Motion analysis laboratory

Introduction

Purpose of human motion analysis is to measure and model human movements during motor task. This information can be used to study for example athletics performance during sports or to look into forces applied in to knee joint in walking. Motion analysis can also be used as clinical tool in variety of different therapies, including estimating the proper surgical procedure in knee injuries, measuring the progress of rehabilitation after surgery, for planning suitable rehabilitation for stroke patients or diagnosing Alzheimer's disease. Motion analysis is used to give quantitative information about the mechanics of the musculo-skeletal system. Information is sought concerning the relative movement between adjacent boner or joint kinematics, the forces exchanged with the environment, loads transmitted across body segments. Motion analysis laboratory is designed for research and development environment for new motion analysis methods and applications. The laboratory equipment gives possibility to test new methods in controlled conditions.

Research in motion analysis laboratory. Measurements consist three parts: photogrammetric data, ground reactions forces and biosignal measurements. Laboratory provides facilities for measuring different types of signals simultaneously. With signal- and correlation analysis tools new methods are developed for motion analysis.

Laboratory

In clinical biomechanics research several different types of sensors are used to measure motion. Sensors give quantitative information about ground reaction forces, accelerations or joint movements and angles. In addition to mechanical measurements, valuable information can also be obtained from physiological signals. Measurements may include electromyography (EMG), which gives insight into muscle activation and fatigue. Overall body fatigue and load can be estimated from heart rate variability measured from electrocardiogram (EKG). Furthermore, central part of motion analysis is the photogrammetry based on high speed camera technology. Video imaging gives valuable information about body and limb movements during motor task. In motion analysis laboratory all these different measurements have to be t ime synchronised in order to achieve correct analysis of the motion.

In our motion analysis laboratory, measurements divide into three parts: video imaging by high speed cameras, force plates and portable biosignal logging system. All these systems can be used simultaneously with precise time synchronization, which gives us an excellent framework for research and development of new motion analysis methods and applications.

High speed camera system

Laboratory is equipped with two Photrhon Fastcam PCI 500 black and white, high speed cameras. Cameras use CCD technology and have 512x480 pixel resolution at speed of 250 frames per second. In speed of 500 frames per second cameras can provide frames with 512x240 pixel resolution.


Photrhon Fastcam PCI 500

Force plates and walkway

Gait and balance analysis requires information on ground reaction forces, which can be measured by force plates. Our laboratory is equipped with two AMTI OR6-7MA force plates mounted under 6 meter walkway. Force plates measure external forces and moments in three directions. Force plates are mounted on 30mm thick aluminium plate, which is bolted on the floor. The walkway was then built over the plates. Two photogates are installed over the walkway to measure the gait speed.



Biosignal and mobile measurements

Important part of motion measurements is to record different physiological and sensor signals. These signals can also be measured outside laboratory, which gives us possibility to develop new motion analysis methods based on wearable sensors and portable datalogging devices.

One of the widely used physiological signals in motion analysis is the surface electromyography (sEMG), which gives information on muscle activation times and levels, and muscle fatigue. By combining sEMG signal with other motion measurements it is possible to study which muscles participate into observed motion and how these muscles correlate to other measured parameters.

In these measurements we use portable datalogging device ME6000 by Mega Electronics Ltd. ME6000 is 16 channel portable device with WLAN connection for data transfer and it can be used to record variety of physiological signals, e.g., sEMG, EKG, or signals from different sensor, e.g., goniometers, accelerometers.


The Mega Electronics ME6000 datalogger

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