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Bent knee fallout

Hip release

8 reps each side · beginner

Lying on the back with the knees bent, the feet flat and the arms long by the sides, one knee opens slowly out to the side, about 45°, the foot rolling to its outer edge, then draws back up to the middle. The pelvis stays still and level, the other knee pointing to the ceiling.

-23°Ankle dorsiflexion
125°Knee flexion
59°Hip flexion
90°Trunk from vertical
29°Arm to trunk
53°Elbow flexion
18Ankle spacing, cm
60Hand spacing, cm
4Knee outside ankle, cm
–Knee cave, ° inside toe line
–Load left / right, %
0Pelvis drop, cm

Load and joint demand

Bodyweight: no weights. Joint demand below is your own body's weight in this position.

Shoulder, per side
11 / 11

N·m now / peak over the rep.

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

Glutes
29 pts
Adductors
22 pts
Abs and core
18 pts

Effort and your quota

4.5/10 effort4.5fatigue per set

8 slow, controlled reps on each side. Pilates is practised for control, balance and mobility, never to failure, so this does not change with your limits.

Level: beginner. One round counts like light conditioning work: 51 legs points, 18 core points.

Prime movers

Transversus abdominis and obliques (keeping the pelvis still), hip external rotators and abductors, adductors (drawing the knee back).

What to look for

  • Open the knee only as far as the opposite hip stays heavy on the mat.
  • Breathe out to bring the knee back, from the deep abdominals.
  • Keep the other knee still, pointing up.
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.