One of the most confusing things I have come across over the past 15 years as a rehabilitation trainer working with many complex injuries and movement dysfunctions is how confusing the role of the quadriceps can be with relation to knee pain. In most cases of knee pain there is significant stiffness at the knee joint leading to conclusions of tight quadriceps and hip flexors. For years I believed the answer for people who had limited knee flexion needed to spend more time stretching and foam rolling their quads and hip muscles to restore full range to the joint. It makes perfect sense, the muscle is noticeably tight and not even close to its full range of motion so it must need stretching to improve it. And while some showed some great results, there were many who showed little improvement with some even becoming worse! This failure led me to find that the solution was not to be found with stretching but from changing the underlying cause of the stiffness. This article I will show you how to find this and what things you can do to correct the problem for good.

What Causes The Quads to Stiffen The Knee Joint?

Knee pain is a very common issue people face that affects their training and activities in daily life. Prior to the onset of pain is when stiffness is felt and it is at this point you need to look closely at what is causing this and put a plan in place to change what is going to become a permanent change. I see so many people with severe loss of knee mobility that could have easily been prevented if the correct action was taken early on.

In many cases the tightness is more to do with weakness and poor alignment than over use and the quads being too strong. The tightness is merely a protective mechanism from the body to protect the knee joint from more harm as the underlying problem is the poor alignment of the patella caused by dysfunctional repetitive movement. Stretching did not change this faulty alignment of movement with the clients I had little success and in some cases stressed the patella even more further complicating the stiffness at the knee. This brought me to the next problem, if stretching is not the answer what do you try next? There are several things you will need to do, and as I found out it was the order these were completed in that led to them working. 

Before jumping into how this works it is important to know exactly what makes up the quadriceps muscle group and how the muscles differ in their function. The quads are one of the most commonly known areas of the body located on the front of the thigh and as their name suggests they are broken into four separate muscles.

1. Rectus femoris occupies the middle of the thigh, covering most of the other three quadriceps muscles. This muscle crosses two joints meaning it can act as a hip flexor and also a knee extensor. This information is very important to remember when assessing hip motion later.
2. Vastus lateralis is on the outer side of the thigh.
3. Vastus medialis is on the inner part of the thigh and is often referred to as the VMO and is commonly linked to stability problems with the knee which we discuss shortly.
4. Vastus intermedius lies between vastus lateralis and vastus medialis on the front of the femur (i.e. on the top or front of the thigh), but deep underneath the rectus femoris.

The interesting thing to appreciate with this muscle group is that they are not all designed to function in the same way. In Vladimir Janda’s book “Assessment & Treatment of Muscle Imbalance” he explains in great detail the complex make up of muscles and the difference between tonic and phasic muscles. See our article on Posture for more detail about this.

Tonic system muscles are prone to tightness or shortness and are more concerned with stability, posture, and working for long periods. They are made up mostly of slow twitch fibres and are easily facilitated with constant repetitive movements. In this case the rectus femoris has been shown to be a tonic muscle.

On the other side is the phasic system muscles who are prone to weakness or inhibition and more concerned with fast and powerful movements. They are predominately fast twitch muscle fibres and require specific movement to keep them functional. And in the case of the quads the vastus medialis has been shown to be a phasic muscle.

The tonic muscles by way of their design begin to develop a method of overworking and dominating all movements and in essence “shut down” or "steal" the phasic muscles workload completely otherwise known as muscle inhibition. This means the rectus femoris has the potential to become dominant at the expense of the vastus medialis.

Now that you are clear on some of the anatomy behind the quadriceps what causes them to tighten up and stiffen the knee joint? By far the most common causes of quad tightness causing knee pain are from two things.

1. Over-use of knee flexion.
2. Poor alignment during movement.

The Danger of Too Much Knee Flexion

Firstly when I refer to over-use I am not only referring to exercise but every day movements we think nothing of like sitting. In one of our articles from last year we examined how much damage is placed upon the discs in the spine from hours of repeated sitting. What surprises most people is the damage sitting causes to the knee which many would not even consider to be a problem.

See article – How much compression is caused by sitting

The quadriceps muscle attaches directly to the knee cap and then the knee cap attaches directly to the tibia. This forms a strap. As the knee flexes further and further the strap tightens and compresses the patella into what is called the trochlear groove causing compression within the joint. If it is left in this position for too long and especially if you love to tuck your legs under the chair it is inevitably going to cause problems at the knee. This is one reason why people with knee pain find it difficult to stand up after prolonged sitting and it takes a while for their knees to loosen up. By leaving their body stuck in this position compressing the joint for a long period of time the body will react to this stress by stiffening muscles surrounding the joint to protect it from more harm, which only serves to make things worse as time goes on.

When we perform movements like squatting, running and stairs the patellofemoral joint takes a lot of stress. This joint is designed exactly for this purpose and was made to handle this stress and has very durable cartilage to help handle the forces of your activities.

The more the knee goes into flexion (knee bending) and the harder the quadriceps contracts, the greater the forces on the patellofemoral joint.

