Coach Bachmann
PER/FORME • 6 Min Read
Ever wonder why you feel super flexible right after a warm-up, but stiff as a board the next morning? Or why you can stretch for weeks and feel like you haven't actually gotten any "longer"? It's because flexibility isn't just about pulling on your muscles until they stretch.
It's a two-part process that happens on a specific timeline. If you want permanent results, you have to understand the difference between updating your software (your brain) and upgrading your hardware (your muscles).
Your Flexibility Timeline
Weeks 0–4 · What's happening: Your brain is taking the brakes off.
When you start stretching, your muscles aren't actually growing longer yet. They're just relaxing.
Your body has a built-in safety mechanism called the stretch reflex. When you go into a deep split or a shoulder stretch, your nervous system thinks, "Warning! Danger! We're going to snap!" and it tightens the muscle to protect you.
For the first month of training, you aren't changing the muscle tissue—you're training your nervous system. You're teaching your brain that this end-range position is safe. Once the brain feels safe, it releases the brakes, and you get access to range of motion that you actually already had.
This is temporary. If you stop here, your brain puts the brakes right back on.
Weeks 4–9 · What's happening: You're actually building a longer muscle.
This is where the magic happens. Once your brain stops fighting you, and you keep showing up consistently for about 4 to 9 weeks, your body realizes it needs to adapt permanently.
It does this through a process called Sarcomerogenesis.
Think of your muscle fibers like a chain made of links. When you consistently load your muscles at their end-range, your body physically adds new links (sarcomeres) to that chain. You aren't just stretching the old rubber band—you're building a longer rubber band.
Sarcomerogenesis: Building Longer Muscles
Your body adds new sarcomeres to the chain = longer muscle
Here's the part most people miss: You can't just relax into flexibility.
To trigger that hardware upgrade (Phase 2), your body needs a reason to build those new links. Passive stretching often isn't enough. You need tension.
Key Insight
When you engage your muscles at your limit, you send a loud signal to your body: "We are using this range, we are strong here, and we need more length permanently."
Not a quick fix. Here's what's actually happening at each stage.
You're negotiating with your nervous system. The brakes are releasing.
Software update complete. Hardware upgrade begins.
You're building new muscle architecture. These gains are permanent.
Remember:
Earn the hardware upgrade.
Your future flexible self will thank you.