Related Experiment Video
Updated: Jul 10, 2026

Inspiratory Muscle Training as an Adjunct to the Treatment of Weaning Failure in Critically Ill Patients: A Practical Guide
Published on: January 30, 2026
Respiratory muscle training and the performance of a simulated anti-G straining maneuver
Pearl Yang1, Bruce C Frier, Leonard Goodman
1University of Toronto, Toronto, Ontario, Canada. pearl.yang@utoronto.ca
Introduction:
Prolonged +G,-exposure eventually decreases a pilot's ability to maintain an effective anti-G straining maneuver (AGSM). Previous studies have implicated the respiratory muscles (RMs) as main contributors to this AGSM-induced fatigue. Thus, this study aimed to investigate if respiratory muscle training (RMT) may be of benefit to improve RM strength, endurance, and performance of the AGSM.
Methods:
Subjects (N=14; 27 +/- 5.3 yrs) trained with a commercially available RM trainer for 6 wk, 4 times/wk 20 min per session. Data collection consisted of pulmonary function tests (PFTs) and a RM testing protocol simulating the AGSM. Testing occurred every 2 wk for the duration of RMT, and similarly during the 6-wk control (CON) phase where subjects did not train. The simulated AGSM performance was evaluated through measures of peak respiratory pressures, peak systolic arterial pressure (SAP), mean arterial pressure (MAP), and tidal volumes.
Results:
Training significantly improved (P < 0.05) RM strength after 6 wk of RMT measured in maximal expiratory pressures (RMT = 207.8 +/- 15.8 cmH2O; CON = 181.3 +/- 13.7 cmH2O) and maximal inspiratory pressures (RMT = -154.7 +/- 8.9 cmH2O; CON = -141.9 +/- 8.5 cmH2O). All other PFTs were unchanged. During performance of the AGSM, only peak expiratory pressure demonstrated an increased performance benefit (RMT = 91.5 +/- 5.9 cmH2O; CON = 82.8 +/- 4.3 cmH2O). Peak inspiratory pressure, SAP, MAP, and tidal volumes remained unchanged.
Conclusion:
Without evident translation of the increased RM strength to performance of the AGSM at +1 Gz, the benefits of RMT for ameliorating AGSM-induced fatigue within the high +G, environment are limited.
Related Concept Videos
Mechanism of Breathing III: The Accessory Muscles
The respiratory system is a complex network that relies on primary respiratory muscles like the diaphragm, but also involves accessory muscles to enhance lung expansion and airflow during both inhalation and exhalation.
Enhancing Inhalation with Accessory Muscles:
Accessory muscles such as the sternocleidomastoid, scalene, intercostal, and abdominal muscles are crucial when additional respiratory effort is required, such as during deep...
Assessment of Airway, Skin Color, and Use of Accessory Muscles
Introduction
The initial evaluation of a patient's respiratory system...
Skeletal Muscle Relaxants: Therapeutic Uses
Myasthenia Gravis: Diagnostic Tests
The edrophonium test is a diagnostic tool for myasthenia gravis. It involves...
Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
Myasthenia Gravis: Overview and Treatment
These antibodies interfere with the function of the nicotinic receptors in three ways: by binding to the receptor and disrupting acetylcholine binding; by causing cross-linking of receptors which leads...

