Every exercise page on this site leads with a 3D demo of the movement. It is built to teach form the way a coach would sketch it: the path of the weight, the key joint angle, the tempo and the most common faults. This guide explains what each part of the demo shows and, just as important, what it doesn’t.
Start the demo
The image at the top of each exercise page is a still of the bottom position. Press Play 3D demo (or any control) to load the 3D version. It loads only when you ask, so the page stays fast on slow connections. If your device can’t run 3D graphics, the step-by-step instructions below the demo describe the full movement.
If your device is set to reduce motion, the demo starts paused at the bottom of the rep, the most informative frame, and camera changes happen instantly.
The phase header and the tempo timeline
Above the figure, the large word tells you which part of the rep you are watching: Lower, Pause, Press or Top. Some exercises rename the top phase when something happens there, like Squeeze on the cable press or Plus on the push-up. The line underneath gives the phase’s length, the breathing for that phase and a short cue.
The strip below the figure is the tempo timeline. Each segment’s width is its share of the rep, and the blue bar moving along it is the playhead.
Tempo on this site is written as four numbers in seconds: lowering, pause at the bottom, pressing, pause at the top. The dumbbell bench press demo uses 3-1-1-1: three seconds down, one second still at the bottom, one second up, one second at the top. The demos use slow teaching tempos so the positions are easy to see; each exercise page explains the tempo to use in your own training.
Speed and scrubbing
Play the demo at 0.5×, 1× or 2×. Slow motion at the bottom of the rep is the best way to check the details that matter most: where the elbows are, whether the forearms are vertical, and how the shoulder blades sit. Drag the Scrub slider to stop at any point in the rep.
Camera views
Each demo has four camera presets, and you can drag to orbit or pinch to zoom.
- 3/4 is the default, closest to how you would see someone in the gym.
- Side shows the path of the weight, the depth and whether the hips stay down.
- Overhead is the best view for the angle between the upper arm and the torso.
- From feet (or Front for floor exercises) shows hand width, symmetry and wrist stacking.
Readouts: live joint angles
The row of numbers under the controls is measured from the animated body in every frame, not typed in.
- Elbow bend is the inside angle at the elbow, between the upper arm and the forearm. About 170° means nearly straight; smaller numbers mean more bent.
- Upper arm to torso is the angle between the upper arm and the body’s long axis, seen from above. It is the number behind cues like “elbows about 45–70° from your body”. It turns red and reads “wide” past about 75°.
- Grip width (barbell) is the distance between your hands as a multiple of shoulder width.
- Body angle (push-up) is the angle of the line from toes to shoulders above the floor.
The same upper-arm angle is drawn as a wedge above the shoulder during the bottom half of the rep: blue when it is in range, red when it is flared.
Correct form and mistake mode
Switch Form shown from Correct form to one of the listed mistakes and the figure blends into that fault: elbows flaring to about 90°, hips lifting off the bench, bouncing the bar, or sagging hips in a push-up. A red label points to the problem, and the camera moves to the view where it is easiest to see. The faults are exaggerated just enough to be visible. Mistakes in an exercise’s “Common mistakes” table that the demo can show have a Shown in demo link that switches the demo to that fault.
Six body types
The figures are built from the open MakeHuman base mesh, released under a CC0 licence [1], shaped into six body types: male and female, each lean, athletic and heavier. Switching body type is not just a new skin: limb lengths and chest depth change, and the motion adapts. A longer-armed lifter has a longer range of motion, and on a deeper chest the dumbbells reach the bottom slightly higher. Watching your closest match is a better guide than a single “ideal” model.
The muscle glow is illustrative
The red glow shows which muscles we expect to work hardest in each phase, based on each exercise’s research doc. It is not measured muscle activity. Nobody wired electrodes to the figure. The curves follow simple rules: emphasis rises when a muscle is stretched under load and in the hardest part of the lift, and for free weights the chest glow fades near lockout, because the load stacks over the shoulder there. Turn it off with the Muscles checkbox if you just want to watch the movement.
Path draws the route of the hands or bar as a dashed line, and Labels toggles the name tags with their leader lines.
Sound
Sound is off until you choose otherwise. Effects adds tempo ticks, breathing cues and a clink when a rep finishes; Coach voice speaks short cues such as “Down”, “two”, “three”, “Hold”, “Press”, and a mistake cue when one is shown. The voice uses your device’s speech engine, so it sounds different on different devices.
What the demos don’t tell you
The demos show good technique for a typical healthy adult. They can’t see your shoulders, your history or how a movement feels for you. If something hurts, stop and check with a physiotherapist or doctor. Start with the dumbbell bench press demo or the push-up demo to try it out.
Sources
- MakeHuman community. Assets licence (CC0 1.0 Universal), makehumancommunity/makehuman repository, `LICENSE.ASSETS.md`; base mesh header states CC0 release (2020). GitHubVerified · checked 22 Oct 2026