Practice › Gym › Tricep extension
Tricep extension form check: a live coach on your phone
The overhead tricep extension loads the long head of the triceps through a deep stretch. The usual faults are elbows that flare or drop forward, a back that arches to help the press and a range that stops short of both the stretch and the lockout.
No equipment needed. Practise at home. Just do the rep properly in front of your phone. Bodyweight squats, push-ups and lunges need nothing at all, and you can check the hinge and press patterns with a very light weight or none: the coach judges your movement, not your kit.
What good looks like
- Hold one weight in both hands overhead with your arms straight and your ribs down.
- Keep your upper arms vertical, close to your ears, and bend only at the elbows to lower the weight behind your head.
- Lower until you feel a deep stretch in the back of the arms, without letting your elbows drift forward.
- Press back up to straight arms and squeeze your triceps at the top, keeping your back neutral.
Common mistakes and how to fix them
Elbows dropping forward
When the upper arms tip forward the movement turns into a press and loses the stretch. Keep your elbows pointing at the ceiling.
Arching the back
Leaning back to push the weight up loads the lower back. Brace your abs and keep your ribs down.
Short range
Lowering only a little means the stretch never happens. Lower until your forearms are behind your head, and finish with straight arms.
What Formanti checks on your tricep extension
The top of every rep, judged the same way.
- Elbows: 120–186°. press up to straight arms
Your lowered
The low point of every rep, judged against the guide ranges.
- Elbows: 60–135°. lower the weight behind your head, elbows well bent
What you hear and see when you are off
Don't drop the weight so deep
The coach says: “Not so deep”
On screen: Don't drop the weight so deep.
Drill: Extensions to a comfortable stretch, then press up smoothly with a lighter weight.
Lower the weight further behind your head
The coach says: “Lower the weight”
On screen: Lower the weight further behind your head.
Drill: Slow extensions: 3 seconds down to a deep stretch, a 1 second pause, then press up. Use a lighter weight.
Press all the way to straight arms
The coach says: “Lock it out”
On screen: Press all the way to straight arms.
Drill: Extensions with a 1 second pause at the top, arms locked, triceps squeezed.
Drills you can do alone
- Seated or wall extensions: sit or stand with your back supported so you can't arch.
- Slow negatives: lower for three seconds to a deep stretch, pause for one second, then press up.
How to set up your phone
Phone at chest height, 2 to 3 metres to your side, with room above your hands. One dumbbell held in both hands, or a bar. Film from the side: back and hip angles cannot be judged head-on. It all runs on your phone and nothing is uploaded.
Counts reps and flags only a clearly short range (not lowered deep enough, or not pressed out). Tested on real phone video of 26 people doing overhead extensions side-on (a public dataset): it could not tell good form from bad (elbow flare and arching did not show up in the numbers), so it checks range of motion only. Not reviewed by a coach.
Frequently asked questions
Can the phone tell if my elbows are flaring?
From the side it measures whether your upper arms stay raised, which catches elbows dropping forward. Elbows flaring sideways need a camera in front or behind you and are not judged.
Which weight should I use?
A lighter one than you expect: the exercise puts the elbows under load at the stretch, and good form beats a heavy weight.
More lifts to check
Deadlift · Squat · Push-up · Lunge · Overhead press · Bent-over row · Romanian deadlift · Bicep curl · Lateral raise · Glute bridge · Pull-up · Dip · Sit-up · Jumping jack · Plank · Wall sit