Is Downhill Walking Good For You After Anterior Cruciate Surgery?

I was digging in the journals again and came across this journal article.

I know it is an old one; from 1994.

I think the main point is a good one, plus I have been on a bit of a knee injury exercises, kick as of late.

Plus, I am always looking to improve the Exercise Rehabilitation of the Knee course.

If you have a client that has had anterior cruciate ligament surgery, there is a lot to consider.

Something that I have not thought about is how the ACL graft will do when walking down hill.

Will walking down hill lead to re-injuring the ACL?

Keep reading to find out.

Downhill Walking After ACL Surgery

Post anterior cruciate ligament reconstruction patients are recommended to engage in accelerated rehabilitation programs consisting of immediate extension of the knee joint and full weight bearing. The protocol aims to improve knee extension, improve muscle strength recovery, decrease anterior knee pain and improve knee stiffness.

Disturbed proprioception occurring after an ACL injury and reconstruction can cause impairment or weakness of muscles stabilizing the involved knee joint. Because downhill walking can place a lot of stress on the involved knee joint, with as much as 7 to 8.5 times the body weight, it must therefore be avoided during the postoperative period to protect the ACL reconstruction. With knee shear forces exceeding the strength of ACL graft fixations, stabilization training of the quadriceps and hamstring muscles, the main stabilizing muscles of the knee, is essential.  The rehabilitation process usually employs full range of motion exercises first, followed by muscle strengthening, then balance and coordination exercises.

5 Key Points to Remember When Performing Downhill Walking After ACL Surgery

1)  The tibiofemoral shear force was 1.2 times body weight for male and 1.7 times body weight for female subjects.

2)  The tibiofemoral compressive force was 7 times for males and 8.5 times body weight for females.

3)  Knee joint shear force was 1000 N for a 70-kg person which is greater than the 200 to 500 N strength that is the typical strength of a typical ACL graft fixation.

4)  There is an increase in hamstring and gastrocnemius muscle activity in order to increase the stability of the tibiofemoral joint.

5)  Downhill walking should be avoided after ACL surgery especially during postoperative phase in order to protect the ACL graft.

The Take Home Message on ACL Surgery and Hills

Downhill walking at a grade of 20% grade puts more shear force on the knee joint that the strength of ACL graft.  It is important to avoid downhill walking after an ACL surgery.

You would think a 20% grade is very steep but it is not.  Most treadmills can easily go to 10% grade which is not much.  Plus I know the little hills in my area of Surrey are at a greater slope than 20% grade in some areas.

This does not mean that someone with an ACL surgery should avoid hills forever but just after the surgery they should and in time hills can be added in.


Kuster M, Wood GA, Sakurai S, Blatter G. (1994). Downhill walking: a stressful task for the anterior cruciate ligament? Knee Surg Sports Traumatol Arthrosc. 1994 March; 2(1): 2-7.

Rick Kaselj, MS.