Discussion
I commend Curves® For Women on an excellent introductory exercise program that has been exceptionally well-received by previously sedentary women of all ages. The brief and basic circuit training protocol using hydraulic resistance machines provides a quick and easy workout that produces good results during the initial exercise sessions. Generally speaking, the Curves® program offers beginning participants effective, efficient and enjoyable exercise experiences.

However, when the women reach a fitness plateau, a more challenging resistance training protocol may be appropriate to elicit further improvement. Based on the results obtained in the Healthy Inspirations® research study, this approach has merit. The 32 second- phase program participants switched from hydraulic resistance equipment (concentric muscle contractions) to standard weightstack machines (concentric and eccentric muscle contractions) for a seven-week training period. The relatively short exercise sessions (8 machines, 1 set of 8 to 12 repetitions each) produced significant improvements in the subjects' body composition, including 4.5 pounds less fat weight and 3.0 pounds more lean (muscle) weight.

Although weightstack machines provide solid resistance and more challenging muscle contractions, most people adjust quickly to this type of equipment and appreciate the two- phase exercise actions (concentric and eccentric loading). Based on our research, individuals who begin exercising with hydraulic resistance equipment should consider switching to standard weightstack machines upon reaching a training plateau in order to facilitate further progress.

Wayne L. Westcott, Ph.D., CSCS, is fitness research director at the South Shore YMCA in Quincy, MA.