Introduction: Although muscle-strengthening exercise has multiple independent health benefits, little is known about muscle-strengthening exercise participation and associations with adverse health conditions among U.S. adults.

Methods: In 2017, data were analyzed from the U.S. 2015 Behavioral Risk Factor Surveillance System. During telephone surveys, respondents reported how many times during the past week they engaged in muscle-strengthening exercise. Weighted weekly muscle-strengthening exercise frequencies were calculated for the total sample and across sociodemographic and lifestyle characteristics. A multivariable logistic regression assessed the odds of having self-reported adverse health conditions (e.g., diabetes, coronary heart disease) according to weekly muscle-strengthening exercise frequency.

Results: Data were available on 397,423 adults (aged 18-80 years). Overall, 30.2% (95% CI=29.9, 30.5) met the muscle-strengthening exercise recommendations (two or more times/week) and 57.8% (95% CI=57.5, 58.2) reported no muscle-strengthening exercise. Older age, insufficient aerobic activity, lower income, lower education, poorer self-rated health, being female, and being overweight/obese were significantly associated with lower odds of meeting the muscle-strengthening exercise recommendations independently of other characteristics. After adjusting for confounders (e.g., age, sex, income, smoking, aerobic activity), when compared with those who did none, muscle-strengthening exercise was associated with lower odds for several adverse health conditions, including prevalent diabetes, cancer (non-skin), poor self-rated health, and obesity.

Conclusions: Three in five U.S. adults do not engage in any muscle-strengthening exercise, despite an association for muscle-strengthening exercise with better health conditions. Future muscle-strengthening exercise promotion strategies should target older adults, females, those with low education/income, and those with a poor health status.