How does Sam Nadler's AI personal trainer adjust workouts after each set?

Short answer: Sam Nadler shows settings for goal, workout days, body focus, experience and equipment. When he logs a set as a struggle, it suggests stepping down, dropping the weight from 20 to 7.5, or ending the exercise.

Watch this answer from Episode 30

Watch this answer from Episode 30 (starts at 8:01) · Episode 30 notes and transcript

What was said on Built This Week

From Episode 30: Claude Opus 4.6, Codex 5.3, and the Rise of Multi-Agent AI, starting at 8:01.

Sam Nadler [8:01]: But, I mean, this is somewhat boring to look at, and I haven't used it all that much, but, just to give a quick demo of what I've built. So this is my day by day personal trainer that's literally dialed in and will give you feedback based off every single rep, based on your goals and your overall plan. So let me back up a little bit, and I'll go to kind of my settings. So my training settings are a plan to workout, a workout duration of forty five minutes. My training goal is to get bigger, not necessarily stronger, just bigger, gain muscle mass, you can do both, and workout days, you have to do a minimum of two days. I chose five and that's based on like a specific split structure. My body focus is upper. You could choose balanced or lower. That doesn't mean you won't do any lower exercises if it's upper. Or if you choose lower, doesn't mean you won't do any upper exercises. It's just gonna be a smaller percentage, maybe 20% versus 50% in the balanced. Experience level is beginner is basically, you have no idea what you're doing versus experience. You've, yeah, you kinda know what you're doing. It's not necessarily an expert. Equipment access, full gym, home dumbbells, basic gym, body weight, and any limitations.

Sam Nadler [9:16]: I don't have any limitations. So, save settings, back to resume the workout. So every day you have a workout, and let's say I was practicing here, but, the AI is today is about executing the plan, not improvising first compound, full control. I've already logged the first set, but I made the I wanted to because I was kinda doing this in my gym already in a ChatGPT thread, and I want it was annoying typing out and letting it know exactly what I did, so I wanted the interface to be super simple. But let's say that I did this and it really felt like a struggle. So it then tells me you've reported difficulty but completed the target reps with acceptable form. On volume days, feeling the work while maintaining control indicates effective training stimulus continue at the same rate. Okay? So let's say, okay, let's maybe do a lot less and still say it was a struggle. Okay. Fatigue check. Step down. Focus on control. Step down at, it's now saying do less if you wanna continue or just end this exercise completely. So let's say do less and log the next set.

Sam Nadler [10:25]: It already pops up the rep, recording kind of element already down from 20 to 7.5 and reduces the rep. So let's log it. Boom. Hand exercise. Energy left. Are you full tank? Feeling good. Half empty. Running low. Still feeling good.

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