Knee CARs
The knee is often treated as a simple hinge, but it also rotates, and neglecting that rotation is how end ranges get weak. Knee CARs actively cycle the joint through flexion and extension while adding controlled internal and external rotation of the lower leg. Done seated with the thigh supported, they build resilient, well-controlled knees for squatting, running and change of direction.
- Equipment
- Bench
- Type
- Functional, Recovery, Stretching
- Browse by muscle
- Rectus Femoris, Vastus Lateralis
- Browse by movement
- Mobility Drill
- Target
- Rectus Femoris, Vastus Lateralis
- Secondary
- Biceps Femoris, Semitendinosus
How to do it
- 1
Sit tall on a box or bench with one thigh fully supported and that lower leg hanging free.
- 2
Straighten the knee into full extension and gently rotate the shinbone outward at the top.
- 3
Bend the knee to draw the heel back and under you into deep flexion, keeping the thigh still.
- 4
As you flex, allow the lower leg to rotate inward, then reverse to unwind it.
- 5
Move through the whole flexion-extension arc slowly, adding the rotation at each end.
- 6
Keep the thigh pinned to the bench so all motion comes from the knee, and breathe steadily.
- 7
Do equal reps, then reverse the rotational bias and switch legs.
Tips
- Keep the thigh dead still; any hip movement steals the drill from the knee.
- Emphasize a strong terminal extension with a deliberate quad squeeze at lockout.
- Introduce the tibial rotation gently and only within a pain-free, controlled range.
Variations
Common mistakes
- The heel stops short of the hip on the way into flexion instead of drawing all the way back, so the knee never actually reaches its deepest range.
- The rotation at the top and bottom happens as a quick twitch instead of a slow, deliberate turn, so the tibia barely rotates before the rep moves on.
- Some people do noticeably more reps or a bigger range on one leg than the other, so the stiffer knee never catches up.
- Breathing gets held through the harder end ranges instead of staying steady, tensing the whole leg right when the knee needs to move freely.
- The bench or box gets swapped for an unsupported seated position with the thigh floating free, so there is nothing to isolate the knee from hip movement.
Frequently asked
- How many reps of Knee CARs should a beginner do?
- Two to three unhurried circles in each direction per leg, once a day or as knee prep before squatting or running, is plenty — this is joint prep, not a volume exercise. Progress by moving slower through the deepest flexion and the rotational ends of the range rather than racking up more reps.
- What can I use instead of a box or bench for Knee CARs?
- Any sturdy surface at about hip height works, such as a stable chair, a bed edge, or a low table, as long as the thigh can rest fully supported with the lower leg hanging free. If nothing at that height is available, sitting on the floor with your back against a wall and the thigh supported on a rolled towel is a workable substitute.
- What are Knee CARs good for?
- They build controlled strength through the knee's full range, including the rotation most training ignores, which benefits anyone squatting, running, or cutting on the knee. They are not a substitute for medical evaluation if you have actual knee pain or a known injury, since this is a mobility drill, not a rehab protocol prescribed for you specifically.
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