movement, with emphasis on locomotion variability. Based on the assessment of stride characteristics, movement variability has been associated with reduced gait stability and unsteadiness. However, based on the measure of joint coordination during locomotion, variability has been suggested to provide a source of adaptation. Therefore, it would appear that the assessment of movement coordination from either the task outcome (i.e., stride characteristics) or the joint coordination patterns provide distinctly opposing views of variability. This paper will discuss the use of the variability measures, specifically joint coordination variability, from a clinical perspective. Investigations will be presented in which a reduction in joint coordination variability has been associated with pathology. Finally, the clinical implications of these measures as well as treatment suggestions are discussed.
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Movement Variability as a Clinical Measure for Locomotion
Bryan C. Heiderscheit
Lower Extremity Coupling Parameters during Locomotion and Landings
Mark D. Tillman, Chris J. Hass, John W. Chow, and Denis Brunt
During ballistic locomotion and landing activities, the lower extremity joints must function synchronously to dissipate the impact. The coupling of subtalar motion to tibial and knee rotation has been hypothesized to depend on the dynamic requirements of the task. This study was undertaken to look for differences in the coupling of 3-D foot and knee motions during walking, jogging, and landing from a jump. Twenty recreationally active young women with normal foot alignment (as assessed by a licensed physical therapist) were videotaped with high-speed cameras (250 Hz) during walking, jogging, hopping, and jumping trials. Coupling coefficients were compared among the four activities. The ratio of eversion to tibial rotation increased from the locomotion to the landing trials, indicating that with the increased loading demands of the activity, the requirements of foot motion increased. However, this increased motion was not proportionately translated into rotation of the tibia through the subtalar joint. Furthermore, the ratio of knee flexion to knee internal rotation increased significantly from the walking to landing trials. Together these findings suggest that femoral rotation may compensate for the increase in tibial rotation as the force-dissipating demands of the task increase. The relative unbalance among the magnitude of foot, tibial, and knee rotations observed with increasing task demands may have direct implications on clinical treatments aimed at reducing knee motion via controlling motion at the foot during landing tasks.
An Alternative Model of the Lower Extremity during Locomotion
Saunders N. Whittlesey and Joseph Hamill
An alternative to the Iterative Newton-Euler or linked segment model was developed to compute lower extremity joint moments using the mechanics of the double pendulum. The double pendulum model equations were applied to both the swing and stance phases of locomotion. Both the Iterative Newton-Euler and double pendulum models computed virtually identical joint moment data over the entire stride cycle. The double pendulum equations, however, also included terms for other mechanical factors acting on limb segments, namely hip acceleration and segment angular velocities and accelerations Thus, the exact manners in which the lower extremity segments interacted with each other could be quantified throughout the gait cycle. The linear acceleration of the hip and the angular acceleration of the thigh played comparable roles to muscular actions during both swing and stance.
