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Vo2 at Threshold

Vo2 at Threshold – Affirming Outdoor Power at Threshold

Richard Wharton Vo2 at Threshold Online Bike Coach
Vo2 at Threshold can reveal a lot about how cardio-vascular fitness and status. The closer that number is to your Vo2Max, the better.

In my last blog post, I mentioned that for my best 10-minute effort while climbing a trail on a mountain bike, my Vo2 at Threshold read as roughly 55ml/kg/min. I also believed that my Vo2Max was roughly 62ml/kg/min. I was curious to see if these values were valid, so I went back indoors. At my home studio, I performed five weekly 20-minute efforts, specifically to determine whether those two values, Vo2 at Threshold, and Vo2Max, were accurate.

 

Percentage of Vo2Max When Cycling at Threshold Intensity

Different Metabolic Thresholds at a Percentage of Max Wattage
I’ve followed Jem Arnold for about a decade now, as he’s been involved in studying SmO2 for cyclists, as well as a lot of other things. This chart he presents, from a lecture, shows wide variation in ‘Thresholds’, where the body begins to migrate from mostly aerobic energy to anaerobic energy. This post is about Vo2 as a % of Max at Threshold.

There’s a lot of new information coming out about the determination of Training Zones. Essentially, each method of measurement tends to come up with its’ own value, and training zones are then based on those values. Let’s face it – Vo2 at Threshold is expensive to acquire, since it requires a Vo2Master, a Polar H10 chest strap, a Moxy, a Power Meter, and probably a Lactate Tester, which is a product I have owned in the past, but do not own at this time. Instead, I use the Moxy and other readings from the Vo2Master and my Polar H10 chest strap, to determine the most accurate Threshold value for myself.

By looking at ALL of the values, however, I could then apply each of them when training. If the goal is to raise Vo2Max to its’ highest time-limited potential, and to raise % of Vo2Max at Threshold, then having those other metric markers can help me take a more holistic approach to every ride.

The Workout

For these five tests (and probably counting), I used my standard indoor training software, PerfPro Studio. My warmup consisted of a 27-minute protocol that I’ve honed using Moxy muscle oxygen sensors. I did roughly four Vo2master O2 calibrations for each workout, but I only recorded the 20-minute effort on the Vo2Master app. The Vo2Master is best used in a consistent atmosphere, so I used a local 8000 btu air conditioner in my small room, to help keep humidity and temperature under control.

PerfPro Studio Vo2 at Threshold Workout
There’s literally no better piece of software in the cycling fitness world than PerfPro Fitness. The amount of information I can read, along with the myriad ways I can build workouts, remains unmatched.

Here are the results:

Date20Min Vo2 Average20Min Power Average20Min HR Average20Min RR Average20Min DFAA1 Average20Min SmO2 Average20Min EqO2 AverageBest 30-sec Vo2maxVo2 as a % of Max
6-Oct53.5271163350.56.822.262.685%
13-Oct55.1287172390.41524.560.691%
20-Oct57.5281170420.42024.565.288%
27-Oct56.9273172430.4310.225.363.290%
3-Nov56.9273172430.410.225.363.290%
AVERAGE55.98277169.840.40.42612.4424.3662.489%
HIGH57.5287172430.52025.363.291%
LOW53.5271163350.46.822.260.685%
RANGE416980.113.23.12.65%

What the Chart Says

There’s more information on this chart than just Vo2 values, but here’s the summary…

  • My 20-minute average Vo2 over 5 efforts was 56ml/kg/min. This is comparable to the 55ml/kg/min that was observed in the mountain bike climb from the previous, outdoor, post.
  • The highest 30-second Vo2 value over the same 5 efforts, which I’ll call Vo2Max, was 63ml/kg/min. Again – I’ve seen this ‘Vo2Max’ value enough to believe it is accurate. Incidentally, my Garmin 1040 and Garmin Connect continue to show my Vo2Max, per calculation only, at 59-60ml/kg/min, which I believe tracks pretty well, even though it is not using metabolic values, and instead uses calculations.
  • When you take the 20-minute Vo2 at Threshold, and divide it by the 30-second Vo2Max, well, my Vo2 at Threshold occurs at about 89% of my Vo2Max.

Notice that I have not mentioned power, or watts. I’ll explain why…

Vo2 at Threshold is a PHYSIOLOGICAL PHENOMENA

For 27 of my 31 years as a Professional Cycling Coach, pursuing watts at Threshold, watts at Vo2Max, and watts per kilogram per minute, has been a stated priority. However, Physics is immutable, while physiology is incredibly mutable.

