Physical Therapy as a profession is moving toward autonomous practice, direct access, and primary care. It is well known that physical therapists are musculoskeletal experts second only to orthopedic doctors/surgeons.11 This expertise has been shown to extend further from the clinic to acute presentations in the emergency department as well.12 The APTA defines us as “movement experts who optimize quality of life through prescribed exercise, hands-on care, and patient education”.13 Dr. Shirly Sarhman argues that physical therapists are more than just a treatment; they are qualified providers to diagnose movement-related impairments and treat the cause of the impairment rather than just the symptoms.14 If somebody has pain, there are often accompanying movement impairments (be it biopsychosocial, kinesiopathologic, referred, or acutely injured), and that pain can lead to further movement impairments. What do physical therapists in primary care and emergency department settings have to do with fatty infiltrates? This article outlines just one of the potential benefits of getting patients to the right provider at the right time and the consequences of having to wait for a medical work up before seeing a physical therapist for movement-related pain.
In the past few decades researchers have discovered that both muscle and adipose (fat) are part of the endocrine system.2,3 Both tissues release hormones that have an effect on homeostasis, immunity, and inflammation in the body.2,3 This is a complex relationship but for the purpose of this article, muscles release myokines and adipose tissue releases adipokines. More recently researchers have learned that muscles and adipose talk to each other in a phenomenon called “cross talk”. When a muscle contracts, the myokines talk to the nearby adipose tissue.4 As a general rule adipose tissue is associated with metabolic homeostasis and is pro-inflammatory with the capability of rapid changes in order to maintain that homeostasis.5 Muscle tissue releases myokines which are, by and large, anti-inflammatory.4 While inflammation plays an important role in healing and tissue remodeling, when it becomes out of balance there can be problems and often pain. Too much adipose without muscle contraction leads to chronic low-grade systemic and/or local inflammation as seen in obesity, paralysis, and sedentary behavior.5 It is as if the fat is talking but the muscles don’t answer, so it just keeps talking to itself and over time creates more fat to talk to.
Not only are muscles and adipose in constant conversation but deep within skeletal muscle are pre-adipocyte stem cells that become activated with disuse. Amazingly this process can start within the first three days.1,6,7 This is called “fatty infiltration.” Fatty infiltration is associated with poor muscle function, decreased muscle strength, increased inflammation, pain, fibrosis, structural muscle type changes from type I to type II and ultimately disability.1,7 According to Hodges and Danneels, the disuse associated with spinal reflex inhibition is sufficient to begin the process of fatty infiltration and atrophy. They suggest treatment of the initial factors driving the pain reflex inhibition with medication, manual therapy, movement, and education to address fear/anxiety. Followed by gentle and precise motor control exercises that activate the inhibited muscle which have been shown to be enough to restore muscle health in the early phases of atrophy.1 As the pain moves from acute to subacute, transition the exercises from motor control to strength and resistance training.
This is an argument for Physical Therapy Services in the primary care and emergency department settings.
As of right now there is not a medication in existence (that I am aware of) that can mimic muscle contraction except for well, muscle contraction.”
Think about it. Most of the patients we see are aging and aging itself is associated with loss of subcutaneous fat and increase in fatty infiltration of bone marrow, organ, and muscle.9 According to Harvard Health, muscle decline starts around age 30 and decreases by 3-5% each decade up to 50% in the eighth decade of life.10, 2 All humans are battling the fatty infiltrates. Add disuse to the equation and the battle becomes more of a slaughter. Physical therapists are the experts at teaching people how to contract muscles and contracting muscle happens to be the exact medicine required to prevent pre-adipocytes from becoming adipose.
The current standard of medical practice is for a patient to receive care first from a primary care provider. For example, if the patient has acute back or shoulder pain, they will likely go to their doctor, an urgent care, or an emergency department where they may or may not be given medication and will be told to remain as active as possible and rest the part that hurts. Physical therapy services are not often considered during the acute phase. If the pain persists then the primary care provider may refer the patient to physical therapy and the patient will likely wait another 1-3 weeks to get an evaluation. By this time the physiologic changes from disuse will be in full swing. Within the muscle there will be newly formed adipose tissue prolonging the inflammatory phase, there will be the beginnings of fibrosis, and the muscle tissue itself will already be changing from Type I to Type II. Now the physical therapist will have to cause more pain in order to begin the process of unraveling the chemical cascade of events that have occurred within the patient’s muscle tissue over the past 4-6 weeks.
