Hike backBalanced over midfoot
Side view
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Kettlebell swing

24 kg, hip hinge from standing to about 60° of trunk angle with the bell swinging between the legs to chest height. Shown quasi-statically: the real lift is ballistic and momentum carries the bell.

-7°Ankle dorsiflexion
12°Knee flexion
21°Hip flexion
2°Trunk from vertical
80°Arm to trunk
23°Elbow flexion
44Ankle spacing, cm
9Hand spacing, cm
-6Knee outside ankle, cm
–Knee cave, ° inside toe line
50 / 50Load left / right, %
0Pelvis drop, cm

Load and joint demand

Load in the model: 24 kg. Balance and joint demand re-solve as you change it.

Lower back
183 / 229
Hip extensors
92 / 129
Knee flexors
39 / 52
Calves
20 / 43
Shoulder, per side
88 / 88
Elbow, per side
42 / 42

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
100 pts
Hamstrings
82 pts
Lower back
64 pts
Forearms and grip
46 pts

Effort and your quota

6.5/10 effort6.8fatigue per set

Your quota per set: 10 reps at 25 kg, stopping 2 reps short of failure.

One hard set earns 182 legs points, 23 arms points, 64 core points.

Prime movers

Gluteus maximus, hamstrings, spinal erectors, grip.

What to look for

  • The hips snap forward; the arms just guide the bell.
  • At the top the body is a vertical plank, not leaning back.
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.