Is it possible for a 16 months old leg to fall a sleep?

last night after supper i got my 16 month old out of his chair and i went to put him down he fell, i stood him up and he was favoring his right leg as if it was hurt, tried again and he fell i wiggled his leg n bent his foot he didnt complain did range of motion he didnt seem to mind, after a mins he was off running again, he was just now sittin on the floor playing with a can of soda and he started to favor his foot again i rubbed and moved it and he was walking like he did last night then he seemed to b fine, some one please help