Importance of Testing Strength

Strength testing at various stages when returning back from an ACL injury is necessary. This allows us as practitioners to understand what we need to do moving forward to get you back to sport. Strength testing gives us objective information that can help tailor treatment. It also gives us an idea of what type of stress our athletes can handle. If you do not meet benchmarks with regards to strength testing then it is best to continue getting stronger and retest before getting back to sport.

Types of Strength Testing

One commonly utilized way of testing strength is using a Biodex machine to determine quadriceps and hamstring strength. Other ways of testing are utilizing a handheld dynamometer. For both of these types of tests the athlete is sitting down and the knee is isolated with belts or padding. This ensures accurate data is being produced. Next, the athlete performs a maximum effort repetition of either knee straightening or knee bending. These instruments will give us data regarding how many pounds of force your muscles produce. The Biodex machine will give more information related to how fast your knee is creating force. Knowing how much force the knee can produce determines if an athlete can be cleared for running or jumping. It also is important to test before returning to sport.

Strength Requirements for Return to Sport

Ideally, we want to see an athlete have 100% strength side-to-side compared to their leg that didn’t have surgery on it. I think it is acceptable for an athlete to pass strength testing with 95% strength compared to their other leg. Strength testing is the first test to see if an athlete is ready for more return to sport testing. Like we mentioned in previous blogs, we need to wait roughly 9-12 months before considering strength and return to sport testing. Having objective data takes the guessing out of the equation when returning to sport. We want to see our athletes be successful. Strength testing is an integral part of our rehabilitation process to improve our athletes confidence with return to sport!


Objective data for strength matters when returning to sport after an ACL reconstruction. It gives us the ability to make decisions about whether or not an athlete is ready for the rigors of sport. We want to have 100% symmetry to your other leg in order to be confident about returning to sport.