These headphones are way too flimsy to stay put when running on the treadmill. They fit fine when I'm still, but as soon as I start running, one side comes out and rests on my outer ear, while the other side is barely in, not to mention the head band keeps migrating down. I kept having to adjust it while exercising, which was super annoying. Next time I'll shell out the extra money to get the Sony MDR-A35G S2, still lightweight but stay put in your ears.