Power Meter Applications For Ironman
Training and Racing - Part I

For some, they may have already purchased a power meter. For others, they are considering the parting of some hard earned cash. Common questions from athletes include;

• Is it worth it?
• What features/data should I be looking at?
• What are the advantages of using a power meter during training and racing?
• What kinds of benefits can I reap from owning a power meter?

Let’s start with the big picture. What is the ultimate goal of owning a power meter and using it specifically for Ironman training and racing?

The ultimate goal of using a power meter is two fold; First, to figure out in training the amount of watts that an athlete can hold for 112 miles and still run 26.2 miles to potential, and second, to use this knowledge during the actual race to assist in executing the cycling portion of the race as flawlessly as possible.

A power meter measures the amount of force being applied to the pedals and displays this power in a metric called “watts.” An athlete that generates higher watts is an athlete that is able to generate more force and apply that force to the pedals. Watts in the application of Ironman cycling is just a measurement term.

Pretend for a moment that we were at a fitness center and were weightlifting. Imagine that all of the weights in the room and all of the machines weren’t marked with a unit of measurement (either pounds or kilograms). Rather, the athlete would have to walk in day after day and just lift by “feel.” They would have to select and lift weights based on what they thought they needed to lift in order to hit a targeted number of repetitions. The actual weight lifted would always be unknown. That method of weightlifting sounds ridiculous doesn’t it? Well, for athletes that own power meters, the thought of constantly riding a bike based on “feel” with no knowledge of quantitative force being applied to pedals is ridiculous. Wouldn’t it be better to know how much force is being applied to the pedals? Knowing this would allow the athlete to know what they are capable of, the ability to benchmark improvement and a target for future workouts designed with intended purposes.

Some might ask a very good question. What does weightlifting have to do with Ironman racing? There are actually more similarities than people give credence to. The principles of weightlifting have taught us some valuable lessons related to the concept of muscular endurance. Muscular endurance is the body’s ability to produce muscular contractions over a particular period of time. In weightlifting the period of time is relatively short and defined by the term “repetitions.” Most people who have participated in weightlifting for the purposes of strengthening muscles typically complete workout sets in the range of 1 to 20 repetitions.

What weightlifting clearly demonstrates is the concept of “total muscle workload.” If an athlete can leg press 315 pounds for a single repetition (one rep maximum), the total workload is 1 X 315 pounds = 315 pounds. At this weight (315 pounds) the athlete’s muscles can contract and create force which can press the weight. Now if the athlete decreases the weight 5% or 15 pounds, the athlete may be able to complete two repetitions, making the total workload 2 X 300 = 600 pounds. Notice, dropping the weight only slightly almost doubles the total workload. Decreasing the weight 90 pounds or almost 30% might allow the athlete to complete 12 repetitions, making the total workload 12 X 225 = 2,700 pounds. As you could see, the further the athlete moves away from maximal muscular output, the greater their ability to increase total workload by lengthening the duration of the work set.

Let’s apply this to Ironman cycling. If the athlete can contract their muscles to create force and apply that force to the pedal at 500 watts for a single repetition, the further the athlete moves away from this maximal output, the greater the total workload that can be generated. The interesting thing about cycling in comparison to weightlifting is the extreme difference in required repetitions. Again, in weightlifting, the athlete might be targeting desired repetitions in the range of 1 to 20. The repetitions required to cycle 112 miles in an Ironman race is significantly more.

If an athlete is capable of completing the 112 miles in 5 hours and 30 minutes, how many repetitions are required during the cycling leg of the Ironman? 5 hours and 30 minutes is 330 minutes in total. If the athlete averages a cadence rate of 85 revolutions per minute, then the total repetitions (per leg) is 85 repetitions multiplied by 330 minutes or 28,050 (per leg). The magic question for the Ironman athlete is, “How much force can I apply per repetition that will allow me to cycle as quickly as possible but also allow me to run 26.2 miles to my potential?” I want to give you one last example on this topic to hammer the point home. What if you are a rider that has a natural cadence of 90 rpm and it takes you 6 hours to complete 112 miles? Then your total repetitions for the bike session would be a mere 32,400 (per leg of course).

When people make reference to “muscular endurance” on the bike related to Ironman, these examples of total repetitions might help keep things in proper perspective of what real “muscular endurance” is during Ironman bike racing. It is NOT generating massive amounts of watts over short periods of time. It is attempting to hold a constant power output for 32,400 repetitions. Learn it, know it, live it!!!

In cycling, applying force to the pedals that nears the force equal to a single maximum repetition is defined as a “power spike.” In Ironman, power spikes, or efforts that are unusually high in power will have a significant diminishing effect on muscular endurance. Simply put, too much force at any point during the 112 mile ride will be very detrimental to the athlete’s racing performance.

The goal of the athlete during the cycling portion of the Ironman race is to produce “smooth” power output. Smooth in terms of power output could be described as consistent power output. Smooth or consistent output is a concept that is well accepted and practiced in other endurance sports but often ignored in Ironman cycling.

Competitive running athletes that race, whether it is a 1 mile track race or a 26.2 mile marathon, use the model of smooth or constant power output and implement the notion into race execution and strategy.

For example, if an athlete is attempting to run a 4:00 minute mile, the strategy that would be executed would be to run four 1:00 minute quarter mile intervals. The athlete would not come out of the gates and run a 0:52 second opening quarter followed by a 0:58 second quarter, a 1:02 third quarter and then attempt to drag themselves across the line in a 1:08 for the final quarter. This method of racing is proven to be very inefficient.

