Notes on an Interview: Mike Robertson’s In the Trenches with Mike Tuchscherer

I’m a big fan of Mike Robertson’s In the Trenches podcast series. The most recent podcast was an interview with Mike Tuchscherer, the founder of Reactive Training Systems (RTS). RTS is not so much a training method in itself, but a system that allows you to train with your program more efficiently and effectively. As Tuchscherer says in the cast, it will help you listen to your body, so you can change your program and do what your body will respond to. I got a lot out of this particular episode (even more than usual) and thought I would share the notes I took from it.

Two basic concepts of RTS include the use of a Rating of Perceived Exertion (RPE) scale, and the use of a Fatigue Index. While I am very familiar with the use of a 0-10 RPE scale to track training loads, the Fatigue Index was a new concept to me. However, once I heard it explained, it not only made perfect sense, I wondered why I hadn’t thought of it in such terms myself. I won’t keep you in suspense any longer:

When the body encounters physical stress beyond what it is used to, it responds via a process of adaptation, whether that be getting stronger, increasing lean muscle mass, or getting more cardiovascularly fit. If the physical stress it encounters is less than that threshold level, or what it is used to, no adaptation will occur. Basically, if it isn’t hard enough, you won’t get anything out of it- you need to work to a certain level of difficultly or fatigue to get the benefits of adaptation. That’s where the fatigue index comes in: identify how much fatigue you need to achieve adaptation, and you can tailor your training session around that. If you need X amount of fatigue and you’re feeling a bit tired, sore, run down, whatever, you might only need three sets of a given exercise to reach that fatigue level. On the other hand, if you’re feeling awesome, pumped up, ready to go, you might need to do the same exercise for six sets to achieve the same level of fatigue. Rather than working for a given number of reps and sets, you end up working to a certain level of fatigue. Since fatigue = adaptation, makes sense to me!

Of course, the intensity you’re working at will make a big difference to your fatigue levels, and this is where the RPE scale comes in. As Tuchscherer points out, lots of program work on a percentage basis (i.e. X% of your 1RM), so that a light day might be 60-70%, a medium day 70-80%, a heave day 80-85% and above. But what happens when you train hard on a regular basis? In theory, you should be getting stronger. And since no one does a max test at the start of every session, you can pretty easily end up with some skewed percentages- by which I mean, your 1RM should be increasing, so your “70%” might actually be closer to a 65%, or a 60%, or lower- depending on how long it’s been since your last max test. Tuchscherer says that your motor units (the actual muscle cells and the neurons that make them fire) only care about how hard they have to work, and how many times they have to work (which goes back to the fatigue index and how that affects adaptation- it’s one big circle). The “percentage” doesn’t matter.

A Basic 0-10 RPE Scale

So using an RPE system means that you can be really accurate with your training from day to day. Just like the fatigue level, your training can change based on whether you’re feeling flat, or feeling awesome. Basically, if you train based on a percentage, you risk training at a lower percentage than you think you are. If you train based on an RPE, you can increase that load as you get stronger, thereby gaining bigger increases in your true strength. What’s not to love?

Admittedly, after a little bit of digging on the RTS website, the RPE method outlined in Reactive Training Systems is somewhat different than the simple 0-10 scale shown here. In fact, Tuchscherer suggests customizing your RPE scale to match to percentages of your lifts in order to really maximize effectiveness (you have to check out the website for more information though- they didn’t actually talk about this during the interview).

While there is much more to Tuchscherer’s Reactive Training Systems, these are two of the basics concepts that were discussed in the interview. You can find In the Trenches at– be sure to check it out for some great info. You can also find out more about RTS at , but even taken on their own the concepts of working towards an RPE or fatigue will go a long way towards appropriate and effective training. Keep it in mind next time you hit the gym, or even better, sit down and write it into your program!