Fig. 2From: Combination of inspiratory and expiratory muscle training in same respiratory cycle versus different cycles in COPD patients: a randomized trialA Photo of the modified trainers./a, for no-load respiratory muscle training; b, for inspiratory muscle training only; c, for expiratory muscle training only; d, for concurrent respiratory muscle training. B General view of the modified trainer. /Threshold PEP and Threshold IMT(Respironics, Pittsburgh, USA) were respiratory muscle trainers designed for expiratory muscle training and inspiratory muscle training, respectively. C Coronal view of the data management device. /Main switch: powering up the data management device; Record button: recording training data when pressed; Pilot light: consisting of switch indicator(turning on when main switch is pressed) and time indicator(turning on when training is completed); Buzzer: ringing when training is nearly done; Detection port: detecting the airflow passing through; Battery: for energy supplyBack to article page