According to the authors of the current study, muscle weakness is a common finding in adult clinical populations and is also a consequence of normal aging. RT is the preferred training regimen to increase muscle strength and mass to perform ADLs, especially for elderly individuals and those who have chronic diseases. According to the authors, there is limited information on the efficacy of RT in improving muscle mass and the capacity of individuals with high or low numbers of metabolic risk factors to perform ADLs.

This is a randomized trial to compare the effect of 10 weeks of RT vs no RT training on individuals with high or low numbers of metabolic risk factors in terms of muscle strength and mass, peak aerobic capacity, and quality of life.

Study Highlights

• Included were 52 untrained men (n = 28) and women (n = 27) aged 50.8 ± 6.5 years (range, 40 - 69 years) who had not been involved in regular exercise within 6 months or RT within 5 years.
• Excluded were those with documented heart disease.
• Participants were classified as having low (? 1) or high (?2) metabolic risk factors based on medical history and results of an initial assessment.
• The baseline assessment consisted of fasting blood tests, dietary logs, anthropometric measurements, aerobic fitness determination, muscle strength assessment, the 36-item short-form health survey (SF-36), and physical performance test.
• The same assessments were repeated after 10 weeks.
• Physical performance test was determined using 4 functional mobility tasks: rapid walking test, up-and-go test, stair climbing, and stair descending.
• The low and high metabolic risk factors groups were randomized to RT and no RT for 10 weeks.
• The RT program was performed 3 days per week for 10 weeks with 48-hour recovery between sessions.
• Each training session included 3 minutes warm-up and 50 to 60 minutes of resistance exercise.
• RT intensity increased with time, with weights adjusted according to individual capacity.
• The exercises were based on recommendations of the American College of Sports Medicine for individuals with insulin resistance and type 2 diabetes and were supervised by a sports physiologist.
• The high metabolic risk factors group had greater waist circumference (101.5 vs 81.1 cm), systolic blood pressure (133.3 vs 116.7 mm Hg), diastolic blood pressure (87.6 vs 77.0 mm Hg), and triglyceride and lower high-density lipoprotein cholesterol levels vs the low metabolic risk factors group.
• Adherence to training was 88% for the high and 96% for the low risk factors group.
• There were no changes in dietary intake during the 10 weeks for either group.
• In both groups, RT had no effect on body mass.
• In the low risk factors group, RT had positive effects on waist circumference, total fat percentage, and total fat (kilograms).
• For both low and high risk factors groups, RT significantly increased lean body mass vs no RT training (by 2.6% and 2.1%, respectively).
• In the low metabolic risk factors group, RT improved both absolute and relative peak oxygen consumption (aerobic power) and muscle strength.
• In the high metabolic risk factors group, RT did not improve aerobic power or reduce body fat.
• Total time to complete the physical performance test was significantly reduced by 8.8% in the low and 9.7% in the high risk factors training groups, with no difference between the 2 training groups.
• RT had no effect on any of the subscales of the SF-36 or the physical and mental health dimensions for the low risk factors group.
• For the high metabolic risk factors group, RT increased the perception of both physical and mental health by 12.9% and 8.3%, respectively.
• Training had more positive effects on self-perceived physical health for the high vs the low risk factors group.

Pearls for Practice

• Resistance training for 10 weeks is associated with improved lean body mass, muscle strength, and capacity to perform ADLs in individuals with low or high metabolic risk factors.
• Resistance training increases self-perceived physical and mental health but does not reduce body fat or improve aerobic power in those with high metabolic risk factors. It reduces body fat and improves aerobic power in those with low metabolic risk factors.