C.T.
Hi H. - It could be very possible that your oldest also has low muscle tone, especially if she hit her milestones late as well. You could have her tested. We had our youngest tested because he also has speech problems. As we were going through the questionnaire, we recognized that our oldest might have some issues as well. (Interestingly, they are extreme opposites in a sensory sense)
My oldest could have benefitted from OT but truthfully, it was just too expensive having them both in treatment every week. He does exercises at home and it's helped all of us. He participates in sports whenever he can - the best choices are ones where he gets a lot of body feedback. ie: basketball, karate, gymnastics. We do a lot of upper body and core strengthening exercises. We bought him a yoga ball chair for his desk, we do a lot of wheelbarrow and crabwalk races and we do the monkey bars alot to increase hand strength. At school he can do "chair pushups" and his teacher allows him to stand at his desk during school work.
by the way - low muscle tone has very little to do with body type or intelligence. My son is very lean and muscular and he excels academically. The exercises have actually helped him to concentrate in school.