Much experimental research is undertaken in the field, but our research base is a modern 46m x 17m laboratory located at the RVC’s Hawkshead Campus in the Hertfordshire countryside. Our huge range of cutting edge equipment, much of which was innovated by our own team, was purchased through a BBSRC grant and other funding awards.
Our gait laboratory equipment includes forceplates, electromyography* (EMG), and high speed and motion capture camera systems. We have specialised facilities for assessing musculoskeletal function; while magnetic resonance imaging (MRI) and X-ray machines are used for our recent research specialisms: evolutionary biomechanics and muscle cell activity. Our team have used their technical expertise to pioneer a number of new and exciting technologies for the measurement and analysis of movement.
Motion Analysis Systems
Twelve Camera Qualisys Motion Capture System
Motion capture has a wide range of applications and can be conducted using a variety of animals. The process used to make CGI effects for blockbuster movies in Hollywood is also used in our lab to analyse animal locomotion. Twelve Qualisys motion capture cameras record the position of retro-reflective markers to within 1mm accuracy at up to 500 frames per second. This system is used both in isolation to assess gait patterns or lameness, and in conjunction with the Kistler force plates to record a thorough gait analysis and to calculate joint moments.
AOS High speed cameras
Our eight AOS high speed cameras are capable of recording video at 1000 frames per second,1280 x 1024 pixel resolution, and over a large distance using gigabit Ethernet connection. These cameras are particularly useful for recording detail during fast movements. They are used frequently in both the laboratory and the field to look at gait patterns, limb movement and strategies for locomoting over uneven terrain.
We have eight Kistler forceplates embedded into a 40 metre runway with rolling shutter doors at each end of the lab space, offering the opportunity to increase this space further if necessary. With the doors open it is possible to record impact forces in horses galloping through the laboratory at full speed.
The plates can also be rotated through 90 degrees to account for differences in stride length, or to increase the collection area up to 5.5m.
Kistler forceplates record the voltage of a piezoelectric crystal when deformed under loading. They are especially useful for measuring large forces of short duration such as foot falls in running or jumping.
These plates traditionally have top plates in the same substrate as the laboratory floor, and it is also possible to cover the top plates with different materials for specific projects or participant requirements - most commonly artificial turf, to facilitate high speed running in greyhounds.
The force plate array is operated using our custom built LabView forceplate script. From the PC we can select sampling frequency, duration, gain (amplification, used to alter sensitivity) and the number of forceplates to sample dependent upon the population. Measuring walking forces from a human will require a lower gain than a turkey, and to record the forces exerted when a horse hoof hits the ground at galloping speed will require a gain lower still.
We also have two smaller Kistler ‘squirrel’ plates. Each plate measures only 120 x 200 mm and has its own external charge amplifier making them ultraportable. These plates are useful for recording accurate kinetic data from smaller animals with smaller strides. Most recently these plates have been used for measuring forces exerted by quail in sit-stand transitions, climbing tree frogs and walking chickens.
AMTI plates use strain gauges to measure force and are better suited to measuring activities with a longer contact time, such as balance and change in centre of mass (CoM) position during stance, but can also measure ground reaction forces with reasonable accuracy. The strain gauge technology is more robust than the Kistler piezoelectric crystals and lends itself more favourably to field studies.The five AMTI plates have most recently been used in the field to measure forces on landing in horse racing.
Treadmills and other equipment
The Säto equine treadmill allows us to treadmill a variety of large animals up to around 1000Kg in weight. Its speed varies from 2 - 20m/s on the flat or uphill. We use this for clinical assessment of horses which are not achieving their athletic expectations and as a research tool. It is equipped with cooling fan and overhead hoist for the safety of all users.
Below illustrates a horse on our treadmill at different speeds: 1) gallop 2) canter
We have two human treadmills suitable for research projects with human participants and can be adapted if necessary for studies using smaller animals.
- The Powerjog GX100, a continuous rolling belt treadmill with speed range from 0-15mph and inclination from 0-25%
- A Woodway Mercury slatted belt system offering a speed range of 0-11mph and an incline range of 0-15%
Our Starker Hund SK03 Canine Treadmill is a continuous rolling-belt treadmill use for training, exercising and rehabilitating dogs of all sizes. Speed, inclination and duration can be individually assigned dependent upon performance demands.
