Knee Joint 101

Even a bum knee shouldn’t be an excuse to skip legs day—not that most guys need one. Just consider that training legs recruits an enormous amount of lower-body muscle, which burns more calories and triggers a flood of testosterone and growth hormone, two hormones that play a massive role in muscle recovery and growth. All it takes to navigate legs day with a bad knee—and not miss out on a bevy of benefits—is a little anatomical understanding and the right exercise selection. We’ll help you train around a knee injury for a lower body that looks and performs better than new.

KNEE JOINT 101

Your knee acts as a stable hinge that allows your quads to flex your lower leg forward and your hamstrings to retract it back. It’s connected to the tibia and fibula bones by a network of ligaments—mainly composed of the anterior cruciate ligament, the medial collateral ligament, the posterior cruciate ligament, and the lateral collateral ligament. And due to the complexity of this network, both the hip and ankle—which are the primary movers of athletic movements like jumping and sprinting—play a role in knee joint health.

KNEE NIGHTMARES

  1. The hinge-like design of the knee does not allow for much side-to-side movement, which is why ACL and MCL injuries are common in sports that require a lot of lateral cuts, like soccer, basketball, and football.
  2. Lackluster mobility in your hips and ankles forces your body to compensate by relying on your knee to pick up some of the slack for movements for which it’s not suited. On the field, this could be juking, and in the gym, it could be a weighted lateral lunge. And as stated before, the knee is a stable joint, so if it’s asked to partake in a movement for which it’s not suited, then, eventually, an injury is likely.
  3. While side-to-side movement can cause a tendon tear, too much forward flexion—which causes the tibia to stray in front of your knee—can lead to wear and tear, also known as osteoarthritis, aka OA. It’s common, too. More than 30 million adults in the U.S. are affected by OA, according to the Centers for Disease Control and Prevention.
1. You’re Doing: Legs Press; Do This Instead: Goblet Squat

WHY

The setup for the legs press requires you to fix your back into place. This takes your hips out of the equation, leaving your knees to do most of the work as you push the sled. Therefore it’s important to focus on moves that engage the hips and help mobilize them better without pressuring your knee joint. The goblet squat does this perfectly while keeping your back straight up.

DO IT

Hold a dumbbell like a goblet, right below your chin. Descend into a squat until your thighs break parallel with the ground, keeping your weight on your heels.

2. You’re Doing: Legs Extension; Do This Instead: Reverse Lunge

WHY

Legs extensions—which lock your knees into place—put a high amount of torque on the joint. And when you’re dealing with an existing injury, the last thing you want to do is add pressure on the knee with minimal reward in return. Instead, try reverse lunges, a great knee-dominant movement that recruits your posterior chain (not just your quads), so you get more bang for your buck. It also teaches your body how to properly decelerate downward, as you won’t have a weight stack forcefully pushing your legs downward after each rep, making them much safer on your joint and limbs overall.

DO IT

From the standing position, step backward while maintaining pressure through the heel of the front foot. Descend down to 90° or when the back knee touches the ground. Return to the starting position by driving through the heel of the front leg while keeping the weight off your back leg.

3. You’re Doing: Barbell Deadlift; Do This Instead: Barbell Romanian Deadlift

WHY

Pulling weight from the ground doesn’t directly stress the knee joint, but it does require ankle and hip mobility, and if you lack in those areas then your knee will feel the effects as it compensates. The simple fix is to keep the weight above the ground to keep the strain off your ankles and to strengthen your glutes and hip muscles.

DO IT

Hold a barbell against your thighs and push your hip back until it descends just past your knees. Keep your chest and head up and your back straight. Once you feel your hamstrings contract, drive the weight back up.

BY DAVID OTEY, C.S.C.S.