Three-Dimensional Interactions in a Two-Segment Kinetic Chain. Part I: General Model

Abstract

The motion of a body segment is determined by joint torques and by the motions of the segments proximal or distal to it. This paper describes a three-dimensional model that was used to determine the effects of the shoulder and elbow joint torques and of the upper trunk and arm motions on the angular accelerations of the arm segments during baseball pitching. Equations were developed to fractionate the three-dimensional components of the angular acceleration vector of each segment into angular acceleration terms associated with the joint torques made on the segment, and into various “motion-dependent” angular acceleration terms associated with the kinematic variables of the arm segments. Analysis of the values of the various motion-dependent angular acceleration terms permitted the determination of their contributions to the motion of the segment. Although the model was developed to provide further understanding of the mechanics of the throwing arm during baseball pitching, it can be used to analyze any two-segment two-dimensional or three-dimensional motion.

A new non-orthogonal decomposition method to determine effective torques for three-dimensional joint rotation

“…Although many studies in 3D kinetics have investigated the profiles of the resultant joint torque during walking and running (Aleshinsky and Zatsiorsky, 1978;Apkarian et al, 1989;Eng and Winter, 1995;Glitsch and Baumann, 1997;Kim and Eng, 2004) and sports movements such as throwing and kicking (Bahamonde and Knudson, 2003;Elliott et al, 2003;Feltner, 1989;Feltner andDapena, 1986, 1989;Fleisig et al, 1995Fleisig et al, , 1999Nunome et al, 2002), only a few studies have examined the interaction torque during 3D movements (Feltner and Dapena, 1989;Hong et al, 2001;Kadota et al, 2004). There are two differences between the interaction torque analysis method presented by the abovementioned authors and our method.…”

Contributions of the muscular torques and motion-dependent torques to generate rapid elbow extension during overhand baseball pitching

“…A previous study analysed motion-dependent angular acceleration of the throwing forearm [8]. Although their model decomposed the joint angular acceleration into the inertial angular acceleration-, velocity-, and linear acceleration-dependent components of the proximal and distal segments, the model was not able to quantify the elbow extension/flexion angular acceleration due to the multijoint actions of the throwing arm and trunk because the two-segment simple model was used.…”

“…Feltner and Dapena [8] analysed the motion-dependent interactions between the throwing upper arm and forearm in baseball pitching. That study showed that the rapid elbow extension that occurred before ball release was primarily generated by the upper arm motion-dependent torque (due primarily to the rotation of the trunk), and not by the elbow extensor torque.…”

Kinetic chain of overarm throwing in terms of joint rotations revealed by induced acceleration analysis

“…Although several researchers have tried to reveal its kinetic mechanism by using the equations of motion (Feltner, 1989;Feltner and Dapena, 1989;Hirashima et al, 2003Hirashima et al, , 2007bHong et al, 2001;Putnam, 1991Putnam, , 1993, no study has accurately assessed the effect of the velocity-dependent torque on the joint angular accelerations. These studies dealt with the equation of each segment separately, and considered that each joint angular acceleration can be explained by the joint torque, gravity torque, and interaction (motion-dependent) torque.…”