Related Experiment Video
Updated: May 1, 2026
3D Ultrasound Imaging: Fast and Cost-effective Morphometry of Musculoskeletal Tissue
Published on: November 27, 2017
Impact of body mass index on the relationship between muscle quality and physical function in older women
A O Brady1, C R Straight, M D Schmidt
1Anne O. Brady, PhD, University of Georgia, Department of Kinesiology, 330 River Road, Athens, GA 30602, USA, anneobrady@gmail.com, Phone: 678-938-8862.
Objectives:
To investigate the impact of body mass index (BMI) (normal weight, overweight, obese) on the relationship between muscle quality (MQ) and physical function in community-dwelling older women.
Design:
Cross-sectional study.
Setting:
University research laboratory.
Participants:
Community-dwelling older women (n = 94, 73.6 ± 5.4 y) stratified by BMI (normal weight: 20.0-24.9 kg/m2; overweight: 25.0-29.9 kg/m2; obese: ≥ 30.0 kg/m2).
Measurements:
Body mass index using height and weight, leg extension power via the Nottingham power rig, body composition using dual-energy X-ray absorptiometry, and physical function (6-minute walk, 8-foot up-and-go, 30-second chair stand). Muscle quality was defined as leg power (watts) normalized for lower-body mineral-free lean mass (kg).
Results:
Following adjustments for covariates, muscle quality was significantly higher in women of normal BMI compared to overweight (10.0 ± 0.4 vs. 8.7 ± 0.4 watts/kg, p = 0.03). Muscle quality was a significant predictor of performance on the 6-minute walk and 8-foot up-and-go in normal and overweight women (all p < 0.05) and performance on the 30-second chair stand in normal and obese women (both p < 0.05). Body mass index did not significantly impact the association between MQ and physical function (all p > 0.05).
Conclusions:
Muscle quality varies by BMI, yet the relationship to physical function is not significantly different across BMI groups. The results imply that interventions that increase MQ in older women may improve physical function, regardless of BMI.
Related Concept Videos
01:29Bone Disorders
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
01:27Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
01:19The Effect of Aging on Tissues