Beware of exercises that can hurt knees when not done correctly

• by Dr. Dev Mishra , Jul 30, 2020

There’s quite a bit of controversy between fitness professionals and medical professionals about the safety of various lower extremity conditioning activities. As an orthopedic surgeon, I typically see folks in the clinic after something has gone wrong so it’s a skewed population. But over and over again I see common themes emerge. I think of these as three easy ways to hurt your knees.

Deep squats (thighs below parallel), lunge with a short stride, and unaccustomed plyometric activities are more likely than not, in my opinion, to land you in the orthopedic or sports medicine specialist’s office. I suggest below some modifications to help you avoid trouble.

Deep Squat (Thighs Below Parallel)

I’m a big believer in the usefulness and effectiveness of dual leg squats. In fact, if I had to pick one resistance exercise for folks to do even into their geriatric years it would be a dual leg squat.

The controversy comes in how deep to go. Do you stop with thighs above parallel to the floor, go to parallel to the floor, or drop thighs below parallel? The argument made by advocates of the deep squat is that it’s the most efficient way to build strength in the glutes, quads and calves, and from a purely muscular standpoint that’s likely true.

But getting thighs below parallel results in a substantial increase in compressive forces at the kneecap (patella), and those compressive forces may eventually lead to tissue breakdown. And that causes conditions such as patella tendonitis and loss of cartilage behind the kneecap.

Ask a former elite baseball or softball catcher how their knees are 20 years out from their sport. Chances are the response is along the lines of “pretty bad”.

Do yourself a favor and don’t go lower than parallel. If you already have some knee arthritis, or if you’re a senior athlete stop above parallel.

For guidelines and best practices for WHEN AND IF your local authorities have deemed it safe to return to the play, check out U.S. Soccer's PLAY ON home page HERE.

Short Stride Forward Lunge

Here’s another exercise I really like, but your form has to be spot on to avoid injury. A single leg lunge teaches your body dynamic stability, which is important for sport performance and fall risk reduction. When done correctly it’s an excellent way to improve glute and quad strength too.

The problem is that it’s hard to do this exercise correctly. If I have a patient in the office with kneecap pain or patellar tendonitis we’ll get into their form on lunges. Invariably they’ll show me a short stride, which results in the front of the knees extending beyond the front of their toes.

A long stride results in roughly a 90 degree angle at the ankle and at the knee, and this reduces kneecap force while maintaining the muscle stimulus needed for strength and stability.

The best option is to take a long stride and move slowly. If you’re unsure how to do this consult a qualified trainer or physical therapist for instruction.

Unaccustomed Plyometrics

Plyometric activities involve bounding and jumping. Many folks are enthusiastic and motivated to restart group fitness in states that are allowing that, and others with exercise from home options.

There’s a lot of good that can come from plyometric activity but like the forward lunge described above, your form has to be right. Additionally there’s a ramp-up period of several days or weeks when you need to get used to doing the activity. This is especially true if you’re a novice.

If you go straight from couch potato to high intensity plyometrics you’re setting yourself up for some rough times ahead. Your safest option to keep your knees healthy is to go through a very gradual increase in plyometric activity. Be mindful of any soreness that you experience the day after your exercise session. That’s often a sign that you need an additional recovery day before trying again.

Each of these three activities, when done correctly, are great exercises. When done incorrectly I find that they’re incredibly effective at killing your knees.

Key Points:
• When done correctly, dual leg squats, single leg lunges, and plyometrics are excellent exercises.
• However, if your form is off or you ramp up too quickly you’re setting yourself up for significant knee issues.

FURTHER READING: Great reasons to do ACL injury prevention warmups

(Dr. Dev K. Mishra, a Clinical Assistant Professor of orthopedic surgery at Stanford University and Medical Director of Apeiron Life, is the creator of the SidelineSportsDoc.com online injury management course and the Good to Go injury assessment App for coaches, managers, parents and players. Mishra writes about injury recognition and management at SidelineSportsDoc.com blog, where this article originally appeared.)