Increase in Leg Stiffness Reduces Joint Work During Backpack Carriage Running at Slow Velocities
Bernard Liew, Kevin Netto, and Susan Morris
running capability, but they involve varying elements of survival and navigation. In order to transport equipment for survival and navigation, runners in these races often have to carry some form of load. 3 Load carriage added to locomotion has been shown to reduce physical performance, 4 which
The Midfoot Joint Complex (Foot Arch) Contributes to the Upper Body Position in Bipedal Walking and Coordinates With the Lower Limb Joints
Leonardo D. Barsante, Paula M.M. Arantes, Daniela V. Vaz, Fabricio A. Magalhães, Diego S. Carvalho, Aline C. Cruz, Renan A. Resende, Juliana M. Ocarino, Sérgio T. Fonseca, and Thales R. Souza
are significant for weight-bearing and locomotion. However, the influence of MJC sagittal kinematics (foot arch raising and lowering) on body kinematics in tasks such as walking has been less explored. 4 , 5 The MJC angular position and motion, as part of the kinematic chain comprising the lower limb
Changes in Spatiotemporal Measures and Variability During User-Driven Treadmill, Fixed-Speed Treadmill, and Overground Walking in Young Adults: A Pilot Study
Hillary H. Holmes, Randall T. Fawcett, and Jaimie A. Roper
-paced treadmill . J Biomech . 2017 ; 65 : 154 – 160 . PubMed ID: 29096982 doi:10.1016/j.jbiomech.2017.10.015 10.1016/j.jbiomech.2017.10.015 29096982 9. Kim J , Stanley CJ , Curatalo LA , Park HS . A user-driven treadmill control scheme for simulating overground locomotion . Annu Int Conf IEEE Eng
Vision Is Not Required to Elicit Balance Improvements From Beam Walking Practice
Natalie Richer, Steven M. Peterson, and Daniel P. Ferris
contributions to the control of locomotion . Current Opinion in Neurobiology, 33 , 25 – 33 . 10.1016/j.conb.2015.01.011 Fitts , P.M. ( 1954 ). The information capacity of the human motor system in controlling the amplitude of movement . Journal of Experimental Psychology, 47 , 381 – 391 . 10.1037/h
An Ankle-Foot Orthosis Powered by Artificial Pneumatic Muscles
Daniel P. Ferris, Joseph M. Czerniecki, and Blake Hannaford
We developed a pneumatically powered orthosis for the human ankle joint. The orthosis consisted of a carbon fiber shell, hinge joint, and two artificial pneumatic muscles. One artificial pneumatic muscle provided plantar flexion torque and the second one provided dorsiflexion torque. Computer software adjusted air pressure in each artificial muscle independently so that artificial muscle force was proportional to rectified low-pass-filtered electromyography (EMG) amplitude (i.e., proportional myoelectric control). Tibialis anterior EMG activated the artificial dorsiflexor and soleus EMG activated the artificial plantar flexor. We collected joint kinematic and artificial muscle force data as one healthy participant walked on a treadmill with the orthosis. Peak plantar flexor torque provided by the orthosis was 70 Nm, and peak dorsiflexor torque provided by the orthosis was 38 Nm. The orthosis could be useful for basic science studies on human locomotion or possibly for gait rehabilitation after neurological injury.
Evaluation of a Treadmill with Vibration Isolation and Stabilization (TVIS) for Use on the International Space Station
Jean L. McCrory, David R. Lemmon, H. Joseph Sommer, Brian Prout, Damon Smith, Deborah W. Korth, Javier Lucero, Michael Greenisen, Jim Moore, Inessa Kozlovskaya, Igor Pestov, Victor Stepansov, Yevgeny Miyakinchenko, and Peter R. Cavanagh
A treadmill with vibration isolation and stabilization designed for the International Space Station (ISS) was evaluated during Shuttle mission STS-81. Three crew members ran and walked on the device, which floats freely in zero gravity. For the majority of the more than 2 hours of locomotion studied, the treadmill showed peak to peak Linear and angular displacements of less than 2.5 cm and 2.5°, respectively. Vibration transmitted to the vehicle was within the microgravity allocation limits that are defined for the ISS. Refinements to the treadmill and harness system are discussed. This approach to treadmill design offers the possibility of generating 1G-like loads on the lower extremities while preserving the microgravity environment of the ISS for structural safety and vibration free experimental conditions.
The Metabolic Relevance of Type of Locomotion in Anaerobic Testing: Bosco Continuous Jumping Test Versus Wingate Anaerobic Test of the Same Duration
Sebastian Kaufmann, Olaf Hoos, Aaron Beck, Fabian Fueller, Richard Latzel, and Ralph Beneke
responses. The large differences in PP and MP between WAnT and CJ30 6 , 7 seem to be related to different types of locomotion with the use of elastic energy during the stretch shortening cycle (SSC) in the CJ30 jumping exercise. During the SSC, tendons and titin filaments can store and release elastic
