graphic depicting a leg and a crutch on a blue background with text and muscle in the background

About MAC

There are negative health consequences of muscular disuse in aging populations. We seek to address key knowledge gaps that limit researchers’ ability to implement evidence-based rehabilitation strategies. The purpose of the study is to examine changes in the structure and function of skeletal muscle during periods of disuse and rehabilitation in middle-aged men and women.

There are two phases of this study:

  • Phase 1 will involve wearing a leg sling and the use of crutches for 1 week.
  • Phase 2 will require 2 weeks of supervised rehabilitation with either resistance exercise or walking.

Healthy, middle-aged men and post-menopausal women (50-65 years) will be recruited from the greater Houston/Galveston area. This under-represented research demographic demonstrates few negative metabolic or phenotypic signs of advanced age but is at increased risk of being hospitalized and experiencing accelerated loss of lean mass and muscle function that parallels a much older population. The goal of this study is to characterize phenotypic and molecular skeletal muscle changes in middle-aged men and women during critical periods of disuse and rehabilitation and ultimately direct the development of targeted and effective prevention and treatment strategies.

Key Personnel

  • Sean Kilroe, PhD, E:, P: (832) 378-8461
  • Zach Von Ruff, MS, E:, P: (832) 356-9469
  • Emily Lantz, PhD, E:
  • Study PI: Doug Paddon-Jones, PhD, E:

We are looking for volunteers who:

  • Are male or female 50-65 years of age
  • Are generally healthy
  • Can attend multiple weekday study visits at the UTMB Galveston campus over a 6-8 week period
  • Download flyer:

Volunteers will be compensated for their participation.



UTMB Department of Nutrition & Metabolism (MAC Study)
Sean Kilroe, PhD
P: (832) 378-8461 E:

This study is supported by a grant from the National Institute of Aging (ROI AG064386-01).