For the same amount of physiological effort on the outdoor effort in the previous post, I averaged maybe 235 watts over 10 minutes, and 207 watts over 20 minutes. For these five indoor tests, I averaged about 277 watts over 20 minutes. The delta is too great to ignore.

On that same ride, I averaged 165 beats per minute for the climb, while on these five indoor rides, the average heart rate was 170 beats. Temperature, convection, and evaporation are important considerations for heart rate intensities.

For my climb outdoors, which was not 20 minutes, the average DFAA-1 on AlphaHRV was about a 0.4. For the 5 indoor efforts, it was 0.43. I am becoming more and more convinced that there is something ‘there’ there when it comes to DFAA-1 and Threshold.

Finally, the SMO2 value for my climb was about 25%, while the SMO2 average for the 5 indoor 20-minute efforts was 12.4%. I’m convinced that this is because of micro-recoveries on a mountain bike trail, vs. the consistent resistance of a 2% slope indoors.

I think I want to optimize my physiological markers going forward, and those of my clients, and let the watts take care of themselves from now on. Chasing watts as a primary metric, especially on a mountain bike, can leave a rider disillusioned and frustrated.

Conclusion

Vo2 at Threshold is a great way to assess your current fitness, but it requires expensive apparatus. I still don’t own all of the kit I could possibly wear that would help with this assessment. Knowing that my Vo2 at Threshold, is roughly 89% of my Vo2Max, does reassure me that my fitness, at least in August of 2024, and again in October of 2024, is pretty close to my genetic potential.

The next step, one I won’t attempt until the Spring of 2025, will be to try and grow that Vo2Max up to a 65, 66, or even 68ml/kg/min. This will be INCREDIBLY difficult to achieve as a 55-year old male, but I’d like to try. The next step would be to see if I can HOLD my Vo2 at Threshold near 90% as that Vo2Max rises. This is going to require losing another 2 kilograms of mass, maybe 3. That MAY affect my power output and fatigue levels, so I have to temper action with wisdom on this as we go into the 2025 PreSeason.

Winter is approaching quickly, and the cooler temps mean that I won’t be able to use the Vo2Master outdoors nearly as much. When the snow finally leaves the trails unrideable, I’ll be hyper focused on my indoor efforts in my VQ Velocity until Spring. But until then, I’ll be riding outside on the mountain bike on my beloved Peavine, trying to keep my singletrack skills and dreams alive until April 2025, when I can get back out there again.

I’ll post some follow up blogs about the other metrics featured in the chart above, but I need to consult with some PhD’s that are wiser than I am on these parameters. I also have to thank my client, Ken O’Brien, a retired Bell Labs professional, on his coding assistance for a new project that I’ll reveal next.

Thanks for reading, and ENJOY THE RIDE!

 
 

Vo2Max and Mountain Biking

Mountain Biking Requires Riding at Vo2Max!

Vo2Master outdoor data collection.
Cross Country Mountain Biking Requires working at or near your Vo2Max for an extended period of time.

CAUTION – THIS POST IS NERD-HEAVY! IT IS DEEP IN THE WEEDS! DO NOT HESITATE TO ASK QUESTIONS!!!!!

Ever since I received my Vo2Master back from my friend and code buddy in Canada, I have been collecting data on inside and outside rides. Not long ago, I rode two laps of my favorite Cross-Country Course, using my Mask, a Moxy, and a Rotor Power Meter, to learn just how hard I was working, and how I might be able to get some faster splits on the climb.

The Course

The course for this study is my all-time Peavine Favorite, which I built in Garmin Connect in a previous post. The course covers 8.6km, climbs 215 meters, and my best time on the loop is about 27:10, though I haven’t seen that time since 2020. I’m convinced that Mountain Bike Cross Country Courses change with use and weathering, and let’s face it – I’m four years older, and probably a little more skittish now than I once was. Health Insurance deductibles are always in the back of a cycling coach’s mind!

This year, my fastest time is a 29:36, and that happens to be the fastest time since a race was held on this course in 2019. It’s my home course, and I spend HOURS on the loop, trying to decipher bike fit, suspension, and tire pressure. When winter shuts me down, this trail is what I dream of for the next spring.

Vo2Max for Climbing on a Mountain Bike

The Climb section of this course starts immediately. The first section is 2.46km, and climbs 144 meters at an average of 5.7% slope.

The second segment, just a few minutes later, is 1.37km long, and climbs 54 meters at 3.9% slope.

