Effectiveness of respiratory resistance training device on respiratory muscles strength and endurance

Abstract

Respiratory muscle strength and endurance play critical roles, like a pump, to continuously ventilate air in and out from the lungs. This makes the body possible to prolong physical activity. Respiratory muscle training is, therefore, necessary for either unhealthy or healthy persons. Various techniques and equipment on respiratory muscle training have been developed with some limitations. Most equipment focused on lung volumes and capacities and flow rates, in which environmental humidity and temperature had not been taken into account. These limitations cause sore throat and frequently bring training to an end. To investigate the effectiveness of respiratory resistance training device, specifically developed with humidity and temperature adjusted to overcome the above limitations, on strength and endurance. Twenty female volunteers (average age = 22.50 ± 2.64) were randomly divided into control (n = 10, no training) and experimental (n = 10, training) groups. The latter group was continuously trained using respiratory resistance training device at 40% of each individual maximal inspiratory pressure (MIP, represents inspiratory muscle strength) for 20 cycles/set (pause 10 sec for every 2 cycles), 5 sets/day, 3 days/week for 6 weeks. To make progression, new MIP was estimated and inspiratory resistance was readjusted on weekly basis for maintain load at 40%MIP. Respiratory muscle strength (inspiratory pressure via MIP and expiratory pressure via MEP) and endurance (via 12 sec maximal voluntary ventilation) were tested on week 1 (pre-training), 3 and 6. The Control group showed no significant change of both respiratory muscle endurance and inspiratory muscle strength. While the training group had higher respiratory muscle endurance and inspiratory muscle strength throughout the studying period. Respiratory muscle endurance in training group was significant higher at week 3 (124.42±3.74; P < 0.05) and 6 (128.02±3.91; P < 0.05) when compared to initial levels (115.79±3.36). Inspiratory muscle strength was significant higher at week 3 (95.60±3.68; P < 0.05) and 6 (103.20±3.57; P < 0.05) respectively when compared to initial levels (79.60±2.57). Whereas, the expiratory muscle strength was not changed in both groups. In addition, training group did not show signs/symptoms of sore throat. Comparison between groups revealed that the training group developed higher respiratory endurance than the control group at week 3 and 6 (p < 0.05). respiratory resistance training device developed in this study exhibits its effectiveness on respiratory muscles for both strength and endurance with no complication.