Exercise devices – Involving user translation or physical simulation thereof – Treadmill for foot travel
Reexamination Certificate
2000-04-10
2003-11-11
Richman, Glenn E. (Department: 3764)
Exercise devices
Involving user translation or physical simulation thereof
Treadmill for foot travel
C482S051000, C482S003000
Reexamination Certificate
active
06645126
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a rehabilitation aid in the form of a treadmill whose belt speed is set to a patient's own step cycle based on leg length or step length. The treadmill helps rehabilitation of stroke, spinal cord, head injury, amputees, orthopedic, neurologic and vestibular patients by improving their gait characteristics, step frequency and stride length to match the user's own step cycle as a function of leg length or step length.
2. Discussion of Related Art
U.S. Pat. No. 5,623,944, entitled METHOD FOR CHARACTERIZING GAIT, issued Apr. 29, 1997 Nashner. This patent contains a description of the Categories of Gait and the characterization of Gait Using A Treadmill. The description is informative in describing the direction that the state of the art has taken and so is reproduced here.
Categories of Gait
The phases of human gait have been described by many authors; some examples include, Inman, et al. (1981) “Human Walking,” Williams and Wilkins, Baltimore; Winter, D. A. (1983) “Biomechanical Motor Patterns in Normal Walking,” Journal of Motor Behavior 15:302-330; and Winestein, et al. (1989) “Quantitative Dynamics of Disordered Human Locomotion: a Preliminary Investigation,” (Journal of Motor Behavior 21:373-391). Human gait may be classified in general categories of walking and running. During walking, at least one foot is always in contact with the support surface and there are measurable periods of time greater than zero during which both feet are in contact with the support surface. During running, there are measurable periods greater than zero during which time neither foot is in contact with the support surface and there are no times during which both feet are in contact with the support surface.
Walking can be separated into four phases, double support with left leg leading, left leg single support, double support with right leg leading, and right leg single support. Transitions between the four phases are marked by what are generally termed “heel-strike” and “toe-off” events. The point of first contact of a foot is termed a “heel-strike”, because in normal adult individuals the heel of the foot (the rearmost portion of the sole when shoes are worn) is usually the first to contact the surface. However, heel-strike may be achieved with other portions of the foot contacting the surface first. During running normal adult individuals sometimes contact a surface with the ball of the foot (forward portions of the sole when shoes are worn). Individuals with orthopedic and/or neuromuscular disorders may always contact the surface with other portions of the foot or other points along the perimeter of the sole when shoes are worn. Similarly, while the ball and toes of the foot are the last to contact the surface at a toe-off event in normal adults, a patient's last point of contact may be another portion of the foot. Thus, regardless of the actual points of contact, the terms heel-strike and toe-off refer to those points in time at which the foot first contacts the support surface and ceases to contact the surface, respectively.
Characterization of Gait Using a Treadmill
Treadmills allowing a subject to locomote over a range of walking and running speeds within a confined space have been described in the prior art (Traves, et al. (1983) “A Speed-Related Kinematic Analysis of Overground and Treadmill Walking”; Winter, et al. (eds.) Biomechanics XI, Human Kinetics Publishers, Champaign, pp. 423-426; Nelson, et al. (1972) “Biomechanics of Overground Versus Treadmill Running,” Medicine and Science in Sports 4:233-240; and Charteris, et al. (1978) “The Process of Habitation to Treadmill Walking: a Kinetic Analysis,” Perceptual and Motor Skills 47:659-666). A treadmill allows the difficulty of gait to be precisely set by independently controlling the belt speed and the inclination of the belt. The subject can be maintained in a fixed position relative to the measuring surface underlying the treadmill belt by coordinating the speed of gait with the speed of the treadmill belt movement. Several prior art research studies have described treadmills in which a single forceplate with mechanically coupled force transducers has been mounted directly beneath the treadmill belt. Kram et al., in their paper “A Treadmill-Mounted Force Platform”, Journal of The American Physiological Society, 1989, pages 1692-1698, describe a treadmill having a single forceplate. This paper is enclosed herewith and hereby incorporated herein by reference. The single forceplate provided continuous measurement of the forces exerted by the combined actions of the two feet on the overlying treadmill belt during gait.
It is sometimes desirable to determine the position of the center of force in relation to coordinates of specified anatomical features of the foot when the foot is in contact with a surface which is moving in relation to a fixed force sensing surface. This occurs, for example, when the foot is contacting the moving belt of a treadmill which overlays a force sensing surface. To determine the position of the center of force in relation to coordinates of the specified anatomical features of the foot, two coordinate transformations are performed. One, the position of the center of force is determined in relation to coordinates of the moving treadmill belt. Two, the position of the moving treadmill belt is determined in relation to coordinates of the specified anatomical feature of the foot. To perform the first of these coordinate transformations requires knowledge of the treadmill belt position in relation to the fixed force sensing surface position on a continuous basis. To perform the second of these two coordinate transformations requires knowledge of the position of the specified anatomical features of the foot in relation to the treadmill belt. Since the position of the foot and its anatomical features does not change in relation to the treadmill belt following each heel-strike event and before the subsequent toe-off of that foot, the position of the specified anatomical features of the foot needs to be determined only once at heel-strike for each step.
One method to determine the position of the treadmill belt on a continuous basis in relation to the fixed force sensing surface is to use one of several sophisticated commercial treadmill systems described in the prior art which measure the anteroposterior speed of the moving treadmill belt on a continuous basis, and which provide the means to regulate the belt anteroposterior speed on a continuous basis. One example of a commercially available treadmill system with automatic speed control and belt speed measurement systems is the Star Trac 2000, manufactured by Unisen, Inc., Tustin, Calif. When one of these treadmill systems is used, the information necessary to determine the continuous position of the treadmill belt in relation to the underlying forceplate is obtained by performing mathematical integration of the belt speed signal on a continuous basis.
There are methods described in the prior art which can be used to determine, at the time of heel-strike, the position of the moving treadmill belt in relation to the specified anatomical features of the foot. One method is to use one of several commercially available optical motion analysis systems. Two examples of commercially available motion analysis systems which describe applications for tracking the motions of identified points on the human body during locomotion include the ExpertVision system manufactured by Motion Analysis Corp., Santa Rosa, Calif. and the Vicon system manufactured by Oxford Medilog Systems, Limited, Oxfordshire, England. In accordance with this method, one or more optical markers are placed on the specified anatomical features of the foot. One or more additional markers are placed on the treadmill belt at predetermined positions. The number and placement of the optical markers on the anatomical feature and the treadmill belt determine the accuracy of the measurement as specified by the systems manufa
Behan Edward
Chilleme Joseph
Martin Matthew
Biodex Medical Systems, Inc.
Gibbons Del Deo Dolan Griffinger & Vecchione
Richman Glenn E.
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