How to exercise without hurting your knees

How to exercise without hurting your knees: Man holding knee in pain while outside
(Image credit: Getty Images)

Want to know how to exercise without hurting your knees? Unfortunately, knee pain is an extremely common ailment, with one in four adults suffering from frequent knee pain, according to a recent paper in the Annals of Internal Medicine. Exercise has been shown to be extremely effective at reducing knee pain, according to a trial from the National Library of Medicine, but it can often be difficult to get started if your knees are already hurting. Finding out how to exercise without hurting your knees can be troublesome, but there are two main routes you can take:

• Stop doing any exercise that hurts your knees
• Strengthen the tissues around your knees to make them stronger and more resilient

Unfortunately, avoiding any exercise or activity that hurts your knees isn’t practical, feasible or even advisable. A large amount of research has shown that not only does activity tends to reduce pain in the long-term, but that sedentary behavior will make it worse – most notably a paper from 2019 in Occupational & Environmental Medicine.

That leaves us with the more sensible, practical option of strengthening the leg muscles and tissues so that you can exercise without hurting your knees. For most of these exercises, you’ll need equipment such as an exercise bike, yoga mat, bench, or some resistance bands

How to exercise without hurting your knees: What to know before you begin

Before embarking on any exercise protocol, especially if you’re suffering from pain or an injury, it’s imperative that you seek medical advice and clearance. Now that you have, let’s get back to learning!

As mentioned above, pain is highly complex, as shown by Physical Therapy Reviews, and there are entire scientific journals dedicated to studying it. That said, there are a couple of simple steps you can take to minimize the pain you feel as a result of exercise.

How to exercise without hurting your knees: Image of legs running up stairs

(Image credit: Getty Images)

The first one should seem quite simple. If an activity causes you pain, but it only comes on at a certain distance/speed/weight/effort level, then stay shy of that point. This will enable you to keep exercising and doing the activity you enjoy while avoiding a lot of the resultant pain.

Second, be careful with how quickly you progress with your chosen exercise. A large amount of research has demonstrated that a rapid increase in workload increases injury rates, most recently a 2020 paper in the International Journal of Sports Medicine. Another 2020 article, from Frontiers in Physiology, has shown the same to be true regarding pain. Keeping week-to-week increases in distance/speed/weight below 5% (2-3% is the sweet spot) is a highly effective way to reduce the likelihood and occurrence of pain.

How to exercise without hurting your knees: How to improve knee pain

Exercise, in general, has been shown to be effective in reducing knee pain, as shown by a 2020 paper from the Scandinavian Journal of Medicine & Science in Sports, but what kind of exercise is best? Luckily, the research is quite clear.

A paper from 2014 in Knee Surgery, Sports Traumatology, Arthroscopy demonstrates that quadriceps muscles are usually weaker, atrophied and less active in those suffering from knee pain compared to those who aren’t. Further, there is often an imbalance between two of the quad muscles which can result in poor knee alignment. It also states that once the immediate pain and swelling is reduced, quadriceps exercise should be implemented for best long-term outcomes.

A 2019 study in the American Journal of Sports Medicine went a step further, comparing quadriceps-focused exercises, glute–focused exercises, and ‘free physical activity’ where participants could do whatever exercise they wanted. After three months, while every group saw a reduction in knee pain, the quadricep exercise group had the largest reductions in their ‘usual’ and ‘worst’ pain that they felt on a day-to-day basis.

With this in mind, it’s clear that any exercises you can do will help, but for the best results, we should be focusing our attention on building strength in the quadriceps. But what even are your quadriceps, and what do they do? 

How to exercise without hurting your knees: Workouts for those with knee pain

The quadriceps (or quads) are made up of four muscles, all of which straighten the knee from slightly different angles, and they aid in keeping the kneecap aligned with the thigh bone - so you can see why they’re such important muscles when it comes to knee pain! While exercises such as squats, lunges and step-ups are great at developing strength and muscle in the quads, knee pain can be most common during those movements, according to a paper in the Cochrane Database of Systematic Reviews, and more recently in American Family Physician

This is likely because, in order to stay balanced, these exercises place a large demand on proper knee alignment, which is often poor in those suffering from knee pain, as discussed above. With this in mind, there are two main exercises that work the quads, don’t have a large balancing component, and are easy to perform.

The first go-to exercise is the leg extension - this can be done with a specialized machine, or simply sitting on a mat or bench, and using gravity to provide the resistance as an entry point. This exercise works all four quadriceps, provides excellent resistance, and can be easily altered through rotation of the leg, range of motion, changes in tempo etc. to ensure that the exercise can be performed without causing knee pain.

How to exercise without hurting your knees: Image of woman working out on a bike at the gym

(Image credit: Getty Images)

The second option is to simply cycle, either on the road or on an exercise bike. Riding a bike primarily works the quad muscles (which was confirmed as far back as 1986 in the Journal of Biomechanics), and because your hips are stationary on the saddle, and feet are planted on the pedals, there is almost no demand placed on knee alignment. It also more closely resembles daily activities like walking and climbing stairs, and we can easily change many aspects of the exercise: resistance level, distance, time, pedaling cadence, range of motion at the knee.

How to exercise without hurting your knees: Take-home message

If you’re suffering from knee pain, fight the temptation to avoid any and all activities. You should absolutely do any exercise you can, and modulate them to be able to perform them pain-free. 

Exercises focusing on the quadriceps have been shown to be particularly effective at reducing knee pain, and the two best exercises are likely leg extensions and bike riding. If you don’t have access to a gym, why not invest in an exercise bike to use at home to get on your way to stronger, healthier and more resilient knees.

Will McAuley

Will McAuley is a London-based Personal Trainer and Nutrition Coach who’s writing has appeared in Men’s Fitness and GQ magazine, covering exercise, nutrition and health. He has a Master’s degree in Strength & Conditioning from Middlesex University in London, is a published scientific author in the Journal of Strength and Conditioning Research, and holds a Bachelor’s degree in Linguistics from Trinity College Dublin.