Can you please share your decision criteria. The Dec/Jan opening was billed as a "pilot", which I recall was said to be successful. But no detail was shared. And if successful, it's not clear to me what the program was not extended to evenings and weekends during the regular school year.
If access to the track/field is through one gate and bathrooms closed (if folks are walking or exercising on the streets there would be no access to restrooms), it would seem that any risk of infection is extremely low.