Anaerobic deficiency?

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  • #45378

    Hello everyone
    I practice endurance sports since about 10 years.. In the last two years I started to do skimo racing as my main sport and trail running in the summer. I use the UA methodology since a year now in my trainings. During this period I did three HR drift test showing significant improvement. The latest test suggests I that my aeT is close to 172 bpm. That high value raised some questions: 1) Did I got good results on HR drift test? 2) Do I have sort of an anaerobic deficiency? 3) Should I add more intensity work in preparation for the coming skimo season? I hope you will find those data interesting.

    For every test, I start with 15 min of easy jog, followed by 5 to 10 min of running drills before starting the test. I always ran for a little more than an hour (66 to 68 min.). My running speed is very consistent through the whole duration. I assume constant speed when calculating HR drift. All tests were performed with temperature between 3 to 12 C and light wind, except the second one where the wind was moderate. I do not use the GPS to track the speed and distance; I calculate it from the lap duration and real lap distance. I use a chess strap HR monitor.

    First test December 2019
    Place: 405 m track
    Time: 1:07
    Distance: 15,8 km
    Avg pace: 4:15/km
    Starting FC (first third avg): 162
    Ending FC (last third): 170
    Drift: +4,2 %

    Mostly nose breathing but starting to be hard in the second half. Slight acceleration in the second half from 1:44 to 1:42 per 405 m laps. Felt god after the test and the next day, I did a 4h run on snow in Z1-Z2 (25 km 1350 m of D+).

    Second test April 2020

    Place: 1500 m perfectly flat loop
    Time: 1:06
    Distance: 16,5
    Avg pace: 4:00/km
    Starting HR: 163
    Ending HR: 165
    HR Drift: 0,6 %

    Increase of pace from 4:15 to 4:00 compare to the first test (5.8 % faster). No clear change in the AeT, but drift is lower so maybe there is an increase.

    Felt well during the test, the main limitation was muscular endurance; I am not used to run that fast and on flat terrain for so long. Drop of 40 bpm after ending the test. Some trouble with FC monitor during the beginning of the test. It goes to crazy high values after 3 min in the test and stabilizes after about 12 min. I just ignore that period to calculate the HR drift.

    Third test September 2020

    Place: 400 m track
    Time = 1:08:22
    Distance = 18 km
    Avg pace 3:47 min/km
    Strating FC: 172
    Ending FC: 175
    HR Drift: 1,74%

    Increase of pace from 4:00 to 3:47 m/km compare to the second test (5.4 % faster). AeT have increase from 163 to 172 (+5.5 %) but the last AeT estimate of 163 is probably too low so the increase would also be lower.

    I felt good during the test. I was breathing thought the nose for the first 12 min. to set in the pace. After this, it would not really have been comfortable to only breathe through the nose. Again the main limitation is muscular endurance; I am still not used to run that fast and on flat terrain. I could have maintained that pace for at least 10 more minutes. Felt well the next day, but my calves were sore. HR monitor still have some problem in the first 10 minutes of the test, so I rejected some data.

    AnT estimates

    I use skimo races as estimates for AnT, even if those events are usually longer that an hour. In the first ascent I basically push like if it was the last so I should be close to AnT. I pick the highest HR value as my AnT.
    January, Stoneham Skimo race duration 1:17 ant=171
    February, Burke Skimo race duration of 1:47 ant=174
    February, Orford Skimo race duration of 1:01 ant=170
    March, Mont Sainte-Anne Skimo race duration of 2:04 ant=174
    July, Uphill run duration 25 min. ant=178 (178 is the max FC, but avg is 173)
    September, Mt Rundle ascent duration of 1:25, ant=175 (HR is dropping at the end because of rough route and snow on the ground; Felt great the next day and climbed Mt Temple by the scrambling route)

    During 30-30 (2X 12 to 14 rep.) uphill running trainings, 183-185 bpm feels like the max I can go, so my AnT is below 183 bpm.

    What I did for training in the last year
    I consistently did 6 to 14 hours of Z1 –Z2 training, some weeks I reached 20 hours. Most of it is done on skis in the winter (70 %, the rest is running) and in the summer I run/hike (80 % on trails or off trails and 20 % on flat roads).

