Short-term effects of respiratory muscle training combined with the abdominal drawing-in maneuver on the decreased pulmonary function of individuals with chronic spinal cord injury: A pilot randomized controlled trial

Abstract

Objective: To investigate the effects of respiratory muscle training (RMT) combined with the abdominal drawing-in maneuver (ADIM) on the pulmonary function in patients with chronic spinal cord injury (SCI).

Methods: Thirty-seven subjects with SCI (level of injury: C4-T6, time since injury: 4-5 years) were randomly allocated to three groups; the integrated training group (ITG), the RMT group (RMTG), and the control group (CG). The ITG performed RMT using an incentive respiratory spirometer (IRS) and the ADIM using a stabilizer. The RMTG received only RMT using an IRS. Subjects in the CG received alternative and routine physical therapy or usual care. The interventions were conducted over an eight-week period. Pulmonary function was evaluated using spirometry to measure the forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁).

Results: The differences between the pre- and post-test values for FVC (0.47 ± 0.05 versus 0.15 ± 0.06 versus -0.03 ± 0.01) and FEV₁ (0.74 ± 0.07 versus 0.27 ± 0.17 versus 0.02 ± 0.67)were significant among the groups. Post-test, in the ITG, the FVC and FEV₁ values showed significant differences from those in the RMTG and CG (F = 11.48 and 11.49, P = 0.002 and 0.001). Furthermore, following the 8-week intervention, the change ratio values of the FVC and FEV₁ of the ITG were increased further by an average of 9.75% and 7.91%, respectively, compared with those of the RMTG.

Conclusion: These findings suggest positive evidence that RMT with additional ADIM training can improve pulmonary function in SCI pulmonary rehabilitation.

Keywords: Abdominal drawing-in maneuver; Incentive respiratory spirometer; Pulmonary function; Respiratory muscle training; Spinal cord injury.

Figure 1

The spirometry (A) illustration showing the experimental settings and Stabilizer^TM pressure biofeedback unit (B) used in this study. (colour online)

Figure 2

The experimental procedures used in this study. ITG, Integrated training group; RMTG, Respiratory muscle training group; CG, Control group.

Figure 3

Comparisons of the improvement rate of the forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁) in accordance with the training methods. ITG, Integrated training group; RMTG, Respiratory muscle training group; CG, Control group. *P < 0.01, **P < 0.001.