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Kettlebell dead bug

On the back with a 12 kg bell held up over the chest in both hands and the hips and knees at 90°. The left leg extends low while the bell stays still, then returns.

-10°Ankle dorsiflexion
90°Knee flexion
90°Hip flexion
90°Trunk from vertical
90°Arm to trunk
6°Elbow flexion
17Ankle spacing, cm
15Hand spacing, cm
0Knee outside ankle, cm
–Knee cave, ° inside toe line
–Load left / right, %
0Pelvis drop, cm

Load and joint demand

Bodyweight exercise: the load slider has no effect here; body mass comes from your limits.

No gravity-based joint demand to show for this exercise.

Faults

Faults grow with knee bend and apply to lifts standing on the floor. The fault check flags a knee caving more than 10° inside the line of the toes and a load split beyond 60/40. Knee cave shows best in the front camera.

Body

Femur changes keep standing height fixed by shortening or lengthening the torso. Longer femurs force more forward lean in any squat.

Muscles worked

Abs and core
35 pts
Shoulders
8 pts

Effort and your quota

2/10 effort2fatigue per set

Your quota per set: 13 reps at bodyweight, stopping 2 reps short of failure.

One hard set earns 8 push points, 35 core points.

Prime movers

Transversus abdominis, rectus abdominis, hip flexors, anterior deltoid (holding).

What to look for

  • Lower back stays pressed to the floor.
  • The bell stays still over the chest.
  • Exhale as the leg reaches long.
How the model works, and its limits

One 3D skeleton drives both views. Segment lengths and widths are Winter's anthropometric ratios of height; segment masses and centre-of-mass positions follow Dempster's data. For free-standing lifts the whole-body angle is found numerically so the combined centre of mass of lifter and load sits over the middle of the foot. Arms and legs use two-link inverse kinematics with a pole direction. Rep timing follows a minimum-jerk profile.

Balance is quasi-static, so ballistic lifts are shown slowed down. Cable pull and pad support forces are not modelled. The spine is one rigid segment and joints have no range-of-motion limits or muscle forces.