About CalmArms

Every lifter deserves
real feedback.

Most people lift with no feedback on their form — they watch a YouTube video, try to copy the movement, and hope for the best. CalmArms turns your phone into a coach that's always paying attention.

The problem

You can't coach what you can't see.

Bad form quietly compounds — a degree of elbow flare here, a few inches of missing range of motion there. Without an outside eye, lifters drift further from ideal with every set. The result is plateaus, nagging pain, and wasted training time.

Our solution

A coach in your camera roll.

Point your phone, start a set. CalmArms reads your body in real time, compares your movement against ideal templates, and gives you an instant letter grade with specific, actionable feedback for the next rep.

Under the hood

How the AI actually works.

On-device pose detection

Apple's CoreML stack reads 33 body landmarks straight from your camera feed. Every frame stays on your device — your video is never uploaded.

Angle comparison against ideal templates

Each exercise has expert-recorded keyframe templates. Your joint angles are continuously compared in real time and scored on similarity.

Exercise-specific scoring

Bicep curls weigh elbow angle and upper-arm stability. Shoulder presses focus on pressing path. The grade reflects what actually matters for that lift.

Form-issue detection

Elbow flare, back arching, momentum, incomplete range of motion — the system names the issue and tells you exactly what to fix on the next rep.

Exercise library

Four lifts, dialed in.

13 variations across the four core arm exercises, each with tailored scoring and form-issue detection.

Bicep Curl

Muscles
Biceps · Forearms · Brachialis
Variations
Standard · Incline · Hammer · Preacher
Form tips
Keep elbows close to sides. Avoid swinging or momentum. Control the descent. Squeeze at the top.

Tricep Extension

Muscles
Triceps (long, lateral, medial heads)
Variations
Standard · Overhead · Kickback
Form tips
Pin elbows to sides. Only forearms move. Full extension without hyperextending. Stand upright.

Shoulder Press

Muscles
Anterior + Lateral Deltoids · Triceps · Upper Chest
Variations
Dumbbell · Barbell · Machine
Form tips
Sit upright, feet flat. Start at shoulder height with 90° elbows. Press straight up, not forward.

Lateral Raise

Muscles
Lateral Deltoids · Upper Trapezius
Variations
Standing · Seated · Cable
Form tips
Slight bend in elbows. Lead with elbows. Raise to shoulder height only. Controlled descent.
The scoring axes

Five components. One grade per rep.

Each rep is scored 0–100 across five components. The weights shift slightly per exercise to match what actually matters for that movement.

35%

Angle accuracy

How well your joint angles match ideal positions throughout the rep

25%

Range of motion

Full extension and contraction for complete muscle engagement

15%

Stability

Keeping your body steady with no swinging or compensating

15%

Tempo

Controlled, consistent rep speed without relying on momentum

10%

Bilateral balance

Even effort between left and right sides on two-arm exercises