Inspiratory muscle training (IMT) is recommended for patients with respiratory muscle weakness or fatigue, aiming to enhance ventilatory capacity and decrease dyspnea. The IMT program includes both strengthening and endurance training, with techniques like deep breathing exercises and resistance methods tailored to the patient's condition. Despite mixed evidence regarding its efficacy, IMT can be beneficial for certain patients, particularly those with neuromuscular diseases or those on mechanical ventilation.

1. INSPIRATORY
MUSCLE TRAINING
DR. T.SUNIL KUMAR

2. • INSPIRATORY MUSCLE TRAINING (IMT) IS
INDICATED FOR PATIENTS WHO EXHIBIT SIGNS
AND SYMPTOMS OF DECREASED STRENGTH OR
ENDURANCE OF THE DIAPHRAGM AND
INTERCOSTAL MUSCLES.
• SIGNS AND SYMPTOMS INCLUDE, BUT ARE NOT
LIMITED TO, DECREASED CHEST EXPANSION,
DECREASED BREATH SOUNDS, SHORTNESS OF
BREATH, UNCOORDINATED BREATHING
PATTERNS, BRADYPNEA, AND DECREASED TIDAL
VOLUMES.

3. • PATIENTS WITH RESPIRATORY MUSCLE
WEAKNESS OR FATIGUE MAY HAVE SUCH
DIAGNOSES AS COPD, ACUTE SPINAL CORD
INJURY, GUILLAIN–BARRÉ SYNDROME,
AMYOTROPHIC LATERAL SCLEROSIS,
POLIOMYELITIS, MULTIPLE SCLEROSIS,
MUSCULAR DYSTROPHY, MYASTHENIA GRAVIS,
OR ANKYLOSING SPONDYLITIS.
• IN ADDITION, IMT MAY BE INDICATED FOR
PATIENTS ON MECHANICAL VENTILATION TO
IMPROVE WEANING FROM VENTILATION.

4. • THE GOAL OF IMT IS TO INCREASE THE
VENTILATORY CAPACITY AND DECREASE DYSPNEA.
• AN IMT PROGRAM HAS TWO PARTS:
STRENGTHENING AND ENDURANCE TRAINING.
• EACH PART WILL HAVE INCREASED OR DECREASED
PRIORITY ACCORDING TO THE NEEDS AND MEDICAL
CONDITION OF THE PATIENT.
• CONCEPTS OF VENTILATORY MUSCLE TRAINING
ARE THE SAME AS THOSE FOR OTHER SKELETAL
MUSCLE TRAINING, INCORPORATING THE
CONCEPTS OF OVERLOAD, SPECIFICITY, AND
REVERSIBILITY.

5. • THE OVERLOAD PRINCIPLE APPLIED TO
ENDURANCE MUSCLE TRAINING REQUIRES LOW
LOAD IMPOSED OVER LONGER PERIODS.
• SPECIFICITY REFERS TO TRAINING THE
MUSCLES FOR THE FUNCTION THEY ARE TO
PERFORM, FOR EXAMPLE, RESISTANCE APPLIED
TO INSPIRATORY VERSUS EXPIRATORY
MUSCLES.
• TRAINING EFFECTS MAY BE LOST OVER TIME IF
TRAINING IS DISCONTINUED.

6. • THE FIRST STEP IN ANY PROGRAM IS TO TEACH
THE PATIENT (IF ALERT AND ORIENTED) THE
CORRECT WAY TO USE THE INSPIRATORY
MUSCLES TO ENSURE EFFICIENT INHALATION.
• INCLUDING FAMILY MEMBERS AND SUPPORT
SYSTEM MEMBERS IN THE TEACHING CAN
REINFORCE THE PROGRAM.

7. • WEAKNESS OF A MUSCLE IS THE INABILITY TO
GENERATE FORCE AGAINST RESISTANCE.
• THE LENGTH OF THE MUSCLE AFFECTS THE
FORCE OUTPUT, AS DEMONSTRATED IN THE
LENGTH–TENSION CURVE.
• IN THE RESPIRATORY SYSTEM, THE STRENGTH OF
THE DIAPHRAGM AND OTHER INSPIRATORY
MUSCLES IS MEASURED AS A FUNCTION OF
STANDARD PRESSURE–VOLUME CURVES.
• WEAKNESS OF THE DIAPHRAGM WILL DECREASE
THE NEGATIVE INSPIRATORY PRESSURE
GENERATED BY THE PATIENT, AND THEREBY
DECREASE THE VOLUME OF AIR INHALED.

