Interview with Brittney Luc-Harkey, PhD, ATC

Brittney Luc-Harkey (BLH): T32 Postdoctoral Fellow at OrACORe

Emma C. Lape (ECL)

ECL: What has been the biggest adjustment for you in coming to OrACORe? Surprises? Things you’ve had to learn on the fly?

BLH: My work here is very different from what my PhD work involved. All my dissertation work was in a laboratory setting, with much more hands-on data collection involved. I took a comprehensive approach to studying underlying physiological mechanisms that could influence disability and OA development for people with ACL reconstructions. We studied biomechanical changes, changes in neuromuscular activation, and more. The biggest adjustment for me since coming to OrACORe is considering how my work in the laboratory can be transitioned into a clinical population.

ECL: Tell me more about that. How did you assess the neuromuscular changes?

BLH: A common issue after joint injury is persistent quadriceps muscle weakness even after finishing physical therapy. Fully restoring quadriceps strength is important for both self-reported function and lower extremity biomechanics. Some of my work focused on understanding how the nervous system changes after ACL reconstruction, and how neural alterations influence how well a patient can voluntarily contract their quadriceps.

We first assess the amount of force a patient can generate voluntarily, or by contracting their muscle on their own. We then apply a stimulus to the muscle, which causes all of the muscle fibers to contract at the same time, to assess the maximum amount of force the muscle is actually capable of producing. The size of the difference between the voluntary force and the maximum force is important; the larger the deficit, the more difficult it is to improve strength.

By understanding changes in the nervous system that contribute to these deficits, and by developing targeted intervention strategies, we could help people optimize their strength gains when recovering from surgeries like ACL reconstruction.

 

 

Figure 1. Quadriceps Voluntary Activation Deficit: We compare the amount of torque a patient can produce on their own (Voluntary Torque) and the total torque the muscle can produce when provided a maximal stimulus which causes all muscle fibers to contract at the same time (Maximum Torque). The difference between voluntary torque and maximum torque is the voluntary activation deficit.

 

ECL: What a cool project. It’s a quick summary, but years of research! Your work at OrACORe is quite different. What are you excited about in your upcoming research?

BLH: I identified OrACORe as a site for my post-doc exactly because the approach here is clinical, rather than lab-based. I wanted opportunities to think about translating what we learn in the laboratory into clinically feasible applications.

I would love to develop clinical tools based on what we learn about these physiological mechanisms, and see how we can improve outcomes for patients. For example, new technologies are becoming available that can collect biomechanical data more quickly and cheaply, making them suitable for clinical settings. These changes in walking biomechanics are important for patient outcomes because they affect the stresses applied to articular cartilage. I’d like to implement this clinically feasible technology in patient populations.

ECL: How could you use what you learn by doing that? Would you be able to change the way the patient walks?

BLH: Yes, we think so! In my PhD research, I used feedback to change biomechanical outcomes in walking in individuals with ACL reconstruction. Being able to change walking biomechanics is important, since they have been associated with negative outcomes in individuals with ACL reconstruction. With further development, we may be able to implement feedback to change biomechanics in a clinical setting.

 

Figure 2. Individuals with ACL reconstruction commonly demonstrate differences in A) the magnitude of force applied to the lower extremity and B) knee flexion angle between the ACL reconstructed limb and contralateral limb during walking

 

ECL: Is there anything about your job that would surprise people? What do people in different fields not understand?

BLH: When I tell people about my current job, they assume that I’m a physician because I have an interest in the OA population. I think people often don’t understand the pathway between lab discoveries and clinical applications. My job is about bridging that divide. I want to change clinical outcomes, and for right now that doesn’t involve interacting with patients on a daily basis.

 

ECL: What are you most excited about in the next year?

BLH: The scope of what OrACORe has to offer. We have such a range of patient populations, key clinical outcomes, and great research development and statistical analysis resources. I’m ready to jump in and learn everything I can and develop my ideas.