No, our foam is completely safe on grass and also bio-degradable.
However, just like any other physical summer activity held on a lawn, running on soggy grass can result in muddy spots, wear and tear, and/or leave temporary brown spots.
Healthy lawns don't have much to worry about. Grass may lay down flat but should come back after a few days of drying out.
We do recommend rinsing the area after a few hours to remove any residue.