Sculpting Strength - But Not in Stone

Resistance-exercise prescription should be much more than the typical three sets of 10 to 12 reps for all major muscle groups, performed two or three days per week. A variety of variables should be considered when writing a strength-training program. In addition, trainers should rewrite the prescription on a regular basis (e.g., every four to six weeks) to improve client interest, and to avoid a physiological stalemate.

Regardless of the type of exercise performed (aerobic or resistance), one variable that needs consideration is training frequency. This will largely be determined by a client's recovery ability (i.e., their ability to repair damaged muscle tissue), and will vary from person to person. A common recommendation is to wait 48 to 72 hours before training a particular body part again. However, muscle recovery depends greatly on the client's training status, the particular muscle group trained (as some groups may recover more slowly than others), the training intensity and the total volume of work performed (number of repetitions and sets). In addition, considering such factors as poor nutritional intake, inadequate rest and a high-stress lifestyle, the common recommendation of 48 to 72 hours may not be adequate for many clients. On average, a hard-working client responds best when training each muscle group every four to six days, while performing resistance exercise no more than three to four days per week.

Intensity

One component that helps to determine frequency is training intensity. Related to exercise science, the term intensity does not simply refer to "how hard a client appears to be working," as described in most fitness publications. Intensity refers, instead, to a specific percentage of weight lifted, and uses a reference point of 100 percent of a client's maximum (i.e., one repetition maximum, 1RM). Therefore, the closer clients work to their 1RM, the greater the intensity of their training.

The prescription for training intensity is important to understand, because it ultimately determines which types of muscle fibers will be recruited to perform the work, in addition to the number of muscle fibers activated. Quite simply, the greater the weight load, the greater the muscle fiber recruitment. This allows for more of the available musculature to be active during a given exercise. For example, assuming a client pushes to failure on a given exercise, sets performed for five or six reps would be a higher intensity than sets performed for 12 to15 reps. As a result, you would expect that there would be a greater recruitment of muscle fibers with the higher-intensity set. The mistake trainers often make is they don't prescribe intensity ranges that involve low-rep sets (e.g., three to five reps). With this scenario, understand that a good deal of muscle is left "untrained." Periodically inserting high-intensity training for short cycles would be a great benefit to many clients, whether or not their goals are biased toward strength gains.

From a pure physiological standpoint, scientific studies suggest that resistance-exercise sessions may be best if kept below the 60-minute mark. In addition, trainers must always consider the fact that longer sessions are often associated with poor training effort. As such, clients may be best served by committing themselves to short sessions, performed every other day. This type of schedule seems to work best for people who have minimal time to exercise, but would still like to achieve superior results.

One of the biggest mistakes made in resistance-exercise prescription appears to be that of exercise selection. Most uncertainty seems to center around the use of free weights (barbells and dumbbells) versus resistance machines. Of course, advantages and disadvantages can be found with both. That being said, it is probably ideal to incorporate both into a well-rounded prescription, following consultation with clients about their interests and comfort level.

More specific to exercise selection, a well-balanced prescription should focus on training the entire body (not necessarily in each session), using few (e.g., four to six) exercises per workout. This allows clients to focus on a few tasks, as opposed to several, in one session. Including too many exercises is often associated with diminished effort. The exercises chosen may consist of both multi-joint (e.g., squats, barbell rows, etc.) and single-joint (e.g., dumbbell curls, triceps extensions, etc.) movements, with exercises chosen based on a client's training goals. In addition, the exercise selection should be varied regularly (every four to six weeks) to assure interest and optimal progress.

A common question among clients is, "How many sets per exercise should I perform?" While some trainers advocate as few as one set per exercise, others believe that more (up to five or six) are needed. For muscle fibers to fully benefit from a training stimulus, the fibers must not only be activated, but also fatigued. For example, one set of an exercise will certainly activate available fibers; however, it will not likely fully fatigue them. This fact lends support to the notion that repeated sets with a given weight may be necessary to receive the greatest training stimulus.

In writing a prescription, keep in mind that the number of sets performed per exercise should be inversely related to the number of repetitions. That is, the higher the number of repetitions per set, the lower the number of sets per exercise. Likewise, the lower the number of repetitions performed, the higher the number of sets. This relationship relates to fatigue, in that a small number of repetitions performed makes necessary for more repeated efforts of a given exercise in order to induce a state of fatigue, and subsequent adaptation.

Popular opinion suggests that higher reps are suitable for "toning," and lower reps for "building." Clearly, it is more complex than this. As mentioned earlier, the number of reps performed relates directly to training intensity, as fewer reps with a higher load represent a greater intensity, and more reps with a moderate load represent a relatively lower intensity. Understanding that the intensity of work will dictate the type and quantity of muscle fibers engaged, it follows that varying the number of reps per set over time will ensure that all available fibers will be trained at some point. A sensible approach would be to include brief (two to four week) periods when sets are performed with four or five reps, eight to 10 reps, 10 to 15 reps, etc. Low-rep training is not just for powerlifters. In fact, most, if not all, clients can benefit from high-intensity, lower-rep work.

Despite all ofthe debate over rep number, the actual number of reps is not of main importance. What may be of greater significance is the total time that the muscle is forced to work during a given movement without resting. This is referred to by exercise scientists as time under tension, and is typically written in the exercise prescription in three phases as follows: eccentric (lowering portion), isometric (pause) and concentric (lifting portion). Each phase can be represented in terms of seconds taken to complete each portion of the movement. For example, a 5-0-1 tempo indicates that a movement takes five seconds in the eccentric phase, zero seconds in the isometric phase and one second in the concentric phase. By varying the tempo, and thus the time under tension, the actual stimulus can vary without directly changing the number of reps or the weight. Attention to this often overlooked variable can improve clients' motivation to train, and can often allow them to break through training plateaus.

The length of time taken between consecutive sets of a particular exercise should be systematically varied based on the training intensity (% 1RM). These variables have an inverse relationship, where the greater RM loads necessitate greater rest. For example, sets that involve three or four reps will require greater rest intervals (two to four minutes) than do those consisting of 10 to 12 reps (45 to 90seconds). This may appear odd, as one may be more fatigued following a set of 12 reps versus one of three. However, performing three reps is much closer to 100 percent of max than is the performance of 12.

While several program variables have been discussed, it is apparent that specific designs can be numerous. Clients should understand that a training program is only as good as the time it takes for them to adapt to it. No matter how effective a program may be at the start, it will eventually lose effectiveness. It is at this time that they will need to adopt a completely different approach, guided by their trainer. Remembering to systematically manipulate the variables discussed here to allow for increased client interest, compliance and optimal adaptations.

Sample Resistance Exercise Program