The Kin Com 500-H isokinetic dynamometer provides the researcher with the ability to execute reliable and repeatable muscle testing on site, providing analysis in both concentric and eccentric spectrums, and in isokinetic, isometric, isotonic and passive states. The attachments and positioning of the seat allow for complete testing of both the upper and lower body in many different movements including flexion/extension, inversion/eversion and internal/external rotation. The machine also has a unique protocol mode to create customised programmes tailored for each project or patient’s needs.
Gait Analysis Facilities
A unique setup for objective gait analysis enables us to provide state-of-the-art objective gait analysis for your horse. Our purpose-built gait lab facilities comprise high-accuracy 3D cameras, multiple force platforms, pressure mats, standard and high speed video equipment and a dedicated equine treadmill. These facilities can be used for customised kinetic (force) and kinematic (movement) gait assessment for your horse.
The latest mobile gait analysis techniques based on novel movement sensors allow unobtrusive measurements during clinical lameness workups. These measurements can be easily augmented by detailed slow motion recordings of your horse in motion (e.g. in combination with corrective or remedial farriery).
An array of eight force platforms has been seamlessly integrated into the floor of the gait analysis lab. These measure the forces acting on each individual limb and reveal subtle gait asymmetries/abnormalities with high sensitivity.
Pressure sensitive mats can accompany force plate measurements when a more detailed view of the pressure distribution under the hoof is required.
A state-of-the art 12-camera 3D motion capture system provides high accuracy (<1mm error) movement information.We quantify basic (stride, stance and swing times) and advanced (movement amplitudes, joint angles etc) stride parameters to reveal gait asymmetries/abnormalities.
High speed (or ‘slow motion’) cameras – capturing images up to 40 times faster than standard video cameras – enable us to produce detailed visualizations of movement that are impossible to perceive with the naked eye. These recordings are particularly beneficial for assessing foot flight and placement and hence are often used in conjunction with corrective or remedial farriery.
Small and lightweight inertial sensors are the most current development in gait analysis as practical yet accurate tools for gait analysis under real-life conditions. Accurate information about horse movement (stride timing, movement amplitudes) can be acquired during clinical lameness exams and the wireless nature of the system allows the most flexible setup under different conditions – different surfaces, during lounging, before and after diagnostic analgesia (nerve blocks) and in the ridden horse.
Watch the following video for a brief tutorial on lameness recognition.
For inquiries about gait analysis please contact Dr. Thilo Pfau.
Instron Servo Hydraulic Materials Testing Machine
This is a computer controlled loading system that we use to carry out mechanical tests on samples of bone, tendon and muscle. It can apply a load of up to 10kN at cyclical frequencies of up to 50Hz.
We also have a portable hydraulic loading jig that is used for studies off site.
EMG, Radiotel, GPS
EMG and Radiotelemetric Devices
We use the MT8 Radio Telemetry EMG System.
This system has the capability of collecting up to 8 channels of EMG data using either surface or finewire EMG electrodes. The MT8 is ideal for field EMG research and has been used in both human and animal studies.
Motion Lab Systems EMG System
The Motion Lab Systems Hard Wire 10 Channel EMG System, although hard-wired, is extremely versatile and predominantly used simultaneously with the CODA motion analysis system. The light weight, but also hard wired, cable connecting the pre-amplified electrodes (either surface or fine wire) to the system provides very little restriction to movement.
This system, currently under development and refinement in the lab, is used to assess locomotion in the field.
Within the context of the horse, custom-built hoof mounted accelerometers have been validated in the lab as a means to accurately assess when the hoof is in contact with the ground (K. Knill et al, 2002).
A telemetry system is used to access the accelerometer data, therefore data can be collected during field exercise.
The Global Positioning System (GPS) has been validated as an accurate measure of speed over ground (T. Witte & A. Wilson, 2002) in field conditions. The advantage of this system is the relative size of the GPS system and its ability to continuously log current speed and position.
