Lunges are one of the best lower-body exercises that also enhance athletic performance and develop core strength. But if your form is off, you have muscle imbalances or you lack mobility in your hips and ankles, you may notice knee pain during this move.
Here, Grayson Wickham, DPT, CSCS, founder of Movement Vault, breaks down why you might feel knee pain during lunges, what your body is trying to tell you and simple steps to fix the problems.
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1. Your Technique Needs a Tune-Up
If the midway point of an exercise like the lunge causes you to screech out in pain, it's time to check your form. When you perform lunges incorrectly, you're putting your knee in a sub-optimal or compromised position, which causes wear and tear to your knee joint over time, Wickham says.
"The human body is resilient, and you can usually get away with poor form in the short term, but eventually, this poor technique will catch up with you, causing pain or injury," he says.
In fact, a small study in the December 2016 issue of the Journal of Orthopaedic and Sports Physical Therapy found that the position of your trunk and shank (the area between the knee and the ankle) has a significant influence on knee loading of both legs during the forward lunge, with more pain experienced in the trailing leg. So it's important to keep both your torso and shin vertical.
Another common technique error is letting your front knee buckle inward when your knee is bent. "This can cause wear and tear to the ligaments and meniscus connective tissues that support your knee joint," Wickham says.
To correct problems with your knee buckling inward, Wickham says to focus on ensuring that your knee always tracks straight forward over the middle of your foot.
“If this is difficult, try limiting the range of motion that you perform the lunge in, which means not bending your front knee as much,” he says.
Improper technique can also happen if you have poor gluteus muscle activation, specifically your gluteus medius muscle.
“Your gluteus medius muscle’s job is to help stabilize your hip, and when you have poor muscle activation in your gluteus medius muscle, your knees will buckle inward,” Wickham says. A great exercise to add to your mobility routine is the active 90/90 stretch.
Move 1: Active 90/90 Stretch
- Sit with your front knee bent to a 90-degree angle — a 90-degree angle between your two upper leg bones (femurs) — and your back knee bent to a 90-degree angle.
- Hinge at your hips, and fold toward your front ankle as far as possible, keeping a flat back.
- Angle your upper body toward your ankle, not your thigh, as this should give you the best stretch. Folding forward directly over your upper leg bone will most likely not give you a good stretch. You should feel this on the outside of your hip and glute.
- Contract your hip muscles by driving your front ankle down into the ground and hold for 20 seconds. You're now contracting these muscles while they're being stretched out.
- Stay in the stretch, let go of the ground, and try to lift your front ankle off of the ground and hold for 20 seconds. It won't go anywhere because it's maximally stretched, but continue to try to contract the muscles on the front side of your hip as you stretch. If balancing with no hands is difficult, use support.
- Perform for 3 reps per side. (One rep equals pushing down and pulling up.)
2. You Have Poor Flexibility or Mobility
"Knee pain or injuries are typically due to tight muscles and tight joints, aka poor flexibility and mobility in your hips and/or ankles," Wickham says. And when you have poor flexibility and mobility in one area of your body, you increase the odds of compensating for it in another part, he says.
Compensation occurs when one joint in your body takes over for another joint that's not doing its job. Wickham says these compensations cause stress to your joints, which can eventually lead to pain and injury. An example of this is tight or weak hip flexors.
"When your hip flexors are tight, specifically your rectus femoris muscle, there is an increase compression of your kneecap into your knee joint, which can cause pain and wear and tear in the front of your knee joint," Wickham says.
To improve the mobility and flexibility in your hip flexors, Wickham says to practice active stretching, which involves stretching a muscle and then contracting it while it's being stretched. According to Wickham, it's the most effective way to increase your flexibility and mobility. Try the active half-kneeling hip flexor stretch.
Move 1: Active Half-Kneeling Hip Flexor Stretch
- Get in a half-kneeling position.
- Move your body and front knee forward over the middle of your front foot until you feel a maximum stretch in the front of your back hip.
- Flex and contract your back hip forward as if you were trying to drag your knee on the ground and hold for 10 seconds. Your knee won't go anywhere as it's on the ground, but you'll be contracting your hip flexors as you stretch them out.
- Stay in the stretch and contract the glutes of your back leg and hold for 10 seconds. You should feel an increased stretch in the front of your hip. Make sure to keep your core engaged the entire time to ensure you don't arch your lower back.
- Perform 4 repetitions per side. (One rep equals contracting forward and squeezing your glute.)
3. You Have Muscle Imbalances
It's not uncommon to have a muscle imbalance between your quads and hamstrings. While minor imbalances may only cause slight problems, more prominent strength differences can cause pain in your knees.
With a muscle imbalance, you lack appropriate strength on all sides of a joint, including the front, back and sides of the joint. Wickham says you can also think of muscle imbalances as having a mismatch of strength on the front of your leg compared to the backside.
"When thinking about the lunge specifically, you want to make sure you have balanced strength in your quadriceps and your gluteus — having weak glute muscles compared to your quadriceps muscles is a common muscle imbalance in the legs," he says.
When this happens, Wickham says the muscles on the front side of your leg can pull more than the backside of your leg and cause improper movement and tightness, leading to pain in injury.
To correct this, Wickham says to make sure you're following a well-designed workout program that's balanced and includes exercises that target the muscles both on the front and back of your legs, also known as your quads and glutes.
You run into trouble and increase the potential for pain and injury due to muscle imbalances when your workout program focuses too much on your quads and not enough on the glutes.
Examples of quadriceps-focused exercises include:
- Narrow lunge
- Jump squat
- Front squat
Examples of gluteus-focused exercises include:
- Standard deadlift
- Single-leg Romanian deadlift
To correct and prevent future muscle imbalances between the front and back of your legs, make sure you include a variety of these exercises in your workout program. If knee pain persists after improving technique, muscle strength and flexibility, consult your physician.