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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- "For the scapula, the landmarks were the root of the spine of the scapula, the posterolateral angle of the acromion and the inferior angle of the scapula. Landmarks for the humerus were medial and lateral epicondyles and the center of the humeral head, estimated as the point that moved the least during midrange passive glenohumeral motion through short arcs (<45°) (An et al., 1990). Before movement data collection, EMG signal was recorded at rest during a 5-s trial, with the participants standing with the arms at the trunk side and head in neutral position. "
ABSTRACT: Scapular kinematics alterations have been found following muscle fatigue. Considering the importance of the lower trapezius in coordinated scapular movement, this study aimed to investigate the effects of elastic taping (Kinesio taping, KT) for muscle facilitation on scapular kinematics of healthy overhead athletes following muscle fatigue. Twenty-eight athletes were evaluated in a crossover, single-blind, randomized design, in three sessions: control (no taping), KT (KT with tension) and sham (KT without tension). Scapular tridimensional kinematics and EMG of clavicular and acromial portions of upper trapezius, lower trapezius and serratus anterior were evaluated during arm elevation and lowering, before and after a fatigue protocol involving repetitive throwing. Median power frequency decline of serratus anterior was significantly lower in KT session compared to sham, possibly indicating lower muscle fatigue. However, the effects of muscle fatigue on scapular kinematics were not altered by taping conditions. Although significant changes were found in scapular kinematics following muscle fatigue, they were small and not considered relevant. It was concluded that healthy overhead athletes seem to present an adaptive mechanism that avoids the disruption of scapular movement pattern following muscle fatigue. Therefore, these athletes do not benefit from the use of KT to assist scapular movement under the conditions tested. Copyright © 2015 Elsevier Ltd. All rights reserved.Journal of electromyography and kinesiology: official journal of the International Society of Electrophysiological Kinesiology 06/2015; DOI:10.1016/j.jelekin.2015.06.005 · 1.65 Impact Factor
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- "The humeral long axis was directed from the midpoint of the epicondyles to the center of the humeral head. The humeral head center was estimated using a pivot point method (An et al., 1990) Subjects were asked to perform two repetitions each for abduction in the scapular plane, forward flexion in the sagittal plane, abduction in the coronal plane, axial rotation with the elbow at the side and axial rotation with the elbow at 90° of abduction. The subjects were asked to raise and lower their arms over 6 seconds for the complete cycle, while guided by a flat plane surface (Figure 1). "
ABSTRACT: Conclusions about normal and pathologic shoulder motion are frequently made from studies using skin surface markers, yet accuracy of such sensors representing humeral motion is not well known. Nineteen subjects were investigated with flock of birds electromagnetic sensors attached to transcortical pins placed into the scapula and humerus, and a thermoplastic cuff secured on the arm. Subjects completed two repetitions of raising and lowering the arm in the sagittal, scapular and coronal planes, as well as shoulder internal and external rotation with the elbow at the side and abducted to 90°. Humeral motion was recorded simultaneously from surface and bone fixed sensors. The average magnitude of error was calculated for the surface and bone fixed measurements throughout the range of motion. ANOVA tested for differences across angles of elevation, raising and lowering, and differences in body mass index. For all five motions tested, the plane of elevation rotation average absolute error ranged from 0-2°, while the humeral elevation rotation average error ranged from 0-4°. The axial rotation average absolute error was much greater, ranging from 5° during elevation motions to approaching 30° at maximum excursion of internal/external rotation motions. Average absolute error was greater in subjects with body mass index greater than 25. Surface sensors are an accurate way of measuring humeral elevation rotations and plane of elevation rotations. Conversely, there is a large amount of average error for axial rotations when using a humeral cuff to measure glenohumeral internal/external rotation as the primary motion.Journal of Biomechanics 03/2012; 45(7):1161-8. DOI:10.1016/j.jbiomech.2012.02.003 · 2.75 Impact Factor
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- "C s and C h can be determined using Gausselimination . This method has been shown to be valid and accurate and has been used by several investigators (An, 1990; Harryman et al., 1990; Stokdijk et al., 2000; Veeger, 2000). "
ABSTRACT: Measure stiffness of the glenohumeral joint during clinical laxity testing with and without muscular contraction of the Internal rotators. Cross-sectional study of normal shoulders. Clinical examination for shoulder instability is based on subjective impression, and is only performed passively. Our study presents a method for quantitative clinical examination of the shoulder under both passive and active muscle contraction conditions. We hypothesized that in a normal shoulder, contraction of the internal rotators will increase the stiffness of the glenohumeral joint, effectively constraining the head of the humerus against anterior directed forces. Ten subjects were instrumented with electromagnetic sensors to record glenohumeral linear displacements. A mini-force transducer recorded forces applied to subjects during anterior drawer testing (forced anterior glenohumeral displacement), which was performed passively, and during isometric contraction of internal rotators. Only mild contraction of the internal rotators is needed to significantly increase the stiffness to anterior directed forces. Greater muscular activation does not result in further increased stiffness. Objective measurement of glenohumeral stiffness during passive and active muscular contraction may be useful for evaluating the capacity of rotator cuff muscles to stabilize the shoulder. The concept of more strength is better, for rotator cuff strengthen programs is questioned.Clinical Biomechanics 02/2004; 19(1):10-5. DOI:10.1016/j.clinbiomech.2003.09.011 · 1.97 Impact Factor