The 5×5 training module is one of the top, original, and most popular muscle-mass-building programs that’s being used by elite bodybuilders and athletes. It's designed to focus hard on one muscle group, 2-3 times per week, while still giving you enough recovery time to promote significant muscle growth.
This program is designed for those that have base training “under their belt” as the intensity and volume is much higher than what most beginner bodybuilders are used to. If your body isn't used to this increased intensity, you may experience prolonged recovery times and, potentially, the risk of overtraining.
The recommended 5×5 ‘cycle’ lasts approximately 7-9 weeks, including 4-6 weeks of ‘prep work’, followed by 3 weeks of the ‘peak phase’. After you have completed the full cycle, it's highly recommended to do a deloading week where you workout with less intensity or if you prefer to just take a week for complete rest.
Prep work phase.
During the first week of your 5×5 regimen it's important to prepare your body, allowing it to grow accustomed to this type of training. Proper prepping starts with finding the right weights to start.
Finding a proper weight.
You should focus on finding a weight range that allows you to complete 5 sets of a given exercise, at 5 reps per set (25 total reps). This weight shouldn't be so easy that you feel you could do a lot more than that, but also light enough to where you're able to finish all 5 sets. The entire training program is centered around being able to complete all 25 reps, so it's entirely important to find the proper weight range for each exercise. It's a key factor in the success of the program and must be followed.
Increasing the weight properly.
After the first week, once you're able to properly complete (emphasis on the word ‘properly') all of your sets at the proper weight range, it's important to gradually increase your weight in order to maximize strength gains. For free weights, it’s recommended to increase the weights by 5lbs per dumbbell and by 10lbs per side on barbells.
If you're unable to complete the entire 5×5 set/rep range with the increased weight then you need to reduce the increased weight to one that allows you to complete the entire program. If, by decreasing the weight, you end up back at your original weight, then perform your exercises for an additional week at their original weights to help build the strength necessary for a weight increase.
With proper nutrition and training, by the time you've reached the 4-6 week mark, you should be setting new weight maxes and seeing significant increases in strength and size (best when done in a “bulking” phase, with calorie surplus). You can sometimes still see strength increases even if you're in a deficit, though it's much more unlikely, especially among the advanced individuals.
5X5 Peaking Phase
After 4-6 weeks of prepping, it's time to move on to the 5×5 peaking phase. What you'll need to do for the first two weeks is drop your sets and reps down to more of a 3×3 set-up. This will allow you to push each set even harder, and up your max by lifting more weight.
For the larger, compound exercises like squats, bench press, and deadlift, you may want to consider only performing the 3×3 program twice per week, as opposed to three times, due to increased intensity.
Round up.
If you’re looking to mix up your workout regimen, the 5×5 training program is one of the most respected and most efficient regimens for gaining lean muscle mass. It's important to note, however, that whenever you're looking to gain muscle mass, or bulk, to be in a caloric surplus, to help with protein synthesis.
During the peak phase you should focus on increasing weight, more so than increasing the number of reps performed. This is the time to train harder and push yourself to new levels.