Objective: To develop quantitative ultrasonography in studying the adaptation of quadriceps muscle mass and composition to short-term physical training and rehabilitation in elderly women.
Design: Randomized control trial.
Setting: Measurements in a research laboratory and training in a fitness center and sports hall.
Participants: Forty-two women, aged 76 to 78 years, with no indications against intensive physical exercise, randomly assigned to strength (n = 16), endurance (n = 15), and control (n = 11) groups. Twelve subjects from the strength, 12 from the endurance, and 11 from the control group completed the study.
Intervention: Supervised physical training 3 times a week for 18 weeks. Strength training: 3 to 4 sets of 8 to 10 repetitions with a load of 60% to 75% of the subjects' 1-repetition maximum. Endurance training: track walking and step aerobics at an intensity of 50% to 80% of maximum heart-rate reserve.
Main outcome measures: Ultrasonographic measurements of the quadriceps cross-sectional area (CSA), thickness, and weighted mean grey shades of vastus lateralis (MGSVL) and femur (MGSF).
Results: No significant interaction of group by time was observed in any of the outcome measures. The changes observed in CSA in the strength group correlated with those measured by computed tomography reported earlier. MGSVL decreased and MGSF increased in the strength group, suggesting a decreased proportion of fat in the muscle.
Conclusions: Quantitative ultrasonography is a potentially useful tool for studying skeletal muscle in elderly women. The precision and accuracy of the method, however, should be improved to reveal the adaptation of aging muscles to short-term physical training and rehabilitation programs.