However, sometimes when there is too much stress too often, the knees can become aggravated and eventually painful. And once again the body will react with stiffness in order to protect itself from more harm and begin to limit activities and movements that take us into more and more knee bending. Even if your technique is fine the volume of training or exposure to too much flexion may be enough to set off pain symptoms.

Activities that require more knee bending tend to place larger stresses through the patella femoral joint:

• 3 times body weight during level
• 3 times body weight during stair climbing
• 6 times bodyweight during running
• 8 times bodyweight during a deep knee bend or squat

It becomes very easy to see why running and squatting can create knee pain if abused and why stairs can be extremely difficult once the knee has been aggravated. This also helps to explain why those who do a lot of gardening in a kneeling position or those who love to squat really deep can find it very painful to their knees over time.

A very interesting thing to remember here and what we will cover shortly is that to improve knee flexibility requires full knee flexion. But if full knee flexion is behind the tightness in the first place you can begin to see how this may not be a viable solution.

Poor Foot, Knee & Hip Alignment Causing Stiffness

This part is much more complex to explain for what you will find is that the knee is affected by the capacity of joints above (hip and pelvis), and below (ankle and foot), for it to maintain optimal alignment during movement. The knee is caught in a crossfire and dependant on these joints to perform their roles correctly to maintain perfect alignment. If any of these joints are unable to complete their role effectively it disrupts the optimal alignment of the patella in the knee and now you are set for trouble as it will be impossible for the patella to track correctly when the knee is fully flexed.

Make sure you read our detailed article – Why the knee itself is not the problem with knee pain

When you lower body into a squat position the knee cap engages into the trochlear groove (track) and is guided down the femur and as you straighten the knee when you begin to stand up the patella tracks back up the groove. This is what is known as patella tracking.

The inside of the joint is covered in articular cartilage designed to reduce the stress that occurs in the joint created by the quadriceps. However, if you lack the correct alignment of the patella in the trochlear groove you can end up with increased stress within the joint usually on the outside or lateral part of the knee as the larger more powerful quadriceps muscles begin to take over the work from the VMO. And eventually this stress becomes pain! This is where you see foam rolling on the outer part of the thigh, (ITB) to release this tension. This may help to some degree.

However, on its own it will do little for it isn't just tightness on the outside of the leg that can produce issues. Weakness and or timing issues of the medial stabilizers can also cause the knee cap to track incorrectly when you move. This is where many people are told to strengthen the VMO in the belief that isolating this muscle with strengthening exercises will automatically correct the problem. Once again though this will do very little if this is all you do.

Why?

Remember the knee is not really the problem. It is the joints above and below forcing it into faulty alignment to begin with. Okay, so what do you do about it?

Very simply you need to do a complete assessment of your body. You need to assess all joints for length tension imbalance, trunk stability, posture and lastly how you move. I will give you some great ideas on how to do this in the remainder of the article, but I suggest if you are someone with a chronic knee problem right now your best bet is to get our 60 minute knee pain video and PDF report. I created this program a few years ago to provide an online program that is easy to follow with a simple step by step process to effectively change all of the things we have just discussed. We have been able to successfully help hundreds of all types of knee injuries, (if not thousands over the internet) using this exact program.

Click here to see more of what is included.

Click here to get an instant copy of this program.

1. Determine if You Need To Stretch the Quadriceps and Hip Flexors

This is where it can get a bit messy for I will say with some people this is a great thing to do but of others I will avoid it completely and focus on releasing the posterior hip muscles. People who have just recently had knee surgery this step is absolutely CRITICAL and considerable time must be spend restoring mobility with flexion and extension to the joint. I cannot tell you how many people I have seen post ACL reconstruction surgery who skipped this stage only to be left with a permanently locked knee afterwards. In these cases stretching is essential.

For people with general knee stiffness however it is not so simple. The key is to identify what their pelvic posture is in static movement and also when they move. I will find stretching of the quads and anterior hip muscles beneficial only to those who have an anterior titled pelvis.

The anterior pelvic tilt provides your lumbar spine with a small lordosis curve which is perfectly normal. This position is essential to the health of the spine and provides a stable and strong base required for efficient movement. Problems arise when there is either too much curve or not enough curvature of the spine and this is greatly influenced by the position of the pelvis.

When there is too much tilt the quadriceps and anterior hip muscles are often stuck in a chronically shortened position creating muscle inhibition with the posterior muscles of the glutes and hamstrings. This inhibition of the glutes in particular contributes to the faulty alignment of the patella we discussed earlier. There are simple ways to assess your own posture which are shown in the video below.

The Best Way to Stretch the Quadriceps

The best way to stretch for someone with a lot of stiffness in the knee will be with a partner, therapist, or trainer to assist you as it is the most comfortable position to get into. Also the use of PNF stretching can be used which is by far the most effective form of stretching. To do this stretch on your own you can do this with a towel wrapped behind your foot.

For most people however the stretch shown in the video below will be superior to all forms of quadriceps stretching as it addresses the rectus femoris muscle at the knee and hip at the same time. The use of foam rolling in combination with stretching is perfect for this person.