Physical therapists are well aware that rest is not the same as “don’t use” and advice to “just use it as tolerated” does not always translate to the correct muscles firing. The human body has many ways of moving and as Paul Hodges points out, muscle disuse due to pain inhibition can certainly co-exist with mobility and even exercise.1
A physical therapist can educate a patient on how to gently and thoughtfully use the acutely painful area while still allowing for relative rest and activity modification.”
Education addressing fear, activity modification, and gentle exercise are the first things any physical therapist would give a patient even during the acute phase. Furthermore, a physical therapist would not stop there but using a holistic movement system approach may educate the patient on why they had the rotator cuff strain or back pain in the first place and begin treating the cause to prevent recurrence.13,14 Physical therapists are one of, if not the most, qualified medical practitioners to teach someone who is experiencing acute orthopedic pain how to specifically and safely use the muscles that hurt so as to prevent chronic and potentially permanent physiologic change.
- Only 3 days of muscle disuse for stem cells to trigger adipogenesis within muscle
- Pain inhibition is enough of a disuse for this process to begin and can occur even in the mobile person (not just ICU bedrest)
- Adipose begets adipose and can lead to a chronic inflammatory state within muscle
- Physical therapists are well trained to see acute orthopedic pain and by seeing patient’s sooner may be able to prevent some of these structural changes from taking place.
1) Hodges P, Danneels L. Changes in Structure and Function of the Back Muscles in Low Back Pain: Different Time Points, Observations, and Mechanisms. Journal of Orthopaedic & Sports Physical Therapy. 2019;49(6):464-476
2) Pratesi A, Tarantini F, Di Bari M. Skeletal muscle: an endocrine organ. Clin Cases Miner Bone Metab. 2013;10(1):11–14. doi:10.11138/ccmbm/2013.10.1.011
3) Coelho M, Oliveira T, Fernandes R. Biochemistry of adipose tissue: an endocrine organ. Arch Med Sci. 2013;9(2):191–200. doi:10.5114/aoms.2013.33181
4) Stanford KI, Goodyear LJ. Muscle-Adipose Tissue Cross Talk. Cold Spring Harb Perspect Med. 2018;8(8):a029801. Published 2018 Aug 1. doi:10.1101/cshperspect.a029801
5) Itoh M, Suganami T, Hachiya R, Ogawa Y. Adipose tissue remodeling as homeostatic inflammation. Int J Inflam. 2011;2011:720926. doi:10.4061/2011/720926
6) Pagano, A. F., Brioche, T., Arc‐Chagnaud, C., Demangel, R., Chopard, A., and Py, G. ( 2018) Short‐term disuse promotes fatty acid infiltration into skeletal muscle. Journal of Cachexia, Sarcopenia and Muscle, 9: 335– 347. doi: 10.1002/jcsm.12259.
7) Odessa Addison, Robin L. Marcus, Paul C. LaStayo, and Alice S. Ryan, “Intermuscular Fat: A Review of the Consequences and Causes,” International Journal of Endocrinology, vol. 2014, Article ID 309570, 11 pages, 2014. https://doi.org/10.1155/2014/309570.
9) Hamrick MW, McGee-Lawrence ME, Frechette DM. Fatty Infiltration of Skeletal Muscle: Mechanisms and Comparisons with Bone Marrow Adiposity. Front Endocrinol (Lausanne). 2016;7:69. Published 2016 Jun 20. doi:10.3389/fendo.2016.00069
10) Preserve your muscle mass: Declining muscle mass is part of aging, but that does not mean you are helpless to stop it. Harvard Health Publishing. Accessed Nov 2019 at https://www.health.harvard.edu/staying-healthy/preserve-your-muscle-mass
11) Childs, J.D., Whitman, J.M., Sizer, P.S. et al. A description of physical therapists’ knowledge in managing musculoskeletal conditions. BMC Musculoskelet Disord 6, 32 (2005) doi:10.1186/1471-2474-6-32
12) Lebec MT, Jogodka CE. The physical therapist as a musculoskeletal specialist in the emergency department. J Orthop Sports Phys Ther 2009 Mar;39(3):221-9. Doi: 10.2519/jospt.2009.2857.
13) Who Are Physical therapists? Accessed Nov 2019 at https://www.apta.org/aboutpts/
14) Sahrmann S. The how and why of the movement system as the identity of physical therapy. Int J Sports Phys Ther. 2017;12(6):862–869.
15) Saladin L, Voight M. Introduction to the movement system as the foundation for physical therapist practice education and research. Int J Sports Phys Ther. 2017;12(6):858–861.