dw wrote: ↑Tue Jun 23, 2020 9:23 am
My question is, what kind of carryover if any do you guys think HIIT conditioning has to training?
IME, HIIT isn't useful to lifting at all. It can be detrimental if you do too much volume and interfere with lifting. Flat-ground, max effort sprints are pretty unwise for lifters from an injury prevention perspective. If you want to do full-effort, anaerobic style 30:90 interval work, a rower is a way better bet. Or a bike... etc. When I've done these I haven't seen improvements in running economy or mid-distance times (2mi, 5k) (also, duh), but my RPE on everything less ballistic improves. HR stays lower during tempo, etc...
Heavy hitters in the field say about the same, but more eloquently (Alex Viada and Nuckols come to mind) - if you're a heavy squatter, your squat sessions are better stimulus for lifting than hill sprints ever will be. LISS will improve your aerobic fitness as well or better, with minimal interference effect. Rest-between-sets recovery and everything but executing comp lifts is basically aerobic-related more than 30:90 related.
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Separately, if you care about running performance as well, you can improve that with a variety of other techniques:
Strides are the easiest and least intensive; 30-60 second accelerations during a standard LISS run. Don't do more than 3-6 per session of 30-45min LISS.
Aerobic intervals are great; 3-5min (5's better) of very high effort non-sprints - actual running, but with the same-ish mechanics as your long runs. Rest 2-4 minutes between bouts, 3-6 repeats per session.
Tempo repeats are similar but a little longer; 6-12min of moderate-high effort bouts of running. Mile repeats or 800's fit this category. Full recoveries (3-6min between bouts), 2-4 repeats per session.