How to Do Isometric Exercises for Knee Pain

If you’ve ever experienced an injury and found yourself working with a physical therapist, you’ve likely done some isometric exercises.

Whether you’ve done them before or not, you may still not know what they really are and if they’re actually beneficial.

This article will look at what isometrics are, how they can help improve strength, and provide you isometric exercises for knee pain.

What Are Isometrics?

When it comes to strength training, we often are taught to do isotonic movements.

Isotonic means constant tension. When you do a bicep curl, you are doing an isotonic contraction. The weight (or tension) in the dumbbell stays the same as you bend your elbow, shortening the length of your muscle.

Isometric means constant length. In an isometric contraction the joint doesn’t move much, so the belly of the muscle doesn’t shorten, but the tension increases. A plank or a wall sit are both examples of an isometric contraction.

When you perform an isometric contraction, there are physiological changes happening within the muscles that help them build. The blood flow is restricted, which allows for buildup of oxygen and metabolites (energy sources) so the muscle is able to absorb more oxygen and get stronger.^1,2

Are Isometric Exercises Effective?

The short answer is yes.

The longer answer is yes, but it depends on your goal.

Studies have found that using isometric exercises can lead to muscle hypertrophy (increase in muscle size), improve tendon quality, and maintain and increase strength.¹

However, studies also show that if you’re looking to increase dynamic strength, isometrics are not the most impactful option.¹

This doesn’t mean that isometrics aren’t beneficial to include in a program. It just means if you’re goal is to improve your leg strength to make quick movements on the pickleball court, you likely want to add some more dynamic strength training.

Keys to an Isometric Contraction

As described above, to complete an isometric contraction, we need to push or pull against a static force.

The goal is not to move through our full range, but hold within a certain range of motion.

Studies have found that it doesn’t really matter how hard you contract, but what’s more important is the duration and range of the contraction.

So you don’t need to exert 100% effort in an isometric contraction. For example, if you’re doing a standing plank, you don’t need to push into the wall until you’re red in the face with effort.

But, it is a good idea to focus on increasing the range of motion you’re holding in.

Isometric movements can be done within various angles of the joint range of motion. For example, you can hold a plank with a slight bend in your elbows, or you can bend your elbows to 90 degrees and hold the plank.

Research has found that moving into the greater ranges ( >70 degrees) has been more effective for increasing strength.¹

Additionally, studies have shown that the amount of time under tension is important. This allows for greater buildup of energy/oxygen in the muscle.

Therefore, it’s better to hold the contraction for 30 seconds and then rest, rather than doing 10 holds for 3 seconds each.¹

Can I Do Isometric Exercises While in Pain?

YES!

This is what I think is one of the greatest benefits to isometric training!

Since isometrics don’t require movement through the full range of motion, many times isometric exercises will be done in a range that’s not painful.

Contracting within the non-painful range still allows for muscle tension (and strength) to build, but it doesn’t exacerbate the pain.

Isometric Exercises for Knee Pain

Click HERE to see Dr. Katie Landier, PT, DPT, GCS complete these exercises!

1. Knee Extension

1. Sit towards front edge of your chair
2. Place a gait belt, strong resistance band, or yoga strap around the leg of the chair
3. Place the strap around your ankle
4. Kick out into the band (about 70% max effort)
5. Hold for 30 seconds
6. Repeat 3 times
7. Repeat on opposite leg

2. Knee Flexion

1. Sit towards front edge of your chair
2. Place a towel or ball between your heel and the leg of the chair
3. Bend your knee into the towel/ball (about 70% max effort)
4. Hold for 30 seconds
5. Repeat 3 times
6. Repeat on opposite leg

3. Hip External Rotation

1. Sit towards front edge of your chair
2. Place a gait belt, strong resistance band, or yoga strap around the leg of the chair
3. Place the strap around your ankle
4. Rotate your foot so the bottom of your shoe is facing your opposite leg and the inner surface of your shoe is facing the ceiling (about 70% max effort)
5. Hold for 30 seconds
6. Repeat 3 times
7. Repeat on opposite leg

4. Hip Extension

1. Stand in front of a wall, hands can rest on stable surface for balance
2. Keeping your leg straight, kick your heel back into the wall (about 70% max effort)
3. Hold for 30 seconds
4. Repeat 3 times
5. Repeat on opposite leg

5. Wall Squat

1. Stand in front of a wall, hands can rest on stable surface for balance
2. Place back and buttocks against the wall
3. Walk your feet out in front of you as you slide your buttocks towards the floor (as if you’re sitting in a chair)
4. Find a squat position where you can feel a challenge, but don’t feel like you’re going to fall
5. Hold this position for 10-30 seconds
6. Stand and rest for 1 minute
7. Repeat 3 times

Have the Strength to Live Life to the Fullest!

Sources:

1. Oranchuk, D. J., Storey, A. G., Nelson, A. R., & Cronin, J. B. (2019). Isometric training and long-term adaptations: Effects of muscle length, intensity, and intent: A systematic review. Scandinavian journal of medicine & science in sports, 29(4), 484–503. https://doi.org/10.1111/sms.13375
2. de Freitas, M. C., Gerosa-Neto, J., Zanchi, N. E., Lira, F. S., & Rossi, F. E. (2017). Role of metabolic stress for enhancing muscle adaptations: Practical applications. World journal of methodology, 7(2), 46–54. https://doi.org/10.5662/wjm.v7.i2.46