Advancing age is often associated with a number of physical changes, such as losses in skeletal muscle mass, strength and power, and an increase in fat mass. These factors are related to important clinical outcomes, including mobility impairments, disability, falls and fractures. There is accumulating scientific evidence from studies focused on middle-aged and mature populations that consistent resistance training will improve functional abilities, prevent osteoporosis, slow sarcopenia (age-related loss of muscle mass, strength and function) and help prevent falls, fractures and disabilities (see Table 1).
Despite a number of published guidelines for resistance training of older adults, the mode, frequency, volume and intensity of resistance training required to optimize muscular strength gains are still unclear. In brief, research has been published investigating the effects of resistance training intensities of 50%–100% of 1RM (repetition maximum), performed for 1–3 sets per exercise, at frequencies of 1–3 times per week on machines and free weights, with protocol durations of 8 weeks to 1 year. Nevertheless, there is no clear evidence whether multiple-set protocols are necessary to gain and optimize strength in older populations. If a single-set program is comparatively effective for muscle strength and daily physical performance, it will save time, possibly minimize residual soreness in the initial workout stages and perhaps enhance exercise participation and compliance.
The main goal of this investigation was to compare the muscular-fitness and functional-performance benefits of a single- set resistance training program versus a multiset training scheme in older men and women.
Thirty-two sedentary men and women, aged 65–78, were randomly assigned either to a single-set or a 3-set exercise group. Four subjects from the single-set group withdrew from the study. Each subject obtained medical clearance and completed an informed-consent agreement and health history questionnaire before participating. Table 2 shows the physical characteristics of subjects at baseline.
All subjects participated in a total of 40 supervised exercise sessions, which were held twice a week for 20 weeks. Make-up sessions were provided for subjects missing a training session owing to travel, illness or personal commitments. Both groups performed chest press, seated row, triceps extension, biceps curl, leg press, leg curl and leg extension exercises on resistance training machines at an intensity of 8RM (the maximal weight that could be lifted eight times). Isotonic, isokinetic and isometric muscle strength and muscle endurance (maximal repetitions in the leg press and chest press at 70% of 1RM) were assessed. On a separate day from the muscle-fitness tests, various tests (chair rise to standing, 6-meter walk, 6-meter backward walk, floor rise to standing, stair climb and 400-meter walk) were completed for functional performance.
Dynamic Muscle Strength
After the 20-week training intervention, both groups showed significant and very meaningful strength improvements in all seven exercises. Improvements were significantly greater for the 3-set group than for the single-set group in the seated row, triceps extension, biceps curl and leg extension exercises (see Table 3).
Isokinetic and Isometric Strength
As shown in Table 3, there was no difference between groups in the isokinetic and isometric tests of the knee extensors. In the isokinetic peak torque test of the knee, both groups improved after training. However, only the 3-set group significantly increased strength in the isometric peak knee extensor torque test.
At the beginning of the study, there was no difference in the maximum number of repetitions the subjects could perform in the chest press and leg press at 70% of 1RM. However, after 20 weeks of training, the groups differed, with only the multiset group showing significant improvements in chest press and leg press endurance.
Table 4 shows the percent improvement within each group and the difference between groups after 20 weeks of training. There were significant improvements in the chair rise, 6-meter backward walk, 400-meter walk and stair-climbing tests for both groups, while only the 3-set group improved in the 6-meter walk and the floor rise to standing tests. There was no significant difference between groups for any test except the 400-meter walk test. Importantly, the changes within each group were similar.
This major peer-reviewed study substantially validates the efficacy of single-set training (performed 2 times a week for 20 weeks) for enhancing functional performance and strength in older men and women. Although the multiset training scheme resulted in greater improvements in some of the strength and muscle fitness parameters, the complete findings indicate that low-volume resistance training elicits similar and very meaningful responses and is an effective strategy for a mature population. This investigation contributes prominently to a broader understanding of the benefits of resistance exercise for functional performance and muscular strength in older adults.
Given that single-set resistance training economizes on exercise time and may reduce injury risk, dropout rate and muscle soreness, this protocol is an excellent exercise design option for personal trainers and fitness professionals to use with their mature clients. The sidebar, left, provides 10 resistance training tips for mature adults.
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