Defend Your Knees Part I
Defend Your Knees… Before They Become An Issue - Part I
And why running may not be as damaging as you think
So you started running and your knees started to hurt. Why does this HAPPEN???
Over the years, running for leisure has grown in popularity. Not only does it benefit your physical health, but it also induces psychological improvements in your well-being (1).Whether you’re running for fun or to compete, it’s an excellent activity for people of all ages and fitness levels.
With the current guidelines for social distancing, running can be a great option to help you stay fit and even improve the intensity of your current training. However, if your knees aren’t strong enough to handle the impact of running then you might be forced to stop prematurely. It’s currently estimated that 50-75% of runners will suffer an injury related to overuse and improper training – this often involves the knee (2)!
But we shouldn’t accept this fate. Although common, many of these knee injuries can be avoided altogether. Prevention starts with early recognition, behavior changes, and ongoing check-ins with yourself. In order to successfully overcome the injury, we need to first understand what makes a healthy knee ‘running’ smoothly.
If your knees are strong and healthy, running should not cause any pain
Anatomy of a healthy knee
The knee joint is an intricate system of muscles, tendons, and ligaments all of which work to both mobilize, stabilize, and distribute force in the leg. It not only supports the weight of our bodies when we stand, walk, and run, but it acts as a shock absorber to help prevent injury (3).
The two major muscle groups act in an opposite fashion, both crossing your hips and knee joints are:
1. Quadriceps(4 muscles) on front of thigh – this muscle causes your leg to straighten (if your knee is bent), and attaches to the quadriceps tendon which crosses over your knee joint.
2. Hamstrings(3 muscles) on back of thigh – this muscle bends your knee (opposite of quad), and also attaches to the hamstring tendon which also crosses your knee joint.
These muscle groups work in pairs, meaning one muscle group contracts while the other relaxes/stretches. For instance, as you extend your knee into a straight leg position you will contact your quadricep muscles (causing them to shorten) while you simultaneously relax your hamstring muscles (causing them to lengthen).
Other key players include the cartilage, which promotes fluid movement of the joint; ligaments, which connect bone to bone and help to stabilize the joint; and tendons, which connect muscle to bone and allow for both the distribution of force as well as to provide some flexibility.
Imbalances in strength and mobility cause the knee joint to lose its functionality entirely. As a runner, you need to ensure all the muscles, tendons, ligaments, and cartilage are working together under the right conditions. This helps to not only avoid injury but to allow you to continue to run comfortably and efficiently as you age.
your quads and hamstrings work in pairs - one muscle group contracts while the other relaxes
the dreaded knee injury
The WHAT
Runners are more likely to injure themselves due to overuse compared to other aerobic activities such as walking, biking, or swimming (4). Whether you’re running for leisure or training for your next big race, you’ve likely set some sort of goal for yourself. Perhaps you said to yourself “I want to run [ insert number of kilometers ] in [ insert number of minutes ].”
But in order to make any improvements you need to increase either your pace, distance or both. Over time, if the structures in your knee are not strong enough to handle the stress of training, it starts to break down and cause pain. When this pain is not addressed early, you are at risk of long term damage. Some of the most common injuries include:
● Runner’s knee / anterior pain syndrome / patellofemoral pain syndrome (PFPS)
● Iliotibial (IT) band syndrome
● Hamstrings issues
The WHO
There’s a variety of factors that influence a runners’ risk of injury, more specifically, that ‘dreaded knee injury’. Current research states over half of all runners suffer a knee injury throughout their careers (5). Although the numbers are clear, the mechanism of injury can be multifactorial and diverse.
Minimal differences are seen between sexes and running injury associated with the knee. Much of the research should be interpreted with caution as there are in fact some differences between sexes (structurally and biomechanically), but do not associate to more or less risk (6).
No differences in the risk of knee injuries are related to age (more on this later).
The WHY
The biggest question remains: why do so many runners develop that dreaded knee injury over time?
Two major factors contributing to increasing your risk of injury are:
1. Structural imbalances
2. Training volume/over-training
Structural Imbalances
Based on the anatomy of the knee joint, certain structural imbalances in muscle pairs can become problematic. This can be in terms of weaknesses, tightness, or overall mobility issues causing unequal force distribution across the joint.
For instance, having excessively strong quadriceps will put more tension on the patellar tendon and more stress on the knee. Alternatively, having tight hamstrings will disallow your quadriceps to fully contract to contribute to force production during a run. This can eventually lead to injury if it’s not addressed early.
Interestingly, when looking at differences between highly trained and recreational female runners, stronger hamstrings compared to quads (H:Q ratio) seems to be advantageous. This was suggested after determining that more economical runners had greater H:Q ratios compared to the less economical runners (7).
Training volume/ over-training
The body requires time to adapt from the stress you put it through during training. Before jumping to more mileage and/or faster pace, your muscles and joints need adequate time to recover. In addition, any structural advances you make in your training will go unnoticed if you continuously put yourself through high physical stress with minimal periods of recovery.
Injuries tend to develop under two main circumstances (8):
a. High volume (based on your km/week)
b. High intensity (based on your km/minute)
Training Volume
For ideal training adaptations, a good rule of thumb is to slowly and progressively increase your weekly volume by no more than 10-15%. However, this may change depending on your fitness level and history of training.
Training intensity
When looking at how much intensity to add to your training, it’s a good idea to work on one adaptation at a time. For example, early in the season, focus on building up your volume, with lower intensity sessions. Later in the season, when you increase the intensity of your training sessions, you generally want the volume to stay relatively consistent.
When athletes increase the volume or intensity of their training too fast, structures in the body tend to break down, causing pain. Some of these injuries that runners are most susceptible to are Patellofemoral Pain Syndrome ( pain in the front of the knee), and Iliotibial Pain Syndrome (pain on the side of the knee/ leg), plantar fasciitis (pain under the foot) and Achilles tendinopathy (pain on the back of heel). The majority of these injuries can be avoided with a slow progression of volume/ intensity in run training combined with a strength program that addresses proper mobility and strength in all major joints.
Where to go from here?
Personally, I love the work Ben Patrick as been doing, in terms of building bullet-proof knees with his athletes and he links some great exercises videos in his Athletic Truth Group instagram. For a deeper dive into the philosophy of building healthy knees for life, Just Fly Performance Podcast (#148)interviews Ben Patrick on how he trains his athletes and some safer exercises beginners can try at home (hint: these include activities such as pulling sleds and walking backwards up a treadmill!). In addition, including lots of single leg exercises such as a Lateral Step Down or Reverse Step Down can be great to get your posterior chain stronger (glutes and hamstrings) and start to correct imbalances. Stay tune for more take-home tips in Part II!
Yes!