Strengthening knees for runners.

I first experienced knee pain as a runner during my first marathon.

About 14 miles into the race, I felt a twinge of pain in the upper part of my right knee.

Since I was in the middle of the race and the pain was noticeable but bearable, I kept going.

As any runner will tell you, getting a running injury during a race is one of the worst times for it to happen. You will be confronted with a difficult decision. Tough it out to finish a race you’ve spent months training for, but risk making the injury worse. Or, throw in the towel and accept that you won’t finish. This is a decision that can only be made by the runner at that moment. You’ll never know if you made the right call, so you must do your best to listen to your body.

That dull pain would stay with me for the next two years every time I ran.

At first, I tried to wait it out to see if it went away with time. For the most part, it did. But occasionally, it would come back, and when it did, it would stick around for weeks.

Finally, I went to the physical therapist, who prescribed some simple exercises. After a few months of consistently following the protocol he gave me, the pain all but disappeared.

Though I’ll never know for certain what triggered the knee pain all those years ago, I can now make an educated guess.

Due to my inexperience with training for a marathon, I attempted to do too much too quickly.

In strength and conditioning talk, I increased volume (the number of miles) and intensity (how hard I was running those miles) too fast.

If I had stopped right then and taken some time off, I would have saved a lot of effort trying to fix the issue. But what can you do when you’re in the middle of a race?

The next best thing was try to fix it and take measures to prevent it from happening again.

In this article, I’ll cover some of the exercises that helped with my knee pain and allowed me to take up long-distance trail and obstacle course racing for the following six years after the pain started.

*This article is for educational purposes only and does not constitute medical advice. Before beginning any training program, consult with a medical professional about any pain or medical concerns. 

Why Strengthening Knees for Runners is Important

Knee strength is crucial for runners for several reasons.

Injury Prevention: Strong muscles around the knee, such as the quadriceps, hamstrings, and calves, help stabilize the knee joint. This may reduce the risk of common running injuries like runner’s knee, IT band syndrome, and patellar tendonitis.

Joint Stability: Strengthening the muscles that support the knee improves overall stability, helping to absorb the impact with each step. This is especially important for runners, as the knee bears a significant load during running.

Improved Running Efficiency: Strong knees contribute to better biomechanics, allowing runners to maintain proper form. This can reduce wasted energy and improves running economy, allowing you to run longer distances more efficiently.

Shock Absorption: The knee joint and surrounding muscles act as shock absorbers. Strengthening the muscles helps distribute impact forces, reducing the strain on the knee and other joints.

Enhanced Performance: With stronger knees, runners can handle more intense training sessions, such as hill running or speed work. This helps in building endurance and speed over time.

How Common Are Knee Injuries in Runners

Knee injuries are some of the most common injuries runners experience. Studies show that knee injuries account for about 20-40% of all running-related injuries, making the knee the most frequently affected joint in runners.

One of the most common knee injuries is patellofemoral pain syndrome (PFPS), often referred to as “runner’s knee,” which can arise from overuse, improper biomechanics, or muscle imbalances. PFPS occurs at the front of your knee between the knee cap and thigh bone.

Research suggests that runner’s knee pain affects about 25% of all runners at some point in their running career. Other common knee injuries include iliotibial band syndrome and patellar tendinitis (jumper’s knee).

Common Causes of Knee Injuries in Runners

There are several reasons a runner might develop a knee injury. Here are a few of the most common.​

​Repetitive stress from running can lead to microtrauma in the knee tissues, resulting in injuries like patellofemoral pain syndrome and iliotibial (IT) band syndrome.

Inefficient running form, such as improper foot strike, over-striding, or inadequate hip and core stability, can increase stress on the knee joint.

Failing to properly warm up before running can lead to tight muscles and increased injury risk.

Rapidly increasing mileage or intensity without proper adaptation can overload the knee tendons and ligaments, leading to injuries.

Weak quadriceps, hamstrings, or hip muscles can result in poor knee stability, increasing the risk of injuries.

Wearing shoes that do not provide adequate support or cushioning for your foot type can lead to improper alignment and increased knee strain.

Finally, a history of knee injuries can predispose runners to re-injury due to weakened structures or poor movement patterns.

What are the Muscles Involved in Knee Movement

The knee joint is a complex structure that involves several muscles responsible for its movement and stability. Here are the primary muscles involved in knee movement.

Quadriceps: The quads are located at the front of the thigh and are comprised of four muscles responsible for knee extension (straightening the leg).

Hamstrings: The hamstrings are located at the back of the thigh and are comprised of three muscles responsible for knee flexion (bending the knee).

Gastrocnemius: The gastrocnemius is located on the calf and assists in knee flexion and ankle movement.

Popliteus: The popliteus is a small muscle located at the back of the knee. It unlocks the knee from full extension and assists in knee flexion.

