Ironman 70.3 Timberman

Weiss Sets SRM-Powered Bike Course Record!

SRM sponsored triathlete, Michael Weiss, raced Ironman 70.3 Timberman as a key training stimulus for October's Ironman Kona. A solid swim performance, the day’s fastest bike split with a new course record and a controlled half marathon ensured a stellar 2nd place overall with a finishing time of 03:49:22, only beaten by former 2x short distance Olympian Tyler Butterfield.

Race day temperatures were ideal and directors ruled a non-wetsuit swim for pros. In the swim Michael immediately found a rhythm exiting the water after 26:20 in 11th position only 2’20” behind the top group. Once on the bike course, he immediately moved up through the field, eventually taking the lead with a course record bike split of 2:01:44. The Austrian pro arrived to T2 in first position going into the half marathon and was eventually only caught by race winner, Butterfield. Weiss finished second, saying “this was probably my best IM 70.3 performance to date!” 

Now let's take a closer look at the SRM data.

The table below details the SRM data from Weiss's Ironman 70.3 Timberman performance. However, caution need to be paid for the negative split when taking a first glance. We will explain the Hows and Whys of such uncommon pacing strategy for a half Ironman.

Bike Setup: Diamondback Serios triathlon bike, SRM PowerMeter with PC8, HED front wheel and rear disk, Atomic High Performance drive train coating, Speedfil hydration system with GQ6.

SRM Race Data

Time 2:01:44 min
AVG Power 348 watts
Normalized Power 366 watts
Watt/kg 4.3 W/kg
Training Stress Score (TSS) 178.6
Intensity Factory (IF) 0.94
Variability Index (NP: avg. P) 1.08
AVG Speed 43.7 kph (27 mph)
AVG Cadence 87 rpm
Distance 90 kilometers (56 miles)
Energy 2,550 kilojoules
Pacing Strategy negative split - 62'01" vs. 60'05" (-3.21%)

SRM Race File | SRMX Software

Click on File to Enlarge.

The bike course was basically a 45 kilometer (28 mile) out-and-back.

Michael's rolling average power was 345W resulting in 366W Normalized Power for the nearly 90 kilometer (56 mile) bike leg.

Variability Index (VI) which compares Normalized Power and rolling average power was 1.05. The closer this number gets to 1.00 the more even the course profile. If we would take a 90km long flat road not taking into account wind scenarios while cycling nonstop, ideally VI should be 1.00 which means Average Power = Normalized Power.

Mean speed was 43.7kph while top speed reached 92.7kph – underlining his downhill skills as a former MTB professional.

Due to the course profile, Weiss accomplished a negative split for the overall bike race time – first half 62’01” vs. second half in 60’45”. However, taking into account his power output we could not find any negative splitting strategy at all – 375W vs. 358W. Thus it would be unlikely that Michi was holding back for the first 45km and riding with less physiological cost. In fact, quite the opposite occurred. Michael invested a lot in the first half to close the gap to the main bunch including Butterfield, Tim O'Donnell before reaching the turn-around point.

As former professional cyclists, both Michael and Tyler Butterfield have extensive experience and skills on the bike which contributes to gains made on the downhill sections of a race. While many athletes tend to be conservative on downhills, Weiss and Butterfield both rode smart and aggressively on the descents. Michi maintained 50kph+ (31mph) for almost 30 minutes, which is significantly influenced by his aero dynamic position, bike set up and technical skills. 

Many thanks to Michael for sharing SRM race data and to Peter Leo and Garth Fox for providing analysis.

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