SIT – Sprint Interval Training

SIT – Sprint Interval Training

"tell 'em they're joking son"

Disclaimer: The information presented here is as personal experience and observation. It is not to be used as a basis for yourself or as medical advice. If you are interested in undertaking this programme and do not have an extensive background in self training, it is suggested you seek either professional medical and/or training advice before starting.

I should have started this with more metrics. But I didn’t. I went for the most basic, which at the time I thought would be fine — hopping on the scales at the right time of day and undertaking the Polar ‘Own Index’ test. Still, those ARE metrics that can be used as a starting point, and ultimately are better than nothing at all. In hindsight though, and after seeing what happened, I should also have taken measurements and possibly some power output tests. Regardless, here we are.

So what’s this business about then? Winter 2015 was a write off. I came off the bike at the start, which kept me idle for a few weeks, then winter proper hit, then business matters went ballistic, then the 3 year old gave me a cold/flu thing that lasted weeks and weeks…. well you get the idea. The net result was by the time winter was coming to an end, bike fitness was all but gone and with little sign of reprieve on several fronts, getting back out on the bike for what was my previous regime was not looking like a possibility.



Then came a program on ABC’s Catalyst (for those outside of AU, ABC is the national non commercial TV station and Catalyst is a locally produced science program) about the concept of 8 minutes of exercise a week. A similar programme was aired in the UK (and locally) by the now somewhat famous Dr. Mosley. The overall gist being that sessions of exercise based on 4 x 30 second, 100% effort ‘sprints’ could be as effective, if not far more so, than sessions much longer in duration. I won’t bore you with the specific details, you can watch the programmes, Catalyst here and Mosley’s here and find out for yourself.

I had watched the Mosley programme some months earlier and really not thought any more about it, it was interesting, sure, but I was riding a lot so it didn’t resonate at all. It was not until watching the Catalyst version that I started pondering. Here we had two programmes discussing the same topic, studied by two very different scientific teams and overall, they were finding the same results – highly condensed intensity can produce some very unexpected outcomes.

While the two programmes did end on somewhat different outcomes, as the specific scientific outcomes being looked at were different, the overall end result was the same - at its most basic, this shit works!

Now I can hear people crying a number of things - this it HIT or Tabata (1) or.. or… or. I can also hear RUBBISH loud and clear.

I, like many out there, have been riding for far too long and have always worked to the accepted basics of mileage establishes base fitness and targeted sessions build strength etc. etc. Nowhere, in all those years, did I ever hear, or read, anyone saying 'sure, 2 minutes a session is all you need'. So before you dismiss this whole thing here and now, rest easy in the thought that I sat in the same camp.


So in lieu of not riding at all, I decided to do a little test and see if this actually does work. I was going to give myself three months of doing nothing but 8 minutes flat out per week and see what happens. Now, as I mentioned at the start of this, I decided to take same basic metrics to use as a before and after.

Firstly weight. I needed to loose some winter weight and this programme was reported to produce weight loss. Secondly, the Polar ‘Own Fitness’ test is still regarded as one of the better measures of fitness outside the lab. I should have taken some more metrics but I worked this out halfway into the programme and at this juncture, there was little point as the before/after would be well off.

I also had a decent benchmark to work to. Late 2014 and into 2015, I had a three day a week routine of early morning rides (around 6-7 hours a week), coupled with a fairly strict diet. Over those three months, I lost around 10kgs in weight (yes, there was a bit to loose), dropping from around 97kg down to 88kg or so; at 6’3” - 187cm, my ideal is supposed to be around 90, so I was entering what I deem to be ‘race weight’ territory.

On October 14th, 2015 my numbers were**:

  • 95kg
  • HR Mx 181 (I aint no spring chicken any more)
  • VO2 Mx 37 (Which based on the Polar own Index rating equaled: Average Fitness).

**see note below re. the fitness test

The plan:

If you’ve got this far and watched both programmes, you can see that the idea, depending on which variation you research (and there are a few), is to do 2 minutes in 4 blocks of 30 seconds, with a rest period between. This programme is based on the incept test (2) and became known as SIT - Sprint Interval Training; it is not HIT (3).

Being on an indoor trainer, I opted to start with 5 minutes gentle spin warm up, 30 seconds on and 4 minutes slow spin rest to ‘recovery’, repeating 4 times. On the last month I moved to 5 x 30 seconds with 3.5 minutes between. This was then repeated 3 times a week, or every second day.

