Predicting Ironman Marathon Potential

There are multiple benefits of having an idea of what our Ironman marathon potential is BEFORE the race which include some of the following;

1. Knowing our potential allows us to establish a goal pace as we exit T2 and provides us with a mental goal to concentrate on during the race.
2. Running to a pace that correlates to our actual physical abilities assists those in establishing a correct pace for those who have difficulty in executing based on rate of perceived efforts.
3. Knowing our potential before the race allows us an opportunity to honestly and objectively assess our race execution AFTER the race to identify areas of weaknesses or failures in execution.

The Protocol

There is a general rule of thumb that has shown that successful Ironman athletes can hold a heart rate approximately 20 beats below their Lactate Threshold (LT). The problem with taking a straight 20 beats off of LT is that 20 beats could be more significant for an athlete with a lower LT of say 150 bpm (13.3%) versus an athlete with a higher LT of say 200 bpm (10.0%). Three percent could make all of the difference in being able to execute throughout the duration of a marathon or blowing ourselves to smithereens. Further, each individual athlete is different, so the percentages may be different from one athlete to the next. However, this method provides a great starting point to work from and to compare against actual training data.

A better rule of thumb for predicting Ironman marathon potential than subtracting 20 beats from LT is to perform a run test at a track using two different effort levels of output which are 82% of LT and 88% of LT. Once establishing the two heart rate testing points, perform the following simple test;

Step 1 – Warm up. Start jogging slowly and gently while increasing the pace. As different athletes warm up at different rates, continue running until you feel that you are running in a loose and fluid motion and just starting to break a sweat. Heart rate should be increasing up to or slightly higher than 82% of LT preferably within 1 to 3 miles of warm up time.

Step 2 – Once you have met or exceeded a heart rate of 82% of LT, immediately run 6 laps at 82% of LT. Record times per lap on wrist watch.

Step 3 – After completing 6 laps at 82% of LT, continue running and elevate heart rate to 88% of LT and run 6 laps. Record times per lap on wrist watch.

Step 4 – Convert average lap splits to mile pace for both LT % efforts.

Step 5 – Add 30 seconds per mile for the 88% LT pace and then compare the two paces to establish a tight range.

Step 6 – Compare this range to actual data obtained from training with actual brick runs following long bike sessions and ask, “Do these numbers correlate?”

Example: Athlete has an LT of 168 bpm for the run which was previously obtained using the testing protocol established at http://www.atickettokona.com/run-assessment.html
82% LT heart rate would be 138 bpm
88% LT heart rate would be 148 bpm
After a two mile warm up, the athlete is running smooth and fluid and has lifted heartrate to slightly above 138bpm. Athlete immediately begins running 6 laps at a track with the following splits;

1. 1:56
2. 1:58
3. 1:59
4. 1:59
5. 2:00
6. 1:57

The average pace per ¼ mile increment is 1:58 per ¼ mile which is 7:52/mile pace.

After the sixth lap, the athlete immediately keeps running and lifts efforts to 148bpm with the following splits;

1. 1:48
2. 1:51
3. 1:53
4. 1:51
5. 1:53
6. 1:51

The average pace per ¼ mile increment is 1:51 per ¼ mile which is 7:24/mile pace. Adding 30 seconds per mile would result in 7:54/mile pace.

Range is now established at 7:52 to 7:54 per mile pace based on the pace per mile established from the two LT levels. Athlete should compare this range to actual data obtained from training while completing brick runs following long bike sessions and ask, “Is this realistic?” If so, goal pace for Ironman marathon is now established at approximately 7:53/mile pace.

Based on the Run Pace Charts at http://www.atickettokona.com/pdf/run-pace-chart.pdf athlete should see that Ironman marathon potential is 3:26:33 on game day which they could use to assess race execution following the race.

Implementing Potential On Game Day

Many athletes experience a phenomenon as they exit T2 during an Ironman. After cycling for 112 miles and feeling really tired with stiff legs, the athlete often finds themselves with the ability to run quite quickly for a couple of miles as they exit the transition area. This fast opening pace proves to be very costly. Not only can the athlete not hold this pace steady throughout the duration of 26.2 miles but they most often experience substantial decline as the race continues giving up large chunks of time in the final miles as a result of poor pacing. Further, many athletes have unrealistic goals that do not correlate to actual physical abilities proven or correlated to training data.

