Lake Taupo Cycle Challenge Power Analysis from Brett Grieve

After racing around Lake Taupo near the front of the field I caught up with Brett Grieve about his performance and here is an analysis of his ride. This ride follows up the great ride he had the previous weekend at the Abel Tasman Cycle Challenge.

For full disclosure, Brett is a friend of Qwik Kiwi Coaching and isn’t coached by me so I can’t take any claim or credit for his training that lead to this result.

Lake Taupo Cycle Challenge is effectively a race of two halves. The first section are the hills that lead the riders down the western side of the lake toward Turangi and the second section is the return through Turangi on the flat back to Taupo but includes the Hatepe Hill which is 3km long at a 5% gradient 125km into the event. Just when the legs are nice and shattered.

As with the Abel Tasman Cycle Challenge Brett didn’t set any power records by racing smart and only riding hard when he needed to for the best effect. As with last week he spent 40% of his race riding at Level I or II. At about the 70km mark Brett was unfortunately involved in a crash. Fortunately himself and a group of other riders formed a chase group and rode hard together to the finish. That meant that he had a similar ride to last weekend (relative to power zones). With 19% of the event riding Tempo (Level III) and 18% at Threshold (Level IV) which is just over 40 minutes riding at Threshold.

As Brett spent most of last week’s race off the front he wasn’t required to put in as many top end efforts over the last week. To maintain his position at the front of the race this week he put in ALL his Peak Power efforts in the first half of the race. This meant that he spent a bit more time at the higher intensities this week than last week, with 23% of the race at Level V.

At first glance at Brett’s power chart for the race you can clearly see that his power (pink line) is a whole lot more stochastic (up and down in apparent randomness) for the first section of the race. It’s interesting to note that his VI (Variability Index) is 1.17 for the race up until he descended down to Tokaanu (~100km) and has a relative flat ride back to Taupo from here (~260m vertical climbing. His VI for the second part of the race from Tokaanu to Taupo is only 1.05 which is more akin to a Time Trial, indicating that he rode pretty consistently with his group rotating through keeping the intensity even along with the rest of the riders.

Brett rode with the front group of riders and actually picked up a couple of Strava KOM’s for the First 40km and also Poihipi Climb to Whangamata. It was within this portion of the race where Brett established most of his Peak Powers. Often when an athlete has their Peak Powers early in an event they blow up later in the event. However in this case when racing for position Brett used his power wisely to maintain position near the front of the field. With his crash near half way, Brett didn’t need to surge and ride hard to defend against attacks but kept things consistent and rode evenly with the other members of the chase group. It’s likely that if he was called upon to surge his power Brett could have launched himself up the road and got higher peak powers later in the race but tactically this wasn’t called upon.

Brett did most of his Peak Power’s on Poihipi Hill and shortly afterwards (where he got the Strava KOMs). His highest Peak Powers were no doubt as he was attacking or counter attacking (Peak Powers less than 1 minute).

  • Peak 2 sec: 1084 Watts (max 1229 Watts)
  • Peak 5 sec: 988 Watts (max 1229 Watts)
  • Peak 10 sec: 890 Watts (max 1229 Watts)
  • Peak 12 sec: 888 Watts (max 1229 Watts)
  • Peak 20 sec: 825 Watts (max 1229 Watts)
  • Peak 30 sec: 738 Watts (max 1229 Watts)
  • Peak 1 min: 578 Watts (max 1229 Watts)
  • Peak 2 min: 445 Watts (max 741 Watts) this occurred earlier on Poihipi Hill and likely resulted from surging to bridge an attack or hang on to avoid getting dropped.
  • Peak 5 min: 426 Watts (max 1229 Watts) this five minute period started early on the hill and encompassed the Peak 2 minute period and also the higher intensity sections further up the hill.
  • Peak 6 min: 400 Watts (max 1229 Watts)
  • Peak 10 min: 391 Watts (max 1229 Watts) this occurred in the ten minutes leading to the summit of Poihipi Hill.
  • Peak 12 min: 377 Watts (max 1229 Watts) this occurred in the twelve minutes leading to the summit of Poihipi Hill.
  • Peak 20 min: 350 Watts (max 1229 Watts) this occurred in the 20 minutes leading to the summit of Poihipi Hill.
  • Peak 30 min: 340 Watts (max 1229 Watts) this occurred in the twelve minutes leading to the summit of Poihipi Hill and then the next 18 minutes of descent and into the next climb on Whangamata Road.
  • Peak 1 hr: 321 Watts (max 1229 Watts)
  • Peak 1:30 hr: 313 Watts (max 1229 Watts)
  • Peak 2 hr: 299 Watts (max 1229 Watts)
  • Peak 3 hr: 297 Watts (max 1229 Watts)

The Peak Powers from 1 hr through to 3 hr all included Poihipi Hill and then the terrain afterwards. The 2 hr Peak Power started a little later than the others and finished at the summit of Kuratau Hill, where as the 3 hr Peak Power continued to Bulli Point and the 1 hr Peak Power and 1:30 hr Peak Power are basically the first 60 and 90 minutes respectively.

Here is a comparison between Brett’s Peak Powers from the Abel Tasman to Lake Taupo Cycle Challenge:

Peak Power (Watts) Abel Tasman Lake Taupo
2 sec 872 1084
5sec 791 988
10 sec 686 890
12 sec 667 888
20 sec 616 825
30 sec 555 738
1 min 495 578
2 min 472 445
5 min 421 426
6 min 404 400
10 min 394 391
12 min 372 377
20 min 348 350
30 min 330 340
1 hr 321 321
1:30 hr 314 313
2 hr 311 299
3 hr 302 297

It is interesting to note that Brett had his Peak Power for 60 min exactly the same for the two events. Due to how the races unfolded for him, the Abel Tasman Cycle Challenge had the higher Peak Powers for the longer durations higher. For the Lake Taupo Cycle Challenge the Peak Powers less than 60 minutes where higher.

Here is a comparison between the other metrics measured or calculated for the event:

Metric Abel Tasman Lake Taupo
Time on Garmin 3:54:17 3:43:09
Distance 153 152
Ave Speed (km/hr) 39.3 40.9
Calories 4073 3961
Elevation Gain 1388 1882
Training Stress Score (TSS) 312 323
Intensity Factor (IF) 0.89 0.93
Normalised Power (NP) 322 336
Average Heart Rate 144 143
Max Heart Rate 166 174
Watts per kg 3.93 3.97
Variability Index (VI) 1.08 1.12
Efficiency Factor (EF) 2.24 2.35
Velocity Ascended in Metres (VAM) 355 506

Both events were similar in duration and distance with the key difference being that the Lake Taupo Cycle Challenge is a hillier course. The VAM as a result was nearly 50% higher. This made it slightly harder and as a result Brett had a high Training Stress Score (TSS) for this event. His Normalised Power (NP) and Watts per kg was also higher as a result. Due to the tactics of how the event unfolded: Lake Taupo involved higher intensities as he maintained his position despite attacks and counter-attacks going up the road he reached higher Power and Heart Rate as a result.

Abel Tasman had a steadier effort due to getting in an early break and not having to attack or counter-attack. This resulted in a lower Variability Index (VI) and lower Efficiency Factor (EF) this is due to the lower Heart Rate.

Check out Brett’s Strava file here:

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