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Understanding Interval Training

posted on March 4, 2019


By Alison Yee

Last week, the first blog in our Cardio Lab series, Ryan talked about the importance of getting back to basics in order to become more efficient and prevent injuries. Teaching the why and the how-to, in short, educating & empowering our clients has always been one of our top priorities here at UF. So step one: Learn (or re-learn) the basics in our Cardio Lab: Basics class. Step two: Learn the ins & outs of the most common type of programming we do in our Cardio Lab classes: High Intensity Interval Training or HIIT.

In my Cardio Lab classes, I always joke that rest is hard to come by. It’s true—I’ve been known to crush the cardio out of you, offering little respite as far as water breaks or downtime. But when we program rest, we expect you to take it and here’s why.

Let’s start with the basics— what exactly are work/rest ratios?

Simply put, it’s a fancy way of explaining interval training. Work/rest ratios are the foundation or framework of all interval training. They describe the amount of work, exercise or effort performed compared to the amount of rest (or sometimes lower intensity work) prescribed. For example, a 1:2 work/rest ratio would be double the amount of rest compared to the work. In a Cardio Lab class it would look something like this: a thirty-second echo bike sprint followed by sixty-seconds of rest.

Intervals are incredibly effective because they can zero in on certain energy systems (we will get to those in a second). Knowing how (and why!) to use which intervals when is a key component to good programming.

So now that we know a little bit about what work/rest ratios are, let’s nerd out on some science behind it. In a very basic sense, we know that we use food to fuel our bodies. But how do our bodies turn that fuel into energy for our workouts? We have three main energy systems for this: Phosphagen, Glycolytic and Oxidative.

Phosphagen System:
-Fastest way to get energy
-High power bursts; only lasts for 0-10 seconds

Remember back when it was nice outside (and the Pittsburgh weather wasn’t doing some weird mixture between snow/rain/slush/false springtime/hurricane winds) and we would do what I lovingly call “window sprints”? You recruit this energy system to perform one of those bad boys.

Glycolytic System:
-Second fastest
-High power energy; only lasts for 30- 60 seconds

A good example of this system would be short-ish intervals on any of the machines in the Cardio Lab or even one of our famous “door sprints”, y’all love those right?

Oxidative System:
-Slowest way to get energy
-Low power energy; lasts for long periods

This one is easy—take one of my classes on a Friday morning and you’ll soon find out what it means to recruit this energy system. It’s basically, any long AMRAP in one of our Grit classes. Run marathons? Then your oxidative system is strong too, my friend.

While all three energy systems have their time and place, it’s important to train all three of them in a variety of ways to optimize your health and fitness. That’s why our Cardio Lab classes are always different and although it may not seem like it at the time, each class has a very specifically designed purpose. You may think the coaches here are just out to punish you, but I promise you that there’s a reason behind it all. (Ok, you got me, sooooometimes I may simply program something because it’ll be “fun”. But we all a need a little fun in our lives sometimes, ya know?)

Understanding the different energy systems is not the only piece of the puzzle we need in order to understand interval training. It’s also important to have a base knowledge of the different types of muscle fibers. We have two main types: fast twitch and slow twitch.

Fast Twitch:
-Recruited for short durations
-High intensity bursts
-Fatigue quickly

Do you feel like an Olympic God(dess) when you’re doing Tabata Intervals but feel like your muscles are made of lead during anything more than a couple minutes? Chances are you probably have a high level of fast twitch muscle fibers.

Slow Twitch:
-Recruited for longer durations
-Low levels of force/Low intensity
-Do not fatigue quickly

Do you feel like you could run/row/ski/bike forever as long as it’s a moderate pace? Do you cringe a little inside when a coach yells FASTER? If so, you probably have a higher ratio of slow twitch muscle fibers. Endurance athletes often have more of these muscle fibers than their sprinting counterparts.

There’s even a third type of muscle fiber, a branch off of the fast twitch muscle fibers even though technically it’s more of a hybrid of both slow & fast twitch fibers. It’s called Type IIa fiber and it is kinda the do-it-all muscle fiber– part aerobic and part anaerobic.

Genetically speaking, everybody is born with a different percentage of each type of muscle fiber. Not happy with the muscle fiber hand you were dealt? Don’t despair! There are ways to work around your genes. Though your DNA may have set you up with the ability to excel at one thing and not the other, it doesn’t mean you have no choice in the matter. Proper training (like knowing how & when to train the energy system specific to your needs) can alter your muscle fiber make up, help your muscles conform and function more efficiently..

Ok ok, this information is all well and good but what does it all mean for you personally at Union Fitness? Well, nothing and everything! It’s means everything because knowledge is power, folks. And the more you know, the better you’ll become. There also may be times when you have to travel for work or can’t make it to the gym in time for class or even need to throw together an in-home workout for yourself. Understanding interval training gives you the knowledge to be your own coach on those days when you can’t make it here. But, on the other hand, all this knowledge can mean absolutely nothing because, let’s face it, sometimes it’s nice just to come into class to sweat out the demons and not have to think about anything at all. And it’s ok to have those days (or have all the days be like that!) because we are here for you to do all the heavy thinking as long as you all just continue to show up and do all the heavy Cardio Lab-ing.

 

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