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What LiftLens checks, and what it can't.

The camera angle each lift needs, what it checks, and what one phone camera can't judge.

Squat

Available

Sit down between your heels with your chest up, then stand back up. Your knees travel over your toes and your heels stay down.

Camera

Best from the side: knee to hip height (a bench or a plate stack), 2.5–3.5 m away.

Side
Depth, torso lean, hips rising first, tempo
Front
Knees tracking over toes, left-right weight shift, tempo
45°
Rep count and tempo only (angles are distorted at 45°)

Checks

  • Knee trackingFront
  • Flat backSide
  • Hips and chest rise togetherSide
  • Torso leanSide
  • Consistent depthSide, Front, 45°

Never judged from video

  • What your spine does inside a flat-looking outline: the back check reads the outline of your back from the side, not the vertebrae, so loose clothing, a hood or long hair can hide or mimic rounding. It is checked only from the side, and only on a kept set video.
  • Heels lifting: the foot landmarks were too unsteady in testing to judge it without false alarms, so we don't check it yet. Watch your heels in the replay.
  • Where your weight sits in your feet (pressure isn't visible).
  • Knees travelling past your toes: that is normal and not a fault.

Romanian deadlift

Available

A hip hinge: keep a soft knee, push your hips back and let the weight slide down your thighs until you feel your hamstrings, then stand tall.

Camera

Best from the side: hip height, 2.5–3 m away.

Side
Hinge depth, knee bend, weight drifting forward, lockout, tempo
Front
Rep count, tempo, left-right symmetry of the hands
45°
Rep count and tempo only

Checks

  • Flat backSide
  • Neutral backSide
  • Weight close to your legsSide
  • Hinge, not squatSide
  • Standing fully tallSide

Never judged from video

  • What your spine does inside a flat-looking outline: the back check reads the outline of your back from the side, not the vertebrae, so loose clothing, a hood or long hair can hide or mimic rounding. It is checked only from the side, and only on a kept set video.
  • Grip and where the bar sits in your hands.

Deadlift

Available

Lift the bar from the floor to standing by pushing the floor away with your legs and bringing your hips forward, keeping the bar close and your back flat.

Camera

Best from the side: knee to hip height, 3–3.5 m away.

Side
Hips rising early, bar drifting from mid-foot, lockout, leaning back at the top, tempo
45°
Rep count and tempo (45° from the front shows the legs past the plates)
Front
Rep count and tempo only

Checks

  • Flat backSide
  • Neutral backSide
  • Hips and chest rise togetherSide
  • Bar close to your legsSide
  • Finishing tallSide
  • Neutral finishSide

Never judged from video

  • What your spine does inside a flat-looking outline: the back check reads the outline of your back from the side, not the vertebrae, so loose clothing, a hood or long hair can hide or mimic rounding. It is checked only from the side, and only on a kept set video.
  • Your knees and shins at the bottom from a pure side view: the plates hide them. Placing the phone a little in front of side-on helps.
  • Grip, bar tilt, and whether the bar touches your shins.

Push-up

Available

Hands a little wider than your shoulders. Lower your whole body as one straight line until your chest nears the floor, then push back up.

Camera

Best from the side: on the floor or a low step, level with your body, 2–3 m away.

Side
Body line (hips sagging or piking), depth, lockout, tempo
Front
Rep count and tempo only
45°
Rep count and tempo only

Checks

  • Straight body lineSide
  • Hips not pikedSide
  • Lowering far enoughSide
  • Full lockoutSide

Never judged from video

  • Elbow flare (how far your elbows point out from your body): that needs a camera above you.
  • Hand position and shoulder-blade movement.

Biceps curl

Available

With your elbows pinned to your sides, curl the weight up by bending only at the elbow, then lower it under control until your arms are straight.

Camera

Best from the side: chest to hip height, 2–3 m away.

Side
Range of motion, elbows drifting forward, body swing, tempo
Front
Range of motion, left-right symmetry, tempo
45°
Rep count and tempo only

Checks

  • Body stillSide
  • Elbows by your sidesSide
  • Full stretch at the bottomSide, Front
  • Full curl at the topSide, Front

Never judged from video

  • Wrist rotation and grip.
  • Shoulder elevation (shrugging) from the side.

Overhead press

Available

From your shoulders, press the weight straight up until your arms are straight overhead. Your body stays tall and braced.

Camera

Best from the side: chest height, 2.5–3 m away.

Side
Lockout, leaning back, weight finishing in front of the shoulders, tempo
Front
Lockout, left-right symmetry, tempo
45°
Rep count and tempo only

Checks

  • Upright torsoSide
  • Full lockoutSide, Front
  • Finishing overheadSide
  • Arms evenFront

Never judged from video

  • Shoulder-blade movement and neck position.
  • Lower-back arch itself: we measure the whole torso leaning back, not the curve of your spine.

Bent-over row

Early access

Hinge forward with a flat back, then row the weight to your lower ribs and lower it under control.

Camera

Best from the side: hip height, 2.5–3 m away.

