The 5×5 is a common set/rep scheme, for squats in particular. I really like to use the 5×5 for my front squat training as I tend to make good progress on it as well of course the low(ish) amount of reps being good for front squats.
I have come across a lot of queries on forums about how to load the 5×5. Many sources state that the load for a 5×5 should be around 80-85% of 1RM. There are a few variations on how we can work the 5×5 with this percentage range, which I will discuss below:
The same weight, 81%, for all sets
The most common figure I see is that a 5×5 workout is best done with about 81% of your 1RM. In this method, each set is done using the same weight. So for example a person who has a 1RM of 70kg, they would do all 5 sets at about 57kg.
Increasing weight for each set
Another method I’ve read about is to start at a particular load and increase it for each subsequent set. What the figure is for the sets is really down to the individual and how they are feeling. If a 5×5 is recommended to be done at 80-85% of the 1RM, I might suggest that the first set could be done at around 80% and possibly worked up to 85% by set 5. The same person who has a 1RM of 70kg might therefore do their sets at 57kg up to 60kg (80-85%).
Lowering weight for each set
This is the reverse of the previous method. The person might do their first set at around 85% load and go down to around 80% by set 5. Personally I am not a fan of this method (or any sort of reverse pyramid scheme), because I never feel warmed up enough to start off at the highest weight. My body works seems to respond best when I go up in weights for sets, not down.
The same weight, 85%, for all sets
If some sources state that the 5×5 can be loaded with between 80-85% then some people might be able to train all sets at the top end of this. The person with their 70kg 1RM would therefore do all sets at 60kg. Most likely the main things to change here, given the higher load, would be: longer rest periods needed between sets, more time taken between reps, slower concentric phases. This just goes to show that you can change the way your body has to function even with the same set/rep scheme.
The conclusion is that the 5×5 is one of the most common training schemes used and surely for good reason! People make good gains from it. But there are still various ways you can do it. Experiment with what works best for you. Also, it’s good to appreciate that you can still adapt your rep/set scheme (which is what we are told is good for the body – to do different things and ‘trick’ it every once in a while), without having to stop doing a 5×5 – through the things discussed above such as increasing weight per set, or doing heavier weights and increasing rest periods between sets, etc.