One of the big questions posed by athletes after an ACL reconstruction surgery is, “When will I be able to run?”
There is no singular answer to this question; however, there are guidelines that can be pulled from current research on the topic. Currently, a widely utilized metric to determine return-to-run in patients is through isokinetic quadriceps testing. Quadricep isokinetic testing is performed by having the patient perform a single leg knee extension at a fixed speed and comparing the peak power of the two limbs.
It has been found that if a patient is able to achieve 65% limb symmetry when performing a knee extension test at 60°/sec, they are ready to begin a moderate-intensity return-to-run protocol. This means that no more than a 35% difference in force production can exist between the quadriceps muscles of the two limbs.
You may be saying to yourself, “That’s amazing, but what if my Physical Therapist doesn’t have the machinery available to do an isokinetic quad test!?” There are many tests and measures that your PT can perform to ensure strength and stability in the knee before initiating a return-to-run protocol. This includes but is not limited to comparing 1 rep maximum single leg knee extension, a single leg squat test, a hop test, as well as comparing hamstring strength to quad strength. If the percent difference between quadriceps and hamstring strength is greater than 30%, a patient is not eligible to begin a return-to-run program. Ensuring adequate knee stability and strength, along with perceived patient readiness, is essential before resuming running post-ACL reconstruction.
A typical return-to-run protocol will usually entail a combination of walking/jogging at a comfortable pace on the treadmill. A recommended guideline is walking at a comfortable pace for 1 minute, speeding up to a light jog for 30 seconds, and repeating for 12-15 minutes. As the patient becomes more comfortable and if there are no gait abnormalities present, the speed of the walk/jog can increase gradually. A further progression can include walking for 30 seconds, jogging for 30 seconds, and repeating for 12-15 minutes, building up to steady-state jogging for 12-15 minutes.
