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Hannah Horris, Barton E. Anderson, R. Curtis Bay and Kellie C. Huxel Bliven

Context: Altered diaphragm function is linked to decreased core stabilization, postural changes, and decreased function. Two clinical tests used to assess breathing are the Hi-lo and lateral rib expansion (LRE) tests. It is currently unknown how breathing classification based on these tests differ and how their results are affected by varying test positions. Objective: To compare the results of breathing tests when conducted in varying test positions. Design: Prospective cross-sectional study. Setting: University laboratory. Participants: A total of 50 healthy adults (females 31 and males 29; age 29.3 [4.1] y; height 170.0 [10.4] cm; weight70.7 [15.1] kg). Intervention(s): Hi-lo and LRE tests in supine, seated, standing, and half-kneeling body positions. All tests were recorded and later scored by a single examiner. A generalized estimating equations approach with breathing test and body position as factors was used for analysis. Pairwise comparison with Bonferroni correction was used to adjust for multiple tests. Statistical significance was set at P = .05, 2 tailed. Main Outcome Measures: Hi-lo and LRE tests were scored based on the presence or absence of abdominal excursion, LRE, and superior rib cage migration. Following scoring, results were classified as functional or dysfunctional based on observation of these criteria. Results: A significant breathing test × test position interaction (P < .01) was noted, as well as main effects for test (P < .01) and test position (P < .01). All Hi-lo test positions identified significantly more dysfunctional breathers in positions of increased stability demand (P < .01), except between standing and half-kneeling positions (P = .52). In the LRE test, all positions were similar (P > .99) except for half-kneeling, which was significantly different from all other positions (P < .01). Conclusions: The Hi-lo test and LRE tests assess different breathing mechanics. Clinicians should use these tests in combination to gain a comprehensive understanding of a person’s breathing pattern. The Hi-lo test should be administered in multiple testing positions.

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Thomas M. Lundin, Dennis W. Jahnigen and Mark D. Grabiner

When rising from a chair, older adults have been reported to use a strategy in which the trunk is flexed to a greater extent than young adults, a strategy attributed by some to concerns with the postural stability demands of the task. This study determined the extent to which maximum trunk flexion angle during a self-paced sit-to-stand from a standardized initial position was influenced by the maximum isometric strength of the knee and trunk/hip extensor muscles in older adults. The hypothesis was that the larger maximum trunk flexion angle attained by older adults when rising from a chair is related to the maximum isometric strength of the knee and trunk-hip extensor muscles. To test this hypothesis, maximum voluntary isometric strength of the trunk extensor and knee extensor muscles of 28 older men and women were measured. Trunk motion during the sit-to-stand by these adults was men assessed using motion analysis. Multiple regression was used to characterize the relationship between the maximum trunk flexion angle and maximum isometric knee extensor and trunk extensor muscle strength. The derived relationship was neither statistically significant nor biomechanically meaningful. This result suggests that the trunk flexion angle attained by healthy older adults when rising from a chair from a standardized initial position is not influenced by knee extension and trunk-hip extension strength as measured in the present study.