Correlation Between Dynamic Inspiratory Muscle Strength and Some Variables Associated with Aerobic Capacity

The aim of this study was to investigate the relationship between dynamic inspiratory muscle strength (IMS) and body composition, peak oxygen consumption (VO2peak), running economy (RE), and pulmonary function test variables. A total of 30 students (8 female and 22 male) (age=21.83±2.09years) from the Faculty of Sport Sciences voluntarily participated in this study. Body composition (with bioelectrical impedance analysis), dynamic inspiratory muscle strength (S-index), and tests of pulmonary function, VO2peak, and RE were performed. VO2peak and RE tests were measured using an ergo-spirometry system. The VO2peak test started with a 5-min warm-up on the treadmill at a 1% constant incline at 6 km/h speed. The test began at an 8 km/h speed, without a break, and persisted by increasing the speed by 1 km/h every 2 minutes until exhaustion. RE was taken on a treadmill with 6-minute tests at a constant speed at 70% and 80% of VO2peak. S-index indicated a significant positive correlation with body composition variables, lean body mass (r=0.661), total body water (r=0.667), and body mass index (r=0.602) (p<0.05). No significant correlation was found between the S-index and VO2 (ml.kg-1.min-1) taken by RE tests (p>0.05). However, a significantly moderate positive correlation was determined between S-index and VO2peak (ml.kg-1.min-1) (r=0.380) (p<0.05). Regarding the pulmonary function test, forced vital capacity (r= 0.634), forced expiratory volume in the first second (r=0.600), peak expiratory flow (r=0.768), and maximum voluntary ventilation (r=0.770) indicated a significant positive correlation with S-index (p<0.05). In conclusion, dynamic inspiratory muscle strength was found to be significantly related to lean body mass and some pulmonary function variables. As a result of VO2peak and RE, which are critical variables of aerobic performance, it is thought that dynamic inspiratory muscle strength may be relevant to oxygen consumption at maximal exercise rather than submaximal exercise.