Moataz Eltoukhy

Comparative Effect of Power Training and High-Speed Yoga on Motor Function in Older Patients With Parkinson Disease.

OBJECTIVES To compare the effects of power training (PWT) and a high-speed yoga program on physical performances in older patients with Parkinson disease (PD), and to test the hypothesis that both training interventions would attenuate PD symptoms and improve physical performance. DESIGN Randomized controlled trial. SETTING A laboratory of neuromuscular research and active aging. PARTICIPANTS Patients with PD (N=41; mean age ± SD, 72.2 ± 6.5y). INTERVENTIONS Two high-speed exercise interventions (specifically designed yoga program and PWT) were given for 12 weeks (twice a week), and 1 nonexercise control group. MAIN OUTCOME MEASURES Unified Parkinson Disease Rating Scale motor score (UPDRSMS), Berg Balance Scale (BBS), Mini-Balance Evaluation Systems Test (Mini-BESTest), Timed Up and Go, functional reach, single leg stance (SLS), postural sway test, 10-m usual and maximal walking speed tests, 1 repetition maximum (RM), and peak power (PPW) for leg press. RESULTS For the posttests, both training groups showed significant improvements (P<.05) in all physical measurements except functional reach on the more affected side, SLS, and postural sway compared with the pretests, and significantly better scores for UPDRSMS, BBS, Mini-BESTest, Timed Up and Go, functional reach on the less affected side, 10-m usual and maximal walking speed tests, 1RM, and PPW than controls, with no differences detected between the yoga program and PWT. CONCLUSIONS Both the specially designed yoga program and PWT programs can significantly improve physical performance in older persons with PD.

Microsoft Kinect can distinguish differences in over-ground gait between older persons with and without Parkinson's disease

Gait patterns differ between healthy elders and those with Parkinsons disease (PD). A simple, low-cost clinical tool that can evaluate kinematic differences between these populations would be invaluable diagnostically; since gait analysis in a clinical setting is impractical due to cost and technical expertise. This study investigated the between group differences between the Kinect and a 3D movement analysis system (BTS) and reported validity and reliability of the Kinect v2 sensor for gait analysis. Nineteen subjects participated, eleven without (C) and eight with PD (PD). Outcome measures included spatiotemporal parameters and kinematics. Ankle range of motion for C was significantly less during ankle swing compared to PD (p=0.04) for the Kinect. Both systems showed significant differences for stride length (BTS (C 1.24±0.16, PD=1.01±0.17, p=0.009), Kinect (C=1.24±0.17, PD=1.00±0.18, p=0.009)), gait velocity (BTS (C=1.06±0.14, PD=0.83±0.15, p=0.01), Kinect (C=1.06±0.15, PD=0.83±0.16, p=0.01)), and swing velocity (BTS (C=2.50±0.27, PD=2.12±0.36, p=0.02), Kinect (C=2.32±0.25, PD=1.95±0.31, p=0.01)) between groups. Agreement (RangeICC =0.93-0.99) and consistency (RangeICC =0.94-0.99) were excellent between systems for stride length, stance duration, swing duration, gait velocity, and swing velocity. The Kinect v2 can was sensitive enough to detect between group differences and consistently produced results similar to the BTS system.

Validation of the Microsoft Kinect® camera system for measurement of lower extremity jump landing and squatting kinematics

Abstract Cost effective, quantifiable assessment of lower extremity movement represents potential improvement over standard tools for evaluation of injury risk. Ten healthy participants completed three trials of a drop jump, overhead squat, and single leg squat task. Peak hip and knee kinematics were assessed using an 8 camera BTS Smart 7000DX motion analysis system and the Microsoft Kinect® camera system. The agreement and consistency between both uncorrected and correct Kinect kinematic variables and the BTS camera system were assessed using interclass correlations coefficients. Peak sagittal plane kinematics measured using the Microsoft Kinect® camera system explained a significant amount of variance [Rangehip = 43.5–62.8%; Rangeknee = 67.5–89.6%] in peak kinematics measured using the BTS camera system. Across tasks, peak knee flexion angle and peak hip flexion were found to be consistent and in agreement when the Microsoft Kinect® camera system was directly compared to the BTS camera system but these values were improved following application of a corrective factor. The Microsoft Kinect® may not be an appropriate surrogate for traditional motion analysis technology, but it may have potential applications as a real-time feedback tool in pathological or high injury risk populations.

