Author: Ainsley Martin, MS, CCC-SLP Edited by: Heather Bolan, MA, CCC-SLP
Book: Respiratory Muscle Strength Training Theory and Practice Authors: Christine M. Spaienza, PhD, CCC-SLP and Michelle S. Troche, PhD, CCC-SLP Publisher: Plural Publishing Copyright: 2012 Cost: $39.95, https://www.pluralpublishing.com/publications/respiratory-muscle-strength-training-theory-and-practice, https://emst150.com/product/emst150-respiratory-muscle-strength-training-guide/ Chapters/Pages: 5 chapters, 86 pages Subject: Respiratory muscle strength training (RMST)
Applicable patients/Disorders: Patients with reduced respiratory support, dysphagia with airway invasion, weak cough, CVA, dysarthria/dysphonia, failure to wean from mechanical ventilation, cardiopulmonary, sedentary elderly, professional singers, ALS, spinal cord injury, MS, COPD, MG, Cystic Fibrosis, vocal cord dysfunction, diaphragm paralysis, Huntington’s Disease, HFNC, and Myotonic Dystrophy (to name a few). RMST is applicable in a wide variety of settings including acute care hospitals, outpatient, SNF, movement disorders clinics, and voice clinics.
Content: RMST is becoming widely used in the field of speech-language pathology for patients with impairments in speech, voice, ventilation, cough, and swallowing. Respiratory Muscle Strength Training Theory and Practice provides a foundational understanding of respiratory anatomy and physiology, primary structures involved, neuroanatomy and physiology of the respiratory system, common disease processes or disorders which can negatively impact respiratory strength and efficiency, implications for use of RMST to address these impairments, as well as treatment devices and protocols to be used in treatment. Case studies are provided detailing impacts of certain diagnoses on respiratory function, description of how RMST may be useful for that particular patient, and suggestions for treatment dose, load, and frequency based on the best available clinical evidence. The book ends by addressing frequently asked questions re: RMST such as the rationale, frequency of training, difference between devices, when to terminate training, and maintenance for respiratory devices. Examples of RMST devices and training instructions are also provided in the appendices.
Breathing, consisting of ventilation (air moving into and out of the lungs) and respiration (gas exchange), is an essential life-sustaining process. Coordination of breathing, control of airflow, and protective functions such as cough are also crucial to swallowing and phonation (communication).
The structures detailed by Sapienza and Troche (2012) which are involved in breathing include;
the lungs
trachea
bronchi
thorax
ribs
diaphragm
abdominal wall
sternum
clavicle.
You may recall from your anatomy and physiology coursework that when a person inhales, or breathes in, the diaphragm presses down on the abdominal contents allowing the rib cage to expand. As the rib cage expands, the pressure inside the lungs turns to negative pressure (less than atmospheric pressure) and the air rushes in. In exhalation, the muscles of the abdomen and internal intercostals pull the ribs down which compresses and reduces the size of the chest cavity. This results in positive pressure in the lungs (higher than atmospheric pressure), causing the air to flow out.
Control of the respiratory system is modulated cortically (voluntary behaviors) and subcortically (involuntary behaviors). The brainstem, specifically the pons and the medulla oblongata, is the area primarily responsible for respiratory control. The muscles involved in respiration receive input that originates in the brain, travels down the spinal cord, emerges from the vertebral column, and travels to the organs under their respective control. Sapienza and Troche further detail nerves which control specific muscles including;
the phrenic nerve located at C3-C5 which controls the diaphragm
spinal nerves T2-T12 which control the internal and external intercostals
thoracic spinal nerves T7-T12 which control the rectus abdominis and external obliques
thoracic spinal nerves T8-T12, the iliohypogastric nerve, and ilioinguinal nerve which control the internal obliques and transverse abdominis
spinal nerves T12 along with lumbar spinal nerves L1-L4 which control the quadratus lumborum.
Drs. Sapienza and Troche have included a detailed chart describing the primary and accessory muscles involved in inspiration and expiration.
