4 1/2 year old son won't participate in group sport

My son is 4 1/2 yrs old.  He has recently enrolled in a group soccer class once a week with 15 other kids and 2 friends from his pre school.  He was very excited to get his new soccer cleats and shin guards to participate in the class.  On the first day of class he did not want to participate in the class
at all.  It is done with parent participation and I went with him.  I  tried in many ways to get him involved, but he only wanted to watch or kick the ball on his own.  I have to admit I was a little embarassed because all the other kids and parents participated. After class, he did play and have fun with his 2 friends I don't undersand why he wouldn't participate.  My son did not want to go back the next week, and my husbund says not to force it or he will not want to do activities in the future.
  

[seattlemomof2]

Give him time, it takes my son several sessions to really engage in any group activity. Even if he has friends in the group, new kids always cause him to tune out until he gets comfortable. It can be embarrassing when it seems like every other kid is into it but don't dispair! Stick it out until the end and don't quit, it will send him the wrong message. After his games make sure to stress what he did well and ask him what his favorite things are about the activity. Even if he only likes the uniform and a snack afterwards, it's better than nothing!

[laurah2010]

My son is 4 1/2 years old as well. For two years now, I've tried to get him involved in extracurricular activities, such as swimming lessons (3 different times), sports ball class, taekwondo, etc. Each time, he refuses to participate and either sulks with his arms crossed or starts crying. When I ask why, he says, "Mom, you know I'm shy."  I also believe in not forcing the issue, so I don't make him do it, as I don't want to traumatize him. We continue to go and watch each lesson and try to encourage him. We've even bribed him with a toy, but he never budges. He loves to swim at grandma's pool and play sports and gymnastics at his daycare that's he has attended since he was 3 months old. I'm just wondering if there's something I could do different or if there could be something wrong with him. I've never had any issues with social problems, etc at daycare, and his teacher says he's do very good in pre-school.  Thoughts?