Ed. note—a new voice joins the Wattie Ink. blog pages today in Derick Williamson. Derick comes to us courtesy of Durata Training in Austin, Texas, and if his last name sounds familiar that's because you're remembering Kelly Williamson, one of the greatest runners in the women's professional field. Derick brings us a new way of thinking about preparing for your next event, whether Olympic, Half, or Full-iron.
Kilojoules over Kilometers:
Elite amateur and well established Ironman athletes can benefit greatly by shifting the focus of their bike volume from distance or time based to kilojoules (Kj) expenditure. By calculating the total work demand of the event you can much more precisely plan the overload and the progression you’ll need to achieve for success. This will ensure that you have accomplished the actual physiological demand and a subsequent overload vs. just doing the distance or time that might appear on the surface as an overload but in reality falls short.
This has several advantages for the coach and athlete. For elite/pro Iron Distance athletes my observations and separate calculations suggest that to be competitive as a professional male you are going to need to average between about 3.8-4.2w/kg (watts/kilogram), a professional female will need an average of about 3.3-3.7w/kg to be a realistic competitor. (There are certainly your uber-cyclist outliers and those have some success here and there but rarely have the run to stay out front very long…or even finish the race).
It’s important to note at the onset that these numbers are irrespective of aerodynamics. Of course the more slippery you are through the air the less power you’ll need to achieve a given speed and this is something that a competitive athlete needs to put time, thought and energy into (and you’ll probably have to put some cash into it as well!). The ultimate goal of course is to go as fast as you can with the least amount of effort, however as you are setting up a training program the idea is to make certain the physiological specificity has been achieved through training and then you maximize supplementary advantages as much as possible. If you’ve trained to average 250w for an Ironman but have done the equipment and positioning work to only “need” 225 of those watts for goal pace, then you’ve just banked a tremendous amount of equity for the run!
By establishing the demands of the event in much more quantifiable parameters as you can then begin to back calculate what you or the athlete will need to achieve in order to be successful. For example let’s use a 150lb (68.18kg) male that needs to be able to split a 4.5h bike split at 4.1 w/kg, we can then calculate the total kilojoules expended for that specific demand and work towards it plus an overload. At 68.18 kg and the need to hold 4.1w/kg this athlete needs to be able to average 280w for the full duration (it’s never bad to estimate and train to a slightly higher goal w/kg or Kj expenditure if the athlete can handle it…better to have more power in the engine and not need it, however there are additional considerations to be made to ensure that the athlete can indeed tolerate and adapt to the load imposed by the over estimation). With all of this in mind we then need to calculate the total work load for the event in kilojoules. The formula is written out below:
(Total Time in seconds x Average Power)/1000
For our example this would work out as:
(4.5h x 60min) x 60sec = 16,200sec
16,200sec x 280w = 4,536,000 joules / 1000 = 4,536 kilojoules
We now have a much more quantifiable number to work toward outside of simply 112 miles, as this athlete needs to be able to accommodate a 4,536kj ride and still run a competitive 26.2 miles. This begins to illustrate that simply because an athlete rides for a duration that is greater than 112 miles or more than 4.5h it does not mean that they will indeed generate the requisite work load specific to their race demands. Take for example the athlete that goes out for a 120mi training ride and they complete the ride in 5.5 hours or at a speed of ~21.8mph (not bad!) but because of terrain, group dynamics or environmental variables the average power was only 225w, this would put the total kilojoules at only 4,455kj which is less than the specific race demands despite the ride taking 60min longer and being 8 miles greater. If the athlete was going off of just time or distance they may be patting themselves on the back for a quality over-distance day, which it technically was (120>112mi) but it was not a specific work load, much less an overload session with respect to the specificity needed for the event (4,455<4,536kj); so if the athlete were to consider this as their longest ride and feel like they are fully prepared they would be doing themselves a disservice. Not only has this example not elicited the specific work demands for the event they have also fallen short of an overload which is the eventual desired outcome of training—to induce a greater load than the event demands.
Now we have a sense of how time and distance can be a bit misleading when it comes to the actual demands of racing and that using power and kilojoules expenditure gives us a much more accurate training metric to work toward. Remember though we not only want to work toward the specific race load but we want to exceed it within reason to gain an adaptation greater than the demand. This is where the overload component comes into play, for my more developed or pro athletes I like to work toward a Kj expenditure that’s about 300-800 Kj greater than the estimated race demand. This is a pretty large range and there is some discretion reserved for the coach and the athlete as to what’s appropriate and realistic for a given individual. The athlete’s overall ride volume needs to be considered (how many Kj/week are they expending) as well as the timing of the preparation (is it coming late in the season where there is significant accumulated fatigue), consideration also needs to be paid to what the bike legs represents, is it a strength or a weakness as well as a sense of how the athlete recovers and adapts to these kind of loads.
For an athlete like Jessica Jacobs who won both IM Wisconsin and Ironman Florida (in a course record) in 2011 our goal was “only” about 3900 Kj on her longest rides which was roughly 300 Kj greater than the anticipated 3600 Kj of the race. The rational for the lower end of Kj overload is that she’s a pro athlete and her weekly ride/training volume is quite a bit higher than an amateurs so the kilojoules were/would be accumulated throughout the week and didn’t all have to be packed into a weekend ride. Additionally we were really pushing her running this year and many of her longer runs had a moderate to significant intensity component to them, so I didn’t want her to be so trashed from a long ride that should could not come back with a strong run 24hrs later much of which would be done at 6:00min/mi pace.
On the other had a very strong AG’er I work with and does not have as much time during the week to accumulate those additional kilojoules had a more aggressive Kj overload in preparation for Ironman Hawaii this year. We pushed his single ride Kj overload all the way up to 4600Kj done within the confines of a 120mi ride (so it was moderately intense the entire time) even though my estimated Kj expenditure for him on race day was only 3700-3900Kj. His ride of 4:52 at Kona this year was a 3807 Kj on his way to a 20+min improvement from the previous year.
Another elite amateur I worked with several years ago was in the same boat as a lot of age groupers: two kids and a job, only so much time for training, but he was not content in the front-middle of the pack—he wanted to lead it! When he and I first started talking the goal was winning the 35-39 AG at Ironman Arizona. I did the numbers and we both agreed it was reasonable; the hitch was that he simply did not have a tremendous amount of time to be on the bike. The work we did had to be time efficient and effective and most would be on the trainer—even the long ones. For his long rides I devised sessions that were a mix of long and short intervals at achievable power but that would amount to the goal Kj expenditure for race day in as little time as possible. Through this approach we could get in a slight event specific Kj overload in what amounted to about 4hrs. Those were some hard sessions but they paid off with a win in the 35-39AG in Arizona that year and a guy who used to call his SRM an idiot box became a quick believer in the power of power!
If you are working with power, I would encourage you to do a little math and focus more on your goal Ironman power and the total Kj expenditure that that will be elicited plus a slight overload. At that point your goal is to work towards that number vs. simply a mileage or minute mark.