Adductors: The hip adductors are located in the inner thigh and help to stabilize the knee during leg movement.

Breaking Down Tendon Strength

When it comes to the front of the knee pain that runners often experience, tendon strength is one of the most important factors in preventing/reducing knee pain. 

Stimulating collagen synthesis is critical to strengthening our tendons. Here’s a breakdown of how to promote collagen production for stronger tendons.

Understanding Collagen and Tendons

Collagen is the primary structural protein in tendons, responsible for their strength and elasticity.

Tendons are the connective tissues that link muscles to bones, transmitting force during movement. Strong, healthy tendons reduce injury risk and enhance performance.

Exercise and Mechanical Loading

Isometric Exercises: Isometric exercises are a great way to start loading the tendons, especially for beginners. The isometric muscle action is where the muscle stays a constant length (think wall sits or planks).

Eccentric Exercises: These exercises (where the muscle lengthens under tension) stimulate collagen production and improve tendon resilience. Examples include slow squats or eccentric heel drops for Achilles’ tendons.

Resistance Training: Progressive loading of tendons through weightlifting and resistance band exercises encourages collagen synthesis, making tendons thicker and more durable.

Plyometric Training: Explosive exercises like jumping stimulate collagen production through high-intensity, dynamic loading. However, they should be introduced progressively to avoid overload or injury.

Blood Flow and Circulation

Tendons typically have poor blood supply, which can limit nutrient delivery. Low-impact activities like cycling, swimming, or light jogging can increase blood flow to tendons, promoting collagen production and repair.

Massage and foam rolling may also increase circulation to tendons, enhancing the delivery of nutrients and stimulating recovery processes.

Rest and Recovery

Collagen synthesis takes time, so allowing tendons adequate rest between high-impact training sessions is essential. Overtraining can inhibit collagen production and weaken tendons.

Quality sleep is crucial for repairing and growing all tissues, including tendons. This is when most of the body’s healing and collagen synthesis occurs.

Progressive Knee-Strengthening Exercises for Runners

There is always a risk of injury with any sport. Running is no exception. The good news is strength exercises can help reduce that risk.

Including a few exercises in your strength training routine may help reduce existing pain and/or help prevent future pain. The below variety of exercises is a handful of movements you can include in your routine that may help with knee pain.

Please remember to speak with your healthcare provider before engaging in a new exercise program.

Wall Sits (Beginner)

Stand with your back against a wall. Slide down into a squat position with your thighs parallel to the floor and knees at 90 degrees, and hold this position. For this exercise, you only need your body weight.

This isometric exercise puts tension on the quads, strengthening the tendons around the knee.

Increase the duration of the hold over several weeks, or perform wall sits while holding a weight (e.g., medicine ball) to increase intensity.

Bodyweight Squats (Beginner)

Stand with feet shoulder-width apart, squat down by bending at the knees and hips, keeping your chest up. Push back up through your heels.

The squat movement strengthens the quads and hamstrings, indirectly strengthening the tendons around the knee.

Start with bodyweight squats, then increase reps or hold weights to increase load.

Isometric Lunges (Beginner)

Start in a lunge position with one foot forward and one foot back. Lower into a lunge, keeping your front knee at a 90-degree angle and your back knee hovering just above the ground. Hold this position for 30–60 seconds, maintaining tension in both legs. If this feels too easy, hold a lightweight (e.g., kettlebell or dumbbell) at chest level.

Isometric lunges engage the quadriceps, hamstrings, and glutes while constantly loading the knee tendons. The static hold helps build tendon strength without dynamic movement.

Increase the hold time, or add weights (dumbbells or a weighted vest) to make the exercise more challenging for both the muscles and tendons.

Step-Ups (Beginner/Intermediate)

Stand in front of a step or bench. Step one foot up, press through the heel, lift the body up, then step down. Alternate legs.

This single-leg movement strengthens the knee tendons by working the stabilizing muscles and improving balance.

Increase the height of the step or hold weights to increase intensity.

Eccentric Squats (Intermediate)

Perform a regular squat but descend slowly (3-5 seconds) and rise quickly. Focus on controlled, slow lowering to stimulate tendon strength.

The squat’s eccentric phase (muscle lengthening) places greater stress on the tendons.

Add resistance (like dumbbells or a barbell) or increase time under tension.

Spanish Squats (Intermediate)

Wrap a resistance band around a fixed object at knee height and step into it with the band just behind your knees. Lean back slightly as you squat, keeping tension on the band and your torso upright.

This exercise targets the patellar tendon, which often experiences strain in runners. It strengthens the tendon by isolating it and taking stress off the kneecap.

To intensify the load on the patellar tendon, increase the time in the position or add weight (e.g., holding a kettlebell or dumbbell).

