Finding Sub Threshold - Norwegian Method Running

I am resetting my training as I continue to focus on running, with my bike sessions relegated to recovery and low intensity endurance rides. In this video I search for my sub-threshold intensity - not easy without a lactate testing kit. But there are other ways to measure the all important Threshold and sub-threshold intensities. I draw on advice from the Marius Bakken book, The Norwegian Method, to link together 3 ways of measuring intensity to ensure I hit that Golden Zone of sub-threshold. Have I found my sub-threshold intensity? #duathlon #running #norwegiansingles #mastersathlete