A study has shown that performing deep abdominal muscle strengthening exercises can help improve both breathing and lumbar stability in people with respiratory function problems. The study group included male and female students whose thoraxes opened no more than 5 cm when breathing in and out and who had reduced flow rates when breathing out. The control group was based on the same inclusion criteria and did not receive any treatment. Results showed that the exercises clearly improved respiratory function and lumbar stabilization.
Kim E et al. The Effects of Deep Abdominal Muscle Strengthening Exercises on Respiratory function and Lumbar Stability. Phys Ther Sci June 2013.