The Differences in Female Levator Ani Muscle Function Between Occupational Lifters and Non-Lifters

Faculty Researcher: Janis M. Miller, PhD, RN, Assistant Research Scientist, School of Nursing, University of Michigan

This study aims to investigate the influence of the presence or absence of a history of occupational stress (such as heavy lifting) on levator ani muscle (LA) function in women. The LA is primarily a pelvic postural muscle, responsible for carrying the load imposed by the pelvic contents in the human upright stature. Weak or damaged LA muscle is associated with the common pelvic floor disorders of prolapse or incontinence. Repetitive loading, as in occupational heavy lifting, may induce conformational changes to the LA. This area of investigation is unexplored in the literature. We will plan to recruit 12 occupational lifters and 12 non-lifters, age and race-matched, all without prior childbirth. An array of tests will be conducted to test LA function using new instrumentation developed at the University of Michigan and recently patented. Comparisons will be made using standard statistics: student’s t-test and logistic regression. The primary outcome of the study is feasibility testing and power analysis calculations for a planned R01 submission to study influence of lifting on LA health while controlling for childbirth. The long-term goal of this line of research is to determine life style risk factors that predict development of pelvic floor disorders across age. Ultimately, the goal is to reduce the statistic of 1 in 10 women undergoing surgery for these disorders.


Grants resulting from this project:
NIH/NICHD. 1R21 HD049818-01. Maternal Birth-Related Neuromuscular Injury and Recovery (PI: Miller). 2005-2006.

Research trainee’s current position:
Janis Miller is currently a Professor in the University of Michigan School of Nursing.