Seppo Kaitenenn wrote:
red_dog wrote:
What do you think about the argument that short reps (like 400m reps) are not the best method of improving VO2max? The reps seem too short (even when resting back to 120bpm) to hit anywhere close to 180bpm for most runners.
On the other hand, if you did 8x1000 at current or goal 5k pace, you'd likely get close to 180bpm within ~800 meters.
Personally, when I do 400m reps at 5k pace on 1 min rec, my HR never drops to 120, and later in the session, I'm up to 180+ within 200-250 meters of each rep. Altitude (6,000ft) contributes to this, for sure, but I'm adjusting the paces for altitude already. Probably should adjust the recovery as well.
Anyway, HR isn't the only measure of effort. Blood lactate and oxygen uptake are going to stay significantly elevated during the reps and the short rest ensures they never drop too much ESPECIALLY if you are jogging the rest period. The idea with the 400s is that blood lactate never gets too high or too low during the session, unlike during longer intervals at VO2 max, where you would see a more spiky HR graph (and lactate profile) mirroring the longer work and rest bouts.
Personnally, when I did 20x400m at 3k-5k pace, even 1.5k pace under JS training, my hr never exceeded even 90%