Development and Validation of a Three-Dimensional Biomechanical Model of the Lower Extremity

One of the important applications of the computer modelling of human body is the area of joint replacement where a validated model can be used for surgery planning. It is known that the evolution of total knee and total hip replacement has been influenced to a great extent by the knowledge obtained from gait analysis studies (Andriacchi and Hurwitz, 1997). Many of the mechanical problems associated with these devices have been evaluated in terms of the mechanics of walking where the magnitude and pattern of the forces at the hip and knee joints obtained from gait analysis studies have been used as design criteria of both total hip and total knee replacements. Gait analysis provides a unique opportunity to obtain objective information that cannot be obtained through other clinical means (Andriacchi and Hurwitz, 1997). For instance, several investigators have advocated the use of gait analysis for planning surgery and therapy treatments for children with cerebral palsy (Lofterod, et al., 2007; Kay, et al., 2000; Molenaers, et al., 2006). Improvement in gait after multi-level surgery using kinematic data has been documented, while kinematics provides information on dynamic joint motion kinetics is essential for differentiating between primary deformities and secondary responses. The potential benefits of gait analysis are improved treatment decision making, so that surgery and other treatments result in improved walking capability. Also, the information generated from the gait analysis of patients with total joint replacements has been utilized as a tool for assessing recovery following these procedures, where the key to the analysis of functionality following joint replacement is the ability to identify the adaptations corresponding to the joint design features. It is very difficult to determine muscle force/power output from multiple muscles simultaneously without affecting the pattern of normal movements (Naganoa, et al., 2005). Fortunately, computer modeling can provide useful insights for human biomechanics. Most in-vivo experiments only reveal the forces in the joint and not the surrounding muscle forces or their point of application. It is also known that finding the internal forces in the body by in-vivo experiments alone is difficult and sometime impossible. Because of the inherited redundancy in the musculoskeletal system (Crowninshield and Brand, 1981b) a desired motion can be achieved by an infinite

Conversion of Fused Hip to Total Hip Arthroplasty With Presurgical and Postsurgical Gait Studies

This case study presents a subject with a fused hip converted to total hip arthroplasty. Kinematic gait analysis was conducted on 3 occasions, presurgery, 4 months postsurgery, and 2.5 years postsurgery. Presurgery data showed decreased cadence and shorter step length; sound limb possessed increased hip, knee range of motion (ROM), and increased knee flexion during stance; the affected limb had minimal hip motion and normal knee ROM with abnormal pattern. At 4 months postsurgery, the sound limb showed decreased step length, whereas the affected limb showed increased knee extension during stance and increased hip ROM. Data obtained at 2.5 years postsurgery indicated decreased cadence and speed and increased ROM in both limbs. The total hip arthroplasty had provided relief of chronic back and affected hip pain and improved mobility. Gait-specific training is recommended.

Kinect-based assessment of lower limb kinematics and dynamic postural control during the star excursion balance test

Assessments using dynamic postural control tests, like the Star Excursion Balance Test (SEBT), in combination with three-dimensional (3D) motion analysis can yield critical information regarding a subjects lower limb movement patterns. 3D analysis can provide a clear understanding of the mechanisms that lead to specific outcome measures on the SEBT. Currently, the only technology for 3D motion analysis during such tests is expensive marker-based motion analysis systems, which are impractical for use in clinical settings. In this study we validated the use of the Microsoft Kinect as a cost-effective and marker-less alternative to more complex and expensive gold-standard motion analysis systems. Ten healthy subjects performed the SEBT while their lower limb kinematics were measured concurrently using a traditional motion capture system and a single Kinect v2 sensor. Analyses revealed errors in lower limb kinematics of less than 5°, except for the knee frontal-plane angle (5.7°) in the posterior-lateral direction. Ensemble curve analyses supported these findings, showing minimal between-system differences in all directions. Additionally, we found that the Kinect displayed excellent agreement (ICC3,k=0.99) and consistency (ICC2,k=0.99) when assessing reach distances in all directions. These results indicate that this low-cost and easy to implement technology may provide to clinicians a simple tool to simultaneously assess reach distances while developing a clearer understanding of the lower extremity movement patterns associated with SEBT performance in healthy and injured populations.

Examination of a lumbar spine biomechanical model for assessing axial compression, shear, and bending moment using selected Olympic lifts.

