Quote Originally Posted by Buffalobiian View Post
You're right about HIIT.

I'll illustrate my point with some examples:

Background: jogging and running lands with either healstrike, midfoot or toe strike. It depends on the runner, if they wear shoes and the speed with which they run. Sprinting uses a toe (forefoot) strike due to the speed and the amount of lean you have when you run.

Your muscles also work on aerobic/anaerobic systems. The anaerobic one can be used for perhaps up to a 30 second burst of intense work. The fuel for that requires something like 5 minutes to rebuild in the body after you deplete it.

You require your anaerobic fuel if you wish to sprint at full speed.

Scenarios:

Sprint training with 5 minute breaks (like they do for track training):
I give my body enough time between sprints to rebuild my anaerobic capacity. I can utilise that system when I do my sprint, which will be as fast as my body can go. I will still accumulate muscle microtrauma, but I should not be hindered by a lack of anaerobic fuel. In this state, I can run in excess of 20km/hr at least for part of the track. This speed requires me to use a forefoot strike. It may be worth my while to use the sprinting form in order to increase my speed.

Someone training for track sprints would do this, but it doesn't mean they don't or can't choose to train with some aerobic capacity built in like below.

HIIT with 1 minute breaks
I will not have enough time to build my anaerobic capacity back up. During my run, I will be more tired and rely more on my aerobic capcity. Without the anaerobic fuel aid, I will probably only be able to run at 14km/hr. At that speed, I may comfortably run with a mid/heal stroke, especially when my speed drops lower by the 10th HIIT burst.

This is more in line with regular HIIT runs.



The above is HIIT, but by the latter stages you should be so tired that you're not even sprinting, but barely able to run hard. Even though you're running hard, you're not running all that fast. I was tossing up about which form would be ideal (both for performance and injury reduction) in this case.
I misunderstood, like an idiot, what you meant by running form. My understanding is that the midfoot strike is best to avoid injury to the knees, shins, and Achilles tendon. As far as sprinting is concerned, I've seen people do it with what looks like a midfoot strike while others seem to be attacking the ground with the balls of their feet and a heavy forward lean. I just tried sprinting for a quarter mile and noticed that there's a very slight difference in the foot strike. It's still mostly a midfoot strike but slightly favoring the front. It isn't a toe strike or even the ball of my foot. I still need to roll on the ball of my foot before I can push off of it. If I were doing HIIT with sprinting, this is how I'd do it.

As far as performance is concerned, toe striking *might* help with the speed and it is good in reducing the impact to your knees and hips, but increases the strain on your calves and shin bones. If it is equally important for you to get the sprinting performance increase as well as the metabolic benefits of HIIT, you might want to do the toe strike, making sure you're eating in a way that is going to alleviate some of the strain you'll put on the aforementioned body parts when you start to kick it up a notch. A google search on this topic though shows a good number of sprinters using a midfoot strike. So I'm not entirely certain about the performance differences between the two foot strikes.

So, if improving your sprinting is important to you as much as the HIIT benefits, I'd suggest finding out for sure if the toe strike does improve your speed. If it does, use it. If it doesn't, use the midfoot strike. If the HIIT metabolic benefits are the main concern, use the midfoot strike. Avoid the heel strike like you avoid the HIV virus. Concerning the rest of the form, the forward lean is recommended for both jogging and sprinting, but its more pronounced in sprinting.