Diaphragm thickness and physical performance in regular smokers and non-smokers: A pilot study.

Background: Despite the understanding of the role of diaphragm role as a crucial element in trunk stabilizer performance, limited research has been carried out on the diaphragmatic features particularly in smoking population.

Objectives: It was aimed to compare the diaphragm structure beside trunk stabilizer performance & body balance of young regular smokers and non-smokers and investigate the relationship between diaphragmatic features and physical performance in regular smokers.

Methods: Asymptomatic regular smoker (n = 22) and nonsmoker (n = 22) young male subjects (21.63 ± 2.37 years) were participated to the study. The diaphragmatic ultrasonic scanning and physical performance tests of core muscle strength and endurance & Y balance test were performed.

Results: The duration of prone and lateral side bridge (t = -3.347, t = 3.477, p < 0.001), and modify push-up test repetition (Z = -2.213, p = 0.027) were detected lower in regular smokers. A positive moderate correlation was observed between the duration of the prone bridge test and the maximum inspiration thickness & the thickness difference at inspiration and expiration (r = 0.545, p = 0.009 & r = 0.468, p = 0.028) and between the number of repetitions of the modify push-up and the maximum expiration thickness (r = 0.530, p = 0.011).

Conclusion: While no difference was detected in terms of the diaphragm structure between groups, trunk stabilizer performance was lower and greater diaphragm thickness was associated with better trunk stability in some performance tasks in smokers. While the diaphragm muscle structure, which is the main respiratory muscle, does not differ in young smokers, the effects of the diaphragm muscle on general body biomechanics have been preliminary demonstrated.