Orthopaedic Basic Science Journal Scan

Correction of Joint Angles From Kinect for Balance Exercising and Assessment.

J Appl Biomech. 2013 Jul 22;

Authors: de Rosario H, Belda-Lois JM, Fos F, Medina E, Poveda-Puente R, Kroll M

Abstract
The new generation of videogame interfaces such as Microsoft's Kinect opens the possibility of implementing exercise programs for physical training, and of evaluating and reducing the risks of elderly people falling. However, applications such as these might require measurements of joint kinematics that are more robust and accurate than the standard output given by the available middleware. This paper presents a method based on particle filters for calculating joint angles from the positions of the anatomical points detected by PrimeSense's NITE software. The application of this method to the measurement of lower limb kinematics reduced the error by one order of magnitude, to less than 10º, except for hip axial rotation, and it was advantageous over inverse kinematic analysis, in ensuring a robust and smooth solution without singularities, when the limbs are out-stretched and anatomical landmarks are aligned.

PMID: 23877057 [PubMed - as supplied by publisher]

Read more... http://www.ncbi.nlm.nih.gov/pubmed/23877057?dopt=Abstract

Shoulder Kinematics is Not Influenced by External Load During Elevation in the Scapular Plane.

J Appl Biomech. 2013 Jul 20;

Authors: de Castro MP, Ribeiro DC, de Forte F, de Toledo JM, Aldabe D, Loss JF

Abstract
The present study aimed to compare the shoulder kinematics (3D scapular orientation, scapular angular displacement and scapulohumeral rhythm) of asymptomatic participants under unloaded and loaded conditions during unilateral shoulder elevation in the scapular plane. We utilized a repeated measures design with a convenience sample. Eleven male participants with an age range of 21 to 28 years with no recent history of shoulder injury participated in the study. The participants performed isometric shoulder elevation from a neutral position to approximately 150º of elevation in the scapular plane in intervals of ≈30º during unloaded and loaded conditions. Shoulder kinematic data were obtained with videogrammetry. During shoulder elevation, the scapula rotated upwardly and externally, and tilted posteriorly. The addition of an external load did not affect 3D scapular orientation, scapular angular displacement, or scapulohumeral rhythm throughout shoulder elevation (p>0.05). In clinical practice, clinicians should expect to observe upward and external rotation and posterior tilt of the scapula during their assessments of shoulder elevation. Such behavior was not influenced by an external load normalized to 5% of body weight when performed in an asymptomatic population.

PMID: 23877028 [PubMed - as supplied by publisher]

Read more... http://www.ncbi.nlm.nih.gov/pubmed/23877028?dopt=Abstract

The Influence of Different Force and Pressure Measuring Transducers on Lower Extremity Kinematics Measured During Running.

J Appl Biomech. 2013 Jul 22;

Authors: Sinclair J, Hobbs SJ, Taylor PJ, Currigan G, Greenhalgh A

Abstract
In running analyses where both kinetic and kinematic information is recorded, participants are required to make foot contact with a force and/or pressure measuring transducer. Problems arise if participants modify their gait patterns to ensure contact with the device. There is currently a paucity of research investigating the influence of different underfoot kinetic measuring devices on 3-D kinematics of running. Fifteen participants ran at 4.0 m·s-1 in four different conditions; over a floor embedded force plate, Footscan, Matscan and with no device. 3-D angular kinematic parameters were collected using an eight camera motion analysis system. Hip, knee and ankle joint kinematics were contrasted using repeated measures ANOVA's. Participants also rated their subjective comfort in striking each of the three force measuring devices. Significant differences from the uninhibited condition were observed using the Footscan and Matscan in all three planes of rotation, whilst participants subjectively rated the force plate significantly more comfortable than either the Footscan/Matscan devices. The findings of the current investigation therefore suggest that the disguised floor embedded force plate offers the most natural running condition. It is recommended that analyses using devices such as the Footscan/Matscan mats overlying the laboratory surface during running should be interpreted with caution.

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Biomechanical maturation of joint dynamics during early childhood: Updated conclusions.

J Biomech. 2013 Jul 19;

Authors: Samson W, Van Hamme A, Desroches G, Dohin B, Dumas R, Chèze L

Abstract