Revisiting sources of variability in gait analysis.

Background: Gait analyses in clinical populations must be considered differently, as variation in measurements may be related to the clinical condition and not just factors of interest. However, measurements taken from gait also have natural variability and this variability is further compounded when multiple factors may be of clinical interest.

Research Question: Do current methods properly assign and quantify the amount of variability in gait data?

Methods: Simulated data were utilized to identify subject and therapist effects using multiple gait trials; data were simulated with and without multiple sessions with therapists.

Feasibility of Using a Novel, Multimodal Motor Function Assessment Platform With Machine Learning to Identify Individuals With Mild Cognitive Impairment.

Introduction: Early identification of clinical conditions associated with Alzheimer disease and related dementias (ADRD) is vital for intervention. One promising early detection method is the use of instrumented assessment to identify subtle motor declines associated with ADRD. This pilot study sought to establish the feasibility of building a machine learning model to identify individuals with mild cognitive impairment (MCI) using motor function data obtained from an inexpensive, portable device.

Association of dual task gait performance with cognitive outcomes among older adults: Piloting an inexpensive, portable assessment platform.

Motor assessment has emerged as complementary evidence for the detection of late life cognitive disorders. Clinicians lack inexpensive, accurate, and portable tools for this purpose. To fill this void, the current study piloted measures from the Mizzou Point-of-care Assessment System a multimodal sensor platform.

Using a Markerless Motion Capture System to Identify Preinjury Differences in Functional Assessments.

Functional assessments identify biomechanical issues which may indicate risk for injury and can be used to monitor functional recovery after an injury or surgery. Although the gold standard to assess functional movements is marker-based motion capture systems, these are cost prohibitive and have high participant burden. As such, this study was conducted to determine if a markerless motion capture system could detect preinjury differences in functional movements between those who did and did not experience a noncontact lower extremity injury (NCLEI).

Objective Clinical Measurement Tools for Functional Evaluation of the Surgical Patient.

Following knee surgery, clinicians have traditionally used visually rated or time-based assessments of lower extremity movement quality to measure surgical outcomes, plan rehabilitation interventions, and measure success. These methods of assessment are prone to error and do not fully capture a patient's inefficient movement patterns post surgery. Further, currently available systems which objectively measure kinematics during these tasks are expensive and unidimensional.

Characterizing Osteochondral Allograft Biomechanics for Optimizing Transplant Success: A Systematic Review.

Osteochondral allograft (OCA) transplantation has been largely successful in treating symptomatic articular cartilage lesions; however, treatment failures persist. While OCA biomechanics have been consistently cited as mechanisms of treatment failure, the relationships among mechanical and biological variables that contribute to success after OCA transplantation have yet to be fully characterized. The purpose of this systematic review was to synthesize the clinically relevant peer-reviewed evidence targeting the biomechanics of OCAs and the impact on graft integration and functional survival toward developing and implementing strategies for improving patient outcomes.

Serial Subtraction Alters Lateral Step-down Tibiofemoral Kinematics in Healthy Adults.

This study evaluated the effects of two types of cognitive dual-tasking on three-dimensional knee kinematics during the lateral step-down. 19 healthy individuals (22.05±1.

Bench to Bedside: A Multidisciplinary Approach toward the Unknowns after ACL Injuries to Drive Individual Success.

ACL injury and surgery are increasing in prevalence. Several challenges exist that can be obstacles to an individual achieving success after ACL surgery. A knowledge of these risk factors alongside a multidisciplinary collaborative team approach can result in a greater likelihood of achieving individual success after ACL surgery.

Comparison of Azure Kinect overground gait spatiotemporal parameters to marker based optical motion capture.

Background: Instrumented measurement of spatiotemporal parameters during walking can provide valuable information on an individual's overall function and health. Efficient, inexpensive, and accurate measurement of overground walking spatiotemporal parameters would be a critical component of providing point-of-care assessments of gait function, concussion recovery, fall-risk, and cognitive decline. Depth cameras combined with skeleton pose tracking algorithms, such as the Microsoft Kinect with body tracking software, have been used to measure walking spatiotemporal parameters.

The effect of an ankle-foot orthosis on tibiofemoral motion during step-up and step-down in healthy adults.

