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Strengthening Your Knees for Stronger Legs

Strengthening Your Knees for Stronger Legs

The knee joint is one of the most important joints in the body. Almost every movement in the lower body involves knee motion. That should be reason enough for our clients to understand the significance of knee strength.

In this article, we provide a basic understanding of knee anatomy, function, and strengthening exercises for muscle groups involved in knee action.

What is the Knee Joint?

The knee joint is one of the largest joints in the body. Four bones make up the synovial hinge joint:

  • Femur
  • Patella
  • Tibia
  • Fibula

The femur connects to the tibia and the fibula sits right next to the tibia. The tibia is known as the larger shin bone while the fibula is the smaller one. The patella sits at the joint where the femur or thigh bone meets the tibia.

Common Knee Injuries

Knee injuries rank high among some of the most common stumbling blocks in sports and fitness. Assisting in almost all lower body movements, knee problems arise mainly because of the joints inability to respond to rotational movement and force paired with lack of strength.

Achieving optimal range of motion, strength, and stabilization is crucial to having strong knees. The knee is active in almost all daily movements such as walking, exercise, getting in and out of bed, and much more.

Injury is more common in overweight individuals due to extra tension on bones, joints, tendons, and ligaments. External forces like a direct blows or excess rotation contributes to common knee injuries as well.

Strengthening your knees will help prevent more serious issues such as knee osteoarthritis. It is unfortunate that wear and tear could occur so easily and be so detrimental. On the other hand, by teaching clients how to maintain strong knees, they become more inclined to excel in sports and achieve better overall fitness.

Starting in the Feet

With the knee joint originating in the leg, a multitude of injuries can occur. Various extensor and flexor muscles of the foot produce dorsiflexion and plantar flexion. Knees and feet have a huge impact on one another, therefore if a client has weak knees, they can encounter different foot injuries.

The big toe is one of the innermost toes that helps keep the entire body stabilized. It plays a role in helping clients maintain balance and withstand their own body weight. Standing, walking, and running does not just involve the heel, but also the toes. Big toe injuries can cause intense disruption throughout the kinetic chain.

Variations of Arthritis

Joint inflammation that occurs within the knee joint is often referred to as arthritis. Arthritis causes pain and stiffness that leads to inactivity and even more injury in other areas of the body. Osteoarthritis is the most prevalent form of arthritis found in the knee joint.

Osteoarthritis results from two bones rubbing against one another, causing inflammation and cartilage deterioration in the joint. Articular cartilage acts as a cushion between two bones and provides protection at the femur and tibia conjunction. 

As a client ages, the body is unable to recover like it used to when they were younger. This contributes to the loss of cartilage in the knees. In addition to loss of cartilage you have overweight clients where excess body fat overloads the body causing more wear and tear.

Female clients are at a much higher risk for osteoarthritis because of the constant hormone imbalance they experience through menopause. This impacts joint health and increases the chances for them to have osteoarthritis as they age.

Ligament Damage

This is a very common form of injury, especially in sports. Cruciate and collateral ligaments are arranged ligaments found in the knee that help stabilize the joint.

You might recognize them as:

  • ACL - Anterior Cruciate Ligament, at the side
  • MCL - Medial Collateral Ligament, at the middle
  • LCL - Lateral Collateral Ligament, at the side
  • PCL - Posterior Cruciate Ligament, at the middle 

Each ligament is responsible for controlling knee motion and the direction in which it can move. Ligament injuries occur often from sudden change of speed and direction, direct blows to the area and planting the foot with undesirable rotation.

Strengthening the Knee Joint Muscles

The quadriceps, hamstrings, and calves all support the knees. The gluteal muscles contribute to knee strength also.

The quadriceps produce knee extension and the hamstring is responsible for knee flexion. The gastrocnemius muscle, part of the calves, plays a role in knee flexion. 

During the eccentric phase of a squat, the hamstrings and calves allow knee flexion. While in the concentric phase of the squat the quadriceps work to produce knee extension.

Just because a client has strong quads and hamstrings does not mean their knee strength is where it should be. The glutes are a problem area in weakness of the knees. The gluteal muscles even attach to the iliotibial band, which is located on the outside of the knee.

The IT band is the tendon that causes lateral knee problems if not trained properly. When a client has a knee injury this should be one of the first areas you address. Weak glutes cause knee instability and allow the knees to collapse inward during movement.