The technical team in the Structure and Motion group have been producing GPS loggers for use in several research projects tracking the movement of pigeons, sheep, and interactions within populations.
Students from a local secondary school came to visit the lab in Spring 2012. Dr Julia Myatt was on hand to speak to the students about her upcoming trip to Botswana, where she was to spend three months attaching GPS collars to wild dogs. The students analysed accelerometer data from the loggers on their hats to see how different movements affected the readings.
Research Aircraft G-SMLI
Why have your own plane for research?
Isn't that hugely expensive? Well, not as much as you might think. It has been funded through research grants to enable us to undertake research into animal locomotion that would not otherwise be possible. We can collect all sorts of data from the air that would not be possible from the ground. As well as helping us to understand more about their behaviour and locomotion, the aerial data will reveal new insights into how animals interact with the natural environment, which will help conservation and land management. And it is a very small plane!
What kind of work is it used for?
The plane is used for studying large African carnivores and their prey in the savannah of northern Botswana. We have developed new ways of recording the detailed movements of these animals without disturbing them using our wildlife tracking collars. From the air, we can film hunts using high speed video cameras which 'lock on' to the collars, thus capturing in detail the manoeuvring of the hunt that would be impossible using a hand held camera or from the ground. Find out more about the LOCATE project.
We can also pick up biomechanics data from the collars by flying within 200-300 metres, which means we don't have to go near the animals on the ground - benefits all round in terms of us not disturbing them and the time we save by not having to drive all over the savannah to get close enough to pick up the collar data.
The plane will carry a LIDAR system. This creates a detailed scan map of the ground, showing the vegetation, areas of water, tracks on the ground, and terrain features such as dips and hollows, termite mounds and mud flats. All of these features contribute to how the animals interact with their environment and are important in understanding their behaviour.
Developing the aircraft and its technologies
The aircraft is a Groppo Trail, bought as a kit and built by us specifically for our research.
We considered a range of aircraft and gyrocopters before deciding on the Trail for several reasons:
- Small low running cost aircraft of conventional design. The tandem arrangement and high wing allow good visibility of the ground, the benign handling and low stall speed is ideal for wildlife tracking.
- Folding wings make it easy to store, trailer and ship in a 20 foot shipping container to Botswana and back.
- Conventional design means that the aircraft is easily modified to equip with camera equipment and aerial LiDAR.
- Graham Smith, the supplier, has an excellent reputation for supporting self-builders. He is a very experienced aircraft builder and pilot.
Why build when you can buy?
The primary reason for building our own aircraft rather than buying one concerns the myriad of national and international regulations applying to commercially-manufactured aircraft. Virtually all such aircraft operate on a full “Certificate of Airworthiness”, and all of the extensive modifications required to make the aircraft suitable for our resarch would have to be analysed and cleared directly by the Civil Aviation Authority, exactly as they would be for an airliner such as the Dreamliner. The cost of this would be prohibitive, and would be on top of the already higher cost of buying a factory-built aircraft. It would also be more difficult to retro-fit our modifications and equipment to an already finished “factory” aircraft.
By building a kit plane ourselves, we could build in much of the supporting infrastructure for our equipment (such wiring and operator displays, etc) during construction. But most significantly, different regulations apply for “home-built” aircraft, allowing the modifications to be analysed and cleared by the Light Aircraft Association, an independent not-for-profit body, at very significant cost saving.
Another major advantage was that we could choose, from the huge range of kit aircraft available, an aircraft type that was extremely well suited to the operating environment and type of flying we envisaged, rather than being restricted to the more limited range of commercial types available.
Fluid Flow Systems
The Structure and Motion Lab is home to both water and wind tunnels. These are designed to reveal how fluids move around biological systems, from frogs swimming to insects in flight.
Our wind tunnels were both purpose built in the lab by Postdoctoral researcher Dr Nathan Phillips. With two tunnels, varying in size to enable analysis of small insects through to larger flying animals, the lab now has one of the county's few dedicated wind tunnel flight research facilities. A combination of smoke passing through the tunnels and high speed cameras catch the fluid flow patterns generated by the animals.