My fastest time for this climb was set in 2020, at 10:33. My closest time this year, however, has been an 11:26. My weight, however, is about the same, at 69kg. The bike weight is similar, though it is a new bike. The difference is that I’m four years older, and maybe the trail has degraded somewhat over those four years.

The ride we’re studying occurred on August 15th, 2024. Here’s the link to the file:

Physiological Demands

I really wanted to see how much Strain was required to perform the climbs on this course, so I gave it all I had. I wanted to witness more than just power and time. I wanted to observe Vo2 demands, Saturated Muscle Oxygen values, Respiratory Rate, and more.

Here are a few graphs of the first climb. I think the results are pretty interesting.

Vo2Master Vo2 and SmO2 while MTB Climbing.
This first image highlights Vo2, elevation, and SmO2. You can see how SmO2 stayed suppressed below 20% for a good chunk of the first climb, roughly corresponding with the high Vo2. I believe my Vo2max is about 62ml/kg/min, and for this climb, I am estimating I climbed it at about a 55ml/kg/min, or 89% of Vo2max. Note also, just how quickly SmO2 recovers when terrain changes, as opposed to Vo2, which takes slightly longer. The legs provide the ‘Demand’ side of the equation, while the lungs in this case reveal the metabolic cost of this demand. 
Vo2master Garmin Connect Vo2max Vo2 Threshold heart rate mountain biking climbs
Traditional heart rate definitely seems to correlate with Vo2 on this effort. However – it does seem like the heart rate ‘drifted’ higher with the effort, while Vo2 was roughly steady, especially around the 14:45 mark. I tend to throw out the short spikes of Vo2, and in after-action, I always try to export the file and extract the highest Mean Max Vo2 for the duration I’m observing.
Vo2Max Mountain Bike Watts Stochastic Power
This is the same time span, showing Vo2 against power on the climb. Look at how incredibly stochastic the wattage is! This is created by terrain and changes in direction, but the metabolic costs (see the above charts showing SmO2, Heart Rate, and Vo2, all remain more consistent. Wattage dictates lots and lots of small, tiny gains, measured in single meters.
Vo2Master Vo2 DFAA1 DFAA-1 DFA Alpha 1 Alpha HRV AlphaHRV
I know there’s debate about the efficacy of DFAA-1, but I thought I’d show it anyway. Compare Alpha1 to SmO2. I usually dictate SmO2 at Threshold to be about 17-20%, and I usually use 0.4 -0.5 for Threshold at DFAA1. For the majority of this climb, once the calculation caught up, DFAA-1 was below 0.5, and was below 0.4 at times as well. It IS useful, especially for longer climbs.

Results

Okay – this is where things get crazy.

I have to believe that some of my results are wind and temperature aided. However, glances on www.wunderground.com history, just do not provide the details I believe are necessary to provide proper context. I also believe the trail conditions change over the course of a season, and over the course of years. I know I’m getting older, and with that age, a lower Vo2max and diminished power at Threshold, but I also believe that I’m giving this climb my best effort. This year alone, I have climbed this hill 24 times, with a best result of 11:26. August 15th’s ride was, however, a lowly 12:31, my seventh-best time this year.

Ironically, on August 18th, I climbed this hill in 12:04, and on August 25th, just 10 days later, I finished in 11:28. Unfortunately, I was not wearing my Vo2Master for those rides. I may follow up this post with an analysis of those rides, since I was using the Moxy, and AlphaHRV on my Garmin 1040.

That’s the Bad News. The Good News is that it’s the fastest time on this segment on Strava for the year, and it’s the fifth-fastest time ever. I now have the Vo2, SmO2, HR, and power metrics needed to determine how to actually IMPROVE my time through increased fitness!

Conclusion

Mountain Biking demands a lot of effort at, or near, your Vo2Max!

I now know just what the physiological parameters are for this climb. Knowledge comes from data, and the data revealed so much. I’m going to work on my 10-minute average power values, and power at roughly 54-55 Vo2. I’m going to work on leg strength, and overall body strength. I still don’t believe I have the best bike/body position for climbing, and I’m going to study that and make changes.

The beautiful thing about mountain biking is that the same course, the same segment, the same trail, is NEVER, EVER, EVER the same. Rocks move. Moisture comes and goes. Wind erodes. Some areas get softer, some areas get more packed. These are all things that GPS trackers cannot measure, and on-bike and on-body metrics can’t perceive or analyze.

