The body is highly adaptive; if you always do the same workout it will stop responding. Eventually, you will hit a fitness plateau. Plus, who wants to repeat the same routine day in and day out? I know I don't.
The standard "three sets of twelve to fifteen reps" is fantastic if you have been training for less than six months, you have an injury or if you are prone to injuries. If you are healthy and have a training base of six months or more, you need to mix things up if you want to continue to get stronger and see further results. Try "pyramid sets" – they are an effective yet simple way to add variety to a workout.
In a pyramid set, the number of repetitions you do increases or decreases throughout the workout. The weight you use usually changes in an inverse relationship to the repetitions you are doing. What that means is, usually the fewer the repetitions, the higher the weight.
For example, if you wanted to do a pyramid set of squats you could warm up with a light weight for 15 repetitions, then do 10 reps, eight reps and six reps, increasing the weight each time.
To really get wild and crazy, super-set two exercises together within your pyramid workout. A super-set is when you do two exercises back-to-back with no rest in between. To do a super-set pyramid you need to first pick two exercises. Any two will do, but I like picking one lower-body and one-upper body exercise.
For example, you could super-set lunges and bent over rows. Do 15 repetitions of each back-to-back using a light weight. Rest for 60 seconds. Then do 10 reps of each back to back with a medium weight. Rest for 60 seconds. Finish with six reps of each exercise back-to-back with a heavy weight.
The repetitions don't always have to pyramid down. You can increase the repetitions as you go. I find this type of pyramid works well as a cardio warm-up.
First, pick three cardio exercises. Try jumping jacks, high knees and bum kicks. Start by doing five reps of each exercise back-to-back. Then do ten reps of each. Next do fifteen reps of all three. Finish by coming down the pyramid. Do ten reps of each exercise and finally five reps of each.