USRPT – how it works… (part 1) – Oxidative Capacity

This is the first part of possibly lots of parts!!! That is to say its not a simple explanation that can be summed up in just one post. Even the USRPT creator Brent Rushall is constantly updating and adding definitions as new questions are thrown up around the subject. So this will be a bit of a drip feed of the information that Dr Rushall has pioneered, hopefully in a summarised version that will be easy (ish??) to digest…

Ultimately the methodology behind USRPT (Ultra Short Race Pace Training) is that of specificity; train the way you plan to race and get as much volume of that type of specific work done as possible. For me that bit is pretty simple, not groundbreaking and makes an awful lot of sense! The issue some folk have with that though is the entrenchment of aerobic systems, VO2 max, anaerobic thresholds etc and all the ‘training’ modalities that as swim coaches we are brought up with. And training short repeats doesn’t really fit with this system.

The great thing about USRPT though is that it isn’t as simple as ‘just do lots of race pace 25s’. There is method to the process, that is pretty groundbreaking, and requires you to forget all you thought you previously knew about training energy systems.

The main misconception with USRPT is that short high intensity work is anaerobic (traditionally described as predominantly using glycogen as the energy source and so work is done without the presence of oxygen) – when in fact the purpose is to train your body at race speeds aerobically (with oxygen as the main energy contributor)!

Studies by Astrand, Tabata et al through the latter part of the 20th Century have shown that short, high intensity bursts of exercise with short rests (10:20 seconds; 20:10 seconds) don’t actually accumulate lactic acid (over a 30 minute period to use the example of Astrand et al, 1960) or deplete glycogen stores whereas 60 second duration work, even with 240 seconds of rest does increase lactic acid substantially and deplete glycogen massively to boot!

So we know we can go all out for short bursts, take a small rest and keep this level of work up for a fair amount of time – but how does that train us aerobically when we all know that aerobic training requires lots of long slow work right?

The key is in the stored oxygen in the muscles – which is ever present – and as we exercise this gets used and replaced as we breathe! If we go hard for a minute the stored oxygen gets used up relatively quickly, but because it takes about 20 seconds for a full circulation of inhaled oxygen to get round the body we tap into the glycogen, H+ ions are increased, acidosis is in motion and cue the elephant on the back!! But by going short duration, we don’t tap into the glycogen stores but instead replace the used oxygen in our 15-20 second rest, before going again! As our repeat quota grows we are training our bodies to efficiently utilise oxygen at the desired pace and continuing to work aerobically in our rest period by repaying the oxygen debt caused by the work! AKA very heavy breathing – although we are ‘resting’, our oxidative system is still working maximally – so completing 20×25 off 30 might only produce 5 minutes of work (assuming 15 second target time) but our oxidative system is working for the full 10 minutes. Thats 10x the amount of time spent training at race specific intensity compared to the amount we will be racing (in a 100m race target time 60 seconds). Not bad going…

The other important factor here is the muscle types and how they are used. Generally fast work is denoted as using type II fibres (fast twitch) which operate anaerobically. However, in the case of USRPT we tap in to the type II b fibres, still fast twitch, but muscles that can be trained to perform aerobically i.e. powered by oxygen!!!

Rushall coins this phenomenon as:

Aerobic capacity + type II b fibres = Oxidative Capacity.

And it is the increase in oxidative capacity as denoted in the example above that can yield such results.

So not only can USRPT dramatically improve your performance, but it does so by making you aerobically fitter!

There is also a big neurological impact with this type of training that is succinctly addressed in USRPT and is what stands it aside somewhat from the general short work, short rest method, that I will talk about in part 2! It is also what ensures the principle of overload is met and how those 20 repeats above are added to on each exposure…

Once again, for those really interested in reading more depth (not just my adaptations from what I have read and studied) visit

And a final homage to minimum dose protocol – this event specific training can produce results in as little as 3 exposures per week. Great if pool time is hard to come by, or great for training for lots of events if it is in abundance!!

One comment

  1. RN · September 30, 2015

    Nice!! More please! Always great to have more of this kind of info… Especially in a newer method like USRPT!!


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