Background: Solid ankle-foot orthoses (SAFOs) are frequently prescribed in conditions such as cerebral palsy and stroke. Although gait is improved in the short term, long-term effects of limiting ankle and foot motion during functional activities on joints such as the knee have not been investigated. Our study purpose was to compare tibiofemoral (TF) motion in shoe and SAFO conditions in healthy adults to inform future studies in clinical populations.

Comparison of Azure Kinect and optical retroreflective motion capture for kinematic and spatiotemporal evaluation of the sit-to-stand test.

Background: The sit-to-stand test (STS) is commonly used to evaluate functional capabilities within a variety of clinical populations. Traditionally STS is a timed test, limiting the depth of information which can be gained from its evaluation. The Azure Kinect has the potential to add in-depth analysis to STS.

Are All Unloader Braces Created Equal? Recommendations for Evidence-Based Implementation of Unloader Braces for Patients with Unicompartmental Knee OA.

Unicompartmental knee osteoarthritis (UKOA) is a complex issue that is estimated to affect roughly 28% of patients with knee OA, and can result in severe cartilage degeneration, meniscus deficiency, and concomitant varus or valgus malalignment. This malalignment results in abnormally high joint reaction forces in the affected compartment, which can elicit pain, cause dysfunction, and exacerbate joint degradation. For more than two decades, the use of knee unloader braces has been advocated as a cost-effective option for symptomatic management of UKOA.

Prospective, Randomized Clinical Trial Comparing a Novel Motion-Assistive Device to Standard Physical Therapy for Initial Management of Knee Range of Motion after Primary Total Knee Arthroplasty.

This prospective randomized clinical trial assessed a novel device for initial management of knee range of motion (ROM), pain, and function after total knee arthroplasty (TKA). Primary TKA patients with preoperative ROM of at least 5° to 115° were randomized to initial knee motion management: Mizzou BioJoint Flex-novel motion-assistive device with prescribed physical therapy or standard physical therapy-prescribed physical therapy. ROM, pain score, and knee injury and osteoarthritis score for joint replacement (KOOSjr) were obtained preoperatively and 2 weeks, 6 weeks, and 3 months postoperatively.

Force-Time Waveform Shape Reveals Countermovement Jump Strategies of Collegiate Athletes.

The purpose of this study was to relate the shape of countermovement jump (CMJ) vertical ground reaction force waveforms to discrete parameters and determine if waveform shape could enhance CMJ analysis. Vertical ground reaction forces during CMJs were collected for 394 male and female collegiate athletes competing at the National Collegiate Athletic Association (NCAA) Division 1 and National Association of Intercollegiate Athletics (NAIA) levels. Jump parameters were calculated for each athlete and principal component analysis (PCA) was performed on normalized force-time waveforms consisting of the eccentric braking and concentric phases.

Efficacy of an 8-Week Resistance Training Program in Older Adults: A Randomized Controlled Trial.

Older adults are challenged with aging-related declines in skeletal muscle mass and function. Although exercise interventions of longer duration typically yield larger changes, shorter-term interventions may kick-start positive effects, allowing participants to begin engaging in more activity. This study aimed to determine whether 8 weeks of a resistance training program (Stay Strong, Stay Healthy [SSSH]) improved dynamic muscle strength, balance, flexibility, and sleep.

The effect of silicone ankle sleeves and lace-up ankle braces on neuromuscular control, joint torque, and cutting agility.

Objective: To evaluate the effects of silicone ankle sleeves (SASs) and lace-up ankle braces (LABs) on neuromuscular control, net joint torques, and cutting agility in healthy, active individuals.

Design: Markerless motion-capture technology tracked subjects fitted with SASs, LABs, or no brace while they performed the movements: Y-excursion, left cutting, right cutting, single-leg drop vertical jump (SLDVJ), 45-degree bound, and single-leg squat (SLS).

Setting: University Laboratory.

Prediction of patellofemoral joint kinematics and contact through co-simulation of rigid body dynamics and nonlinear finite element analysis.

