[nsgi]

They also post a few times a day on Twitter vs about daily on Instagram, so the interactions are split between more posts. Other users post many more times a day (most likely because they are posting text rather than photos/videos), so they have more posts to compete with.

[jonknee]

Yes, but photos of extreme athletes is literally perfect for Instagram. They also advertise quite a bit which is how I see their posts on their. Twitter isn't a great venue for sharing epic photos, it's much better for current events.