I picked this up from a Charles Poliquin article in Muscle Media (July 1996), and it’s a great method for boosting your strength on certain exercises and for blasting past any sticking points you may have within a movement itself (for example, the midpoint of a biceps curl).
Isometronics is practical for only certain kinds of movements, namely pressing movements (bench press, incline, military, close grip, etc.) and curling movements (barbell curls). This means only your chest, delts, triceps, and biceps can benefit from isometronics. Too bad, because the increases in strength using this method are truly phenomenal.
What you need is a power rack, an Olympic-size barbell, some Olympic plates, and two pairs of rack pins (meaning 4 pins altogether). Using the bench press as an example, here’s how it works:
1) Divide the movement’s range into three equal parts. You will perform partial reps in each portion of the bench press inside the power rack, using the two sets of pins to mark off the upper and lower boundary of the partial movement.
2) Start off with the lower portion (3 sets), then the middle portion (3 sets), and finally finish off with the top portion (3 sets). Note, that for the top range of the bench press (or for any movement, for that matter), place the pins just short of lockout. Rest 3 minutes between sets.
3) You will perform 6-8 partial reps to failure for each set. At the end of the 6-8th rep, press the bar against the top pins. Press as hard as you can for 6-8 seconds, as if you’re trying to complete a full rep by breaking through the pins.
4) After the 9 sets of partial reps, do one set of full-range bench presses.