For the first few miles, the athlete should ensure that they run their goal pace OR SLOWER and it would be wise to ensure that they lower their heart rate down to appropriate levels for the first 5k until they get into a good running groove. Running a little slower during the first few miles often makes the athlete feel impatient as they feel they are giving up time. However, walking a single mile past mile 18 of the run as a result of inappropriate pacing will often cost the athlete greater than 10 minutes alone which is certainly more than giving up 30 to 60 seconds within the first 5k of the race.

The athlete should be aware that their “rate of perceived effort” during the first 20 or 30 minutes of the Ironman marathon will often lead us to making very substantial and costly mistakes during the marathon. Perceived efforts are more accurate after the athlete establishes a good running groove and shakes off the residual effects of riding for 112 miles in the aero position.

Once in a good running groove, the athlete should concentrate on running goal pace from one aid station to the next (as most aid stations are spaced one mile apart). Break the race down into 26 individual segments trying to hold goal pace.

After the race, the athlete now has an effective benchmark for assessing race performance and should ask, “Did I run to my potential?” If the athlete slowed and was not able to hold pace based on their potential, the athlete should honestly try to assess the reasons for lack of performance on race day. A good place to start the assessment is to review the Four Systems http://www.atickettokona.com/four-systems.html and generate questions which may include some of the following;

1. Did I fuel properly prior to the race?
2. Was I properly hydrated prior to the race?
3. Did I swim appropriately or did I swim too hard? Swimming too hard at the beginning of the day immediately causes our bodies to switch to our anaerobic systems and move away from burning fat as the primary fuel source?
4. Did I execute my nutrition and hydration plan on the bike?
5. Did I bike a smart race? Did I hold a smooth power curve that was void of power spikes?
6. Did I stay in an aerobic heart rate range during the bike?
7. Did I pace myself appropriately during the first 5k of the marathon?
8. Did I properly fuel and hydrate during the marathon?
9. Did I lack muscular endurance due to a lack of running volume prior to the race?
10. If I didn’t perform to potential, why is that?

Making mistakes during an Ironman race is all part of building race experience. Learning as quickly as possible what those mistake were and how we could correct them will allow us to progress and get faster more quickly than those who just keep making the same mistakes over and over again.

Having an understanding of our Ironman marathon potential ahead of time and comparing that against actual training data will provide us with an extremely valuable post race assessment tool. We will have the opportunity to self judge our own performance to identify areas of weakness, limiters and most importantly race execution mistakes.

Frequently Asked Questions

Question #1 - What if I feel like I could run faster on race day?
Answer – Be patient on the run. Most pacing mistakes are made within the first few miles that result with very negative consequences down the road. Ideally, athletes should seek to even split the marathon (attempting to negative split is a great approach from a perceived effort standpoint as this is VERY difficult to do). If the athlete begins the second half of the marathon and feels good, they could slightly pick up the pace for the next 10k. If the athlete still feels great at mile 20, then they should continue picking up the pace being cautious not to cramp up and overextend themselves so close to the end.

Question #2 – Why shouldn’t I just run on perceived effort?
Answer – Perceived efforts often give us very misleading information coming off of the bike and exiting T2. Athletes often feel fine during the first few miles and end up running much faster than a realistic goal pace. Can you say KA-BOOM!!!

Question #3 – If we are running at a heart rate of 88% of LT on race day, why do we need to add 30 seconds to this time from our testing numbers or use the 82% of LT data from our testing?
Answer – There are many factors that result in slower running at certain heart rates on race day which include, but are not limited to the following; glycogen depletion after racing for 8+ hours, dehydration, cardiac drift, diminishment in neuro-muscular recruitment abilities, inability to mentally focus, general fatigue, cramping/stiffness, and a sincere hatred for Ironman triathlon at mile 20 of the marathon.