8. • PATIENTS WITH COPD HAVE HYPERINFLATED
LUNGS AND A FLATTENING OF THE DIAPHRAGM,
WHICH ALTERS THE LENGTH–TENSION
RELATIONSHIP OF THIS MUSCLE.
• FATIGUE OF THE INSPIRATORY MUSCLES,
PARTICULARLY OF THE DIAPHRAGM, WILL RESULT
IN FAILURE TO MEET THE DEMAND FOR
ADEQUATE ALVEOLAR VENTILATION.
• HYPOVENTILATION WILL DECREASE THE
ARTERIAL PARTIAL PRESSURE OF OXYGEN (PAO2)
AND INCREASE THE ARTERIAL PARTIAL
PRESSURE OF CARBON DIOXIDE (PACO2), AND
CAN LEAD TO ACUTE RESPIRATORY FAILURE.

9. • THE DIAPHRAGM IS MADE UP OF ALL THREE
TYPES OF MUSCLE FIBERS, INCLUDING SLOW-
TWITCH OXIDATIVE (SO), FAST-TWITCH
OXIDATIVE GLYCOLYTIC (FOG), AND FAST-
TWITCH GLYCOLYTIC (FG).
• THE ADULT DIAPHRAGM IS APPROXIMATELY 55%
SLOW-TWITCH FIBERS, COMPARED WITH ABOUT
10% IN THE INFANT.
• FATIGUE IS RELATED TO THE ‘SO’ FIBERS,
WHEREAS WEAKNESS IS ATTRIBUTED TO THE
FG FIBERS.

10. • WHEN INITIATING PHYSICAL THERAPY
TREATMENT, THE THERAPIST SHOULD REALIZE
THAT ALL FIBERS NEED TO BE ADDRESSED IN THE
CARDIOPULMONARY TREATMENT PROGRAM.
• WHILE MECHANICALLY SUPPORTED ON A
VENTILATOR, THE DIAPHRAGM CAN LOSE 5% OF
ITS STRENGTH PER DAY.
• WHEN THE PATIENT BEGINS THE WEANING
PROCESS, THE INSPIRATORY MUSCLES WILL GAIN
ENDURANCE WHILE PERFORMING INHALATIONS
WITHOUT THE ASSISTANCE OF THE VENTILATOR.

11. • ENDURANCE TRAINING OF THE DIAPHRAGM
WILL INCREASE CAPILLARY DENSITY,
MYOGLOBIN CONTENT, MITOCHONDRIAL
ENZYMES, AND THE CONCENTRATION OF
GLYCOGEN.
• OVERALL, IT WILL INCREASE THE PROPORTION
OF FATIGUE-RESISTANT SLOW-TWITCH FIBERS.
• THE RECOMMENDATIONS INCLUDE TWO TO
THREE DAILY SESSIONS OF 30 TO 60 MINUTES
OF DEEP BREATHING, CONCENTRATING ON
USING A DIAPHRAGMATIC BREATHING PATTERN.

12. • AN EARLY-STAGE IMT TECHNIQUE IS SNIFFING.
SNIFFING NATURALLY ENLISTS THE DIAPHRAGM.
• WITH THE PATIENT IN A COMFORTABLE POSITION
SUCH AS SIDE-LYING OR RECLINED, THE
THERAPIST MAY ASSIST THE PATIENT IN PLACING
BOTH HANDS ON THE ABDOMINAL AREA TO
PROVIDE PROPRIOCEPTIVE FEEDBACK.
• THEN, IN A RELAXED TONE OF VOICE, THE
THERAPIST INSTRUCTS THE PATIENT TO SNIFF
QUICKLY THROUGH THE NOSE THREE TIMES WITH
SLOW, RELAXED EXHALATIONS.

13. • THE THERAPIST GIVES FEEDBACK THROUGHOUT
THIS TECHNIQUE ON THE QUALITY OF SNIFFING,
ASSESSING WHETHER THE PATIENT IS SHOWING
A DIAPHRAGMATIC BREATHING PATTERN.
• IF THE PATIENT IS ABLE TO PERFORM THIS
EFFECTIVELY, THE PROGRESSION OF THIS
TECHNIQUE IS TO REDUCE THE NUMBER OF
SNIFFS FROM THREE DOWN TO ONE AT AN
INCREASINGLY SLOWER PACE.
• THE GOAL OF THIS TECHNIQUE IS TO INCREASE
THE AWARENESS OF CORRECT USE OF THE
DIAPHRAGM.

