Upper body contributions to pitched ball velocity in elite high school pitchers using an induced velocity analysis.

Interest in joint and segment contributions to pitched ball velocity has been dominated by inverse dynamic solutions, which is limited in ascertaining complex muscle/joint interactions. Our purpose was to use induced velocity analysis to investigate which joint(s) made the largest contribution to the velocity of a pitched ball. Pitching data were collected from six elite high school-aged pitchers with no history of arm injury.

The foot and ankle structures reveal emergent properties analogous to passive springs during human walking.

An objective understanding of human foot and ankle function can drive innovations of bio-inspired wearable devices. Specifically, knowledge regarding how mechanical force and work are produced within the human foot-ankle structures can help determine what type of materials or components are required to engineer devices. In this study, we characterized the combined functions of the foot and ankle structures during walking by synthesizing the total force, displacement, and work profiles from structures distal to the shank.

Using a Real-Time Locating System to Measure Walking Activity Associated with Wandering Behaviors Among Institutionalized Older Adults.

A real-time locating system (RTLS) can be used to track the walking activity of institutionalized older adults in long-term care who are at risk for wandering behaviors. The benefits of a RTLS are objective and continuous measurements of activity. Self-report methods of activity, especially wandering, by health care staff are vulnerable to floor effects and recall bias, and continuous clinical or research observation over the long-term can be time-consuming and expensive.

Balance ability and cognitive impairment influence sustained walking in an assisted living facility.

Purpose Of Study: The purpose of this study was to determine the influence of cognitive impairment (CI), gait quality, and balance ability on walking distance and speed in an assisted living facility.

Materials And Methods: This was a longitudinal cohort study of institutionalized older adults (N = 26; 555 observations) followed for up to 8 months. Hierarchical linear modeling statistical techniques were used to examine the effects of gait quality and balance ability (using the Tinetti Gait and Balance Test) and cognitive status (using the Montreal Cognitive Assessment) on walking activity (distance, sustained distance, sustained speed).

A mathematical analysis to address the 6 degree-of-freedom segmental power imbalance.

Segmental power is used in human movement analyses to indicate the source and net rate of energy transfer between the rigid bodies of biomechanical models. Segmental power calculations are performed using segment endpoint dynamics (kinetic method). A theoretically equivalent method is to measure the rate of change in a segment's mechanical energy state (kinematic method).

Constituent Lower Extremity Work (CLEW) approach: A novel tool to visualize joint and segment work.

Work can reveal the mechanism by which movements occur. However, work is less physically intuitive than more common clinical variables such as joint angles, and are scalar quantities which do not have a direction. Therefore, there is a need for a clearly reported and comprehensively calculated approach to easily visualize and facilitate the interpretation of work variables in a clinical setting.

Changes in relative work of the lower extremity joints and distal foot with walking speed.

The modulation of walking speed results in adaptations to the lower limbs which can be quantified using mechanical work. A 6 degree-of-freedom (DOF) power analysis, which includes additional translations as compared to the 3 DOF (all rotational) approach, is a comprehensive approach for quantifying lower limb work during gait. The purpose of this study was to quantify the speed-related 6 DOF joint and distal foot work adaptations of all the lower extremity limb constituents (hip, knee, ankle, and distal foot) in healthy individuals.

The Bridging Advanced Developments for Exceptional Rehabilitation (BADER) Consortium: Reaching in Partnership for Optimal Orthopaedic Rehabilitation Outcomes.

The Bridging Advanced Developments for Exceptional Rehabilitation (BADER) Consortium began in September 2011 as a cooperative agreement with the Department of Defense (DoD) Congressionally Directed Medical Research Programs Peer Reviewed Orthopaedic Research Program. A partnership was formed with DoD Military Treatment Facilities (MTFs), U.S.

Loaded Vertical Jumping: Force-Velocity Relationship, Work, and Power.

