High intensity training (HIT) is a style of weight training that heavily influences the way that both bodybuilding and recreational weightlifting are performed today. First introduced as a mainstream training protocol by the founder of Nautilus, Arthur Jones, HIT is not to be confused with high-intensity interval training (HIIT), a form of cardiovascular training. Rather, high intensity training is a method of training one’s muscles that is intended to bring about strength and size gains by emphasizing muscle fiber recruitment. It is characterized by slow, steady lifting technique, by using a maximal amount of weight that can be lifted in a relatively low number of repetitions — rarely more than 15 — and by performing only one set and no more than one or two exercises per muscle group.
Made popular in the 1970s when Nautilus machines first were introduced, high intensity training was devised by Jones as a method of making strength training more accessible and less time-consuming, and to place emphasis on using his machines rather than free weights. The idea behind HIT principles is that rather than spend several hours a day and six days a week training, one could cut his lifting regimen to three or four 30-minute sessions by emphasizing intensity. Lifting at a maximum intensity for a given muscle group by selecting a weight that would bring the lifter to momentary muscle failure within a brief number of repetitions meant similar if not better results with increased exercise efficiency.
An example of a typical high intensity training routine is as follows. Three times a week, one would perform a full-body strength-training workout, keeping the session to 30 minutes. He would select an exercise for each of the major muscle groups: chest, shoulders, biceps, triceps, lats, upper back, lower back, abs, glutes, quads, and hamstrings. Each set would take approximately 90 seconds to perform if the goal is to perform ten reps, with three seconds to lift each rep, four seconds to lower, and a one-second pause apiece at the top and bottom of the movement. A minute or two would be allowed between each exercise for rest, depending on the lifter’s goals, and an additional exercise might be performed for a muscle group that one wanted to emphasize.
High intensity training principles recommend six to 10 repetitions for upper-body muscle groups, and eight to 12, sometimes as many as 15, reps for the lower body. The amount of weight selected will depend upon the number of repetitions the lifter wishes to perform, and a trial period may be required to become familiar with the appropriate load that one can handle. High intensity training also emphasizes proper technique, so an exercise professional should be consulted to determine the amount of weight to lift as well as whether correct form is being exhibited.