Joint-level rigid body dynamics simulations, when coupled with tissue-level finite element analyses, can simultaneously provide movement and tissue deformation metrics to understand mechanical interactions within the joint on a multi-scale level. In this study, a co-simulation workflow of a joint-level rigid body model that predicts the relative motion as a function of the non-linear cartilage response predicted by a non-linear implicit finite element solver is presented. Predictions are compared to measurements (The Open Knee(s) project) in terms of the mean error and level-of-agreement: pressure = 0.

Femoral Component Malrotation Produces Quadriceps Weakness and Impaired Ambulatory Function following Total Knee Arthroplasty: Results of a Forward-Dynamic Computer Model.

Proper placement of the prosthetic components is believed to be an important factor in successful total knee arthroplasty (TKA). Implant positioning errors have been associated with postoperative pain, suboptimal function, and inferior patient-reported outcome measures. The purpose of this study was to investigate the biomechanical effects of femoral component malrotation on quadriceps function and normal ambulation.

Do neoprene sleeves and prophylactic knee braces affect neuromuscular control and cutting agility?

Objectives: To evaluate the effects of neoprene sleeves (NSs) and prophylactic knee braces (PKBs) on neuromuscular control and cutting agility.

Design: Markerless motion-capture technology tracked subjects (1) without a brace as a control (2) with NSs and (3) with PKBs during single-leg drop vertical jump (SLDVJ), single-leg squat (SLS), Y-excursion, and cutting movements. Movements were recorded five times per bracing condition in three different sessions.

Relationship Between 2-Dimensional Frontal Plane Measures and the Knee Abduction Angle During the Drop Vertical Jump.

Knee abduction angle (KAA), as measured by 3-dimensional marker-based motion capture systems during jump-landing tasks, has been correlated with an elevated risk of anterior cruciate ligament injury in females. Due to the high cost and inefficiency of KAA measurement with marker-based motion capture, surrogate 2-dimensional frontal plane measures have gained attention for injury risk screening. The knee-to-ankle separation ratio (KASR) and medial knee position (MKP) have been suggested as potential frontal plane surrogate measures to the KAA, but investigations into their relationship to the KAA during a bilateral drop vertical jump task are limited.

Electromyography-Driven Forward Dynamics Simulation to Estimate In Vivo Joint Contact Forces During Normal, Smooth, and Bouncy Gaits.

Computational models that predict in vivo joint loading and muscle forces can potentially enhance and augment our knowledge of both typical and pathological gaits. To adopt such models into clinical applications, studies validating modeling predictions are essential. This study created a full-body musculoskeletal model using data from the "Sixth Grand Challenge Competition to Predict in vivo Knee Loads.

Youth Baseball Pitching Mechanics: A Systematic Review.

Context: Pitching injuries in youth baseball are increasing in incidence. Poor pitching mechanics in young throwers have not been sufficiently evaluated due to the lack of a basic biomechanical understanding of the "normal" youth pitching motion.

Objective: To provide a greater understanding of the kinetics and kinematics of the youth baseball pitching motion.

Development and Validation of a Portable and Inexpensive Tool to Measure the Drop Vertical Jump Using the Microsoft Kinect V2.

Background: Noncontact anterior cruciate ligament (ACL) injury in adolescent female athletes is an increasing problem. The knee-ankle separation ratio (KASR), calculated at initial contact (IC) and peak flexion (PF) during the drop vertical jump (DVJ), is a measure of dynamic knee valgus. The Microsoft Kinect V2 has shown promise as a reliable and valid marker-less motion capture device.

Function of the Anterior Intermeniscal Ligament.

The function and importance of the anterior intermeniscal ligament (AIML) of the knee are not fully known. The purpose of this study was to evaluate the biomechanical and sensorimotor function of the AIML. Computational analysis was used to assess AIML and tibiomeniscofemoral biomechanics under combined translational and rotational loading applied during dynamic knee flexion-extension.

Loading of the medial meniscus in the ACL deficient knee: A multibody computational study.

The menisci of the knee reduce tibiofemoral contact pressures and aid in knee lubrication and nourishment. Meniscal injury occurs in half of knees sustaining anterior cruciate ligament injury and the vast majority of tears in the medial meniscus transpire in the posterior horn region. In this study, computational multibody models of the knee were derived from medical images and passive leg motion for two female subjects.