22nd March Powertap v Lifefitness Comparison - results

The results of the tests are summarised on graph above mapping HR against Watts. Powertap is blue, Lifefitness green, dark lines the first session on each, light lines the second.

Observations:

• The shapes of the graphs are clearly pretty similar. The Lifefitness ones seem to be smoother than the Powertap which is consistent with me having to "hunt" the desired watts on the latter, while simply dialling it in on the Lifefitness


• At lower watts (100-178) the Lifefitness HR is slightly below the Powertap. Speculating this may be because the Lifefitness is recumbent. At the 2 higher values (219, 261) the difference is less. In fact for this range the first sessions on Powertap and Lifefitness are almost exactly the same as the graph below for just sessions 1 and 2 shows pretty well.
  

• Strangely session 3, the second Lifefitness session had a HR line less than the first.
• The second Powertap session showed the highest HRs. This may have been because it was after 90 minutes of exercise, also not helped by having the highest variation in watts during each ramp due to me being daft and looking to see what gear I was in (so having to pedal harder to get average up)

Overall on the basis of this first test it looks as if the Lifefitness power is comparable to "real" power as on a bike. I will do a couple more tests to check (in the interests of science but also a good reason to train indoors when the weather is rubbish). Plan to do:

• Same sessions as above but do Lifefitness first and last with Powertap in between.
• Same sessions as above but all on same bike. Expect some variations between each session as happened above but will be interested to see how wide these are. Also interesting to see if the slightly strange result in session 3 (second Lifefitness) repeats and heart rate actually decreases with time.
• Similar sessions to above but with longer time in each interval (time/enthusiasm permitting)
• Carry out some higher power workouts. Problem here is that heartrate can lag power so becomes less useful as a comparison tool. Also difficult to carry out comparable sessions on same day as fatigue is more likely to affect results. But will try nonetheless and see what results follow.

22nd March Powertap v Lifefitness Comparison - the test

Day off today so carried out the comparison test I have been planning since getting the Powertap. Most of my power measures to date have been on my Lifefitness exercise bike so interested to see how that compares in terms of watts to the "real" thing.

Premise was that I could use heart rate as a measure, the correalation between it and power on Powertap/Lifecycle should give a measure of how similar when displaying watts.

Decided to carry out test as follows:

• Do 4 sessions each 30 minutes long. Sessions 1 and 4 done on Powertap, 2 and 3 on Lifecycle.



• Target watts for each session is 100W for 10 minutes then 4*3 minutes ramps increasing to 140W, then 180W, then 220W, finally 260W (so up to 22 minutes) then back to 100W for 8 minutes. Pedal at a cadence of 80-85 rpm throughout until the last 8 minutes which would be at 70-75 rpm.



• Logic behind these values is that I know I can do these comfortably so will not tire during the 2 hours the test takes. (Also eat a small 150-200 cal snack at the end of each session to keep topped up. ) These power values are also where most training is carried out. Having the long run in/out of 100W should give enough time for my heart rate to return to normal between sessions and also provides a good base value.

Session 1 Powertap. First session on Powertap was interesting. It took a while to get the cadence/gear right so that the power was in the 100W average. Again each ramp up took a while to get used to in terms of target watts. This can be seen in the power graph below where within each stage of the test the actual power can be seen to be varying quite a lot around the average, with a noticable spike up at each ramp up.

In the end though managed fairly well to make the actual power hit target. Actual averages were 98W, 138W, 178W, 219W, 261W and 103W. As expected at the end of the session I was not feeling at all tired. One good thing about having to concentrate on the average watts measure was that I had not much idea what my HR had been. So I would do the Lifefitness tests blind in terms of expectations of HR on the Powertap. Had a Twix at the end of this session.

Sessions 2/3. These were a lot easier in terms of carrying out the test as it was just a question of choosing the "Watts" program and setting the same watts as done on the Powertap. Subjectively the sessions felt similar in effort to the Powertap and again at the end of them felt not at all tired. Had a break between the two, having a banana and cereal after session 2 then some chocolate (not planned but my son had some on offer) after session 3.

Session 4. The second session on the Powertap and the hardest in terms of hitting the desired watts target. This was partly my own fault as I wanted to try to make a note of the gears I was using so a number of the ramps show sudden dips as I look down to check the gear being used.

Anyway finally finished. Followed up with some roller work (see other posts)

21st March Road Club Turbo Training

Last session of the road clubs winter training. This one was for a "warm up" to be done day before a time trial.


Consisted of 3 sets of 5*15secs max effort WI, 1 min RI.













