I was curious about this and asked ChatGPT......
Lindsey Vonn is attempting to ski with a completely ruptured ACL because her knee still feels unusually stable, she’s using a specialized brace, and elite downhill skiers can sometimes compensate with strength, technique, and pain‑free mechanics — but doctors warn it carries major risk.
Even though it sounds impossible, several factors make it physically possible — though far from safe:
1. Some skiers can function without an ACL
Downhill racers have extremely strong quadriceps, hamstrings, and glutes. These muscles can partially substitute for the ACL’s stabilizing role. This is a known — though rare — phenomenon in elite skiing.
2. Her knee is not swollen and she reports no pain
Vonn said her knee “feels stable and strong,” with no swelling, which is unusual for a complete rupture but makes weight‑bearing and controlled movement possible.
3. A specialized knee brace provides external stability
She is relying on a brace designed to limit the forward tibial movement that the ACL normally controls. This helps her knee resist the forces of high‑speed skiing — though it cannot fully replace the ligament.
4. Elite technique reduces unpredictable knee motion
Downhill skiing at Vonn’s level involves carving with consistent edge pressure rather than sudden lateral cuts. That reduces the kind of pivoting that typically requires an ACL.
5. She has decades of experience skiing through injuries
Vonn has a long history of returning from major injuries and understands how her body responds under stress. She said this gives her confidence in what she can and cannot do.