Why is my 13yo DS having difficulty with basic physical activities ?

[Nicole1976]

I recently made a post about my sons weight gain and how rapid it was, but now I am starting to worry about his physical ability and exercise rate.
He doesn't do any exercises or sports now, which I wasn't too concerned about at first but now I have noticed that his walking is slower and when I gave him a lift to school this morning I saw that he was out of breath from just crossing the road and walking into the school,something which certainly doesn't seem normal.

P.s he is 4"11 and 8 stone 3pounds

Anyone with advice would be much appreciated

It sounds like he's put quite a lot of weight, and now the exercise is hard work.
Can you try to keep his food intake so he doesn't put (any) too much more weight on til his height has caught up with his weight?
You also need to get him moving. Walking/biking (scooting - will 13 yr olds scoot?) to school. Swimming at the weekend? Get him moving to get his body used to moving again - you mention he isn't doing anything now.

I have the same concern about my 13 year old. I know one of his problem is connected to his slightly S shaped spine and heel pain when he walks.We had some custom ortho insoles made which helped with pain but he still doesn't get enough exercise and put a lot of weight on. He does get out of breath easily. What I find strange is that other children seem to have a natural need to move around, run, jump etc but he would sit still all day if allowed.
He swims twice a week and his diet is very sensible (never been anywhere near a fast food place, I mean NEVER had a McDonald for example, doesn't overeat).
Neither myself or DH have anyone overweight in the family so can't be genetic. Other DC always have been active.
I am hoping its hormonal/pre-puberty "puppy fat"?