If training time is really limited, one study (Westcott 1990) reported excellent results from just three multiple-muscle exercises. These were the leg press (quadriceps and hamstrings), bench press (pectoralis major, deltoids and triceps), and compound row (latissimus dorsi and biceps).
Training Frequency: Strength exercise may be productively performed two or three days per week. In terms of strength development, a recent study by DeMichele et al (1996) found two and three training sessions per week to be equally effective. With respect to body composition changes, subjects in the Westcott and Guy (1996) study who trained twice a week attained almost 90 percent as much improvement as subjects who trained three times a week (see Figure 1).
[Please insert Figure 1 about here.]
Because two and three training sessions per week appear to produce similar muscular benefits, the exercise frequency factor may be a matter of personal preference and scheduling ability.
Training Sets: Single and multiple-set training protocols have proven effective for increasing muscle strength and mass in senior men and women (Frontera et al 1988, Fiatarone et al 1994, Nelson et al 1994, Campbell et al 1994, Westcott and Guy 1996, Westcott et al 1996). However, studies comparing one and three sets of exercise have found no significant developmental differences during the first few months of training (Starkey et al 1996, Westcott 1995). It is therefore suggested that seniors begin strength training with one properly-performed set of each exercise. This time-efficient approach to strength exercise is safe, effective and well-received by senior men and women.
For example, in the Westcott and Guy (1996) study, the 341 older adults added 2.4 pounds of muscle and lost 4.1 pounds of fat after two months of single-set strength training. Perhaps more important, 95 percent of the participants continued to strength train after completion of the exercise program. Of course, as the senior exercisers become better conditioned, they may perform additional training sets if they desire to do so.
There is a range of training weightloads, generally between 60 to 90 percent of maximum resistance, that is productive for developing muscle size and strength. Weightloads below 60 percent of maximum are relatively light and provide less muscle building stimulus. Conversely, weightloads above 90 percent of maximum are relatively heavy and may present more injury risk.
For most practical purposes, training with 70 to 80 percent of maximum resistance represents a safe and effective weightload range. In fact, many of the studies with senior subjects have successfully used 70 to 80 percent of maximum resistance in their training programs (Frontera et al 1988, Nelson et al 1994, Fiatarone et al 1994, Westcott and Guy 1996). As these studies have reported no training-related injuries and high rates of muscle development, exercise weightloads between 70 and 80 percent of maximum resistance are recommended for senior strength training programs.
Research (Westcott 1995) indicates that most people can perform about 8 repetitions with 80 percent of their maximum resistance, and about 12 repetitions with 70 percent of their maximum resistance. This represents a moderate number of repetitions per set, and requires about 50 to 70 seconds of continuous training effort when performed at a moderate movement speed. The recommended number of training repetitions for senior exercisers is therefore between 8 and 12 repetitions per set.
Although it is not problematic to train with more than 12 repetitions, the key to muscle development is progressive increases in the exercise resistance. Therefore, it is advisable to add a little weight whenever 12 repetitions can be completed in proper form. The recommended training approach is to work with a given resistance until 12 repetitions are performed, then to raise the weightload by five percent or less. For most senior exercisers, this corresponds to about 2.5 to 5.0 pounds more weight, which in turn reduces the number of repetitions that can be completed. This double-progressive training system gradually increases the exercise demands and reduces the risk of doing too much, too soon.
There is general consensus that older adults should use controlled movement speeds when performing strength exercise. One study (Westcott 1994) showed excellent and almost equal strength gains for subjects training with four-second, six-second, and eight-second repetitions, indicating that there is a range of effective training speeds. Because six-second repetitions have a long and successful history, this repetition speed is recommended for senior exercisers. The preferred cadence is two seconds for the more demanding lifting phase (concentric muscle action), and four seconds for the less demanding lowering phase (eccentric muscle action).
About The Author
Wayne L. Westcott, Ph.D.,
is fitness research director at the South Shore YMCA in Quincy, MA. He is strength training consultant for numerous national organizations, such as the American Council on Exercise, the American Senior Fitness Association, and the National Youth......more