THE WHAT AND WHY OF METABOLIC PROFILING

The constant adaptation and refinement of the tools and processes of performance are endlessly intriguing! Things like the continual improvement of VO_2max increasing ones sustained duration at supramaximal intensities, and pushing maximal force generation catch my attention. The intrigue of advancing athletes season to season over a long period of time and consistently trying to push those athletes to performance optimization is one of the key responsibilities of both coach and athlete, working in tandem. INSCYD, a metabolic profiling and performance optimization company that’s been around for about a decade, is bringing some novel tools to the job for coaches, athletes and physiologists

In September I went to INSCYD’s Coach Conference with a slew of other deep divers looking for insights, understanding and some coveted CEU credits. We dug into the essentials and the subtleties over four days, with break-out discussions overlooking the Park City Olympic ski jumpers twisting and flipping into an aerated pool on a gorgeous fall weekend.

A few takeaways:

1. Fat Metabolism: The first qualifier is that “maximal fat metabolism” occurs across a range of roughly 50-65% of VO_2max, or 65-75% of MLSS. That range covers a fairly wide swath of power distribution. For example let’s say your VO_2max power is 400W, that gives you a target range of 200-260W for a generic “FATMAX”, that’s quite a range to base your training on! We’d like it to be a bit tighter in order to be maximally useful (ok, alot tighter!). There is “a number” (and a range) that represents that maximum fat combustion and knowing it really cleans up your training efficacy, so do the testing!
2. Lactate re-uptake also occurs below MLSS, most often in the 70-85% VO_2max range, once again presenting a conundrum of where your “optimal” is. Testing gives us that number, unique to you and highly changeable. With that number, and a small range on either side, we can target not only your ideal intensity for development – how hard you have to push to make improvements, but equally as importantly your target recovery. For reference, most athletes will self select roughly 50% of VO_2max as their recovery intensity, but if your optimal lactate metabolism occurs at 65% of VO_2max you’re missing some critical efficiencies in your training.

My last point for today is to reinforce the idea that separating these two intensities in your training is actually quite important. There is a measure called Velocity of Lactate Accumulation (VLa_max for short). This represents the maximal rate of rise in lactate, generally expressed as mmol per Liter per minute on a scale of 0.0 – 1.0. For example, a sprinter, with high type II (fast twitch) muscle mass will have a much higher value (eg 0.7 mmol/L/min) than a true Type I endurance dominant athlete who will have a lower value, 0.35mL/mmol/min for example. In practice this means the “sprinter” type adds lactate more easily, which actually impedes aerobic recovery (and performance too) on those type of intervals. If you are a high VLa_max kind of rider and you keep “hitting out” those little surge efforts in the midst of an “aerobic” interval because they feel good – or the workload doesn’t seem hard enough – you’re only derailing your own aerobic system from the actual recovery needed to repeat the target effort. It’s a similar story on the other side of the glycolytic divide; doing your recovery at the wrong intensity also impedes lactate clearning and the hoped for re-set of your engine for the next round.

Madness, sheet madness I say 😉

High lactate producing efforts flood the system, immediately compromising the efficiency of the aerobic pathway needed to recover and reset for the next effort. A key part of training is developing these systems independent of each other, then combining them into performance – a tricky balance that we’ll explore soon in another post. Of course this is where the testing component adds levels to your game. Using statistically valid models and algorithims, INSCYD can give you an accurate cross systems metabolic profile that helps you refine and target both improvments and existing strengths. If you’re just using your FTP as a guide, you are definitely leaving performance on the table.

Now let’s help YOU find those optimal values and integrate them into your own training! Thru the end of 2025 I’m offering a discount on INSCYD Power Profiling thru my new SONIC Online Training Center. SONIC is a web based testing and training platform where you can take the INSCYD Power Performance test and then join me for a 30 minute Zoom discussion of the results, I’m pretty excited to launch of SONIC OTC and will detail it more in my next post, but for now, and thru the Holidays, schedule a test and start the New Year with some new insights

SIGN UP FOR INSCYD TESTING SPECIAL – ONLY $149 PER TEST THRU DECEMBER 31