Resistance Training Frequency

How many repetitions?
Performing a moderate number of sets (say three) of one to five repetitions with extremely heavy resistances tends to stimulate strength, presumably via neural mechanisms, whilst having only a minor effect on muscle growth. An increase in 'neural drive' is thought to enable an individual to more fully activate the motor units within the trained muscles, the result of which is an increase in strength even if muscle hypertrophy does not occur.

The primary effect of performing three sets of six to fifteen repetitions with moderate to moderately heavy loads is to stimulate muscle hypertrophy. This repetition range (especially the 12-15 range) is thought to induce a less dramatic neural adaptations. Another major effect of moderately high repetition ranges (10-15) is to stimulate increases in local muscular endurance.

Training with 15 repetitions or more tends, primarily, to increase local muscular endurance although it also has the potential to stimulate increases in muscle mass, particularly in the 15 to 20 repetition range.

It should be recognised that in terms of the physiological outcomes a considerable degree of overlap exists between repetition ranges. As a result it is not possible to state the exact repetition range which will bring about any single type of adaptation. Furthermore, the number of sets performed will also influence the primary adaptation and it appears likely that three sets of 10 reps (3*10) and 10 sets of three reps (10*3) will trigger similar muscle growth as the total volume of the workout, rather than the number of reps in each set, is likely to be the more fundamental variable.

How many sets?
As long as the intensity of effort is adequate, novices may require only one or two sets per muscle group in order to improve their strength quite rapidly. However, the rate of progress made with such a low training volume will start to decrease after six to 12 weeks unless a greater number of sets is performed. At this stage three sets per muscle group would stimulate further increases in strength.

Advanced strength trainers usually utilise more sets per body part although the most appropriate range is hotly debated amongst strength training experts. For anyone exercise it is uncommon for advanced powerlifters to perform more than six sets, although the total number of sets per muscle group may be anywhere between six to twelve.

Until now we have carefully avoided discussing the number of sets appropriate for developing muscular hypertrophy. In the field of bodybuilding very little truly scientific research has been done and it seems, from a cursory view of the training practices of elite bodybuilders, that opinions on the matter are divided. Those from the high intensity school argue that between two and five sets per muscle group are most appropriate. However, an analysis of training programmes used by elite bodybuilders suggests that a majority utilise moderate intensity and high volume methods where the number of sets may range between ten and thirty per muscle group. Even if the performance of extremely high training volumes proves effective this method is too time consuming for all but a few highly committed professional bodybuilders.

If the programme is appropriately planned it is apparent that depending on the training background of the individual, significant muscle hypertrophy can be stimulated with any where between two and six sets per muscle group. Slightly higher training volumes (at the expense of training intensity) are sometimes used quite successfully, although there is no conclusive evidence that these methods are any more effective than the more moderate volumes.