Good article by Charles Staley at T Nation on how many reps you should do.
Here’s what you need to know…
• It’s not what you can do in a set, it’s what you can do in a workout. It’s not what you can do in a workout, it’s what you can do in a training cycle.
• If you’re interested in maximal strength, tension is the name of the game. That can mean lifting a very heavy weight as fast as you can, lifting a moderately heavy weight as fast as you can, or ideally, both.
• If your main goal is strength, you should terminate any given set just short of technical breakdown, or for stable lifters, always leave one solid rep in the tank for any given set.
• If your main goal is hypertrophy, you should use a wide range of reps, from as few as 1 to as many of 30. This can be done by pyramiding up to a few heavy sets, followed by a few higher-rep “back off” sets with lighter weights.
• Most trainees need to address both strength and hypertrophy in their training, regardless of what they consider their primary goal to be. The “sweet spot” between these two adaptations seems to be 5-8 reps per set.
• Training to failure is only advisable for technically stable athletes on their last set. Blowing your wad on your first set will limit the overall amount of volume you’d otherwise be able to rack up.
Whenever you’re doing a set, there are only two real decisions you need to make:
1. How many reps should I do?
2. How close to failure should I go?
Aside from exercise selection and training frequency, these are possibly the two most important decisions you’ll need to make in order to obtain optimal results from your training. To answer these questions, you’ll in turn need to ask two additional questions:
1. What’s my goal?
2. How many total sets am I going to do for that exercise?