Session left me knackered. Mistake was to try to go to hard too soon so WIs show peak then sharp decline as struggle to hold power through interval

Clearly something I need to work on as I know I am no sprinter but think could do better than this. Peaks of 5s 720W and 15s 646W were pretty poor too, partly I guess because went quite hard last night as well.

This was followed by 10mins at race pace but by then pretty tired. Started too hard on 350W and dropped back to a pretty weedy 270 average at the 10 minute end.

20th March - Hard life cycles

Couple of hard sessions on the Lifecycle.

Intervals on the max 20 setting for 20 minutes. Actually only means 2 intervals on the full 400W (1 minute each) but tough nonetheless.

Then speed on varying intensities from 15 up.

Overall nearly half the hours session at levels 4/5 (21 mins 4 and 6 minutes 5)

Weekend rides

Hectic weekend playing with my powertap and starting into build phase.

Saturday did the Lamborn triangle, with goal of averaging 200W. Managed, starting well with 235W to first Ridgeway point, 215W at Wantage then finally 209W at end.

Found keeping the watts up when going fast on level, downhill is bit tricky and something I will need to learn. Frustratingly found that when Powertop fills up it does not wrap round like the HAC so data from end of ride was lost. Still proved benefit of the Powertap as day was very windy and so speed at 27km Avs not good, but sure if did same Power on a calm day would get close to 32km PB.

Sunday went on club run, taking it easier as 147W average showed.

Monday is a rest day, Tuesday plan to compare Powertap and Lifecycle to see how they match up.

March Jersey Trip

Spend a long weekend enjoying the delights of Jersey.

Great trip from start (via the excellently near and easy to use Southampton airport) to finish.

Very lucky with weather as sunny most of the time and not too windy.

Spend 4 days on the island

Thursday: Arrive, pick up Powertap wheel and BMC loan and go for exploratory ride.

Friday: Easy day of riding up and down to St Catherines then test with Tony of Flamme Rouge. Do CP6 test and end up with a result comme this

Saturday: Go out for a ride with Tony and mates. Includes several max effort sprints that leave me gasping (so need to start training on these) plus a few hills that go a bit better. End up doing about 120km

Sunday: Do the tourist trail round the island visiting every bay on the way. Turns out to be a lot hillier than I thought as the bays are usually 100m or down some cliffs. So plenty of short sharp climbing.

Monday return and of to Strasbourg so some rest days coming.

6th March Roller time

Finally get the hang of rollers, doing 35km in total as a gentleish recovery ride. Find that need to go very fast in order to get any noticable heart rate increase, which is limiting factor as start to wobble at high speed.

Also get in touch with Tony from Flamme Rouge re Channel Isles trip this weekend

5th March Well Earned Day Off

Day off today after the Audax. Legs tired but only sore bit on behind as result of 4 hours saddle rubbing against wet shorts....

4th March Wed and Windy Audax

No club run today, its the Newbury Audax.

This runs 106km south and west of Newbury up and over the downs. 3 climbs apparently, Shurlock Hill, Rivar Hill out and Asmansworth on the way back.

Weather forecast had the two words no cyclist wants to hear. "Wet and Windy". Fortunately when we (about 35 of us) started it was neither but this soon changed. Got absolutely soaked and my bottom bracket got even more noisy.

I had thought Audaxes were meant to be easy events so had planned this as a recovery day. Turned out not to be as I wanted to keep up with the lead group so as to get back asap and out of interest as to how Audax compared with Cyclosportif. Turned out very similar. Pace was quick(ish) at 26kph (considering the conditions). Eventually just two of us in front and I dropped of on last climb up to Ashmansworth as did not want to push it to the limit on what was planned as a recovery day.

All in all interesting. May do some more a bit farther afield.

Details here: http://www.aukweb.net/index2.htm

2nd March Max Intervals

End of last base period so decided to push it a bit on the Lifecycle. Sport 19 (almost max) for 30 mins then did 15 mins of Intervals at 20. Meant in practice doing 2*400W for 45 seconds. Managed no problems

1st March Day off

Day off. Got submerged in Oblivion instead, deciding to take it easy following unexpected exertion night before and bearing in mind got a long weekend of training planned.

28th February Training - Unexpected exertion

Went to NRC turbo training class. Was expecting it to be a bit tough, but not as tough as it turned out to be. Training schedule said 4*5mins at 90% MHR with a minutes rest. Actually we did 3*10mins at 90%MHR with 4 mins rest. But survived.

Still felt well enough on return to brave the rollers again and managed to do 4km without needing to grab the step ladder for support.