MULTI-SEGMENT CONTRIBUTIONS TO INDUCED BALL VELOCITY IN COLLEGIATE BASEBALL PITCHERS

The purpose of this study was to implement an induced acceleration analysis (IAA) to estimate the contributions of multi-segment motion to the forward velocity of the ball in collegiate baseball pitchers. Marker-based motion capture and ground reaction force data were collected from a sample of 17 pitchers throwing off an instrumented mound. Kinematic and kinetic data were extracted to drive the IAA model to calculate the muscular and non-muscular contributions to ball velocity. The shoulder joint torque and velocity-dependent torque collectively made up the largest contribution to the total induced velocity of the ball at 61% and 37%, respectively. The model underestimated ball speed by 16%, owing to limitations in distal segment definitions. Although this IAA showed that the proximal segments make a small, direct contribution to forward ball velocity, decomposition of the velocity-dependent torque could further clarify the extent to which the legs, pelvis, and trunk indirectly contributes to ball velocity

A rehabilitation program for lung cancer patients during postthoracotomy chemotherapy

Objective: The objective of this pilot study was to describe the effects of a 16-week home-based rehabilitative exercise program on cancer-related fatigue (CRF), other symptoms, functional status, and quality of life (QOL) for patients with non-small cell lung cancer (NSCLC) after thoracotomy starting within days after hospital discharge and continuing through the initiation and completion of chemotherapy. Materials and methods: Five patients with NSCLC completed the Brief Fatigue Inventory (measuring CRF severity) and the MD Anderson Symptom Inventory (measuring symptom severity) before and after thoractomy, and at the end of each week of the 16-week exercise program. Additionally, the Medical Outcomes Study Short Form-36 (measuring physical and mental functional status) and the Quality of Life Index (measuring QOL) were completed before and after thoracotomy, after weeks 3, 6, 12, and 16 (the end of the exercise program). Further, the 6-minute walk test (measuring functional capacity) was administered before thoracotomy, prior to the initiation of chemotherapy and/or radiation therapy, and at the end of the 16-week exercise program, after completion of chemotherapy. Results: Participants had a mean age of 63 years and a mean of five comorbid conditions; the exercise program was initiated within 4 days after hospital discharge. Participants\u27 CRF severity scores were reduced to mild levels, while the mean number of symptoms decreased from 9 postthoracotomy to 6 after the exercise program, with mean levels of severity and interference decreasing to below prethoracotomy levels. Likewise, participants\u27 functional status and QOL after completing the exercise program improved to near or above prethoracotomy levels. Conclusion: The home-based, light-intensity exercise program for NSCLC patients receiving and completing adjuvant chemotherapy postthoracotomy showed promising trends in improving CRF severity, other symptom severity, functional status, and QOL. Further testing via a two-arm randomized controlled trial is being conducted

EMG Activation of the Vastus Medialis Oblique and Vastus Lateralis During Four Rehabilitative Exercises

The purpose of this study was to compare four common rehabilitation exercises used in physical therapy clinics for activating the vastus medialis oblique (VMO) and vastus lateralis (VL). Thirty-four subjects, aged 22-28 years, without patellofemoral pain syndrome (PFPS) (18 females and 16 males) were recruited. Subjects performed four exercises—straight leg raise with neutral and externally rotated hip positions (SLRN, SLRER), and short arc quad with neutral and externally rotated hip positions (SAQN, SAQER). The integrated electromyographic (iEMG) activity of the VMO and VL and were recorded, with means of the VMO, VL and VMO/VL compared across exercises. No significant difference was found for the VMO/VL ratio across the four exercises (p=0.147). However, for the VMO and VL individually, a significant difference was found (p=0.0001), SAQER was significantly greater than SLRN and SLRER; SAQN was significantly greater than SLRN and SLRER. These findings suggest that exercises including short arc quad knee extensions are more effective for both the VMO and VL activation than those incorporating straight leg raises, and potentially more beneficial in the rehabilitation of patients with PFPS

Approximate Entropy and Velocity of Center of Pressure to Determine Postural Stability: A Pilot Study

The body’s postural control system is responsible for responding to perturbations of balance and keeping the body upright. During quiet standing, the center of pressure oscillates about the center of mass, counteracting imbalances. These oscillations can be analyzed to determine the degree of stability, which could be helpful in quantifying the effects of brain injuries. In this research, the center of pressure was recorded for stances with feet together and feet tandem, with eyes opened and eyes closed, in neurotypical participants. These signals were analyzed using indices of approximate entropy and velocity to determine how sensitive the measures were in tracking changes to stability levels. One-way ANOVA test results showed increased approximate entropy in anterior/posterior and medial/lateral directions (p = 1.21 × 10−11, 3 × 10−14) and increased velocity in both directions (p = 2.87 × 10−6, 4.87 × 10−7) during conditions with decreased stability. Dunnett’s post hoc testing indicated that approximate entropy was significantly greater in all the less stable feet tandem trials in comparison to the most stable eyes open, feet together condition with p p < 0.01 in nearly every participant

