After today´s pain I feel I have to get some serious information about that. Here is what I found: 

Delayed onset muscle soreness (DOMS) describes a phenomenon of muscle pain, muscle soreness or muscle stiffness that is felt 12 to 48 hours after exercise, particularly at the beginning of a new an exercise program, after a change in sports activities, or after a dramatic increase in the duration or intensity of exercise.

This muscle pain is a normal response to unusual exercising and is part of an adaptation process that leads to greater stamina and strength as the muscles recover and build hypertrophy.

There is no proven effective method to reduce or avoid the pain, but gentle stretching or even anti -inflamatory medication such as aspirin, can be helpfull for me together with  a warm bath , but it helps just for a little while.  I did not find anything on the internet that is proven effective, some tricks help some people and not others,  it is more how the individual react to different and own methods.

What I really want to know is why do I have to go through this every single week? This is a normal reaction after unusual exercise or change of activity. Well after 4 years what is unusual about what I do ?  In this case this is related to the fact that I give much more during those sessions than before , increasing intensity must be  why I get this.

I found myself some light about this today and even if I feel I have been hit by a truck , it feels good to know why  🙂