You cannot gain muscles without gaining weight, unless you carry excess fat already.
Gaining weight will always be composed of both factors (like losing weight also is).
In any strength discipline (bodybuilding, power lifting, strong man) you will need to gain weight, fat also, to become stronger and more muscular.
Rn, I am just sitting on my rollers or do intervals outdoors (when the weather allows it), so being light doesn’t help my performance much over the next 6 months or so.
I am not talking about becoming fat, but rather not being as lean as I am now, to gain strength faster and grow my muscles, in order to benefit from that over the season.
I mean strength training is a major factor in base training (in any endurance sport also), and from all I know, strength training strives on a caloric surplus…