Kinematic and kinetic analysis of push-up exercise.
ABSTRACT The purpose of this study was to experimentally measure and analytically determine the load across the wrist, elbow, and shoulder joints during push-ups to better understand the nature of this exercise. A piezoelectric force platform was used to measure the vertical and two shear forces as well as the moment and the location of the center of pressure on the hand during a push-up. The electromagnetic tracking system was utilized to associate the force and moment measurement on the hand to the joints of the upper limbs. Factors which affect the intersegmental loads on the joints during push-ups include the location of the palm relative to the shoulder joint, the plane of arm movement, and the relative foot positions. In addition, the speed of push-ups also affects the amount of inertial load on top of the base static load.
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ABSTRACT: Study Design Randomized controlled trial with immediate follow-up. Objective To evaluate the immediate effects of a low-amplitude high-velocity (thrust) thoracic spine manipulation (TSM) on pain and scapular kinematics during elevation and lowering of the arm in individuals with shoulder impingement syndrome (SIS). The secondary objective was to evaluate the immediate effects of TSM on scapular kinematics during elevation and lowering of the arm in individuals without symptoms. Background Considering the regional interdependence among shoulder, thoracic, and cervical spine, TSM may be effective to improving pain and function in individuals with SIS. Comparison with individuals without shoulder pathology would provide information on the effects being specific to those with SIS. Methods Fifty subjects (mean ± SD: 31.8 ± 10.9 years old) with SIS and 47 subjects (25.8 ± 5.0 years old) asymptomatic for shoulder dysfunction were randomly assigned to 1 of 2 interventions: manipulation or sham. Scapular kinematics was analyzed during elevation and lowering of the arm in the sagittal plane and a numeric pain rating scale was used to assess shoulder pain during arm movement at pre- and post-intervention. Results For those in the SIS group, shoulder pain was reduced immediately after TSM and sham intervention (mean ± SD, 2.9 ± 2.5 pre-intervention; 2.3 ± 2.5 post-intervention; P<.01; moderate effect size; d-Cohen=0.2). Scapular internal rotation increased 0.5 ± 0.02 degrees (P=.04; small effect size; d-Cohen<0.1) during elevation of the arm after TSM and sham intervention in the SIS group only. Subjects with and without SIS who received TSM and asymptomatic subjects who received sham intervention had a significant increase (1.6 ± 2.7 degrees) in scapular upward rotation post-intervention (P<.05; small size effect; d-Cohen<0.2) which was not considered clinically significant. Scapular anterior tilt increased (1.0 ± 4.8 degrees) during elevation and lowering of the arm post-manipulation (P<0.05; small effect size; d-Cohen<0.2) in the asymptomatic subjects who received TSM. Conclusion Shoulder pain in individuals with SIS immediately decreased after a TSM. The observed changes in scapular kinematics following TSM were not considered clinically important. Level of Evidence Therapy, level 4. J Orthop Sports Phys Ther, Epub 22 May 2014. doi:10.2519/jospt.2014.4760.Journal of Orthopaedic and Sports Physical Therapy 05/2014; · 2.95 Impact Factor
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ABSTRACT: The upper trapezius (UT) has been widely studied and related to alterations in clavicular kinematics in subject with shoulder disorders. However, the most common electrode site used to capture UT EMG is between C7 and the acromion, placing the electrodes over the acromial fibers rather than clavicular ones. Therefore, this study aimed to investigate the relationship between clavicular movements (elevation and retraction) and UT EMG recorded from three electrode sites (traditional electrode positioning and two different sites proposed for clavicular fibers evaluation). Furthermore, the position associated with the highest EMG during maximal isometric voluntary contractions (MVIC), for each electrode site, was determined for normalization purposes. EMG was simultaneously captured in the three electrode sites of 20 healthy subjects, during MVIC at five different positions and during shoulder elevation and abduction in scapular plane. Clavicular kinematics was recorded using an electromagnetic tracking system during the dynamic contractions. Shoulder abduction with head rotation and lateral flexion elicited the highest EMG amplitude on the three electrode sites and was used to normalize the signals. A cross-correlation analysis showed high correlations between all electrode sites and clavicular movements. However, the traditional electrode site seems to record more informative signals in healthy subjects.Journal of Electromyography and Kinesiology 07/2014; · 1.64 Impact Factor