Unlike the 3 months on the bike, this time I did not really change diet all that much; experience told me heading into Christmas, trying to ‘diet’ is a futile task. So on the average I kept to my regular eating habits, which really was pretty good by all accounts as I don’t eat much (if any) junk and not much sweet stuff. In the last weeks going into February 2016, I reverted to the 5:2 system, which I had done for some time prior (and almost through the entire time on the bike in 2014), simply because I feel better for it overall (school of thought: we eat too much).

How it went...

If you are thinking of trying this, don’t think there is any realistic way you can do it actually riding (or running, or anything requiring balance and control). You need to do it on a stationary trainer of some sort. I say this because if, after 30 seconds (at a target of 130 rpm, sustained from the get go), you feel ‘coherent’, then you are not going hard enough!

Honestly, I discovered what flat out really meant doing this... flat out as in to the point you see stars; you can’t output like this and stay in control… of anything.

If you’re curious, the type of sprint undertaken doing this is also known as being very similar to Wingate (4). In no way either can doing this can be described as comfortable, let alone anything resembling mildly pleasant. It’s not. What’s more, after one session, your legs feel as if you’ve been for a hard 2 hour ride - I kid you not. In fact, I’d say I’ve felt sorer, more often doing this, than I have on any other training programme.

Starting from a pretty average base i.e. a somewhat dedicated rider who’s not ridden for some months, the first month was hard work. Sweaty, drooly, muscle soreness inducing hard work. In the second month though, things started to happen. The first and most noticeable was the increase in strength and with it, muscle endurance. Where I started sprinting mid cassette (pushing on a 48T ring), by the second month I was lower on the block for longer and by the time three months rolled by, I was pushing the bottom end of the block for a good 20 seconds flat out before having to climb to keep the spin and intensity. That rate of increase came as a surprise as it happened much faster than expected for the given amount of time spent. Recovery times too started to noticeably shorten.

Now one can say, well, duh! You’re exercising so this stuff happens. Let’s keep in mind here we are talking 8 minutes a week, albeit 8 at full intensity, but still 8. My benchmark was training for 6-7 hours a week, yet I was starting to see very similar gains, if not greater, for the same amount of calendar time spent.

At the end of the session though, sure I was tired and it took some time for the body to recover (probably in the area of half an hour to go back to a relaxed state), but the most evident thing was the total lack of ‘feel good factor’. In fact, there was nothing. Go for a ride, easy or hard and you come back and feel ‘good’, everyone knows that feeling and it’s that feel good factor that keeps you going back for more. Doing SIT though there is none of the feel good and as a result, where a good ride might in fact eventuate in an elated and relaxed state, the SIT routine is completely devoid and leaves you with nothing; I would actually say you just end up feeling a little smashed.. all of the time.

In regards to this, this passage sums it up quite well:

Given that enjoyment is associated with exercise adherence (Ekkekakis et al, 2009; Tritter et al, 2013; Williams, 2008), the general population should be encouraged to engage in a physical activity of their own preference in order to achieve the recommended government exercise guidelines. At present, it may be premature to advocate SIT to the general public (Whyte et al, 2013). It is apparent there is a severe lack of research regarding SIT and feeling states and future research must investigate the acute and chronic psychological and physiological responses to SIT in a real-life setting.”(5)

In other words, if a big part of why you ride is to feel good, best to avoid SIT;  it’s akin to strapping an engine to a dyno and whomping the crap out of it… and that’s all.

But do the numbers say anything? At the end of the period, which admittedly went over, due to getting a 2 week cold in the middle of summer (I know, right?), what I ended up with was this**:

  • 89.4kg
  • HR Mx 187
  • VO2 Mx 41 (Which based on the Polar own Index rating equaled: Good Fitness)

**see note below re. the fitness test

From the metrics I have, weight loss is on par, if not better than what I achieved through the sessions on the bike when combined with dieting. HR Mx and VO2 Mx also both increased. At its most basic, these are fairly evident improvements.

Anecdotally, I can say that there also has been noticeable muscle gain at least equal to the on bike training. This is one area I wish I had taken measurements but all I can say is before the SIT programme, the bibs were not tight through the legs but after the 3 months, they are. Visually (hence anecdotally), I’d say the lower quads have not developed as much as on the bike but from there up the gain has been the same.