Surface Electromyographic (sEMG) Transduction of Hand Joint Angles for Human Interfacing Devices (HID)

PURPOSE: This study investigates the use of surface electromyography (sEMG) as a tool to improve human interfacing devices (HID) information bandwidth through the transduction of the fingertip workspace. SUBJECTS: A Sollerman Hand Function Test (SHFT) sEMG dataset of twenty-two subjects performing 26 activities of living (ADL) is utilized, seven sEMG spots and Fingertip Joint Angles recorded in 18 degrees of freedom are observed for each subject. METHODS AND MATERIALS: Electrophysiology, physiology, and anatomy of the forearm and hand are investigated to optimize sensor location, and viable command gestures. Enveloping, spectral, and coherence analysis are applied to the SHFT dataset to differentiate pinching and grasping tasks. ANALYSES: Pinches and grasps were found to cause very different activation patterns in sEMG spot 3 relating to flexion of digits I - V. Spectral moment was less correlated with differentiation and provided information about the degree of object manipulation and extent of fatigue during tasks. Coherence increased between flexors and extensors with intensity of tasks but was found corrupted by crosstalk with increasing intensity of flexion. RESULTS: Viable gestures for detection algorithms are identified based on the muscles discerned to be visible in the dataset through intensity, spectral moment, power spectra, and coherence. The study also designed an sEMG amplification system capable of capturing HD-sEMG for future work. CONCLUSIONS: The study shows pinch and grasp differentiation through intensity envelopes of digit I-V flexors. Methods for further analysis of the SHFT dataset and design tools for a new dataset are provided

Three-Dimensional Kinematics and Kinetics of the Overhead Deep Squat in Healthy Adults: A Descriptive Study

The squat, a fundamental functional movement, is prone to biomechanical inefficiencies. Several screening batteries utilize the Overhead Deep Squat (OHDS) to assess individuals for stability and mobility deficits. The purpose of this study was to create a comprehensive description of the three-dimensional (3D) kinematics and kinetics for normal, healthy participants during an overhead deep squat. This descriptive study containing 70 healthy young adults (31 male, 39 female; aged 18–35) utilized a video motion tracking system interfaced with force plates to obtain full-body 3D kinematics and kinetics. Seventy-three retro-reflective markers from the combined Plug-in Gait, Vicon upper limb, and Oxford Multi-segment foot models were used. Visual 3D software was used to determine joint kinematics and kinetics. Means and standard deviations of lower limb and trunk segment joint angles in the sagittal, transverse, and horizontal planes, as well as the ground reaction forces and net internal joint moments, were computed. The largest movements and joint moments occurred in the sagittal plane; however, the frontal and transverse plane appear crucial to providing stability and mobility. These results can be used as pilot normative data for both future studies and during assessments of biomechanical abnormalities in training and rehabilitation settings

Dynamic Measures of Balance during a 90° Turn in Self-Selected Gait in Individuals with Mild Parkinson’s Disease

The risk of falls is common in the aging and Parkinson’s disease (PD) populations. There is limited research on dynamic gait stability, i.e., margin of stability (MOS), in the PD population while turning. The purpose of this exploratory study was to examine the dynamic balance control in individuals with mild to moderate PD and healthy individuals while walking and performing 90° turns utilizing computerized three-dimensional gait analysis. Specifically, we examined the anteroposterior and mediolateral margins of stability and their effect on the dynamic balance during turning in participants. A total of 11 individuals with mild to moderate idiopathic PD and 10 healthy controls (CON) participated in this study. Individuals with PD were tested during the “on phase” of PD medication. The Vicon Nexus camera system, force plates, and Visual3D software were utilized for three-dimensional motion analysis of three right and three left turning trials. A mixed-model ANOVA was used to analyze the primary dependent variables of dynamic balance (p p < 0.0056). No significant differences in the spatiotemporal parameters or dynamic balance variables were observed between the groups. Gait velocity, center of mass-center of pressure (COM–COP) inclination angle at midstance, and MOS variables showed marginally significant group differences. We found no differences in dynamic balance during gait while performing turns betweenthe healthy elderly and individuals with PD. This finding may be related to the early stage of disease progression in the PD group