14. • THE TECHNIQUE PROGRESSION CONTINUES
UNTIL THE PATIENT SHOWS THE
DIAPHRAGMATIC BREATHING PATTERN AT A
NORMAL RATE AND DEPTH FOR ALL LEVELS OF
FUNCTIONING.
• ACCORDING TO MASSERY AND FROWNFELTER,
THERE IS AN 80% SUCCESS RATE, WITH
PATIENTS AFFECTED BY PRIMARY PULMONARY
PATHOLOGIES OR NEUROLOGIC IMPAIRMENTS

15. • STRENGTH TRAINING CAN BE PERFORMED IN A
NUMBER OF DIFFERENT WAYS, DEPENDING ON
THE INITIAL STRENGTH OF THE DIAPHRAGM.
• ONE METHOD THAT CAN BE UTILIZED EASILY
FOR THE PATIENT ACHIEVING TIDAL VOLUMES
OF 500 ML OR BETTER IS RESISTED INHALATION.
THIS CAN BE PERFORMED MANUALLY BY THE
THERAPIST.
• THE THERAPIST HAS THE PATIENT ASSUME A
COMFORTABLE POSITION AS DESCRIBED
EARLIER TO PROMOTE DIAPHRAGMATIC
EXCURSION.

16. • THE THERAPIST GENTLY PLACES THE HANDS
JUST BELOW THE RIB CAGE ON BOTH SIDES OF
THE PATIENT’S THORAX.
• BEFORE THE PATIENT INITIATES AN INSPIRATION,
THE THERAPIST GIVES A SMALL AMOUNT OF
RESISTANCE TO THE DIAPHRAGM BY PUSHING
GENTLY UP AND IN, AND CONTINUES THIS
PRESSURE THROUGH THE INSPIRATORY PHASE.
• NO RESISTANCE IS GIVEN DURING EXHALATION.

17. • THE THERAPIST MAY ALSO USE WEIGHTS FOR
DIAPHRAGMATIC STRENGTHENING.
• TO EVALUATE IF THIS IS AN APPROPRIATE
METHOD, THE THERAPIST FIRST OBSERVES TO
DETERMINE WHETHER NORMAL
DIAPHRAGMATIC EXCURSION OCCURS AT REST
AND THEN WITH THE ADDITION OF WEIGHTS.
• THE PATIENT SHOULD BE ABLE TO BREATHE
COMFORTABLY AND WITHOUT ACCESSORY
MUSCLES FOR 15 MINUTES; IF THE AMOUNT OF
WEIGHT IS EXCESSIVE, THE PATTERN OF
INSPIRATION WILL BECOME UNCOORDINATED.

18. • SEVERAL AUTHORS SUGGEST THAT STRENGTH
TRAINING IN THIS MANNER SHOULD INCLUDE
TWO OR THREE SETS OF 10 REPETITIONS ONCE
OR TWICE A DAY.
• HOWEVER, WITH EITHER THE MANUAL OR THE
WEIGHTS METHOD, THE QUALITY OF THE
CONTRACTION NEEDS TO BE MONITORED.
• THE PATIENT SHOULD NOT BE “PUSHING” WITH
THE ABDOMINAL MUSCLES AGAINST THE
RESISTANCE, WHICH ENHANCES THE
EXHALATION PHASE OF BREATHING RATHER
THAN THE MUSCLES OF INSPIRATION.

19. • FOR A PATIENT WITH “FAIR OR REDUCED”
DIAPHRAGMATIC STRENGTH (TIDAL VOLUME
LESS THAN 500 ML), ACTIVE BREATHING
EXERCISES ARE INDICATED WITHOUT
RESISTANCE.
• A PATIENT WITH POOR STRENGTH WILL FIND IT
DIFFICULT TO EXERCISE WITH THE HEAD OF THE
BED ELEVATED; A SUPINE POSITION WILL
PREVENT THE ABDOMINAL CONTENTS FROM
PUSHING UP ON THE DIAPHRAGM AND LIMITING
ITS EXCURSION.

20. • ANOTHER FORM OF RESISTIVE TRAINING UTILIZES
SPECIFIC HANDHELD TRAINING DEVICES, SUCH AS
THE P-FLEX, DHD DEVICE, THRESHOLD, OR THE
PEACE PIPE.
• THE RESISTANCE IS INCREASED BY DECREASING
THE RADIUS OF THE DEVICE’S AIRWAY.
• THE PATIENT INHALES THROUGH THE DEVICE AT A
LEVEL THAT DOES NOT CAUSE ADVERSE EFFECTS,
SUCH AS DYSPNEA OR A DROP IN OXYGEN
SATURATION, FOR A 15- TO 30-MINUTE SESSION
TWICE PER DAY.
• WHEN THIS LEVEL IS COMFORTABLE FOR THE
PATIENT, THEN THE RESISTANCE IS GRADUALLY
INCREASED.

