Why you're getting strong, but not throwing harder.

written by JOSH GESSNER |

Good morning to all new and old readers! Here is today’s newsletter, exploring stories, ideas, and frameworks to be the best Baseball Player you can be.

I’m going back to doing highly in depth, educational emails to help pitchers. I’ll be sending these 2-3x week… Hope you get value!

Why You're Strong… But Still Not Throwing Hard

(if you’d rather watch than read, you can do so here):

Today we're talking about lifting as a pitcher.

If you want to be throwing 90mph and beyond, you HAVE to be doing the right stuff in the weight room.

But here's the thing:

I'm not going to give you the generic advice of progressively overload, get strong, and gain weight — because that’s just not what you need.

You’re probably someone who’s already strong. You’ve been gaining strength for years.

Your squat is going up.
Your deadlift is going up.
You’re hitting all the metrics in the 90mph formulas you see online.

But you're still not where you want to be.

Here’s the good news:

There’s a much better way to transfer all the strength you’ve built into throwing velocity — with one simple addition to your lifting program.

If you implement this, you’ll start throwing harder.

And I know this works… because I used it myself to gain 3mph in just 4 weeks.

And we’ve seen it help our guys at The Pitcher Lab too.
So what is it?

Let’s dive in.

The One Addition: Overcoming Isometrics

Overcoming ISOs are basically pushing as hard as you can into an object that won’t move.

That might look like:

• Driving a barbell into the safety pins

• Pulling on a belt that’s anchored to the ground

• Pushing against a wall with full effort

Does it look underwhelming?
Yes.

Is it effective?
Hell yes.

I stumbled onto this type of training when I was researching Triphasic Training.
Cal Dietz — one of the smartest minds in athletic performance — developed it.
He wrote a book on it.
I read the whole thing in a day.
And by the end, I couldn’t believe I hadn’t been doing this during my entire professional career.

Now, as I train to throw 100mph, overcoming ISOs are a big part of my lifting program.

Why It Works

1. It Forces Maximum Force Production

When you're pushing against something that won’t move, your body recruits more and more motor units to try to make it move.
The force production keeps climbing.

This matters because it improves rate of force development — how quickly you can produce force.

That’s everything for pitchers.

The delivery happens in milliseconds. You need to be able to produce serious force in a tiny window.

Strength work builds available force.
RFD work lets you tap into it when it matters most.

Overcoming ISOs are one of the best ways to build RFD.

There’s a great 4-week study on this.
One group did traditional lifting — squats, deadlifts, etc.
The other group did overcoming ISOs.

At the end, the ISO group had significantly increased their vertical jump.
Why?
Their rate of force development went up — fast.

2. It Builds Isometric Strength

Think of a powerlifter squatting 700 pounds — but it takes him six seconds to stand up.
That’s force, sure.
But it’s useless in a pitching delivery that happens in milliseconds.

To throw hard, you have to tap into your force quickly.

Force plate data shows that the hardest throwers generate the most vertical and horizontal force — and they do it quickly.

One specific correlation:
Lead leg extension velocity and throwing velocity.
When your lead leg hits, you need to brace and block hard and fast — so energy can transfer up the chain.

It’s not just about being strong — it’s about how quickly you can use that strength.
That’s where overcoming ISOs come in.

You can’t afford to “muscle” your way through the delivery. It’s too fast.

3. It Trains the Isometric Phase

Every movement has three parts:

• Eccentric (lowering)

• Isometric (the switch — the pause before reversing direction)

• Concentric (lifting or rising)

The isometric phase gets skipped over — but it’s everything in explosive sport movements.

That’s where energy is absorbed and redirected.

Think of the lead leg in pitching:
You’re not lowering and rising — you’re landing and bracing.
That’s an isometric + concentric action.
The rebound happens instantly.

The stronger you are isometrically in that position, the more force you can rebound — and transfer up the chain.

That’s why overcoming ISOs are so valuable.
They build position-specific isometric strength — right where you need it most.

4. It Trains the Nervous System

The pitching delivery is CNS-driven.

If you’re only lifting to get big, you’re falling behind.

When you push against something that won’t move, your brain is forced to fire every muscle fiber it can.
It recruits more.
Fires faster.
Coordinates better.

One study showed this clearly:
Athletes who did 4 weeks of overcoming ISOs had better muscle activation without gaining muscle size.
Why?
Their nervous systems got better at firing — not just their muscles getting bigger.

This is neural adaptation. And it’s massive for pitching.

How To Use Overcoming ISOs

My Favorite Exercises:

1. Split Squat ISO (my go-to)

• Get in your delivery position

• Push up with a belt or pull on a bar

• Build force and speed in the exact position you throw from

2. Two-Leg Variations

• Deadlift ISO against pins

• Belt squat ISO

• Heavy pin squats
  These build peak force output. Not position-specific, but still valuable.

3. Upper Body Variations

• Bench press ISO into pins

• Row variations (pulling a rope, pull-up bar, etc.)

• Shoulder ISOs (internal + external rotation)

Sets and Reps

Start with:

• 3–5 sets

• 5–7 second holds

Go 100% effort.
3 seconds can work too if you're new or get lightheaded (I’ve been there).
But longer holds — 5–7 seconds — yield better results if you can handle them.

Optional: French Contrast

Pair your ISO with an explosive movement right after.

Example:

• Split Squat ISO → Banded Split Squat Jump

This combo teaches your body to explode — fast.

Bonus: Use ISOs to Prime Your Throwing

Overcoming ISOs can also be used before throwing to boost performance.

This is called Post-Activation Potentiation (PAP).

Here’s how:

• Do 1 short ISO (3–5 seconds)

• Then throw

This primes your nervous system.
You’ll feel more explosive instantly.

There are studies showing athletes jump higher after doing a max overcoming ISO first.
And since vertical jump correlates with throwing velocity — this carries over.

So instead of foam rolling and static stretching before you throw, try this:

• Warm-up

• Add 1–2 overcoming ISOs

• Then throw

You’ll feel it immediately.

Final Thoughts

If you're strong…
But it's not transferring to the mound…

You need to stop doing what everyone else is doing.
Add overcoming ISOs to your training.

They’ll help you:

• Improve rate of force development

• Build position-specific strength

• Fire your nervous system faster

• And ultimately throw harder

If you want the full breakdown of how I went from 78 to 95mph…

Go watch my FREE 95 MPH Guide Here.