It's very good, that's a hard pose to pull off without it looking wonky. :> Though (I think this has been said before I think) he only looks like he's touching his ankle, as opposed to stretching. There doesn't appear to be any sort of strain in the muscles, so it appears to be a more reclining pose rather than one to limber up. Nonetheless, I envy you greatly for your talents in both anatomy and poses!
Hmm...I like that one, but it doesn't look energetic..I think? It looks like he's only touching his ankle, but aint stretching. Cannot describe cuz I cannot draw it myself even a bit awesome like that XD Just wanted to give some uh..advice..Since comments like "ohh this is good" are nice to read but well..only nice to read <3