Let’s keep this intro short...you want to get faster on your run right? Well you know high intensity interval training is the way to go. Unfortunately, you're probably doing them wrong and not getting anywhere near the full benefits from them as you should. Here are five strategies to help you get the most out of your intervals:
1. You're doing too much high intensity
There's no argument against the research backing up high intensity training. We know it can boost your fitness and make you a faster runner (improved utilization of fast twitch fibers). Consequently, we start thinking if some is good, then more is better. Not so fast my friend. Doing too much high intensity limits your body from full recovery and thus can lead to higher risk of injury and limit your overall performance gains.
Increasing evidence boasts that 80% of your running should be at slow speed, with the other 20% at fast (to medium/tempo) speeds. This way you can maximize the benefits of high-intensity workouts (and minimize fatigue and related hunger swings).
In fact, a 2013 research study compared the 80/20 approach to a 57/43 approach and found the gains in speed were more than twice as high in the 80/20 training group. Another study from the Journal of Sports Physiology and Performance found superior results in faster 10k times with the 80/20 approach over groups spending more time in high intensity.
Remember, slow intensity training (less than 77% of HRmax) should feel ‘conversational comfortable’. An easy way to assess: “Can I hold this pace forever?” If not, you should back it down.
2. You go straight into your intervals
What an easy mistake to make (meaning I did it for years). You're short on time so you do some dynamic stretching for 2-3 minutes, and jog for 4-5 minutes then go straight into your 400 repeats. Workout done in under 25 minutes! Sounds great, however the problem is this isn't very applicable to that half marathon, 10k, or whatever distance you are probably training for.
First off, you are throwing off your natural pacing gauge or 'feel'. If you start early with your intervals your body is real fresh and can handle that intensity. But what happens when you start your normal paced runs or your long aerobic runs. Your body is gonna want to start off too hard, because thats the feedback you have given it. The 'feel' is off. Although not running at 90%+ intensity, your body doesn't notice that it's creeping up to a higher intensity that it will not be able to maintain over the expected race distance. You can handle it for a while, because you trained with the intervals but then you start shutting down in those last miles. You’ve burnt yourself out, because your 'feel' was turned up too high at the start, likely from training too hard during your training.
Think about this way, you want to run hard at the end of your race and finish strong? Then save your strong stuff (intervals) for the end. Train under slight fatigue; train the way you want to race. The best times are always negative splits so including intervals at the end will be more beneficial and functional.
I would suggest an easy run of 3 miles minimum before starting the intervals. Your interval times may increase slightly but your race time will decrease. Additionally, it will improve your pacing during the intervals because...
3. You start way too hard
Its easy to want to run real hard on the first interval. It takes a lot of discipline to hold back. However, if we start so fast that our times drop off too dramatically (see below) than form will follow suit. Training with bad form and a lowered cadence will also carryover to race day. Training under excessive neuromuscular fatigue is detrimental to getting faster.
In short, your intervals should only have a 5% difference between their times (3% for expert runners and 8-10% for novice runners). So if you go over 5%, then you are done with you intervals. Adding reps over that is building strength on dysfunction.
Here's an example of the 5% rule:
So, if you run your first 400m interval at 1:23 that would be your total time at 83 sec. 10% is 8 sec. 5% is 4 sec. Therefore, your stopping point is when you can't stay under 1:27. (1:23+4).
Now you see the importance of pacing the first interval. You are using it to determine the rest of your splits. I suggest running the first one at least 5% easier then you will for the second. In addition, you should plan on the second one being faster.
4. You don't assess/reassess
We assess and reassess are Fran times, deadlift maxes, etc; your intervals should be no different. Specifically, your 5% range (above) should lead optimally to 6-8 reps (3-5 for long intervals). If you complete less than 6, then next time do the same workout with ~30 sec increase in your rest period (RP). Conversely, if you get too many, decrease your RP. Track and alter your progression based on RP (not your fastest interval time)! Running faster but fewer splits is much less beneficial to your functional speed than maintaining a quality time with more reps.
5. You're doing too many varieties of intervals.
Choose a few different interval distances and stick with them, don't go constantly bouncing around. Stick to one distance for each week. This way you can track more efficiently. “Constantly varied” doesn't mean completely different each time. Remember, were talking about making people actually faster, not just fitter.
Based on your race distance here are my options for optimal interval distances (choose 2 or all 3 to work on):
- 5Ks can run 200, 600, and/or 1200
- 10k: 400, 800, 1600
- 13.1: 600, 1200, 1600
Example Application of interval progression:
Go after just one of them each week (follow the 80/20%). So for a 10k run: 400 repeats wk 1 (striving for 6-8reps), 800 repeats wk2. 400 repeats wk 3 (altering the RP, amount of warm up running, or reps), 800 repeats wk 4....
Run Hard. But Run Smart. Now go implement!
Contributed by Dr. Jake McCrowell, PT, DPT, CMTPT