kishimoto knows this but the viewers dont and he indirectly already confirmed body and charkra are different when he introduced lee and gai, most viewers see charkra as more physical strength and more speed, they don't realize that charkra and physique/Body are completely different categories.
1= Human Adult Male
2= Bodybuilder Male/Power lifter
Average Ninjas Body= 1, exactly as it was since the day they became able to extract charkra, most future ninjas learn charkra extraction by the age of 4-7 which is the time they enter ninja school, before charkra they are normal human no superstrength or anything.
Naruto/Sasuke Body= 2, slightly higher even tho they never done training for physique just because they are talented individuals and have bloodlines/tail beast since birth.
Kakashi= 4, trained to open 1 gate
Lee=20, train enough to make muscles, bones and body stronger to survive gates being release upto 6.
Gai=30, can survive without breaking bones up til 7 gate.
all ninjas can use charkra to directly enhance power/speed depending on charkra and charkra control, some like tsunade and sakura have extremely talented control thus are able to create similar feats of superhuman strength when they fight, others like kakashi are lower tier when they fight in close combat as seen with his fight against obito, while lee and gai do have stronger bodies but because they have bad charkra control there increase from charkra enhancement is not like tsunade or sakura.