So the question is will I continue with this? For the time being, without a doubt. As said before, it’s not fun and one does not get any feel good, so for many out there, that’s reason enough to stay away. But for me as a way to not only keep, but improve, base fitness, without having to spend hours on end (equation = trade joy for saving time) to do so, it's ideal for the here and now.

I have always found nothing worse than being unable to put in the time, so when I did go for the odd ride it was ultimately a drag because I spent most of the time being miserable that I was not where that part of one’s brain tells you should be. Even when back on the bike, I see little reason not to keep SIT as part of the weekly routine.

Addendum: And on the road?

But all this seems quite academic, doesn’t it? What happens when having done this you get back on the road, does it translate?

Well, this is where the biggest shock came.

Keeping in mind by this point I had not put any decent ‘real’ riding time in since winter 2015, the impending ‘getting back on the bike’ was being met with some very serious trepidation, especially as 1. I had to do so and 2. in having to do so, it was a one way trip with no bail out options - I had to drop the car into a new shop for some work, and the shop was not at all close by. What’s more, the trip home ended up a race against the rain and in traffic.

I won’t bore you with a blow by blow description of the rides (I had to ride back to collect it a few days later) but I easily rode as well as if I had spent the months clocking up miles on the road. The most eye opening part though was not only the ability to easily maintain a solid average speed but when hitting long gradual climbs. It could be that in doing 100% efforts for 30 second intervals you find where your real limits lie, or maybe the muscles become accustomed to being pushed to full exertion, but whatever it is, the ability to push harder, then harder again, on long gradual climbs without feeling that there was a limit was an eye opener. Without exaggeration, it was a feeling I had never felt in over 30 years of riding; and that says something.

The question I have though, and one I will try on very soon, is how SIT holds up to rides into the 2-3 hour mark.

A final note:

After the 3 month trial, I continued with the programme and ended up putting my FS mountain bike on the trainer as I stripped down my ‘road’ bike. I pretty much thought this would be a dud idea and with the MTB geared 1x10, with a 38T ring, when compared to the 48T I had been pushing, I expected the net efforts and hence results, to be much, much less.

By dropping to smaller gearing, hence increasing RPM (now in the 130-145 mark rather than the 120-130 mark), the sprint session efforts did not decrease in intensity but significantly increased. So much so in fact that I was working much, much harder for a longer portion of the 30 second block, fully exhausting the muscles and cardio systems each time. Perhaps most interestingly, over the weeks of doing this not only did the exhaustion factor remain much higher, regardless of how accustomed I became to the gearing, but there has been a visually noticeable increase in muscle development; not Schwartzenneger territory mind you but when compared to the previous 3 months with taller gearing, noticeable.

* A quick note about the fitness test…

Polar classification “… is based on a literature review of 62 studies where VO2max was measured directly in healthy adult subjects in the USA, Canada and 7 European countries. Reference: Shvartz E, Reibold RC. Aerobic fitness norms for males and females aged 6 to 75 years: a review. Aviat Space Environ Med; 61:3-11, 1990.” .

There is much discussion about the effectiveness of measuring VO2 and even HR as a gauge for assessing fitness. Opponents of using VO2 capacity claim its effectiveness is limited as max capacity is genetic trait with limited scope for significant improvement. HR as well, is generally an unreliable indicator as it can be affected by numerous factors such as illness, fatigue, stress and even climate, all of which can give an unreliable reading. One also has to take into account the margin of error in the results of between 6-8% of Polar’s test, which does seem to correlate the results gained from the Polar test and clinical measurements.

Looking through the logs on my Polar dating back quite a few years, the highest VO2 Mx I have achieved in the past few years was a rating of 43, which was the top end of the ‘Good’ category for the age group. That was with months of serious of riding under my belt. As such I feel that the claims of VO2 as a measurement being only so accurate are somewhat true as no matter how much riding I have done, my results always sat in the same bracket.

As a test, my own view is that the Polar Own Index system is a tool that can show improvement over time and as such, for this experiment, was more than adequate to judge the effectiveness of the programme.




(3) HIT is comprised of efforts ranging between 80 and 100% of VO2max while SIT intervals are all run at 100% VO2max.