Physiologically, the opening 1:00 minute quarter is the easiest quarter to run. The athlete would have a lower heart rate and a lower perceived effort on this opening quarter. As each quarter progresses, speed remains CONSTANT and heart rate and perceived effort continues to increase with each lap. Keep in mind that there is currently no way to measure power output while running. However, if the athlete is on a flat track, with no wind, the athlete will be able to use pace at the measuring tool for work output and through training will test and train their ability to hold that running pace (which is a demonstration of their specific running power).

OK, so we know the most effective and efficient way to run a mile which is a steady and consistent pace (or power output). Pace/power remains constant while heart rate and perceived effort increase. Now, what if the athlete wanted to run two miles as quickly as possible instead of one mile? They would use the same racing protocol. They would run with consistent pace/power output. However, an athlete cannot run two miles as quickly as one mile. Obviously as duration increases, pace/power has to decrease. The key then is to figure out (prior to the race) what pace/power can be held for two miles and then hold that consistent pace on the track.

The key point is that regardless of race duration, the concept of consistent pace/power utilization remains constant. The fastest, most effective, most efficient race is the one with the smoothest power output. Let’s look at a real example.

On September 30 of 2007 Ethiopian marathoner Haile Gebrselassie broke the marathon world record, by winning the Berlin Marathon in 2 hours, 4 minutes and 26 seconds. The Berlin course is pretty flat (and fast) which aids in the ability to hold constant power output (pace) as it takes more power to run up hills as it does running on flat or descending hills. So how does one allocate power output (pace) for a world record performance? Here are the official splits broken out in 5km increments for his performance:

There are a couple of questions to ask at this point. First, how many of us run our Ironman marathons at a pace that varies by 8 seconds per mile at most throughout the entire 26.2 mile event? To run a marathon in 2 hours, 4 minutes and 26 seconds averages out to a 4:44.76 average pace per mile. If we look again at the data for Haile Gebrselassie we can see that all of his miles were within 4 seconds per mile +/- of the average pace throughout the entire run. That’s a professional and that is a world record. The second question I have to ask myself is, “how does somebody even run a single 4:44 let alone 26 of them in a row?” That’s a question for another day though.

Let us get back to the point of this entire article. What is the concept that we should comprehend at this point? The concept to comprehend is that the fastest, most efficient, and most effective way to travel between two points is to do that with a CONSTANT POWER OUTPUT. Get it…got it…good!

How do we use this concept in terms of Ironman cycling? Enter the power meter. As opposed to running where we still do not have a method of assessing true power output (thus we need to use pace which gets complicated if we are running on a hilly course) we can measure power output very accurately on the bike if we own and use a power meter. The power meter can capture and display our real time power output. A cyclist using a power meter can therefore apply more or less force to the pedals if they are targeting a certain power goal.

By using some standard testing protocols, an Ironman cyclist can obtain an approximate target power goal to use in training. Through monitoring and experimenting in training, the cyclist can ascertain fairly accurately what they are capable of doing in race conditions and more importantly, what THEY CANNOT DO in race conditions.

Frequently Asked Questions

Question #1: Why should I use a power meter for Ironman racing?

Answer: We have learned from other sports (rowing, speed skating, running) that the fastest, most efficient and most effective race is by using constant power output. Most of the other sports have to use pace as a metric to assimilate approximate power output. However, through innovations in technology, power meters can be installed on bicycles to give us a very accurate and immediate measure of power output. The athlete that uses a power meter has the advantage of knowing if they are allocating too little or too much force on the pedals during a 112 mile time trial while still trying to preserve enough energy to run a full marathon to potential.

Question #2: Power meters are expensive. Is it worth it?

Answer: This can only be answered by the individual. The power meter allows an athlete to benchmark quantifiable progress throughout training. Further, based on training data, the athlete has data and knowledge that becomes very useful during the actual Ironman race. How much one athlete is willing to pay for this data and knowledge is specific to the individual. However, if one has the financial means to afford a power meter, it is an incredible investment in the pursuit of your Ironman racing potential.

Question #3: What features should an athlete look for in a power meter?

Answer: The most important feature to look for is a power meter that gives accurate power data. The three products on the market that have shown to meet this criteria in a reliable fashion are the following:

SRM - http://www.srm.de/

Power Tap by Saris - http://www.saris.com/c-11-power-meters.aspx

Ergomo – Google “ergomo” as the manufacture website is in German

In addition to purchasing a power meter unit, I would highly “HIGHLY” recommend the purchase of a analysis software package called CYCLINGPEAKS. This software will allow the athlete to analyze all important aspects of rides, intervals, sets or races to obtain the relevant information. To buy a power meter without this software is like buying a desktop computer without extra software; what’s the point? http://www.cyclingpeakssoftware.com/power411/

Question #4: What are the advantages of using a power meter during training and racing?

Answer: The advantages of using a power meter is that it provides much more accurate data on the muscular system than any other available tool. Many athletes use and are familiar with a heart rate monitor (another valuable tool). A heart rate monitor does a good job of measuring the amount of work being placed on the aerobic system but can not and does not have the means of assessing the amount of force being placed on the pedals of the race bike.

Question #5: What kinds of benefits can I reap from owning a power meter?

Answer: Athletes that train and race with a power meter are much better positioned to allocate power output as opposed to other athletes that are basing efforts on “feel.” Feel or perceived efforts are often extremely misleading especially in early portions of races when an athlete is rested, tapered, and the adrenaline is pumping. Those athletes that are racing with a power meter will have immediate feedback on the actual power output being applied to the pedals. Again, an athlete that has trained with a power meter will know prior to the race what they can do and what they cannot do on race day (although that doesn’t stop some athletes from trying to do something beyond their limits on race day.) These athletes can use the power meter to assist them in applying a constant power output strategy during the 112 mile cycling portion of the Ironman.