Data in Science and Medicine

Science figure

The benefits of better patient movement data for your clinic’s bottom line.

By Merci Greenaway, PT, & Henry Liu, MS, MBA

The fundamental principle that underlies the scientific method is the evaluation of hypotheses through the collection and analysis of data to shape our understanding of the world.

As a result, the importance of collecting and actually using data is ingrained in the scientific and medical world. Heart rate and blood pressure measurements form the baseline of cardiovascular health examinations. Basic metabolic panels are routinely performed to ensure that we exhibit an optimal range of electrolytes, enzymes, and proteins.

What about data in physical therapy?

The use of data in the world of physical therapy is also substantial. One of the key ways in which this manifests itself is through our use of outcome measures. An outcome measure is the result of a test that is used to objectively determine the baseline function of a patient at the beginning of treatment. Once treatment has commenced, the same measure can be used to determine progress and treatment efficacy.1 Moreover, with the health sciences’ move toward evidence-based practice, objective measures of outcomes are important to provide credible and reliable justification for treatment.2

We can broadly categorize the outcome measures used in physical therapy in two domains: patient-reported outcome (PRO) measures and performance-based measures (PBM). PROs are a well-accepted way to understand a patient’s progress through treatment. In most physical therapy clinics in the United States, we distribute questionnaires at patient intake and discharge to understand the improvement in physical condition we were able to achieve from the patient’s perspective. However, the shortcomings of PROs are also quite numerous. Patient-reported outcome measures are by definition biased.3 Some PRO measures can be precise but not accurate (i.e., since they are subjective rather than objective measures). Furthermore, many PRO measures involve a pain incidence and severity rating. While this is integral to understanding the patient’s experience, this process reinforces the misplaced notion that pain is the key indicator of physical health and that we should strive only to be “pain-free” as opposed to recovering optimally.

Performance-based measures are another way to measure a patient’s physical health. In contrast to PROs, they are more objective. Many of us have employed PBMs such as Timed Up and Go (TUG), Sit to Stand, Functional Movement Screens (FMS), etc. They offer a myriad of ways to better understand, and track over time, the capability of the patient. That being said, they are heuristics of the patient’s underlying physical condition. For example, many of these tests evaluate the number of repetitions of an action in a set amount of time, or time required to perform an action, but fail to capture the manner in which the tested action was performed, which would have revealed potentially many more problems. The FMS, which attempts to capture such form-related issues, is very broad in nature, and as a result lends itself, once again, to subjectivity.

New technologies give us a glimpse into underlying biomechanics

As physical therapists, we have all studied the foundations of human biomechanics. Many of us, in our day-to-day, apply these principles when treating patients. We will look for valgus collapse and cervical spine flexion/extension. In the past, we did so by relying on visual observation and our experience. At times, we employed a goniometer or an inclinometer, but the difficulty and impracticality of such tools in a clinical setting meant that we rarely brought them out.

Thanks to recent advances in computer vision and camera technology, there exist products that can give clinicians the capabilities to quickly and accurately measure motion: new-age motion capture. These new technologies have significantly reduced the cost, time required, and complexity of traditional motion capture systems and made them practical for the clinical setting. Motion capture is no longer limited only to academic and research facilities or elite athletic institutions.

The impact of biomechanical data in physical therapy

The first impact of the proliferation of such data is improved patient outcomes. We make measurements to determine the progress of a patient and to make decisions about the treatment plan. It therefore goes without saying that more accurate and trackable data can positively affect patient outcomes. Measuring outcomes for every patient is critical to ensuring effective delivery of care.4

The second impact is increased patient engagement and retention. While physical therapists encounter a high amount of patient churn, it has been shown that improving communication and engagement with patients leads to improved patient retention.2 The use of such motion capture technology and the data that come out of it offers a new way to educate and engage patients, to show patients what it means to move properly and improperly. Getting patients to have the “aha” moment of understanding and recognition goes a long way to improving compliance and satisfaction.

Last but not least, accurate biomechanical data will empower clinics to smoothly navigate the transformational shift of the American health care industry from a fee-for-service model to an outcomes- and value-based model. Equipped with more accurate and more complete data on patient recovery and progress, physical therapy clinics will have the capabilities to easily and objectively demonstrate the value and the outcome they deliver to their patients.

This new wave of technology brings with it a tremendous opportunity to improve your physical therapy clinic and distinguish your practice. As professor Michael Porter of Harvard Business School states: “To properly manage value, both outcomes and cost must be measured at the patient level”5 and “The question is, which organizations will lead the way and how quickly can others follow?”6

Will you choose to be a leader or a follower?


1Evidence based practice (EBP). Physiopedia. 2018, July 25. Accessed October 31, 2018.

2Fetters L, Tilson J. Evidence based physical therapy. Philadelphia: F.A. Davis; 2012.

3Black N. Patient reported outcome measures could help transform healthcare. BMJ. 2013;346:f167.

4Finkelstein J, Knight A, Marinopoulos S, et al. Enabling patient-centered care through health information technology. Evid Rep Technol Assess (Full Rep). 2012;(206):1-1531.

5 Kaplan RS, Porter ME. How to solve the cost crisis in health care. Harvard Business Review. September 2011.

6Porter ME, Lee TH. The strategy that will fix healthcare. Harvard Business Review. October 2013.

Merci Greenaway, PT, is the head physical therapist at EuMotus. She can be reached at

Henry Liu, MS, MBA, is the chief executive officer of EuMotus. He can be reached at

*These authors have a professional affiliation with this subject.

Copyright © 2018, Private Practice Section of the American Physical Therapy Association. All Rights Reserved.

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