Following an extensive review of respiratory and neuro anatomy and physiology, as well as the characteristics of respiratory muscles, information is then provided on the type of muscles used for respiration and the response of these muscles to aging, training, and detraining. The muscles required for respiration are skeletal. Skeletal muscles, compared to cardiac or smooth muscles, can be voluntary or involuntary. With age, skeletal muscles begin to atrophy and decrease. Respiratory muscle strength training can result in enlargement of the respiratory muscles (hypertrophy). However, similar to the process of aging, once training has ceased, it takes approximately one month for muscles to return to their pre-training. This is why, as with any exercise program, continuation of training through maintenance programs is so important to maintain progress. Think about working out and training at the gym. If you are not continually training and you just stop your exercise program, you will lose the gains and progress you’ve made. (But finish this article first before you run off to the gym.)
Now that we have a foundation of understanding of respiratory and neuro anatomy and physiology, it is not a large leap to understand why so many of our patients present with respiratory difficulty, weak cough, inefficient respiratory driving force for phonation, or even the ability to breath independently without assistance (think supplemental O2 or mechanical ventilation).
As previously mentioned, the structures involved in breathing are the same structures required for phonation and swallowing. These systems must take turns in completing their desired functions (Coyle, 2010). Neuromuscular, respiratory, or cardiopulmonary diseases, trauma, cancer, spinal cord injuries, and various other causes such as CVAs and TBIs can result in interruptions in the coordination of these symptoms. RMST has implications for addressing breathing (e.g., reducing dyspnea or shortness of breath), cough (to expel foreign substances from the airway), swallowing (submental force generation and increased movement of the hyolaryngeal complex), and speech (improving vocal quality and increasing respiratory driving force for phonation). Drs. Sapienza and Troche provide examples of patients who may benefit from either inspiratory muscle strength training (IMST) or expiratory muscle strength training (EMST).
IMST is most appropriate for patients who experience decreased ability to fill their lungs with air. Examples include;
Athletes
Chronic Obstructive Pulmonary Disease
Diaphragmatic paralysis
Obesity
Upper airway limitation
Amyotrophic Lateral Sclerosis (ALS)
Myasthenia Gravis
Cystic Fibrosis
Duchenne Muscular Dystrophy
Cardiopulmonary Disease (disease that affect the lungs and heart)
Pompe Disease
Spinal Cord Injury
Asthma.
EMST is most appropriate for weak cough resulting in poor airway protection and reduced vocal intensity. Examples include;
Athletes
Singers
Divers
Young and healthy
Sedentary elderly
Spinal cord injury
Multiple Sclerosis
Parkinson’s Disease
Myotonic Dystrophy
Chronic Obstructive Pulmonary Disease
Military Personnel
Professional voice users
Instrumentalists.
*Please note that since this book's publication in 2012, a great deal of research has been completed in RMST. Many populations also benefit from a mixed IMST/EMST approach. Additional patient populations which may benefit from RMST include;
Mechanical ventilation
Paradoxical Vocal Fold Motion
Progressive Supranuclear Palsy
Huntington’s Disease
Cerebrovascular Accidents
Dysarthria
Dysphonia
Reduced maximum inspiratory pressure (MIP)
Reduced maximum expiratory pressure (MEP)
Additional research articles will be provided for further reference.
At this point, you should have a good understanding of how RMST can be beneficial to our patients. You may even have an idea of a patient who might be perfect for RMST. But now, how do you know which device to use?
Fortunately, Sapienza and Troche provide descriptions of different device types and samples of these devices. The main types of devices used for RMST are resistive and pressure threshold devices. Resistive devices provide resistance through either smaller orifices or a decreased number of orifices where air can flow through. Resistive training devices may be easier to use for weaker patients, but are subject to airflow meaning the speed with which air flows through the device vs actually meeting the resistance. Pressure threshold devices have a spring loaded valve, so the patient must reach the actual resistance in order for the valve to release. Much of the research has been completed with pressure threshold devices; however, there is some research to support that resistive devices can also be beneficial. Examples of resistive devices include the Breather and the Power Lung. Examples of pressure threshold devices include the EMST 150, Philips Respironics Threshold Positive Expiratory Pressure (PEP), and Phikips Respironics Threshold Inspiratory Muscle Training (IMT).