21. • MUCH CONTROVERSY HAS SURFACED
REGARDING THE EFFICACY OF IMT SINCE ITS
INTRODUCTION INTO CLINICAL PRACTICE.
• EVIDENCE HAS BEEN PRESENTED BOTH
SUPPORTING AND DISMISSING IMT AS A
RELIABLE TREATMENT METHOD.
• THE MAJOR DISCREPANCY MAY EXIST IN THE
DIAGNOSIS FOR WHICH THIS TREATMENT IS
PRESCRIBED. A PATIENT WITH INSULT TO THE
LUNG TISSUE ITSELF—FOR EXAMPLE, COPD OR
ARDS—MAY NOT TOLERATE IMT.

22. • INSPIRATORY MUSCLE TRAINING, WHICH IS A
STRENGTHENING EXERCISE, WOULD INCREASE
THE DEMAND FOR OXYGEN DELIVERY IN THE
DISEASED LUNGS.
• HOWEVER, A PATIENT WITH A NEUROMUSCULAR
DISEASE AND INTACT LUNGS MAY BE MORE
LIKELY TO TOLERATE THE INCREASED OXYGEN
DEMAND AND DERIVE A BENEFIT, AS WOULD THE
PATIENT ON MECHANICAL VENTILATION WHO IS
TRYING TO BE WEANED FROM THE VENTILATOR.

23. • DEEP BREATHING EXERCISES ARE INDICATED
FOR THE PATIENT WITH ATELECTASIS, WHICH IS
CAUSED BY HYPOVENTILATION AND THE
COLLAPSE OF ALVEOLI IN THE LUNGS.
• THE USE OF AN INCENTIVE SPIROMETER IS AN
EFFECTIVE WAY TO PRACTICE DIAPHRAGMATIC
BREATHING, PREVENT OR REVERSE
ATELECTASIS, AND STIMULATE A COUGH.
• OFTEN, IT IS GIVEN TO THE PATIENT
PREOPERATIVELY SO HE OR SHE CAN PRACTICE
DEEP BREATHING.

24. • THEN, AFTER SURGERY, THE PATIENT MAY BE
ABLE TO PERFORM THIS TECHNIQUE FROM
MEMORY AS THE EFFECTS OF ANESTHESIA START
TO DIMINISH.
• THE PATIENT IS INSTRUCTED TO PERFORM DEEP
BREATHING EXERCISES WITH THE INCENTIVE
SPIROMETER 10 TIMES EVERY HOUR TO
REPLENISH SURFACTANT, WHICH IS LOST IN THE
PRESENCE OF ATELECTASIS.
• THE PATIENT NEEDS TO BE INSTRUCTED TO
PERFORM A SLOW, RELAXED BREATH THROUGH
THE MOUTHPIECE.

25. • IT IS OFTEN HELPFUL TO HAVE THE PATIENT
PLACE A HAND ON THE ABDOMINAL AREA TO
FEEL THE DIAPHRAGM WORKING IN THE
CORRECT WAY.
• IF THE PATIENT IS HAVING A DIFFICULT TIME
PERFORMING THIS TECHNIQUE, THE THERAPIST
MAY PLACE A HAND OVER THE PATIENT’S HAND
TO FACILITATE THE PROPER TECHNIQUE.
• THEN THE THERAPIST SHOULD INSTRUCT THE
PATIENT TO PERFORM THE BREATHING SLOWLY,
WITH THE ABDOMEN RISING OUT DURING
INSPIRATION.

26. • THE GOAL IS FOR THE PATIENT TO BE ABLE TO
USE THE INCENTIVE SPIROMETER
INDEPENDENTLY WITHOUT PROPRIOCEPTIVE
OR VERBAL FEEDBACK.
• ALTERNATIVELY, EARLY MOBILIZATION HAS BEEN
SHOWN TO BE AS EFFECTIVE AS DEEP
BREATHING EXERCISES AFTER GALLBLADDER
AND CARDIAC BYPASS SURGERY

27. • ENDURANCE TRAINING OF THE EXTREMITIES IS
ANOTHER TECHNIQUE THAT HAS BEEN
EXPLORED IN AN EFFORT TO INCREASE
VENTILATORY MUSCLE ENDURANCE.
• STUDIES ON PEDIATRIC PATIENTS WITH CYSTIC
FIBROSIS AND FOUND THAT UPPER EXTREMITY
ENDURANCE TRAINING DID INCREASE THE
ENDURANCE OF THE VENTILATORY MUSCLES.
• SOME STUDIES EXAMINED THE EFFECTS OF
UPPER AND LOWER EXTREMITY TRAINING ON
VENTILATORY MUSCLE ENDURANCE WITH ADULT
PATIENTS WITH COPD AND FOUND NO
CORRELATION.

28. THANK YOU