Lunges (Intermediate)

Stand with your feet hip-width apart. Step forward into a lunge position, bending both knees to 90 degrees. Push back to standing. Alternate legs.

Lunges work both the quads and hamstrings.

Start with bodyweight lunges, then increase reps, hold weights, or perform walking lunges to increase difficulty.

Eccentric Step-Downs (Intermediate)

Stand on a step or box with one foot and lower the opposite foot slowly to the ground without touching down. Use the standing leg to control the descent.

This is excellent for strengthening the patellar tendon, which is often stressed in running. The slow descent builds tendon strength.

Increase the step height or add weights as you build strength.

Banded Jumps (Intermediate)

Place a resistance band around a pull up bar. Hold the band in both hands. Squat down into a half-squat position, then explode upward into a jump. Land softly with knees slightly bent, immediately going into the next squat and jump.

The explosive jumping motion helps build tendon strength and elasticity, which is important for dynamic movements like running or sprinting.

Cossack Squat (Intermediate)

Stand with your feet wider than shoulder-width apart. Shift your weight to one leg and squat down on that side, keeping the other leg straight. Lower yourself comfortably while keeping your chest up and back straight. Push back up through your bent leg to return to standing, then alternate to the other side.

This lateral movement strengthens the quadriceps, glutes, and adductors while increasing mobility in the hips and knees. It targets the tendons around the knee with a lateral range of motion than standard squats, helping improve flexibility and strength.

Add weights (like holding a kettlebell or dumbbell) or increase the squat depth to further challenge the knee tendons and muscles.

Bulgarian Split Squats (Advanced)

Place the back foot on a bench and lower the back leg toward the ground, keeping the front knee in line with the toes. Push back up through the heel.

This unilateral movement strengthens the tendons in the front leg by placing a large load on the knee joint.

Add weights or increase reps as you become stronger in the movement.

Nordic Hamstring Curls (Advanced)

Kneel with your feet anchored, slowly lower your body forward, using your hamstrings to resist gravity. Try to keep your body straight.

This focuses on the eccentric contraction of the hamstrings, strengthening the tendons connecting to the knee.

Control the lowering phase for longer periods or add resistance bands for more challenge.

Single-Leg Romanian Deadlifts (Advanced)

Stand on one leg, hinge at the hips, and lower your torso toward the ground, keeping your back straight and core engaged. Return to standing.

This strengthens the hamstrings, glutes, and tendons around the knee, challenging balance and stabilizing muscles.

Start with body weight, then progress by holding weights or increasing reps.

Box Jumps (Advanced)

Stand in front of a sturdy box, jump explosively onto it, and land softly with your knees slightly bent.

Plyometric exercises like box jumps promote tendon elasticity and strength, especially for high-impact activities like running.

Increase the height of the box or perform with a weighted vest for added intensity.

Plyometric Lunges (Advanced)

The starting position will be a lunge position. From here, jump up explosively, switching the position of your left leg and right leg in mid-air, and land softly in a lunge on the opposite foot (if you started with your left foot forward, then you will land with your right foot forward).

This dynamic, high-impact movement builds tendon strength and elasticity, particularly in the patellar and quadriceps tendons.

Increase height in the jumps or add weights to further challenge tendon strength.

Sample Circuits for Runners

Even if you’re a more advanced lifter, it’s a good idea to start at the lower level and gradually advance to more strenuous exercises.

Level 1: Perform each exercise for 3 rounds

• Wall Sit: 20 seconds
• Eccentric Step Down: 5 each leg
• Step Up: 5 each leg

Level 2: Perform each exercise for 3 rounds

• Spanish Squat: 20 seconds
• Lunges: 10 each leg
• Banded Jumps: 3

Level 3: Perform each exercise for 3 rounds

• Iso Lunge: 30 seconds each leg
• Bulgarian Split Squat: 12 each leg
• Nordic Hamstring Curls: 4
• Plyometric Lunges: 3 each side

Strengthening Knees for Runners Wrap-Up

If you think you may have patellofemoral syndrome or you’re experiencing any sort of pain in general, see a medical professional.

Whether you’re training for your first race or want to spend more time running, strength work is an essential aspect of any training program.

Remember to subscribe to the Outdoor Muscle Newsletter and YouTube Channel for strength training tips to apply to your next race or adventure!

If you found this article valuable, make sure to check out these!

10 Exercises for Trail Runners to Build Full Body Strength

The Ultimate Guide to Strength Training for Hiking (+Training Plan)

Your Guide to Trail Running Basics for Complete Beginners

References

“Running-related injuries: A systematic review of the literature.” Van Mechelen, W., Twisk, J. W. R., Post, G. B., & Verhagen, E. British Journal of Sports Medicine, 1992.

“Epidemiology of running injuries.” Clarsen, B. E., Rønnestad, B. R., & s K. S. British Journal of Sports Medicine. 2013