Immediate Effects of Thixotropy Conditioning of Inspiratory Muscles on Chest-Wall Volume in Chronic Obstructive Pulmonary Disease

The full text article is temporarily unavailable.

We apologise for the inconvenience. Please try again later.


INTRODUCTION:Thixotropy is a passive property of the skeletal muscle that depends on the muscle's immediate history of contraction and length change. Inspiratory-muscle thixotropy affects the end-expiratory position of the rib cage in normal subjects. OBJECTIVE: To determine whether a reduction in end-expiratory chest-wall volume occurs after thixotropy conditioning of inspiratory muscles in patients with chronic obstructive pulmonary disease. METHODS: Ten male subjects with chronic obstructive pulmonary disease (mean ± SD forced expiratory volume in the first second 70 ± 20% of predicted) showed an increased ratio of residual volume to total lung capacity (49 4.7%). The subjects conducted inspiratory muscle thixotropy conditioning maneuvers at 3 different chest-wall volumes (end-expiratory volume of baseline breathing, residual volume plus 40% of expiratory reserve volume, and residual volume) and with 3 levels of inspiratory effort (0%, 30%, and 100% of maximal inspiratory mouth pressure at each volume), with airway-closure, in the sitting position. Using respiratory induction plethysmography, we measured the effect of effortintensity and volume at the time of the conditioning maneuver on the end-expiratory chest-wall volume of the 5 respiratory cycles immediately following the conditioning maneuver. RESULTS: There was a reduction in end-expiratory chest-wall volume after the conditioning maneuver, except when conditioning was performed at end-expiratory baseline with 0% effort. The reduction increased as effort intensity increased (p = 0.011) and as volume decreased (p < 0.001), and the reduction was attained by rib-cage movement rather than abdominal movement. CONCLUSIONS: Thixotropy conditioning of inspiratory muscles, at a reduced chest-wall volume, decreased end-expiratory chest-wall volume in the 5 subsequent breaths in patients with chronic obstructive pulmonary disease.


Document Type: Research Article

Affiliations: 1: Department of Physiology, Showa University School of Medicine, Tokyo, Japan, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan;, Email: 2: Department of Physical Therapy 3: Department of Internal Medicine, Toyosu Hospital, Showa University, Tokyo, Japan 4: Department of Physiology, Showa University School of Medicine, Tokyo, Japan

Publication date: July 1, 2006

Related content

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more