Notes
At the Peachtree Ridge HS track, doing 1wu+1@9:47+1+9:36+x@9:30, and actually did:
1@11:38+1@9:47+1@9:34+5@9:29, so the 7 faster miles averaged 9:32.3 with avg HR of 127. Happy with the HR. Was too heavy though.
This 9:32.3 * 127 = 1211.37 beats per mile.
Ran with both the 310xt and 920xt but took the measurements from the 310xt which showed the better tracking.