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Philosophy

Why I built this.

I freakin love swimming man. I had a lot of ups and downs with it over my life but it truly is the one workout that makes me feel joy. I love the feeling of cool water, seeing the sunrays glisten off the tile in a clear outdoor pool, almost hearing the steam rising off the water on a cold morning, watching the little bubbles that form on the tips of your fingers hang on for dear life when you’re reaching out ahead of you. The Apple Watch really connected me back to swimming in a way I haven’t felt in a long time. A personal coach on my wrist was awesome and I wanted to make an app that expands upon that functionality, keeps things fresh, and is super duper easy to use. No friction to getting up and going for a swim.

Core Principles


When I started swimming again I scoured the web, USA Swimming, Facebook, Reddit, and a randomly stumbled upon Tumblr account to find any and every workout. They’re all fixed and not very interesting. That or they require a whiteboard at the end of your lane. Almost none of them accounted for the rest of your life.

But also calling it “cross-training” is sort of lame. You lift because you want to and you like getting a pump. You run because you like running with your friends Saturday mornings and you sign up for maybe 2 or 3 10ks a year and a turkey trot. You keep trying new meditation apps in the hopes that one will stick — heard. We’re all just trying to be a little bit better.

With those things in mind I put together everything I know about swimming, why I swim, and what I do in life. One calculator that sees all of it.

What’s baked in

Maglischo periodization

EN1/EN2/EN3/SP energy system sequencing, the foundational framework of competitive swim training applied to a non-competitive context. I grew up swimming in the 90s and early 2000s and this is how we did it.

General Adaptation Syndrome

three weeks progressive load, one week consolidation. The body adapts during the easy week, not the hard ones. Deload is non-negotiable.

Autoregulation

the recovery score infers how ready you are from HealthKit signals and swim recency instead of asking you to rate every session.

Connective tissue lag

cardiovascular fitness returns 3-4× faster than connective tissue. Shoulder protection in Chapter 1 exists because of this. Your rotator cuff needs more time than your lungs. Plus we’re old now.

Hypoxic progression

the Lungbuster sets are a structured CO2 tolerance program, not just a drill. Remember doing 500s of these?

Technical integration

drill work embedded into every session. Mechanics improve faster when you practice them kinda worn out.

Life-aware scheduling

you lift, you run, you have bad weeks, and sometimes you miss. The calculator sees all of it and adjusts. Strength work and cardio create different downstream fatigue. It knows the difference.

Adaptation windows

stimulus rotation sequenced around recovery time. EN2 threshold first when you’re freshest.

Benchmark sets

same three sets recur every 4th week so you can see whether you’re actually getting faster or just feeling like it.

Set shape variety

29 named set shapes rotating through the program. Interesting on purpose.

Enjoyment as a training variable

variety, named progressions, humor, interesting set shapes. A swimmer who enjoys the session works harder without noticing.

What’s NOT here (and why)

No taper planning

you’re not racing. If you are, get a coach.

No CSS / lactate threshold testing

a time trial at the public lap pool while sharing a lane is not happening.

No HIIT

SP sets use full rest. Compressed intervals in the pool are a different methodology for a different goal. Did HIIT in the gym yesterday? The calculator sees it.

No explosive power development

no dryland, no resistance bands, no block work. You’re probably doing other exercises anyway.

No stroke-specific strength targeting

butterfly lat work, breaststroke hip flexors, etc.

No nutrition or hydration guidance

this is a workout app. Drink your Gatorade and take your creatine.

No sleep tracking

beyond passive HealthKit data. Go to bed.

No meters

Not sorry.

No heart rate sets

When I was 17, heart rate sets meant keeping it above 205. Today, getting to 205 without cardiac arrest isn’t happening. Sets are prescribed by pace and effort. Your watch can read your heart all it wants.

No competitive programming

if you’re racing again, you need a coach, not this app.

No multi-stroke programming

public lap pool, shared lane, butterfly sets aren’t happening. Binary stroke toggle only.

No race-specific taper engine

see above.