<div></div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">what do you mean by metabolic work? Cardio?</div>
Metabolic work, as used in HST, denotes an exercise induced occlusion environment (i.e. lack of oxygen). Basically it is an attempt to activate the erk1/2 pathway, which is believed to facilitate hypertrophy (all these are described in the FAQ). So, after the work sets (which aim primarily at the activation of the p38 pathway, especially when the rep count is low), metabolic work can be done to top things off. This is typically achieved by a high-rep set (15-20 or even more reps), by the use of rest-pause techniques, loaded stretches etc. With metabolic work we normally aim for that "burning" feeling deep in the muscle being worked (which is due to occlusion and its byproducts). See also the "Pimp my HST e-book" by Jules (aka Vicious).
Hope this helps,
Dimitris