CONTROL OF ERRORS USING A SIMPLIFIED CLINICAL SETUP FOR MOTION ANALYSIS: ERRORS DUE TO CALIBRATION AND THREE-DIMENSIONAL RECONSTRUCTION

2005 ◽  
Vol 05 (04) ◽  
pp. 491-505 ◽  
Author(s):  
ERIC BERTHONNAUD ◽  
JOANNÈS DIMNET

Different systems of motion analysis have been described. They usually associate several cameras with a force platform. They can analyze very sophisticated human movements. They are, however, expensive and require significant technical formation from users. A new system is proposed for simple and standard clinical applications. It uses only two cameras and a coupled force plate delivering only the vertical component of the patient weight and the location of his center of mass. It is inexpensive, simple to use and delivers accurate results. This is obtained through a strict experimental protocol, and a new method of data treatment which allows the control of errors at each step of the successive calculations. This paper describes the new system, the new calibration procedure and the control of errors.

Author(s):  
S. F. Almashqbeh

The kinematic and kinetic differences between two styles of stair climbing, namely regular stair climbing (RSC) and lateral stair climbing (LSC), was studied. A four-step wooden stair instrumented with two force plates was used as the action platform. The kinematic and kinetic recordings were collected using a 6-camera, 2-force plate commercial three-dimensional motion analysis system. The LSC activity was subdivided into LSCL activity, where the right leg was the leading leg, and LSCT.


2016 ◽  
Vol 28 (12) ◽  
pp. 1533-1552 ◽  
Author(s):  
Hadi Aryan ◽  
Mehdi Ghassemieh

Vertical component of seismic excitations tremendously affects the performance of bridges during the earthquakes. Several conducted studies identified the lack of engineering attention to the vertical seismic excitation as the main reason of various considerable bridge damages during the past earthquakes. Thus, in this article, an innovative system with superelastic properties is proposed for retrofitting and also new design of the bridges which can simultaneously mitigate the effects of vertical and horizontal seismic excitations. In order to investigate the efficiency of the new system, an evaluation is performed through many nonlinear time history analyses on a three-dimensional model of a detailed multi-span simply supported bridge using a suite of representative ground motions of the bridge region. The analyses are conducted separately on the pertinent issues that affect the performance of the new proposed system. As a part of the study, to identify the sensitivity of the new system and evaluate the overall seismic performance, several assessment parameters are utilized. The results show that the proposed system is efficient for reducing bridge responses as well as improving nonlinear performance of the columns during vertical and horizontal seismic excitations.


Scanning ◽  
2006 ◽  
Vol 22 (4) ◽  
pp. 249-257 ◽  
Author(s):  
David R. Soll ◽  
Edward Voss ◽  
Olof Johnson ◽  
Deborah Wessels

1987 ◽  
Vol 3 (3) ◽  
pp. 242-263 ◽  
Author(s):  
Richard N. Hinrichs

Ten male recreational runners were filmed using three-dimensional cinematography while running on a treadmill at 3.8 m/s, 4.5 m/s, and 5.4 m/s. A 14-segment mathematical model was used to examine the contributions of the arms to the total-body angular momentum about three orthogonal axes passing through the body center of mass. The results showed that while the body possessed varying amounts of angular momentum about all three coordinate axes, the arms made a meaningful contribution to only the vertical component (Hz). The arms were found to generate an alternating positive and negative Hzpattern during the running cycle. This tended to cancel out an opposite Hzpattern of the legs. The trunk was found to be an active participant in this balance of angular momentum, the upper trunk rotating back and forth with the arms and, to a lesser extent, the lower trunk with the legs. The result was a relatively small total-body Hzthroughout the running cycle. The inverse relationship between upper- and lower-body angular momentum suggests that the arms and upper trunk provide the majority of the angular impulse about the z axis needed to put the legs through their alternating strides in running.


2014 ◽  
Vol 40 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Bessem Mkaouer ◽  
Monèm Jemni ◽  
Samiha Amara ◽  
Helmi Chaabène ◽  
Johnny Padulo ◽  
...  

Abstract Arms swing during standing back somersaults relates to three different “gymnastics schools”, each is considered “optimal” by its adepts. In the three cases, technical performance, elevation and safety differ. Therefore, the aim of this study was to compare the mechanical variables of three different arms swing techniques in the performance of a standing back tucked somersault. Five high-level male gymnasts (age: 23.17±1.61 yrs; body height: 1.65±0.05 m; body mass: 56.80±7.66 kg) randomly performed standing somersaults under three conditions, each following a different arms’ swing technical angle (270°, 180° and 90°). A force plate synchronized with a three dimensional movement analysis system was used to collect kinetic and kinematic data. Significant differences were observed between somersaults’ performance. The back somersault performed with 270° arms swing showed the best vertical displacement (up to 13.73%), while the back somersaults performed with 180° arms swing showed a decrease in power (up to 22.20%). The back somersault with 90° arms swing showed the highest force (up to 19.46%). Considering that the higher elevation of the centre of mass during the flight phase would allow best performance and lower the risk of falls, this study demonstrated that optimal arms’ swing technique prior to back tucked somersault was 270°.


Sign in / Sign up

Export Citation Format

Share Document