The aims of the current study were to explore the pattern of the force-velocity (F-V) relationship of leg muscles, evaluate the reliability and concurrent validity of the obtained parameters, and explore the load associated changes in the muscle work and power output. Subjects performed maximum vertical countermovement jumps with a vest ranging 0-40% of their body mass. The ground reaction force and leg joint kinematics and kinetics were recorded.

Passive-dynamic ankle-foot orthosis replicates soleus but not gastrocnemius muscle function during stance in gait: Insights for orthosis prescription.

Background: Passive-dynamic ankle-foot orthosis characteristics, including bending stiffness, should be customized for individuals. However, while conventions for customizing passive-dynamic ankle-foot orthosis characteristics are often described and implemented in clinical practice, there is little evidence to explain their biomechanical rationale.

Objectives: To develop and combine a model of a customized passive-dynamic ankle-foot orthosis with a healthy musculoskeletal model and use simulation tools to explore the influence of passive-dynamic ankle-foot orthosis bending stiffness on plantar flexor function during gait.

Passive-dynamic ankle-foot orthoses substitute for ankle strength while causing adaptive gait strategies: a feasibility study.

Bending stiffness of passive-dynamic ankle-foot orthoses (PD-AFOs) is a functional characteristic thought to restore lost ankle function due to weakened plantar flexors. However, lower extremity impairment profiles of patients are seldom limited to plantar flexion weakness, and PD-AFO characteristics often influence gait in other ways. Combined, all PD-AFO characteristics and patient impairments likely mask the main effect of PD-AFO bending stiffness and complicate the PD-AFO bending stiffness prescription process.

Comparison of mechanical energy profiles of passive and active below-knee prostheses: a case study.

Background: With the recent technological advancements of prosthetic lower limbs, there is currently a great desire to objectively evaluate existing prostheses. Using a novel biomechanical analysis, the purpose of this case study was to compare the mechanical energy profiles of anatomical and two disparate prostheses: a passive prosthesis and an active prosthesis.

Case Description And Methods: An individual with a transtibial amputation who customarily wears a passive prosthesis (Elation, Össur) and an active prosthesis (BiOM, iWalk, Inc.

Assessment of a virtual functional prototyping process for the rapid manufacture of passive-dynamic ankle-foot orthoses.

Passive-dynamic ankle-foot orthosis (PD-AFO) bending stiffness is a key functional characteristic for achieving enhanced gait function. However, current orthosis customization methods inhibit objective premanufacture tuning of the PD-AFO bending stiffness, making optimization of orthosis function challenging. We have developed a novel virtual functional prototyping (VFP) process, which harnesses the strengths of computer aided design (CAD) model parameterization and finite element analysis, to quantitatively tune and predict the functional characteristics of a PD-AFO, which is rapidly manufactured via fused deposition modeling (FDM).

Mechanical energy profiles of the combined ankle-foot system in normal gait: insights for prosthetic designs.

Over the last half-century, the field of prosthetic engineering has continuously evolved with much attention being dedicated to restoring the mechanical energy properties of ankle joint musculatures during gait. However, the contributions of 'distal foot structures' (e.g.

Sensitivity of joint moments to changes in walking speed and body-weight-support are interdependent and vary across joints.

We investigated the effect of simultaneous changes in body-weight-support level and walking speed on mean peak internal joint moments at the ankle, knee and hip. We hypothesized that observed changes in these joint moments would be approximately linear with both body-weight-support and walking speed and would be similar across joints. Kinematic and kinetic data were collected from 8 unimpaired adult subjects walking on an instrumented treadmill while wearing a dynamically controlled overhead support harness.

A unified deformable (UD) segment model for quantifying total power of anatomical and prosthetic below-knee structures during stance in gait.

Anatomically-relevant (AR) biomechanical models are traditionally used to quantify joint powers and segmental energies of lower extremity structures during gait. While AR models contain a series of rigid body segments linked together via mechanical joints, prosthetic below-knee structures are often deformable objects without a definable ankle joint. Consequently, the application of AR models for the study of prosthetic limbs has been problematic.

