Effects of usual yoga practice on the diaphragmatic contractility: A cross-sectional controlled study

Objectives: The aim of this study is to observe and compare the effects of regular yoga practice on the main inspiratory muscle, the diaphragm, by analyzing its thickness, excursion, velocity and contraction time, using ultrasound.

Design: A Cross-Sectional Controlled Study.

Participants: 80 healthy subjects (40 habitual yoga practitioners and 40 non-practitioners), without previous respiratory pathology participated in this study. During maximum diaphragmatic breathing, the diaphragmatic thickness (at rest and after maximum inspiration), excursion, velocity and contraction time were measured by ultrasound.

Results: in the experimental group, practicing yoga, statistically significant differences (p < 0.001) were observed compared to the control group, not practicing, in the thickness of the diaphragm at rest (0.26 ± 0.02 vs 0.22 ± 0.01 cm); the diaphragmatic thickness in maximum inspiration (0.34 ± 0.03 vs 0.28 ± 0.03 cm); contraction velocity (1.54 ± 0.54 vs 2.23 ± 0.86 cm/s), contraction time (3.28 ± 0.45 vs 2.58 ± 0.49 s) and Borg scale of perceived exertion (1.05 ± 1.6 vs 1.70 ± 1.34), p = 0.05. However, the diaphragmatic excursion was greater in the control group (5.45 ± 1.42 vs 4.87 ± 1.33 cm) with no statistically significant differences (p = 0.06).

Conclusions: the regular practice of yoga improves the parameters of diaphragm thickness, speed and contraction time measured in ultrasound and the sensation of perceived exertion during a maximum inspiration. So it can be considered as another method for training the inspiratory muscles in clinical practice.