Try to make the activity seem fun before you go outside. Get them excited to participate in the activity beforehand. That will be easier to get them to participate than waiting until they are outside. When I taught Pre-K, we would do planned activities with sidewalk chalk, or just simply playing duck-duck-goose. The kids seemed to enjoy those activities because they saw it as me playing with them.

I know that you cannot take recess (actual play time away), but maybe stating to them that in order for you to go play at recess, we have to do this activity first to help us loosen our muscles and get us all ready for recess. Verbally praise those who you do see actually participating in the activity and make a big deal about it.

Ask the students for ideas about outside activities. Maybe if they see you are listening to them and using their ideas, they will be more excited about participating.

I would make it part of the routine at the beginning of the year. That way the students know what to expect. I would tie this physical activity with a lesson that was just taught, or maybe a review of what they learned the previous day. Be creative, and imagine if you were playing it, might be more fun for the students if it was a group game or activity. You're not going to intrigue all of your students, but hopefully you will find an activity that most of your students enjoy. That way you have a back up activity if you're unable to think of a new one.

I would conduct any acitivty where the students are active and walking or running on the playground gathering material from around the field or looking for thinking using their cognitive abilities to solve problems and such. Keeping the students engaged will stop them from wanting to do other things.

I would maybe ask the students what they would like to do and try to integrate their ideas into your planned material.

A good way to keep them involved in the activities is to have fun activities and not lose their interest. A good way to do this is to introduce them to a few activities, and then allow them to then maybe chose which one they'd like to do for the day. This gives them the power to vote for their favorite and also gives you an idea of the type of activities they enjoy. Also try to make the activities as similar to playing as you can, that way it doesn't seem like work instead of play.