In Chapter 4 of this book, case studies are provided to demonstrate practical applications of RMST including how it may best be used with that particular population, areas to be targeted by RMST, and suggested frequency, load, and dosage. Patient populations addressed in the case studies include; Parkinson’s Disease, Progressive Supranuclear Palsy, bilateral abductor vocal fold paralysis, sedentary elderly, spinal cord injury, Multiple Sclerosis, Chronic Obstructive Pulmonary Disease, and professional voice users. I found this chapter to be helpful in detailing actual real life applications of RMST.
In the final chapter, information is provided re: frequently asked questions specific to RMST including suggested dose and frequency, research supporting RMST, caregivers role with RMST, and device maintenance. Patients who would not be appropriate for RMST were also identified including “untreated gastroesophageal reflux, untreated hypertension, reactice airway disease, and pregnant women.'
I first became interested in RMST when I had a patient who was admitted with CHF exacerbation who also presented with mild dysphonia and dyspnea with exertion. When this case was brought up during the weekly Medicare A team meeting at my facility, I asked if he could be put on my schedule and I said I’d “give working with this patient shot.” We began RMST (both inspiratory and epiratory) with the Breather, as resistive device, as that was what was available to me at the time. My patient used his device religiously as it became part of his daily routine and evidenced improvements in cough to clear material from the lungs, vocal quality, and reduced dyspnea.
While I cannot attribute all of his progress to the use of RMST (as there were other factors at play), I can say that my patient felt it was helpful and his cardiologist was thrilled with his RMST exercise program.
Respiratory Muscle Strength Training Theory and Practice is an excellent resource for clinicians who are beginning to use RMST. This book provides a solid foundation in respiratory anatomy and physiology which explains the why and how of RMST. As mentioned additional resource articles will be provided for more information. Stay tuned for a review of RMST continuing education courses and an article on how I started an RMST program at my facility!
References:
Sapienza, C. & Troche, M. (2012). Respiratory Muscle Strength Training Theory and Practice. San Diego, CA: Plural Publishing Inc.
Coyle, J. (2010). Ventilation, Respiration, Pulmonary Diseases, and Swallowing . Perspectives on Swallowing and Swallowing Disorders (Dysphagia) 19(4), p 91-97.
Additional Resources:
Medical SLP Collective Understanding Respiratory Muscle Strength Training (RMST) Series
Cheah, B., Boland, R., Brodaty, N., Zoing, M., Jeffery, S., Mckenzie, D., & Kiernan, M. (2009). INSPIRATIonAL - INSPIRAtory muscle Training In Amyotrophic Lateral sclerosis. Amyotrophic Lateral Sclerosis, 1-9.
Chiara, T., Martin, D., Davenport, P., & Bolser, D. (2006). Expiratory Muscle Strength Training in Persons With Multiple Sclerosis Having Mild to Moderate Disability:Effect on Maximal Expiratory Pressure, Pulmonary Function, and Maximal Voluntary Cough. Archives of Physical Medicine and Rehabilitation, 87 PP 468-473.
Hsiao, S., Wu, Y., Wu, H., & Wang, T. (2003). Comparison of Effectiveness of Pressure Threshold and Targeted Resistance Devices for Inspiratory Muscle Training in Patients with Chronic Obstructive Pulmonary Disease. Journal of the Formosan Medical Association, 102(4), 240-245.
Hutcheson, K. A., Barrow, M. P., Plowman, E. K., Lai, S. Y., Fuller, C. D., Barringer, D. A., . . . Lewin, J. S. (2017). Expiratory muscle strength training for radiation-associated aspiration after head and neck cancer: A case series. The Laryngoscope, 128(5), 1044-1051.
