The Sports Physical Therapy Podcast · Mike Reinold

Arthrogenic Muscle Inhibition with Dave Sherman - Episode 46

·33 min·2 clips

Arthrogenic muscle inhibition is a reflex driven by pain and swelling in the joint.

1. The Sports Physical Therapy Podcast episode centers on arthrogenic muscle inhibition, or AMI, after ACL reconstruction. 2. Mike Reinald hosts Dave Sherman, a physical therapist, athletic trainer, PhD graduate from the University of Toledo, and Boston University postdoctoral researcher. 3. The episode asks what AMI is for clinicians and what to do when quadriceps strength stays down after knee injury. 4. Dave says his clinical frustration in Fort Worth pushed him back to research after five years working with patients. 5. He describes a "research bug" that started in PT school and grew while he worked with force plates, motion capture, and patient data at Texas Health Sports Medicine. 6. Dave says AMI is hard to treat unless a clinician can assess it, because the nervous system is not easy to see in routine practice. 7. He compares AMI to touching a hot stove, where the agonist is inhibited and the antagonist is facilitated. 8. He says a patient can have good quad activation before surgery and then show inhibition after a meniscectomy or ACL-related joint irritation. 9. He explains that pain and swelling are the early catalysts for inhibition and that the effect can last hours, days, or months depending on the pathology. 10. Dave describes the study methods: decomposition EMG, Hoffman reflex testing, and central activation ratio testing in ACL reconstruction patients. 11. Decomposition EMG used a higher-density electrode array to separate electrical activity into individual motor units. 12. Dave says the study measured when motor units turned on and off, how fast they fired, and how large their firing amplitude was. 13. The main finding was slower motor-unit firing in the involved limb after ACL reconstruction. 14. He says the ACL reconstruction group also showed muscle weakness and was below the 3.0 newton-meters-per-kilogram threshold he uses as a practical reference. 15. Dave notes that central activation ratio and spinal reflex excitability were not different between groups in this sample. 16. He adds that the sample was far enough from surgery that spinal reflex recovery had likely already happened. 17. For early post-op patients, Dave recommends reducing pain and swelling with focal joint cooling or cryotherapy before exercise. 18. He pairs that with NMES and biofeedback, saying the two tools use different mechanisms and should both be applied when appropriate. 19. The conversation is practical, technical, and clinician-focused, with Mike Reinald pressing for direct application to rehab decisions. 20. Clinicians working with ACL reconstruction, knee osteoarthritis, or stubborn quadriceps weakness will get the most from it, while listeners wanting a light general-sports episode may skip it.

As heard by us

A technical sports physical therapy conversation that links ACL reconstruction research to clinical rehab questions.

Dave Sherman and Mike Reinald keep the focus on arthrogenic muscle inhibition, quadriceps weakness after ACL reconstruction, and the neural drive and motor unit findings that sit behind it.

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Why you'd press play

You want the ACL rehab details behind quadriceps inhibition after reconstruction.

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