Just to clear up potential confusion: Is HIIT the same as the sprint workouts Mark puts out. Where one sprints for about 50-100m, then rests a minute, repeated about 6-10 times. Those take me about 10 min, and they certainly get the heart rate up, but the rest time seems too long to be considered HIIT. Though quite honestly, I'm not sure I want to do HIIT if it means wanting to puke my guts out everyday. PB sprinting on the other hand is something I could see myself doing everyday. I actually kind of enjoy it.
When I woke up this morning, I tried a HIIT workout off youtube that involved jump squats, jumping jacks, and high knees. It used tabata-style intervals. I wasn't even able to finish the 20 sec of jump squats without stumbling a couple of times. Probably due to my legs in a recovery state from my strength training. Clearly, such motions will be impossible for me to sustain everyday.
I think I'm going to try a full body strength workout twice a week, and sprint on all the other days (except my 24 hr fast day). In the morning, I'll give my self a boost using a mini-HIIT session doing a motion like jumping jacks so as not to aggravate recovering muscles. How does this sound? Or is this still not high intensity enough based on your experience?
We're different, with different bodies, and what is "enough" is going to be different for you than it is for me. I'd say just add in 2 or 3 HIIT sessions a week, and if you feel like you can handle and would benefit from more, do more.
Also, you'll get better at stuff like jump squats and other plyometric moves. Endurance is a skill just like anything else. You have to practice and push and pretty soon you'll be able to do the entire 20sec.
Mark's sprint intervals are definitely HIIT. Anything with a sprint/rest interval is HIIT. As far as the rest period goes, some exercise scientist a while back (this is from memory so don't ask me to cite the source) figured out that the work:rest ratio in HIIT that gets the best results is 1:2. So, 20 seconds : 40 seconds, 30 seconds : 1 minute. You could even do 10sec:20sec (kind of a reverse Tabata).
I don't think Mark would recommend sprinting that many times a week. As movements go, the sprint is one of the most taxing on the entire body. If you're truly sprinting correctly, you shouldn't be able to do it more than once or twice a week.
The best advice I have is to get a speed rope and a kettlebell. You can find KBs cheap on Craigslist.
Sprinting doesn't seem too taxing to me. Though I think I have pretty powerful legs (actually a trait of endomorphs according to some of my reading). I always wondered why heavy squats were my favorite lift before the injury. I sprinted last night on top of the HIIT workout I did in the morning. I did a strength training workout on Friday. My calves right now are absolutely destroyed. Other than that, I feel like I could sprint again right now. I just ordered some creatine and some Xtend BCAA (which has other stuff as well). Hopefully, I can boost my recovery to continue down this path. As it stands right now, I'm already please with the results. I did my weekly carb refeed on Friday, which usually leaves me a couple pounds heavier from water weight. Less than 2 days later, the scale reads 1/2 lb less than it ever has since the holidays. So far, I've been bouncing around in the range of 165.5-168 lbs, despite weeks of "doing the right things." This morning was the first time it read below that. Looks like HIIT is the key. Thanks for all the advice.
BTW, what is a speed rope? Is that different than a jump rope?