There are many reasons why training on grass is a great idea for all runners—regardless of experience or ability level. Most obvious is the fact that grass offers runners the benefit of a softer surface, which is an excellent way to reduce the chances of impact-related injury. There are non-intuitive benefits as well. “Grass workouts are an excellent way to improve overall balance and proprioception as well as strengthen the feet,” says Pete Rea, the elite athlete coach and coordinator at ZAP Fitness in Blowing Rock, N.C.
If you have a nice curated field like the one in the pic, yes, but I won’t even run on grass next to the sidewalk because that smooth layer of grass on top can hide nice little holes that can seriously injure you.
Trails are the best IMHO because you can see what you are running on.