Design, Fabrication, and Validation of a Portable Perturbation Treadmill for Balance Recovery Research.

Trips and falls are a major concern for older adults. The resulting injury and loss of mobility can have a significant impact on quality of life. An emerging field of study, known as Perturbation Training, has been shown to reduce injury rates associated with trips and falls in older adults.

Combined musculoskeletal finite element modeling of femur stress during reactive balance training.

The purpose of this study was to determine the material stresses experienced in the femoral neck during the stepping phase of recovery from a forward loss of balance achieved both using release from a static forward lean and rapid treadmill accelerations in 8 older adults. A scalable musculoskeletal model with 23 degrees of freedom and 92 force actuators was used to calculate joint reaction forces. A finite element model of the femur used joint reaction forces calculated by the musculoskeletal model to calculate the material stresses during stepping.

A pilot study comparing prosthetic to sound limb gait mechanics during a turning task in people with transtibial amputation.

Background: Observational gait analysis is frequently used by clinicians to subjectively assess straight walking but is not often used to examine turning. Interlimb comparisons of phase- specific turning biomechanics in people with unilateral lower limb amputation has not previously been documented.

Methods: A retrospective examination of gait kinematics and kinetics from five participants with unilateral transtibial amputation was performed.

Analysis of the Relative Motion Between the Socket and Residual Limb in Transtibial Amputees While Wearing a Transverse Rotation Adapter.

The coupling between the residual limb and the lower-limb prosthesis is not rigid. As a result, external loading produces movement between the prosthesis and residual limb that can lead to undesirable soft-tissue shear stresses. As these stresses are difficult to measure, limb loading is commonly used as a surrogate.

Ideal operating conditions for a variable stiffness transverse plane adapter for individuals with lower-limb amputation.

Transverse plane shear stress between the prosthetic socket and residual limb often results in soft tissue breakdown and discomfort for individuals with lower-limb amputation. To better understand the effects of reduced transverse plane stiffness in the shank of a prosthesis, a second-generation variable stiffness torsion adapter (VSTA II) was tested with individuals with a transtibial amputation (n = 10). Peak transverse plane moments, VSTA II deflection, range of whole body angular momentum (WBAM), ground reaction impulse, joint work, and personal stiffness preference were evaluated at three fixed stiffness levels (compliant: 0.

Second generation prototype of a variable stiffness transverse plane adapter for a lower limb prosthesis.

The prescription and fitting of a traditional lower limb prosthesis often focuses on straight walking, neglecting maneuvers such as turning and pivoting that require flexibility in the transverse plane. Current devices that allow transverse plane movement only offer a fixed stiffness and are incapable of adapting to varying daily activities. Pilot testing of a first-generation variable stiffness torsion adapter (VSTA I) showed a benefit for individuals with lower limb amputation by reducing peak transverse plane moments at the residual limb which could lead to increased comfort, but testing was limited due to excessive device height and mass.

Turn Intent Detection For Control of a Lower Limb Prosthesis.

Objective: An adaptable lower limb prosthesis with variable stiffness in the transverse plane requires a control method to effect changes in real time during amputee turning. This study aimed to identify classification algorithms that can accurately predict turning using inertial measurement unit (IMU) signals from the shank with adequate time to enact a change in stiffness during the swing phase of gait when the prosthesis is unloaded.

Methods: To identify if a turning step is imminent, classification models were developed around activities of daily living including 90° spin turns, 90° step turns, 180° turns, and straight walking using simulated IMU data from the prosthesis shank.

Pilot testing of a variable stiffness transverse plane adapter for lower limb amputees.

Amputees often experience soft tissue breakdown and discomfort from the high transverse plane shear stresses between the residual limb and prosthesis. To evaluate the effects of varying the transverse plane stiffness, a small sample population of lower limb amputees wore a novel variable stiffness torsion adapter (VSTA). Peak transverse plane moments were evaluated for three fixed stiffness levels (compliant: 0.