Cool Running, the site that made the Couch to 5k program, has rated running surfaces on a scale of 1-10, 10 being the best surface.
- Grass 9.5
- Wood chips 9
- Dirt 8
- Cinder track 7.5
- Track 7
- Treadmill 6.5
- Asphalt 6
- Sand 4
- Snow 2.5
- Concrete 1
As you can see, running on sand is drastically worse than a bike path made of dirt. So I would suggest you avoid the sand as much as possible. The reason sand is so bad is simply because it is an unstable surface, so injuries (especially joint injuries) are more common. If you only have sand to run on, be really careful. Some people, when they get tired, stop focusing on what they’re doing and focus on the fact that they’re tired out. If you get tired on sand, and you can’t focus as much on your running form, slow down or take a break. Having breaks in your runs is much better than injuring yourself.
