Browsing by Subject "Rehabilitation science"
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Item Comparison of 3D shoulder kinematics, thoracic posture and shoulder strength between asymptomatic elderly and young population(2014-08) Sarkar, SanjayThe elderly population are at risk of having shoulder pain and dysfunction. One possible contributor to shoulder impairment is abnormal scapulothoracic and glenohumeral motion. Comparing the elderly and young age groups based on changes in kinematics and thoracic posture during completion of day-to-day functional tasks is not well understood. The purpose of this study was to compare three-dimensional shoulder kinematics, thoracic posture and shoulder strength between asymptomatic elderly and young individuals. Subjects included 50 asymptomatic right dominant, gender and BMI matched individuals equally divided into young (20 to 40 years) and elderly (above 65 years) groups. A 3D electromagnetic motion capture system was used to record scapulothoracic and glenohumeral angular positions during scapular plane abduction, forward reach, reaching the back, reaching the wallet and touching the head tasks. Kinematics were computed at 25%, 50%, 75% and 100% of the humeral angular motions. A 3D CT based reconstructed anatomical model was animated based on group mean motion data to compute the minimum linear distance from rotator cuff footprints to potential impinging structures. Thoracic posture in static and dynamic conditions was measured for flexion-extension. Isometric shoulder strength was measured in four directions with a portable dynamometer and strength ratios were computed. Significant kinematic differences between groups were present for humerothoracic elevation range of motion, scapular internal rotation during scapular plane abduction, scapular upward rotation during forward reach, glenohumeral external rotation during forward reach, scapular internal rotation during reaching the back, scapular posterior tilt during reaching the back and scapular internal rotation during reaching the wallet. The mean differences between groups were less than 8° with the exception of glenohumeral external rotation (<19°) during the forward reach task. Overall, relative to the number of comparisons, few group differences existed for the tested conditions and those that were different had small magnitude. It was believed that these differences represent natural consequences of aging even in the absence of shoulder pain or dysfunction. Minimum linear distance was reduced in the elderly for forward reach and reaching the wallet tasks. It was believed, however, that position was the issue during reaching the wallet task since both groups had submillimeter minimum distances for that task. Significant dynamic thoracic flexion-extension differences between groups existed for reaching the back and reaching the wallet tasks. However, the magnitudes of the differences between groups were less than 2°, so it was thought that these differences were not clinically meaningful. Significant reduction in shoulder strength for the elderly group was evident in flexion, abduction, external rotation and internal rotation directions, but strength ratios were similar for both the groups. Based on the findings it was assumed that forward reach and possibly reaching the wallet tasks may benefit from further investigation due to the possibility of higher potential for rotator cuff compression in the elderly group. Maintaining strength ratios may be protective for developing rotator cuff disease. Modification of the forward reaching and reaching the wallet tasks may be considered while planning shoulder intervention strategies for the elderly.Item Hand force profiles of women with hand osteoarthritis during sealed jar opening(2014-10) McGee, Corey WestonPurposes: Joint protection strategies are often recommended for individuals with hand arthritis. However, there is little research regarding their effectiveness or on the use of measures in evaluating the effects of joint protection strategies. The purposes of this study were to 1) evaluate the effects of the type of grasp, the hand grasping the lid, and the use of non-skid material on the hand forces acting upon a jar lid when breaking a jar's seal, 2) examine the hand forces requirements when opening a sealed jar and 3) investigate relationships between several measures of hand function and the actual hand forces used during the everyday task of opening a sealed jar in order to validate their use in measuring the effectiveness of joint protection strategies such as using a counterforce such as a table or opposing extremity and using a nonskid material.Methods: A novel jar device created by McGee, Nuckley, and Mathiowetz was used to gather measurements of grip force, compressive force down through the lid's axis of rotation (Fz) and compressive force perpendicular to the side of the lid (Fx/Fy) when attempting to open a `sealed jar'. The jar lid's torque requirement was set to 4.24 N*m, a torque commonly imposed by the manufacturer when creating a seal on larger diameter jars. Thirty-one women with hand osteoarthritis were asked to complete 16 jar opening simulations by alternating three different factors: hand turning the jar lid, position (supinated/vertical and oblique/diagonal), and use of a non-skid material. After each jar turning simulation, participants were asked to report their perceived level of pain and exertion using the 0 to 10 scales of the NRS and Borg CR10, respectively. Additional measures of hand function were quantified to determine if and to what extent they predicted success and the capacity to generate forces when opening a sealed jar.Results: The impact of arthritis on our sample's function was modest (AIMS2-SF2 Total Health Score; x = 10.62) and the distribution of arthritis between hands was not dissimilar. Use of the supinated grasp required less force/time in Fx [F(1,419)=30.5, p<.0001], Fy [F(1,419)=34.5, p<.0001], and Fz than power grasp [F(1,419)=23.5, p<.0001]. Participants used less grip force to twist the lid with their left hand than with their right hand [F(1,419)=21.7, p<.0001]. Participants also perceived their effort to be less when using their left hand, a supinated grasp, and non-skid material. Additionally, participants rated their pain as lower when using their left hand and when using a supinated grasp. Lastly, a left supinated grasp with a non-skid material was a significantly more successful strategy to open jars than was any other (χ2=9.4, p<.001). Across all approaches, participants who were successful used 149.2±6.2 N of grip force and 47.8±2.8 N of `compensatory' forces when opening the sealed jar. Perceived effort was a significant positive predictor of grip force across time and is a significant negative predictor of peak M(z). Palmar abduction of the stabilizing thumb was a significant positive predictor of torque and a negative predictor of grip forces. Total active motion of the stabilizing and turning thumbs was a positive predictor of grip force and an increase in pain from baseline was a significant negative predictor of grip force and a positive predictor of torque.Conclusions: The counterforce offered by the supinated `stabilizing' hand results in the use of fewer compensatory forces by the turning hand. The left hand requires less grip force to successfully open a sealed jar and pain as well as perceived effort were least among those who used a non-skid material when opening. This data supports that women with hand arthritis will know more success, perceive less pain and effort, use less grip force, and will more efficiently generate the forces required to break the seal of a large jar when using a left hand, supinated counterforce, and non-skid material. These findings validate the use of non-skid material to reduce hand forces with jar turning but only when combined with a supinated approach. Perceived effort, and a change in pain from baseline are strong predictors of the forces used during jar opening and thus should be considered when considering the effectiveness of joint protection strategies used by women with hand osteoarthritis when attempting to open sealed jars. Other measures of hand function were also predictive of the hand forces generated when opening a sealed jar and these factors should be considered during assessment and intervention planning.