Use REFRESH to repeat from the beginning. Use STOP to stop on particular "frame"
Skeletons are best viewed in "full screen mode".
To invoked "full screen" select FUNCTION 11 key (F11 again will return to "normal view")
 
If the skelton fails to label all the bones down to the feet i.e. seems to stop early, try using BACK from the toolbar to jump to the previous screen, and then use FORWARD to see if now loads successfully the second time.

Montage created by John Martin for gif43