Coming soon · Center STL
A Southside Prospects × M4P pitching program
The Arm Barn: Throw harder. Stay healthy.
A data-driven velocity program for pitchers: a measured baseline, individualized throwing progressions, biomechanics and arm care — assessed, programmed and re-tested in 4-week blocks. Built in St. Louis.
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- Status
- Coming soon
- Where
- Center STL · 6727 Langley Ave
- Who
- Pitchers, youth – HS
- Built by
- Southside × M4P
Not a lesson. A program.
Every pitcher is assessed, programmed and re-tested in 4-week blocks — the way the best velocity programs in the country build arms, run here in St. Louis.
- Assess
- Program
- Re-test
- Every 4 weeks
Velocity & movement assessment
Rapsodo, radar and a mobility screen. Know the baseline before anyone touches a weighted ball.
Individualized throwing program
Weighted-ball and plyo progressions built from the pitcher's own numbers, not a template — in 4-week blocks, for arms that are ready for them.
Biomechanics breakdown
Frame-by-frame film, joint by joint, graded against pro checkpoints — so the fixes are specific.
Arm care & strength
Workload, recovery and force production — so the velocity sticks and the arm holds up through the season.
The right work for the age of the arm
Every pitcher gets a program. Not every pitcher gets the same one — weighted balls and velocity work are earned, not handed out by age group.
Younger arms
Mechanics & arm care
The foundation first: a delivery that repeats, strikes on demand, and arm-care habits that keep a young pitcher throwing for years. No weighted-ball velocity work.
- Delivery mechanics on slow-motion film
- Strike-throwing and command
- Movement quality and mobility
- An arm-care routine that sticks
Around 13–14 through high school
The full velocity program
Once the assessment shows the base is there: weighted-ball and plyo progressions built from the pitcher's own numbers, in 4-week blocks with a re-test at the end of each.
- Weighted-ball and plyo progressions
- Velocity tracked with Rapsodo and radar
- Strength and force production
- Workload and recovery built in
Age is where the conversation starts, not where it ends — the assessment decides when an arm is ready for more.
Southside Prospects × M4P
Southside builds the teams. M4P builds the athletes. The Arm Barn is where the two meet on the mound — a pitching program from Southside Prospects Baseball Club and Movement 4 Power, run on M4P's development system and the technology in M4P's cage.
It's open to any pitcher. You don't need to play for Southside to train in The Arm Barn.
M4PThe club where pitchers compete, and the program that develops them — same coaches, same building, one plan for the arm.
Be first in the barn
The launch date, schedule and pricing are being set now. Get on the list and you'll hear it from us first — no posts to catch, nothing to chase.
- The launch date and schedule
- Pricing
- How to claim a spot
Coaching a staff that wants structured pitching work? Get in touch and we'll talk about what fits your program.
Open now
Get a pitching baseline now — the $50 assessment
A movement screen, a measured baseline, film, and a written evaluation with a 4-week plan built from it. It's an M4P service, separate from The Arm Barn— you don't need it to get on the list.
What we can tell you now
When does The Arm Barn open?
Soon. The launch date, schedule and pricing are still being set, and we won't publish a date until it's real. Everyone on the first-access list hears it first.
Who is it for?
Pitchers from youth through high school. Younger arms train mechanics, strike-throwing and arm care; weighted-ball and velocity work starts around 13–14, once the assessment shows the base is there.
Do you have to play for Southside Prospects?
No. The Arm Barn is a Southside Prospects and M4P partnership, and it's open to any pitcher from any school or club.
How much will it cost?
Pricing comes with the launch announcement. Get on the first-access list and you'll hear it first.
Do young pitchers throw weighted balls here?
No. Younger arms build mechanics, strike-throwing and arm care first. Weighted-ball work comes after the assessment, for pitchers around 13–14 and older with a base underneath them, inside a progression with workload and recovery built in. No program can promise an arm never gets hurt — and pain is a doctor's call first, always.
Where is it?
Center STL — 6727 Langley Ave, St. Louis, MO 63123. The same building M4P trains in.
Can we start before it opens?
Yes. M4P pitching lessons are open now at Center STL, and every athlete starts with the $50 assessment: a movement screen, a measured baseline, film, and a written evaluation with a 4-week plan built from it.
Pitching Instructor
College or pro playing experience required
If you played college or pro ball and want to coach velocity the right way — data, weighted-ball progressions, biomechanics, arm care — we want to talk.
Email Your BackgroundSend your playing and coaching background and your availability to connor@southsideprospects.com. Know someone who fits? Send them this page.
Played at the next level
College and/or pro playing background — you've lived the process you'll be teaching.
Coach velo with data
Mechanics, weighted-ball progressions and arm care, using Rapsodo, radar and video.
Hours grow with demand
Evenings and weekends to start — could be close to a full-time role as the program fills.
Driveline / Tread a plus
Experience running velocity programs and tracking the numbers, youth through high school.
Don't wait for the barn to open.
M4P pitching lessons are open now at Center STL — mechanics, command and arm care, starting with the $50 assessment and a 4-week plan built from it.