Take a guy with lower back and left sided sub patellar pain that also has a left anatomically short leg (tibial) and bilateral internal tibial torsion and put him in these baby’s to play pickleball and you have a prescription for disaster.
Folks with an LLD generally (soft rule here) have a tendency to supinate more on the short leg side (in an attempt to make the limb longer) and pronate more on the longer leg side (to make the limb shorter). Supination causes external rotation of the lower limb (remember, we are trying to make the foot into a rigid lever in a “normal” gait cycle). this external rotation with rotate the knee externally (laterally). Folks with internal tibial torsion usually rotate their limb externally to give them a better progression angle (of the foot) so they don’t trip and fall from having their feet pointing inward. This ALSO moves the knee into external rotation (laterally), often moving it OUTSIDE the saggital plane. In this case, the knee, because of the difference in leg length AND internal tibial torsion AND the varus cant of the shoe, has his knee WAY OUTSIDE the saggital plane, causing faulty patellar tracking and LBP.
Moral of the story? When people present with a problem ALWAYS TAKE TIME TO LOOK AT THEIR SHOES!