The anatomy of a 5 minute interval

The 5 min interval, more accurately the 5 min effort - the interval refers to the rest period – has currency in the cycling world with good reason. They are a mental and physical journey as those familiar with the experience will attest to. Painful, grim, soul sucking, the list of descriptors is endless and yes, all true, but oh so very useful.

To put them in context, we’re talking about bloody hard multiple over FTP kick ass high Zone 4/low Zone 5 efforts. Individually they represent the kick you find at the end of a race or when trying to establish or get across to a break. In time trial parlance, they can be used in multiples for training – 4 of them if you’re superhuman and can break 20 mins for 10 mile TT, 6 if you’re a beginner trying to hold 20 mph for 30 mins or 5 if you’re a mid-marking improver looking to get under 25 mins. More broadly, they are used to induce an element of overload and, applied judiciously, are effective in increasing FTP.

So, shall we see if we can sneak up behind one, tap it on the back of the head and get in on the bench for a figurative dissection? 
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The first minute
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What’s happening inside – if you’re reasonably fit, you carry enough ATP (Adenosine triphosphate) in your muscles to produce something like a 45 second to 1 min hard effort meaning you’re get the first part of this for ‘free’. Flat out, your ATP will go in less than 10 seconds but at a (high Z4, low Z5 power) or 10 mile TT pace, you’re going to be able to eek it out a bit longer. The ATP systems is handy from an evolutionary perspective when you’re escaping a sabre tooth tiger attack. You won’t be able to outrun the tiger but you might be quicker than your hunter gatherer mate who’s overdone it on the nuts and berries.

How it feels – cadence up, power up, relaxed but pumping legs. Heart rate low but starting to react to the effort. Breathing easy, no real noticeable strain in the legs.  
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What you’re thinking – this is a piece of piss, I’ve probably undercut the power target I was aiming for by 30w or more. There are a few pro teams out there who are going to be mighty sorry they missed out on signing me I can tell you. Sub 20 minutes for a club 10 this season and no mistake. I’m a Legend me. 

1 minute – 2 mins 30 seconds
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What’s happening inside – you’ve burned through most of your immediately available ATP and you’re having to synthesise it for which you need oxygen and as much of it as you can get. Your body doesn’t know what you’re doing because it can’t see a tiger but it will put up with it because your mind is telling you it’s important and it probably knows best.

How it feels – BIIIIGGGG intake of breath after 45 secs to 1 minute, rapidly rising heart rate, legs slowing a little under the resistance, noticeable strain in the legs.

What you’re thinking – Right, let’s just try to hold the original power target. I can do this; I know it’s going to be tough but I CAN and WILL push through this. I’ll he halfway through in a minute. Oh Christ, I’m only halfway through but I'll hang on. 

2 mins 30 secs to 4 mins
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What’s happening inside – heart rate well over what is sustainable for anything more than an emergency, your synthesising ATP as fast as you possible can and your body is pulling in oxygen and using water like it’s going out of fashion. Your blood lactate levels are rising rapidly and you’re unable to clear it as fast as you’re making it so you’re over your lactate threshold. Somebody will have told you that lactate makes your legs burn, slows you down and gives you that dead feeling. It doesn’t, but that what’s people say sometimes.

​How it feels – Hard to know as your teeth are now biting down hard on the handlebars. Your breathing is noisy and laboured and you’re looking for new holes to breathe through. Heart rate revving like an F1 car but starting to drift and you sound like a Astramax diesel van with 250,000 miles on the clock.
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What you’re thinking – This is unpleasantly difficult and you’d very much like to stop. However, you’ve invested in getting this far and even though your cadence and power is dropping, you're not going to blow it by giving in now.  You're thinking you might have to knock this down a gear and pick the cadence up – this might Sting a bit. 

4 mins – 5 mins

What’s happening inside – your systems are becoming overloaded and staring to get fatigued. You’ll be running on fumes and your engine management chip (your mind) is going to be balancing the need to achieve your objective of finishing this effort against the significant physical cost. It will probably be breaking down fibres in your muscles and stretching your aerobic capacity to the maximum. Arguably, this is the most important part of the effort if you’re striving for performance improvements.

What you’re thinking - More hallucination than thinking. Superman zooms past. His warp speed passage has instigated time going backwards. You are now sitting in HG Wells time machine as the world ages around you, the sun sets a few thousand times and you’re surrounded by a heard of triceratops. A diplodocus moos plaintively in the background whilst munching on giant fauna. You see God. 

How it feels – Like the Ninth Circle on Dante’s Hell. Your body is screaming at you to stop and but you’re telling it you don’t want to yet. Muscle pain, gasping for breath, sweating profusely on to your headset. A sense of elation at the completion of the effort is marred by an instantaneous sense of dread at the approach of the next one. Time accelerates forward as you sling shot around the moon… 

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​Rich Smith loves prescribing sessions that include 5 min efforts - his riders have invented new words for their coach. He has coached the Great Britain Transplant Cycling team for over 10 years, is a British Cycling qualified Level 3 coach and a mature psychology student. He spent 30 years responding badly to people in authority in senior roles for Barclays, HSBC, British Waterways and National Grid Property before launching RideFast Coaching which is much more fun