3 Ironman fitness tests for gauging progress

Include these three tests every eight to 12 weeks to gauge progress and help set training zones, ideally in a recovery week and with 48hrs between tests…

ironman fitness tests to include in your training


Coach Phil Mosley, myprocoach.net


Benefits The Critical Swim Speed (CSS) test provides an accurate gauge of current swim fitness and can also be used to set your pace-based training zones for swimming. It predicts current pace for 1,500m but is still useful for long-course (see Test Notes box, below right).

Kit Swim clothing, goggles, friend with a watch!

Nutrition Electrolyte drink, maybe an energy gel

Warm-up 200-400m gradual progression of effort

Main set To test your current CSS pace, swim both 400m and 200m time-trials within this session. You should swim as hard as you can for both trials with around 5-10mins of active recovery between. A friend or coach should record your 100m splits and strokes per minute. Or you can go solo and simply record the 400m and 200m times yourself. Then go to tinyurl.com/yydzlmhk to calculate your current CSS per 100m and subsequent five training zones.

Cool-down 5-10mins easy


Coach Phil Mosley

Benefits The Critical Power 20min test (CP20) gives you a good idea of your current fitness, as well as providing the basis to set power-based training zones for cycling. The CP20’s aim is to predict your best average power output for a one-hour steady-state time-trial without needing to ride for an hour.

Kit Bike, bike clothing, helmet, power meter

Nutrition Electrolyte drink, maybe an energy gel

Warm-up 15mins easy to steady with
at least 5 x 10sec bursts at approximate test pace

Main set Ride for 20mins at your hardest, most sustainable pace. Make sure that you measure your average (mean) power and heart rate during the 20mins. Once the cool-down’s complete, look back and see what your average power output was. This is your CP20 but can also be used to calculate your CP60, or functional threshold power, by multiplying the result by 0.95. So if your CP20 was 200 watts, your CP60 would be 190. This 60min threshold is perfect to set training zones for all distances.

Cool-down 5-10mins easy spin


Coach Phil Mosley

Benefits Similar to the swim and bike, the Threshold Run Pace test measures your current best pace for a certain time – in this case 60mins – but the results can be extrapolated to create pace-based training zones.

Kit Run clothing, run shoes, GPS watch or smartphone

Nutrition Electrolyte drink, maybe an energy gel

Warm-up 15mins easy with three or four 15sec accelerations to approximate 5km race pace

Main set 30min time-trial. Simply start your watch or phone and run at your hardest, most sustainable pace for 30mins. Once you’ve completed the cool-down, see what your average run pace throughout the test was. This is your threshold running pace. What was your average heart rate? This is your threshold HR.

Cool-down 5-10mins  easy

While the three tests measure your ability to perform for 60mins in cycling and running, and around 20-30mins in swimming, they’re still a useful measure of long-course fitness.
Unlike a physiological test in a laboratory, these aren’t direct measures of your endurance; yet improved test scores will signal improvements in your stamina. That’s because the higher your FTP, CSS and Run Threshold Pace, the easier it’ll feel to maintain a given pace.