I agree with socgirl, you shouldn't force or push a child. I relate alot with this post. My just-turned 5 year old son is very strong-willed and on the cautious side. He will try almost no new activites and the same goes for new foods. A year ago, I sat in envy while all the other preschool kids were going on bike rides with their moms following behind pushing their little ones in their strollers. My son could ride his tricycle but just a couple of minutes at the most around our driveway.
A couple of months ago, he got out the little, red two wheeler with training wheels I bought for him this winter. He got on it and drove it around the block. Now he likes to ride it a couple of times a day on a special route to see a water fountain. We clocked his favorite ride and its over a mile! Big difference from riding around in the driveway a year ago!
I still get frustrated when he won't try the cherries we bought at the store, or when he doesn't want to try to play sports etc. but I think about his little red bike and how far he has come from last year, literally.
Lots of kids are cautious, like your son and my son. Its not a bad thing, it just means that they are thinking and weighing risks. Later on his tendency to favor caution over impulsivity may be a real asset. At 6, your son is quite young in the scheme of things and he's got alot of developing to do. He is not at all behind in sports at 6. All kids develop at different rates and paces by age 9, under normal circumstances things are pretty even. At 6 there is alot of variation in terms of physical, social and emotional development. So what he isn't doing now, he may very well be doing before you know it.
I think the best think you can do, from experience is to adopt an easy-going manner about this matter. Offer him opportunities to try new things and experience if he refuses well, then ok, no big deal. Don't feed into any complaining or overly emotional behavior. Just say: "Well, you don't want to try skating i.e., thats ok maybe another time. Don't try to make an argument or a case for why he shouldn't be afraid or why he should try something. Try yourself not to be stressed or worried about this matter because your son will pick up on your anxiety and it could make matters worse. Best wishes...
I wouldn't "force" him to do anything he doesn't feel comfortable doing. Chances are, it's a phase and he may grow out of it. Have you tried modeling certain behaviors? For example, do you and your husband ride bikes,etc? If you do, maybe suggest having a family bike ride and go as slow as he feels comfortable going and make sure he has all the gear that makes him safe (helmet, elbow pads, knee pads, etc). Maybe if he can even pick out a really cool bike helmet or something. Don't rush him and give him time. Explain to him that if he doesn't want to partiiciapte, that's his choice, but he may be missing out. My guess is he'll come around. My older brother was the same way when he was 7. He played baseball until he got hit in the face with the ball...after that he was terrified...and would cry everytime he had to go up to bat....eventually, he outgrew it and my parents were patient with him and didn't make him play ball until he felt ready. It was the same thing with other sports for him...he got hurt in wrestling, football, etc and temporarily was afraid to participate...by the end of middle school, he pretty much outgrew his fears and he became a really good athlete. so, give him some time.