Jederlinic, P., Muspratt, J. A., & Miller, M. J. (1984). Inspiratory Muscle Training in Clinical Practice. Chest, 86(6), 870-873.
Laciuga, H., Rosenbek, J., Davenport, P., & Sapienza, C. (2014). Functional outcomes associated with expiratory muscle strength training: Narrative review. Journal of Rehabilitation Research and Development, 51 (4), PP 535-546.
Larson, J. L., Kim, M. J., Sharp, J. T., & Larson, D. A. (1988). Inspiratory Muscle Training with a Pressure Threshold Breathing Device in Patients with Chronic Obstructive Pulmonary Disease. American Review of Respiratory Disease, 138(3), 689-696.
Martin, A., Smith, B., Davenport, P., Harman, E., Gonzalez-Rothi, R., Baz, M., et al. (2011). Inspiratory muscle strength training improves weaning outcome in failure to wean patients: a randomized trial. Critical Care, 15 PP 1-12.
Menezes, K. K., Nascimento, L. R., Ada, L., Avelino, P. R., Polese, J. C., Alvarenga, M. T., . . . Teixeira-Salmela, L. F. (2019). High-Intensity Respiratory Muscle Training Improves Strength and Dyspnea Poststroke: A Double-Blind Randomized Trial. Archives of Physical Medicine and Rehabilitation, 100(2), 205-212.
Park, J., Oh, D., & Chang, M. (2016). Effect of expiratory muscle strength training on swallowing-related muscle strength in community-dwelling elderly individuals: A randomized controlled trial. Gerodontology, 34(1), 121-128.
Pitts, T., Bolser, D., Rosenbek, J., Troche, M., Okun, M. S., & Sapienza, C. (2009). Impact of Expiratory Muscle Strength Training on Voluntary Cough and Swallow Function in Parkinson Disease. Chest, 135(5), 1301-1308.
Plowman, E., Watts, S., Tabor, L., Robison, R., Gaziano, J., Domer, A., et al. (2016). Impact of Expiratory Strength Training in Amyotrophic Lateral Sclerosis. Muscle Nerve, 54 (1), PP 48- 53.
Reyes, A., Cruickshank, T., Nosaka, K., & Ziman, M. (2014). Respiratory muscle training on pulmonary and swallowing function in patients with Huntington’s disease: A pilot randomised controlled trial. Clinical Rehabilitation, 29(10), 961-973.
Troche MS, Okun MS, Rosenbek JC, Musson N, Fernandez HH, Rodriguez R, Romrell J, Pitts T, Wheeler-Hegland KM, & Sapienza CM. Aspiration and swallowing in Parkinson disease and rehabilitation with EMST: a randomized trial. Neurology. 2010 Nov 23;75(21):1912-9.
Weiner, P., Magadle, R., Beckerman, M., Weiner, M., & Berar-Yanay, N. (2004). Comparison of Specific Expiratory, Inspiratory, and Combined Muscle Training Programs in COPD. Cardiopulmonary Physical Therapy Journal, 15(1), 27.
Weiner, P., Magadle, R., Beckerman, M., Weiner, M., & Berar-Yanay, N. (2004). Maintenance of inspiratory muscle training in COPD patients: One year follow-up. European Respiratory Journal,23(1), 61-65.
Wheeler-Hegland, K., Davenport, P., Brandimore, A., Singletary, F., & Troche, M. (2016). Rehabilitation of Swallowing and Cough Functions Following Stroke: An Expiratory Muscle Strength Training Trial. Archives of Physical Medicine and Rehabilitation, 97PP, 1345-1351.
Wingate, J. M., Brown, W. S., Shrivastav, R., Davenport, P., & Sapienza, C. M. (2007). Treatment Outcomes for Professional Voice Users. Journal of Voice, 21(4), 433-449.