I feel this sensation too. When i do reps of calf raises on a machine or with dumbells at my sides, my tendons in the bottom of my feet burn and ache terribly. I am flat footed, i have no arch in my feet, and my ankle bone is disproportionate. One side is larger than th other. I walk with my feet pointing slightly inward. I am sure this is linked to this soreness. I believe it might be beneficial because it reinforces the bone structure of the lower leg and its muscle, but u should really check it out with a specialist.