Dimensional accuracy of ankle-foot orthoses constructed by rapid customization and manufacturing framework.

Passive-dynamic ankle-foot orthoses (PD-AFOs) constitute a class of ankle braces that rely on material properties and physical features to establish functional characteristics such as bending or rotational stiffness. We have developed a novel framework that combines a fully parameterized PD-AFO computer-aided design (CAD) model and free-form fabrication to rapidly manufacture customized PD-AFOs. The three-dimensional locations of select anatomic landmarks serve to fit customize the PD-AFO CAD model.

Methodological issues in monitoring health services and outcomes for stroke survivors: a case study.

Background: Obtaining comprehensive health outcomes and health services utilization data on stroke patients has been difficult. This research grew out of a memorandum of understanding between the NIH and the ISS (its Italian equivalent) to foster collaborative research on rehabilitation.

Objective: The purpose of this study was to pilot a methodology using administrative data to monitor and improve health outcomes for stroke survivors in Tuscany.

Strength asymmetry and osteoarthritis risk factors in unilateral trans-tibial, amputee gait.

Persons with a unilateral, trans-tibial amputation have an increased risk of developing osteoarthritis (OA) in the knee of their intact limb. Between-side strength discrepancies observed in individuals with an amputation may indicate overuse of the intact limb and increased osteoarthritis risk; however, the relationship between lower extremity strength and gait mechanics has not been addressed in previous literature. It was hypothesized that amputee subjects' strength and gait would be more asymmetrical than controls, and that strength asymmetry would positively correlate with gait variable asymmetry and intact side gait variables associated with osteoarthritis risk.

In situ calibration and motion capture transformation optimization improve instrumented treadmill measurements.

We increased the accuracy of an instrumented treadmill's measurement of center of pressure and force data by calibrating in situ and optimizing the transformation between the motion capture and treadmill force plate coordinate systems. We calibrated the device in situ by applying known vertical and shear loads at known locations across the tread surface and calculating a 6 x 6 calibration matrix for the 6 output forces and moments. To optimize the transformation, we first estimated the transformation based on a locating jig and then measured center-of-pressure error across the treadmill force plate using the CalTester tool.

Visuomotor adaptation of voluntary step initiation in older adults.

It has been suggested that feedforward planning of gait and posture is diminished in older adults. Motor adaptation is one mechanism by which feedforward commands can be updated or fine-tuned. Thus, if feedforward mechanisms are diminished in older adults, motor adaptation is also likely to be limited.

Using two palpable measurements improves the subject-specific femoral modeling.

Subject-specific musculoskeletal models are essential to biomedical research and clinical applications, such as customized joint replacement, computer-aided surgical planning, gait analysis and automated segmentation. Generating these models from CT or magnetic resonance imaging (MRI) is time and resource intensive, requiring special skills. Therefore, in many studies individual bone models are approximated by scaling a generic template.

Impaired reactive stepping adjustments in older adults.

Background: The ability to redirect the path of the foot during walking is critical for responding to perturbations and maintaining upright stability. The purpose of the current study was to compare mechanisms of reactive stepping adjustments in young versus older adults when responding to an unexpected perturbation during voluntary step initiation.

Methods: We tested 13 healthy community-dwelling older adults and an equal number of young control participants performing stepping movements onto a visual target on the floor.

Community-based adaptive physical activity program for chronic stroke: feasibility, safety, and efficacy of the Empoli model.

Objective: To determine whether Adaptive Physical Activity (APA-stroke), a community-based exercise program for participants with hemiparetic stroke, improves function in the community.

Methods: Nonrandomized controlled study in Tuscany, Italy, of participants with mild to moderate hemiparesis at least 9 months after stroke. Forty-nine participants in a geographic health authority (Empoli) were offered APA-stroke (40 completed the study).