    Most of the week I do one intensity training, Most of it is in Z4 (30-30 uphill). I rarely do Z3 intervals, the time I spent in it is during races or long run/ski activities. On average I spend about 5 % of my training time in Z3 + Z4. The peak weeks are at 10 %.

    I did a 12 week gym ME progression last spring and did a couple of maintaining trainings during the summer.


    Is it possible I got bad results/interpretation from the third HR drift test? 173 bpm seem to be very high, could it be above my AnT, explaining why it plateaus. On the other hand, the pace progression seems to fit with the first and second test and the HR drift is low. I also still had some reserve to go faster or longer so I should not have been at AnT, thus I assume that there was space for HR drift during the test. I would consider the 172 bpm value good and used 170 bpm as AeT on the field. The low drift of 1,7 % of HR drift could suggest AeT higher, but I don’t think it is really the case.
    Assuming an AeT at 172 bpm and an AnT close to 175 bpm, my Z3 is basically absent. Moreover, I really struggle to get to 183 -185 bpm, therefore I only have about 10-12 pbm between AeT and something like max HR. Does it mean I have sort of an anaerobic deficiency? I guess I should add more intensity work in my training plans. I think I will try to do longer Z4 running intervals (2 to 3 min.), every 5 days, any other suggestions?

    I guess It could also be interesting to test AnT on flat terrain, I may try a 10 km test this fall and post results here.

    I find those data interesting regarding the significant speed improvement on flat terrain, even though I have not work on that specific ability in the last year. The gym ME could have an effect even for running on flat terrain.

    Thanks for reading

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  • Participant
    Dada on #45382

    Also interested.

    Anonymous on #45419


    Congratulations on doing such a good job raising your AeT (HR and Pace). These tests for AeT seem valid to me and I would also call your AeT something close to 170. Remember that both these thresholds will move from day to depending on your recovery status.

    I recommend that you don’t do any Z3 training and instead use Z4 intervals to increase your speed at AnT. At the same time you should drop all Z2 and do all your aerobic base training in Z1. Your Z2 pace is too hard to use it for base training any longer.

    With your high level of fitness you need to make your training ‘polarized’: Easy days are easy so that hard days can be HARD.

    For someone with a high fitness if you do the AeT tests on the flats and the AnT tests uphill you will be comparing apples to oranges. Both tests should be done on the terrain you train on. I recommend doing your AeT test on a steep treadmill. The Canmore Nordic Center has these.

    Continue with the ME workouts. Yes they will help yo run faster on the flats and not just hills.

    Keep it up and you will see even more gains.

    Marcus on #45462

    Thanks Scott for your advises.

    I will keep working on speed at AnT.
    I am not a fan of treadmills, but I will try the AeT on a treadmill. Unfortunately, I was in Rockies only for the summer, now I am back in Quebec. I should be able to find the good equipment here too, just need to wait until the end of our second lockdown.


    Anonymous on #45515

    A couple more thoughts:

    * You don’t have an anaerobic deficiency, quite the opposite. Because you’ve raised your AeT to a high level, you can probably now withstand harder, longer anaerobic efforts. These should be measured by duration X at Y intensity, not through HR.

    * The high leg fatigue from running during an AeT test is normal for mountain athletes with strong aerobic systems. I know several skimo athletes with the same issue. The reason for this is that the cardiovascular system is much stronger in relative terms than the legs in a running context. So the local muscular load has to be very high when in an untrained activity in order to tax the heart and lungs. As Scott J. suggested, you should make your tests sport-specific to avoid this.

    * The treadmills at the Canmore Nordic Centre are reliable and go up to 25%. I would test at that grade. Bear in mind that if you compare to another treadmill, the speed will likely be different. Woodway (at the CNC) is an accurate brand, but something like a NordicTrack will likely be off in speed upwards of 12-19%…

    Marcus on #45588

    Thank Scott for the precisions.


    Anonymous on #45606

    Here’s a great video that shows the benefits of a big aerobic engine allowing for more anaerobic performance. It’s a gold medal skier (Sundby) versus a bronze medal wrestler (Berge):

    Marcus on #45626

    Wow, it looks fun! Really nice treadmill.

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