BACKGROUND/AIMS Loading during concurrent bending and compression associated with deadlift, hang clean and hang snatch lifts carries the potential for injury to the intervertebral discs, muscles and ligaments. This study examined the capacity of a newly developed spinal model to compute shear and compressive forces, and bending moments in lumbar spine for each lift. METHODS Five male subjects participated in the study. The spine was modeled as a chain of rigid bodies (vertebrae) connected via the intervertebral discs. Each vertebral reference frame was centered in the center of mass of the vertebral body, and its principal directions were axial, anterior-posterior, and medial-lateral. RESULTS The results demonstrated the capacity of this spinal model to assess forces and bending moments at and about the lumbar vertebrae by showing the variations among these variables with different lifting techniques. CONCLUSION These results show the models potential as a diagnostic tool.

Using vicon bodybuilder and plug-in-gait to generate L5/S1 angles, forces and moments

Currently the most widely used and accepted Vicon model is the Plug-in-Gait (PIG). Unfortunately, the PIG output value for the lumbar section only provides the angle difference between the thorax and the pelvis. Because the PIG is so widely used by advanced biomechanical analysts for defining body segment kinematics for aerospace and other industries, it would be a great advantage to be able to enhance the fidelity of the PIG model outputs by attaching body regions, such as spinal sections. Thus, the work explained in this paper describes how a virtual lumbar segment which generates model angle output values for the L5/S1 can be easily added to the PIG body segment definition, using the BodyBuilder (BB) for Biomechanics programming language. The methodology described in this paper utilizes the original PIG marker set and does not require any additional markers. Furthermore, the same method and model can provide L5/S1 forces and moments.

Prediction of ground reaction forces for Parkinson's disease patients using a kinect-driven musculoskeletal gait analysis model

Kinetic gait abnormalities result in reduced mobility among individuals with Parkinsons disease (PD). Currently, the assessment of gait kinetics can only be achieved using costly force plates, which makes it difficult to implement in most clinical settings. The Microsoft Kinect v2 has been shown to be a feasible clinic-based alternative to more sophisticated three-dimensional motion analysis systems in producing acceptable spatiotemporal and kinematic gait parameters. In this study, we aimed to validate a Kinect-driven musculoskeletal model using the AnyBody modeling system to predict three-dimensional ground reaction forces (GRFs) during gait in patients with PD. Nine patients with PD performed over-ground walking trials as their kinematics and ground reaction forces were measured using a Kinect v2 and force plates, respectively. Kinect v2 model-based and force-plate measured peak vertical and horizontal ground reaction forces and impulses produced during the braking and propulsive phases of the gait cycle were compared. Additionally, comparison of ensemble curves and associated 90% confidence intervals (CI90) of the three-dimensional GRFs were constructed to investigate if the Kinect sensor could provide consistent and accurate GRF predictions throughout the gait cycle. Results showed that the Kinect v2 sensor has the potential to be an effective clinical assessment tool for predicting GRFs produced during gait for patients with PD. However, the observed findings should be replicated and model reliability established prior to integration into the clinical setting.

Impact of quadriceps strengthening on response to fatiguing exercise following ACL reconstruction

OBJECTIVES Patients commonly experience altered response to fatiguing exercise after ACL reconstruction (ACLR). The objective of this study was to assess the impact of quadriceps strengthening on response to exercise after ACLR. DESIGN Clinical trial. METHODS Ten participants with a history of primary, unilateral ACLR (sex=9F/1M, age=21.0±2.8 years, BMI=23.7±2.7kg/m2) and 10 healthy participants (sex=9F/1M, age=22.2±3.2 years, BMI=23.8±3.9kg/m2) participated. ACLR participants completed a 2-week quadriceps strengthening intervention including 14 progressive strengthening exercise sessions. Normalized knee extension maximum voluntary isometric contraction (MVIC) torque (Nm/kg) and quadriceps central activation ratio (%, CAR) were measured before and after a 30-minute fatiguing exercise protocol. ACLR participants completed testing before and after the 2-week intervention while control participants completed a single testing session. RESULTS The intervention significantly improved normalized knee extension MVIC torque (pre-intervention=1.85±0.67Nm/kg, post-intervention=2.09±0.81Nm/kg, p=0.04) and quadriceps CAR in the ACLR involved limb (pre-intervention=86.51±5.03%, post-intervention=92.94±5.99%, p=0.02). Quadriceps CAR (pre-intervention=1.13±9.04%, post-intervention=-3.97±4.59%, p=0.16) and normalized knee extension MVIC torque (pre-intervention=0.26±20.90%, post-intervention=-8.02±12.82%, p=0.30) response to exercise did not significantly change from pre-intervention to post-intervention conditions. CONCLUSIONS Two weeks of quadriceps strengthening reduced this between group difference in the involved limb which may indicate restoration of more optimal quadriceps neuromuscular function and increased demand on the quadriceps during physical activity.