The effect of ventilation on one legged squats
Nicole Burge, SPT; Thomas Johnson, SPT; Chelsea McClenning, SPT; Jessica Meyer, SPT; Brendon Stewart, SPT; Jean Hiebert, PT, Ph.D.
Purpose/Hypothesis: During ventilation, concentric contraction of the diaphragm decreases intrathoracic pressure allowing air to be drawn into the lungs. Though normal exhalation is a passive process, a controlled exhalation requires an eccentric diaphragm contraction. Besides its role in ventilation, the diaphragm also aides in postural control. The purpose of this study was to determine if the ability of the diaphragm to assist in postural control was affected by its simultaneous role in ventilation. Specifically, the purpose of this study was to determine if performance during a one legged squat test was different when the diaphragm contracted concentrically (inhalation), eccentrically (controlled exhalation), or isometrically (held breath). A previous (unpublished) study utilizing college aged subjects demonstrated improved performance on the squat test when subjects performed a controlled exhalation while squatting. Subjects: Ten healthy female subjects 40 to 60 years old (49.8 ± 7.44 years) volunteered for the study. Subjects were excluded if they had present or past history of neuromuscular, cardiopulmonary, genitourinary, gastrointestinal, or musculoskeletal disorders affecting the ability to perform one legged squats. Methods and Materials: Subjects performed bilateral single leg squats using the Y-Balance Test™. This test required subjects to squat on one leg while sliding a box with the opposite leg in three different directions: anterior, posteromedial, and posterolateral. Three slides in each direction were performed with subjects utilizing one of three breathing patterns: inhaling, exhaling, or holding breath. Performance was assessed by noting the distance the box was pushed in the given direction. Subjects rested after every 9 set of 3 trials. Breathing pattern was monitored via spirometer. As urinary incontinence increases as women age, the subjects wore a sanitary pad while performing the tests. The pad was weighed before and after testing to assess for presence of urinary leakage. Results: A 3x3 repeated measures analysis was performed to evaluate the relationship between the breathing conditions and the distance subjects were able to slide the box. There was a significant difference based upon direction but not breathing condition. Paired samples t-tests indicated subjects were able to slide the box farther both posterolaterally versus anteriorly (p=0.00) and posteromedially versus anteriorly (p = 0.00). There was no significant difference between posterolateral and posteromedial directions (p=0.315). There was no significant difference in weight of the sanitary pads before and after the test, indicating no urinary leakage during the performance of the test. Conclusion: Breathing pattern did not affect the ability to perform a single leg squat in this subject population. These results are different than those obtained when using younger subjects where greater ability to squat was noted when performing a controlled exhalation. Further studies are indicated in order to more accurately assess the relationship between balance, breathing pattern, and incontinence.