I've been working with an ex forces guy who had a very tough time in Afghanistan. He suffers with pretty acute PTSD but for him it presented as terrible sleeping and waking nightmares where he relives young guys in his platoon being shot or blown up by IEDs. He tells a story of one young squaddy having his legs blown off and being placed on a hard stretcher. The guy at one end slipped and sat down on another IED and was blown to pieces, the force of this blast bounced off the underside of the stretcher and took the other stretcher bearers legs off. If you think it can't get any worse bone fragments from the last guy went under another soldiers glasses and blinded him!!!
You can understand why my buddy attacked a painter at work because his ring tone was a song that had been playing in Afghanistan.
One of the big issues is that soldiers won't admit to PTSD because it might lead to what they fear the most, getting kicked out. The guy in the video mentions just how difficult civvy life is so if riding a bike helps I'm all for it. I think the scariest thing is how many guys there are out there not getting help.