Implementing these exercises to help strengthen the glutes and IT band might be a good idea. Contrary to popular belief, foam rolling does not provide the same benefit for the IT band as it does for muscles.

Strength training can help reduce joint pain and keep the knee in good health.

Exercises for the Knees

There is no ideal or terrible group of exercises for the knees. Squats and lunges seem to be labeled as “not so good” for the knees. But this is different for each client and the type of issue they have.

Takeaway: Avoid any exercise that causes pain, not just squats or lunges.

Isometric exercises help in strengthening the knee. They limit the risk of injury or further damage because of less joint range of motion. Avoiding as much change in muscle length as possible will help alleviate pressure that is normally placed on the joint. 

Try these exercises with your clients to help strengthen knees. A lot of these are also found in corrective exercise programs.

Wall Squats

Have the client begin by standing with their back against a wall. Instruct them to place their feet a couple feet away from the wall and shoulder width apart. Next have them get in starting position by squatting down until their thighs are parallel with the ground. Make sure they their back remains against the wall and have them hold the position for time. This is a great isometric exercise.

Hip Extensions

The client starts in a supine position on the ground. Each leg is bent with feet flat on the ground. Keeping the heels as close to the glutes as possible and arms to the side have them begin the exercise. They will drive through each heel extending their hips towards the ceiling. They should contract the glutes and hold at the top, then slowly lower back down to the ground and repeat.

Straight Leg Raises

Client will get in position flat on their back with one leg bent and the other straight out. Have them begin by raising the straight leg up as high as they can without going past being perpendicular to their body. Have them return their straight leg to the ground and repeat. Be sure perform repetitions on both legs.

Mini Band Lateral Walks

Client begins with a mini band around the thighs located above the knee. In a quarter squat position and feet separated a foot apart, have them walk laterally. Ensure your client looks ahead, keeps feet aligned and toes pointed forward remaining in a squat position for the entire set. Choose a band that provides appropriate resistance for your client to perform the walks without the band overcoming their strength. This can be the case if the client's knees are caving inward when doing the exercise.

Step Ups

Client will start by stepping up on a box leading with one leg. Have your client drive through the heel and glutes of the lead leg on the box. As the client steps up, the other leg follows behind and is placed on the box. In the standing position, instruct your client to return to the starting position by stepping down with the same leg they stepped up with. Rotate legs and be sure to choose a box that provides enough height for the client to stand up on without ease, but still able to maintain stability and balance with added resistance.

Do’s and Don’ts When Strengthening Knees

  • Don’t have your client perform fast or ballistic type movements, instead teach slow and controlled movement only.
  • Don’t allow them to flex or point their toes when performing knee extensions or curls, instead keep the foot in a neutral position.
  • Don’t overload the body with too much weight, instead start light and gradually build up.
  • Don’t allow them to lock out the knees on exercises like step ups, instead always emphasize keeping a slight bend at the knee.
  • Don’t squat so low that it brings on pain, instead have clients squat as low as their body will allow them without them experiencing discomfort.
  • Always stretch the quads, hamstrings, glutes, and calves after a workout and incorporate foam rolling in your clients’ routines.

Knee Stretches for Joint Flexibility

Try these exercises with your clients to help with flexibility and reduce the risk of injury.

Seated Hamstring Stretch

Have your client start by sitting on the floor with both legs straight out. Next have them extend their arms and reach for their toes. While bending at the waist and reaching for the toes hold a static position for 30 seconds.

Standing Quadriceps Stretch

Start by grabbing the leg above the ankle and pull it towards the glutes. Make sure your client remains upright and holds for at least 30 seconds. Rotate back and forth between the legs.

Standing Calf Stretch

Client will position themselves in front of a wall with one foot in front of the other. With the front knee slightly bent have them lean toward the wall with the front leg keeping their heel on the ground. Hold for 30 seconds, then switch.


The right exercise and flexibility program is crucial for clients to achieve optimal knee strength. Knee strengthening programs should always focus on muscle groups that assist with the entire joints range of motion. The best approach consists of slow and controlled movements focusing on the quadriceps, hamstrings, and calves. Building stability and strength in the knee helps prevent osteoarthritis and other detrimental injuries that can occur in and around the knee.

Want to learn more about increasing strength in the knee? Check out the ISSA Corrective Exercise Specialist Certification and expand your knowledge to help provide more awareness to your clients.