Side
Torso angle held, standing up during the rep, range of motion, tempo
Front
Rep count only (foreshortened)
45°
Rep count only

Checks

  • Flat backSide
  • Neutral backSide
  • Torso angle heldSide

Never judged from video

  • What your spine does inside a flat-looking outline: the back check reads the outline of your back from the side, not the vertebrae, so loose clothing, a hood or long hair can hide or mimic rounding. It is checked only from the side, and only on a kept set video.
  • Shoulder-blade squeeze.

Bench press

Early access

Lie on the bench, lower the bar to your mid-chest under control, and press it back up to straight arms.

Camera

Best from the side: bench height (a box or plate stack), 2–3 m away.

Side
Depth, lockout, tempo

Checks

  • Full range downSide
  • Full lockoutSide

Never judged from video

  • Elbow flare (how far your elbows point out from your body): it needs a view from above.
  • Your hips lifting off the bench and your back arch: lying down, the tracker is much less sure of your hips.
  • Where the bar touches your chest, the bar path, your grip and wrists.
  • Bouncing the bar off your chest: watch for it in the replay.

Lat pulldown

Early access

Sit with your thighs under the pad, pull the bar down to your upper chest, and let it back up to straight arms.

Camera

Best from the side: chest height when seated, 2–3 m away.

Side
Full pull, full stretch, torso swing
Front
Arms even, full pull, full stretch

Checks

  • Torso stillSide
  • Full pullSide, Front
  • Full stretchSide, Front
  • Arms evenFront

Never judged from video

  • Shoulder-blade movement.
  • Grip width and hand position.
  • Your legs: the thigh pad hides them.

Seated cable row

Early access

Sit tall, pull the handle to your stomach, and let your arms straighten forward again.

Camera

Best from the side: chest height when seated, 2–3 m away.

Side
Torso rocking, full pull, full stretch

Checks

  • Torso stillSide
  • Full pullSide
  • Full stretchSide

Never judged from video

  • Shoulder-blade squeeze.
  • Back rounding as you reach forward: the back-outline check is for standing hinges.
  • The far arm: the machine frame can hide it.

Lateral raise

Early access

With a slight bend in your elbows, raise the weights out to your sides to shoulder height, then lower them under control.

Camera

Best from the front: chest height, 2.5–3 m away.

Front
Arm height, arms even, elbows fixed, shrugging (shown)

Checks

  • Arms to shoulder heightFront
  • Arms evenFront
  • Elbows fixedFront

Never judged from video

  • Swinging your body to lift: that’s a front-to-back movement a front view can’t see well. Keep your torso still.
  • Shrugging: measured and shown in Detailed mode, but not judged until it’s been tested.
  • Where your thumbs point and your wrist position.

Triceps pushdown

Early access

With your elbows pinned to your sides, push the handle down until your arms are straight, then let it back up to about chest height.

Camera

Best from the side: chest height, 2–3 m away.

Side
Full lockout, elbows at your sides, torso still

Checks

  • Elbows at your sidesSide
  • Full lockoutSide
  • Torso stillSide

Never judged from video

  • Wrist position and grip.
  • Shoulders rolling forward.

Overhead triceps extension

Early access

Hold the weight overhead with straight arms, lower it behind your head by bending your elbows, then extend back up.

Camera

Best from the side: chest height, 2.5–3 m away.

Side
Full lockout, full stretch, elbows still, leaning back

Checks

  • Elbows stillSide
  • Full stretchSide
  • Full lockoutSide
  • Upright torsoSide

Never judged from video

  • Elbows flaring out to the sides: that needs a front view, where the elbows point at the camera.
  • Wrist position and grip.

Leg press

Early access

Lower the platform by bending your knees under control, then press it back up without locking your knees hard.

Camera

Best from the side: seat height, 2–3 m away.

Side
Depth, depth consistency, tempo

Checks

  • Range of motionSide
  • Consistent depthSide

Never judged from video

  • Your lower back lifting off the pad at the bottom: the seat hides it. Stop the rep before it lifts.
  • Knees caving in: that needs a front view, which the machine blocks.
  • Foot position on the platform.

Leg extension

Early access

Sit with your knees at the edge of the seat and straighten your legs against the pad, then lower under control.

Camera

Best from the side: seat height, 2–3 m away.

Side
Full extension, swinging, tempo

Checks

  • Full extensionSide
  • Body stillSide

Never judged from video

  • Knee alignment: it needs a front view, which the machine blocks.
  • Where the pad sits on your shins.

Running (treadmill)

Early access

Run on a treadmill at your usual pace while the phone records 30 seconds, from the side and from behind.

Camera

Best from the side: hip height (a tripod or stand beside the treadmill), 2–3 m away.

Side
Where your foot lands, shin angle, knee bend, lean, bounce, step rate
Front
From behind: hip drop, knees drifting in, feet crossing the midline, bounce, step rate

Checks

  • Feet under your hipsFront

Never judged from video

  • Foot strike (heel, midfoot or forefoot): it’s a style, not a fault, and a phone can’t time the moment of contact.
  • Ground contact time: that needs a high-speed camera; a phone films at 30 frames a second or less.
  • What your feet and ankles do inside your shoes.
  • Which leg is left or right from behind is the tracker’s call: check it against the replay.
  • How far ahead your foot lands, your shin angle and your hip drop are measured and shown, but not judged: there are no agreed cut-offs.