Research equipment and techniques
The Human Motion Lab is equipped with high-speed motion capture cameras, ultrasound imaging, and other devices used to precisely measure human motion and calculate how the tissues in the body are functioning to move the body during activities of daily living and athletics. We utilize a nail-first, hammer-second approach: first identifying the problem and then selecting the right tool for the job. Because of this philosophy, lab equipment may change to support clinically relevant research by making the right measurements with the right equipment.
The Human Motion Lab is equipped with a 12-camera motion analysis system that accurately track 3-dimensional locations of reflective markers to sub-millimeter accuracy at up to 500 samples per second. Although cameras only see in 2-dimensions (photo graphs lack depth), 2-dimensional images of the same object can be combined to create a 3-dimensional approximation of where the object actually is located. Motion capture uses this concept to achieve incredible feats and is the corner stone of labs studying human motion. While everything from movies and video games to cable news now use motion capture, labs studying human motion used these techniques before it was cool!
In addition to a high-speed 3-dimensional camera system, the Human Motion Lab utilizes three force platforms that are embedded in the lab floor to measure the interaction between study participants and the ground. Essentially, very expensive bathroom scales, these force platforms measure the interaction between the ground and the foot — called ground reaction forces — which are essential for calculating the loads generated by each joint in order for motion to occur.
Ultrasound imaging is a cost-effective and non-invasive tool that helps researchers study the interaction between soft tissue structure and function. Unlike other medical imaging techniques, portable ultrasound systems can be used in just about any setting to study tissue biomechanics. To this end, we can study larger patient populations to develop a better understanding of how certain musculoskeletal disorders affect tissue structure and function.
Instead of quantifying just the structure of specific parts of the body, we incorporate other research tools (like motion capture and dynamometry) to accurately measure how muscles and tendons work together to generate healthy motion and how injuries limit this normal function.
The Human Motion Lab has an isokinetic dynamometer — historically used for measuring the power generated by engines, the technology has been implemented in assessing joint strength and function in humans. This device can go through prescribed motions while measuring how hard patients press against the device to assess functional deficits brought on by injuries or improved function following an intervention.
The Human Motion Lab uses computational modeling to predict what is going on inside the body that cannot be directly measured. These models use tried-and-true techniques (established by Sir Isaac Newton) to approximate the loads that are being exerted by each joint to produce the measured motion. Some assumptions are then made to estimate how each muscle contributes to generate motion. These results can identify strategies used to compensate for pain during activities of daily living or determine if patients are safely loading their total joint replacement. More sophisticated computational models are at our disposal to investigate the effects of joint replacements on motion and loading.
Recent advances in low-cost sensors and electronics have opened new doors to expanding the analysis of human motion past the lab setting into the clinic and home. We are developing low-cost sensors to measure everything from knee motion when climbing stairs to thumb motion when opening a jar. These little devices may help change the landscape of clinical care by providing patients and clinicians with objective feedback regarding functional improvements during treatment and raise warning flags when certain benchmarks aren't been met.