These facilities can be dismantled and rebuilt, and have been used throughout the UK and Europe for industrial and commercial collaboration.
The muscle mechanics lab equipped for the studies of muscle contraction both in vitro and S, with three Aurora muscle motors controlled though Keithley Instruments A/D boards run by Test point software.
This lab also has state of the art equipment for measuring heat production of a single muscle fibre during contraction, using an Aurora muscle motor and a colorimeter designed and build in house by Professor Roger Woledge.
The Structure & Motion Laboratory and Clinical Services forge provides a facility for construction of custom designed horseshoes used during biomechanical assessments of equine shoeing and lameness studies. It is also used to train veterinary students in basic farriery techniques. The forge and farriery service is led by two RVC staff who are members of the Worshipful Company of Farriers, Mr Peter Day DipWCF and Dr Chris Pardoe BSc PhD AWCF.
Imaging equipment and tools
The Structure & Motion Laboratory is located on the same site as the UK's largest Emergency and Critical Care Unit for animals, allowing access to advanced imaging equipment.
Ultrasound, x-ray, CT and MRI are all available on site, with the Structure & Motion Laboratory also housing one of the UK’s only cine-x-ray facilities. This system allows us to capture high speed (500Hz) x-ray information for up to 16 seconds at a time. It is invaluable in quantifying bone and hard tissue movement and assessing performance in locomoting animals. The system has two 38cm diameter x-ray image intensifiers and allows up to 16 seconds of high speed acquisition.
Dr Renate Weller holds postgraduate qualifications in imaging and has extensive experience in the use of such equipment.
We have operators using a variety of platforms, the majority of the team using Windows or Mac, with a small number also working frequently in open source systems.
Many users are proficient in Labview and/or Matlab and these packages are used extensively within the department for data collection and processing. The forceplates are operated exclusively using a custom built Labview script.
The unique and varied nature of the research undertaken in the Structure & Motion Laboratory is reflected in the number of software packages available.
- SIMM (musculoskeletal modelling)
- Abaqus Simulia (finite element analysis)
- Adobe Creative Suite
- Qualisys QTM
- AOS imaging Suite
and many more.
XROMM (X-ray Reconstruction of Moving Morphology)
Measuring how the skeleton moves in animals is done using an advanced technique called XROMM; or biplanar fluoroscopy. It is like using “X-ray video cameras”.
XROMM gives precise measurements of skeletal positions and motions and has revolutionized the study of animal biomechanics and behaviour, especially recently with advances in computational measurements as well as 3D imaging and animation.
The principle of XROMM is similar to getting an X-ray of a broken bone at the hospital, but XROMM uses a rapid succession of x-ray ‘photos’ to create a high-speed video of the skeleton in motion. By using two high-speed x-ray video cameras (fluoroscopes) at the same time from two different sides, we can measure the positions of the bones in a 3D space. We then combine our measurements of bone positions with a 3D scan of the skeleton, and animate the skeleton to match the bone motions.
The combination of all these measurements allows us to learn precisely what the skeleton is doing in 3D space, at high recording speed and resolution, during any behaviours.
The accuracy of this method tends to be 1-2 orders of magnitude better (<0.1mm accuracy) than motion capture, calculating rigorous 3D joint axes and motions. This is an enormously important reason why this method is favoured over motion capture or other externally-measured methods of motion analysis. By giving the best possible measurements of skeletal motions, all other calculations (e.g. in computer models) can be of the highest possible precision.
XROMM is a vital technique used in the DAWNDINOS ERC funded research, led by Professor John Hutchinson, to test the “locomotor superiority hypothesis for early dinosaurs.”
XROMM data analysis follows protocols established in our lab and by the Brown University-based XROMM Research Coordination Network. It involves short-duration, relatively low-intensity exposure to X-ray radiation. For more information, see www.xromm.org.
Purchase of our four fluoroscopes (two C-arm units for measuring smaller animals in varied views; two custom vertically-mounted units for measuring larger animals in side/front view) has been funded by the BBSRC and ERC. Our C-arm fluoroscopes are connected to Photron FASTCAM Mini WX50 high-speed cameras and we appreciate their generous support.