I’ve spoken before about a term I learned when I was flying sailplanes. It’s called “Whipadilling”, and it’s sort of a 6th Sense. In aviation, it’s the ability to ‘read the air’ and ‘see the sky’. For me, on a mountain bike, it’s about reading the terrain, picking lines, making mistakes, rolling over those mistakes and remembering the next obstacle. There are SO MANY VARIABLES. The goal, however, is to optimize what I can on my body and my bike, and then practice, practice, practice, until the trail shuts down for the season, due to rain, snow, and short days.

 

Until then…

ENJOY THE RIDE.

 

 

 

The Road to 300 Watts FTP

Right Now, It's NOT about 300 Watts; It's About Raising LOWER THRESHOLD

The goal of base is to train the body for Economy. Stamina is the fundamental Pillar for Polarized Training. When you train using DFAA-1, you can get a clearer picture of how your body is responding to the training. Wattage and traditional heart rate become
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Xert Breakthrough With Physiological Metrics

Xert Is On Board With Some Serious Physiological Observations

My Client, Dusty, achieved an Xert Breakthrough while I observed his Physiological Metrics. This is Part 2 of what will now be a 3-part series of videos. In Part 1, I described the physiological phenomena behind a good warmup. Today, we’re going to show how Xert MPA metrics correlate with physiological phenomena.

The protocol are my favorite Billat 30-30’s. This means a cyclist pedals for 30 seconds of intensity, followed by 30 seconds of recovery. After five to ten intervals above Threshold Power, the cyclist then begins to pedal at intensities above the 3 Minute Mean Max Power.

THE CLIENT

Dusty came into the office with an Xert Fitness Signature of 306 Watts at Threshold, 21.4 KiloJoules of High Intensity Energy (HIE) available, and a Peak Power of 854 Watts. The goal was to attempt an Xert breakthrough, while using a Moxy Monitor and a Vo2 Master, to observe his physiological markers under intensity. I’ll explain what these numbers mean in Part 3.

Dusty is 44 years old, has been back on the bike for about a year, but has no long-term history of fitness or exercise. The bike was borrowed – he did not have a power meter for a road bike at that time. He has been training via Peloton bike and classes, roughly 5 hours per week. His goal is to be a competent coach to his son and friends in their High School Mountain Bike League. He has a power meter for a mountain bike, and a modern Garmin. At the time of the test, he had been using Xert for about 6 weeks. We had some data, but we needed to get a proper assessment.

XERT BREAKTHROUGH WITH BILLAT 30-30’s

Dr. Veronique Billat remains one of my favorite Exercise Scientists. She is the author of vVo2max exercise studies, and I translated those values over to wattage at Vo2max efforts, beginning in 2001. They are the cornerstone of any Alpine Mountain Bike athlete. While Dr. Billat uses 6MMP values, Xert uses 3MMP values to get cyclists to work harder. This is my own interpretation of “Polarized” training. Work done above 3MMP to 5MMP is highly effective for anaerobic intensity and success, just as work performed BELOW Lower Threshold Power, is also highly effective for aerobic economy.

In Part 3, I’ll perform a review and assessment of the activity, and will reveal Dusty’s new Xert Fitness Signature.

Thanks for reading, thanks for watching, and ENJOY THE RIDE!

Xert Breakthrough With Physiological Metrics Part One – Warmup

We Use a Moxy Monitor, a Vo2 Master, PerfPro Studio, and Xert To Show a PROPER Warmup

I continue to learn something almost daily when it comes to mixing Physics and Physiology. The data that we get and use for wattage training, is almost always complemented by the information I collect from physiology. We have to look at EXTRINICS and INTRINSICS. Extrinsic information revolves around information that the bike provides; Wattage, Cadence, Speed, etc. INTRINSIC information comes from Heart Rate, Saturated Muscle Oxygen, Total Hemoglobin, Gas Exchange Analysis, and even Lacate, when I can get it.

This video is part one of a two-part program where I helped a friend determine just what his fitness signature really was. This Intro explains the metrics on the video, and the proper way to warm up the body for work. Part Two is the Billat 30-30’s that we used to actually achieve a fitness breakthrough, and set Dusty’s Fitness Signature in Xert.

Since accomplishing this test in mid-February, Dusty has improved his fitness signature even more, and he is implementing the concepts of Polarized training, for himself and his entire family.

Thanks for watching, and ENJOY THE RIDE!

Coach Wharton believes in sharing his passion for cycling and fitness with everyone. IF you feel you got something rewarding out of this post, click on the link below and show some support!