Forward hopping can be reduced in patients who have had an anterior cruciate ligament (ACL) repair. It may depend on the type of graft used to reconstruct the ruptured ligament.
Two types of tendon grafts are used most often for ACL repairs. The first is the patellar tendon graft. This graft comes from the front of the knee just below the kneecap. It can cause significant knee pain especially when kneeling.
To avoid this, surgeons may use the hamstring tendon graft. A piece of the hamstring tendon behind the knee is used. Although kneeling isn't a problem, sometimes decreased leg strength is a byproduct of this approach.
Recently, a study done at the University of Louisville in Kentucky measured the strength of 20 patients after ACL repair with a hamstrings graft. They found loss of motion and weakness in the knee up to 2 years after the surgery. Patients were tested in their ability to hop forward. They did tend to jump shorter distances with the ACL-repaired leg compared to the normal side.