Interval training (aka HIIT) has been around for a long time and is a popular and effective use of our time in the gym. The idea behind it is that rather than spending a long time working at a lower intensity (like a long-distance run), the trainee would be doing shorter workouts but at higher intensities.
This style of workout generally consists of repeated bursts of effort, alternating with short recovery periods.
Interval training has been acknowledged as a more efficient way to improve general cardiovascular fitness and many advocates believe it to be superior for fat-loss as well.
However, one of the drawbacks of generic interval programmes is that they are not tailored to the individual trainee, and as a result they are often not as effective as they could be.
There are lots of ways to individualise your training so as to make it specific to you and you alone; heart rate monitors are a common tool and they can work well but it can be very complicated for the average person to know what “zones” to work at and for how long.
One of my favourite methods of personalising interval training is based on what is known as your MAS (Maximal Aerobic Speed). It is used mostly to train competitive athletes but I have had great success applying it to recreational trainees.
Using a simplified version of this method, you can easily establish a speed “sweet spot” unique to you. This pace can then be used to design your own interval running programme.
Here’s how it works: Without getting too complicated, research has identified an optimal pace to run at, in order to improve both aerobic (lower intensity) and anaerobic (max or near-max intensity) performance.
(If you really want to know, this pace is 120% of the speed you reach VO2max at, but it isn’t necessary to go into too much detail on this. Suffice to say, it works!)
Typically, the easiest way to perform the intervals is to work them 15 seconds on, 15 seconds off, in sets of several minutes.
If you are doing your interval runs outside, you will need to be able to measure out the distance you are going to run. You simply mark the distance off between two points on a straight track and run it every 30 seconds, repeatedly going back and forth. It should take you 15 seconds to run the marked distance (you will obviously need a watch or timer) and you will have another 15 seconds to rest before turning around and running back. This is repeated a number of times.
While I prefer running on a track or path for this method, you can also use a treadmill. It is admittedly easier to set up than outdoor runs. You simply set the treadmill at the desired pace and run for 15 seconds, then take 15 seconds rest before repeating. The downside is that it requires having to jump on and off a moving treadmill, which I am not a huge fan of for safety reasons.
You can calculate this optimal speed or distance to use for intervals by using your 1km time and the steps below (if you don’t know your exact 1km pace, finding out is easy: after a proper warm-up, run 1 km as fast as you can and note exactly how long it takes! You can do this on a treadmill or outdoors, but a treadmill is probably simpler for most people).

Step 1: Calculate your 1km pace in metres per second.
Simply divide 1,000m by how many seconds it took to run the kilometre
(eg 1,000 divided by 4 mins is 1000/240 which comes to 4.16 metres per second)
This is your Maximal Aerobic Speed.

Step 2: Multiply it by 1.2 to get your optimal interval pace
(eg 4.16 x 1.2 = 4.992)

Step 3: Find your (15 second on/ 15 second off) interval distance in metres by multiplying this number by 15
(eg 4.992 x 15 = 74.88 metres)
or if you are using a treadmill, multiply it by 3,600 to find the speed you should be using
(eg 4.992 x 3,600 = 17.9 km per hour)

I know this might look complicated, but it really isn’t once you take a couple of minutes to absorb it. The most important element of all of this is running at the correct pace (ie 120% of your best 1km pace) regardless of how you arrange the intervals.

I would recommend beginning at 1 – 2 sets of 5 minutes each (one 5-minute set would be 10 intervals) and increasing from there each session. If you are well conditioned you could begin with a little more, perhaps sets of 2 – 3 sets of 5 -10 minutes each. If you are new to training or coming from a layoff, you might benefit from taking a couple of weeks to build up to the calculated pace/distance.

In my opinion, this is a great example of something that was originally designed for athletes that can be used by everyday gym-goers to make their training more personalised and effective. Try it and see what you think.