Expiratory muscle strength training (EMST)

What is EMST?

EMST is a rehabilitation approach which uses a device to exercise and increase the maximal pressure of the expiratory muscles. These muscles are important for breathing out forcefully, coughing, and swallowing. The muscles are exercised by blowing into the device until you generate enough pressure to open the spring-loaded valve (described below).

Why have I been advised to perform EMST?

A speech and language therapist (SLT) has assessed your swallowing and identified that you may benefit from EMST to make your swallowing easier, safer or more efficient.

When you swallow, the voice box (larynx) needs to move upwards to protect your airway and reduce the risk of food or drink ‘going down the wrong way’. If your airway is not fully protected when you swallow, it could put you at risk of ‘aspiration’ (food or drink entering the airway and possibly entering your lungs).

The movement of the larynx is important in helping to open the entrance to your oesophagus (food pipe). This allows food and drink to enter your stomach and reduce the risk of food and drink remaining in your throat (pharynx) after swallowing.

A high pressure needs to be generated when swallowing to ensure all the food and drink is cleared through your throat and does not fall into your airway.

Cough strength is also important in protecting your airway. If any food or drink does enter the airway a strong cough will help to clear it back out and help stop it reaching your lungs.

Benefits of EMST

EMST protects your airway during swallowing by focusing on improving:

• cough strength, which helps clear any food and drink from the airway
• the movement and strength of your swallowing muscles to help clear food and drink through the throat
• the upwards lift of the larynx during swallowing

Reduced airway protection increases the risk of aspiration. EMST aims to try and reduce this risk.

How to use the EMST device

To begin

1. Turn the knob (adjustable valve) of the EMST 150 all the way to the left (counter-clockwise).
2. Remove the cap from the mouthpiece and insert the mouthpiece in the EMST 150.
3. Put on the nose clip.
4. Take a deep breath in and insert the mouthpiece of the EMST device behind your teeth forming a tight seal (use your free hand to secure your lips around the device if needed).
5. Breathe out hard and fast so air rushes through the device.
6. If air went through, turn the knob one full turn to the right and repeat step five.
7. Continue to increase the pressure by one full turn until you can’t blow any more air through.
8. Turn the knob back one quarter turn to the left; this is your maximum expiratory pressure and where you will begin training.

While training

1. Set aside 20-30 minutes each day.
2. Sit or stand during your session (sitting is recommended).
3. Place the nose clip on your nose.
4. Take a deep breath in, hold it, and place the mouthpiece in your mouth forming a tight seal.
5. Breathe out hard and fast.
6. Rest for at least 15 to 20 seconds.
7. Repeat this exercise five times, then take a one minute break, this completes one set.
8. Complete five breath sets for a total of 25 training breaths.
9. Aim to complete breath training sessions five days a week.

At the end of each week, turn the knob to the right by a quarter turn. After five weeks, you can switch to a maintenance programme of training three days a week using the final knob setting achieved in week five.

If you feel lightheaded, stop your breath training session.

How long do I use the device for?

The SLT will provide guidance on how long you should continue with these exercises. Usually they will recommend you use the device for five weeks; five repetitions ('reps'), five sets per day, five days per week.

At this stage, the SLT may reassess your swallowing to see if the device has helped. Some people may need to use the device for longer periods; you will be advised on this depending on how effective it has been for you.

Make sure you continue with any other rehabilitation exercises the SLT may have set for you (in addition to the EMST) unless advised otherwise.

The SLT will advise on a maintenance programme if this is indicated. This is usually five reps, five sets per day, three days per week.

How to clean the device

We recommend the trainer be cleaned monthly. The mouthpiece should be removed before cleaning. The mouthpiece is the only removable part of the trainer; to remove it, pull gently until loosened.

Use washing up liquid and warm water to rinse the trainer. Air dry before re-using.

Do not use harmful cleaning agents such as bleach, and do not share your EMST 150 trainer with anyone else.

Risks

You may feel lightheaded during your EMST sessions. If this happens, sit or lie down until the dizziness passes, then get up slowly and carefully. When able, report this to your SLT who may be able to adjust the programme for you.

Contacts/further information

Please contact the speech and language therapy team on 01223 216200 if you have any questions regarding your EMST device or training programme.

References/sources of evidence

• Brooks M, McLaughlin E and Shields N (2019) ‘Expiratory Muscle Strength Training Improves Swallowing and Respiratory Outcomes in People with Dysphagia: A Systematic Review’, International Journal of Speech and Language Pathology 21 (1): 89-100
• EMST (2018 online) EMST How It Works. Online. [Accessed 12.02.20]
• Hutcheson K, Barrow M, Plowman K, Fuller C and Barringer D (2018) ‘Expiratory Muscle Strength Training for Radiation-Associated Aspiration after Head and Neck Cancer: A Case Series’, the Laryngoscope 128 (5): 1044-1051
• Kuo Y, Chan J and Bernard J (2017) ‘Effect of Expiratory Muscle Strength Training Intervention on the Maximum Expiratory Pressure and Quality of Life of Patients with Parkinson’s Disease’, Neurorehabilitation Journal 41 (1): 219-226
• Laciuga H, Rosenbek J, Davenport P and Sapienza C (2014) ‘Functional Outcomes Associated with Expiratory Muscle Strength Training: Narrative Review’, Journal of Rehabilitation Research and Development 51 (4): 535-540