Test Your Fast-Twitch Fibers
You can activate your fast-twitch fibers two ways—by lifting heavier weights or by lifting lighter weights very quickly. Take this test to determine your fast-twitch ratio. The result will tell you how you need to lift in order to see the fastest improvement.
Step 1: Test your 1-rep max on the bench press (See below). Then rest five minutes.
Step 2: Select a weight that's 45 percent of your 1-rep max. (So if your max is 225 pounds, you'll start with about 100 pounds.) Try to perform five reps in five seconds.
Step 3: If you succeed, rest 1 to 2 minutes and then repeat the test, this time using 5 to 10 percent more weight. Keep adding 5 to 10 percent until you can no longer complete five reps in five seconds.
Step 4: Calculate your fast-twitch ratio: Simply divide the heaviest weight you could lift in five seconds by your 1-rep max. If you lifted 135 pounds in five seconds and your max is 225, your ratio would be 60 percent.
5-rep test/1-rep max
= fast-twitch ratio
How to Test Your 1-Rep Max
Using a spotter, perform a barbell bench press. Start with half of your estimated 1-rep max, or 1RM (the amount of weight you think you can press only once). Do five or six reps with perfect technique. Now add 10 percent more weight but subtract one rep. Rest two minutes. Repeat this pattern until you do one rep with about 90 percent of your estimated 1RM. Rest three to five minutes, and try your estimated max. If you achieve it, then that's your true 1RM. If you fail, then use the 90 percent weight; if it's too easy, add 10 percent to your estimated 1RM.
Now that you've determined your fast-twitch ratio, select one of the workouts below to do as your upper-body routine at least twice a week, making sure you never do an upper-body routine two days in a row. Alternate between exercises that share the same number (1A and 1B, for example) until you complete all exercises in the pairing. Then move on to the next exercise. Select a weight that allows you to perform at least the minimum number of reps listed.