I was wondering if anyone can explain the correlation between muscle soreness after training and muscle growth.

I am now training with my brother who has trained hard for the past 10 years. Whatever he is doing works.

He is always more sore then his partners and claims its always been this way. No matter who, when or where. We train at the same intensity for the same number of reps and he is alwats very sore. (You know the can't sit down to take s**t after legs day feeling).

Is this a good thing? Is he growing more then me? Why is he more sore? We both lift to failure, work negatives etc the same.

I don't kno a whole lot about this. Can you explain

1: Why our muscles get sore?
2: If they are really sore does that mean we had a better work out?

And tell me everyhting else about it, I am sponge soak me full of knowledge. By the way we eat the same, take the same supplements, have similar sleep and work paterns etc.

Thanks for the answers guys