*IMPORTANT NOTE – You are not finished yet! Even if you are able to restore mobility at the knee by using stretching and foam rolling you must address the weakness and any dysfunctional movements which we will cover in the following steps.

When I Would NOT Stretch the Quadriceps

Many individuals who sit for long periods of time and older individuals with chronic back issues are sitting in a posterior pelvic tilted position. In this position, their quadriceps and hip flexors tend to be over-lengthened and weak. Therefore, in these cases stretching the quadriceps tends to exacerbate the weakness and length-tension relationship between the anterior and posterior hip muscles. Watch the video below of an example of how easily the knees are placed under extreme stress due to the poor position of the pelvis being tucked under in posterior tilt. The lack of hip movement forces excessive movement into the knees and this will continue to happen until this person learns how to change this pattern. 

In addition to this is people who tend to move in a chronically positioned in posterior pelvic tilt from poor exercise technique or improper cuing such as squeezing the butt and/or pulling the abs in. Again, these people will benefit more from releasing their posterior hip muscles being the glutes, hamstrings, and external hip rotators instead of trying to stretch their quadriceps and hip flexors. The use of foam rolling as shown in the video earlier will be very beneficial for this person, but make sure you DO NOT stretch the quads.

Below is a quick video of some simple hip mobility drills you can try.

Don’t Forget About Ankle Mobility

Lastly do not discount the value of mobilizing the ankle for this can severely ruin the movement up the kinetic chain and rob the quadriceps of strength in movements like the squat. This applies to all types of postures and is very often a huge factor with knee pain. We will need to consider foot stability in line with this but for now to keep things simple just look at ankle mobility on its own.

The ankle must be mobile enough to allow dorsiflexion needed to align the lower limbs correctly and allow an even distribution of load to be placed through the powerful muscles of the legs. If the mobility is lacking here the body must compensate and create new methods of movement that eventually lead to weakness and dysfunction causing pain. We will explain shortly how disastrous this can be to the knee.

Below is a video of how to restore ankle mobility.

This step of restoring mobility MUST be completed first before attempting to move to the next stage where we address weakness. If you do not move to the next stage of improving stability and strength you will not make any permanent change.

2. Correcting Instability & Weakness

This is the part where many people get confused. For it makes no sense to try and strengthen an area that is already too stiff. I know I used to think exactly the same way but I came to realize that a big part of the reason it was stiff is due to weakness and poor stability. If I do not address this I will get nowhere.

It becomes a real paradox in that to loosen up, you need to stiffen up!

Exactly how you do this will vary considerably from person to person so it is impossible for me to give you a template to follow. You must complete a thorough assessment of your body with a series of tests to find where to start. I will be looking very closely for weakness with these tests.

• Foot stability and big toe function
• Abdominal control over hips
• Hamstring cramping during glute isolation drills
• Reflex stability in single leg stance

The results of these tests will determine the focus of the strength and stability training. To see these tests in action and more detail about this read our article – How to complete a knee pain assessment

 A lot of people still believe that isolating the vastus medialis with various exercises will make all the difference here. Unfortunately it achieves nothing for the VMO muscle has no influence over the alignment of the knee joint which it depends on greatly to perform its role. In addition to this many researchers have recently found that it is delayed activation of this muscle more than loss of gross muscle strength that is more of the problem. This is very similar to the delayed reaction we see with the TVA muscle with back pain clients.

Therefore, only exercises requiring dynamic stability will provide any effect and these exercises are all performed standing up where they work in combination with multiple joints and muscles. Watch the video shown below to see how this works.

There are many other exercises you could use to assist in this stage and we have covered this before in the article - Top 5 vmo exercises for patella tracking

The two biggest movements I am concerned with for this article in terms of releasing stiffness is the squat and the single leg stance.

3. Why I Use The Squat & Single Leg Exercises To Release Stiffness?

The squat is an interesting movement for as much as it is a great way to develop strength into the all of the muscles around the knee and prevent injury and pain it is also one of the reasons people get into trouble. The problem is not with the movement itself but the way it is taught. One of the worst coaching techniques that is still used today is where people are told to “keep the knees behind the toes.”

This cue came about to prevent knee problems as it significantly reduces the stretch on the patella which we discussed earlier. Unfortunately this short term solution creates a multitude of long term problems as it prevents the quadriceps from developing strength relative to the posterior chain for they are in such a poor mechanical position to get any work. But, even worse is this instruction distributes more of the load into the lower back exposing the lumbar spine to severe damage.

However, if you spend the time to really learn this exercise you will see that you can teach your body to control full flexion of the knee and regain any lost strength into the quadriceps relative to their synergistic partners of the hamstrings and glutes. I do not suggest you squat to full depth as not many people are mobile enough at the hips to do this but I would be using tools like heel plates, ramps, micro bands on the knees, and even TRX straps to assist people in learning the correct positions and technique.

Watch the video below to see an example of squat technique and 10 different ways to improve your mobility and strength.

This one movement can really unlock all the things we have tried to do separately so far. It demands ankle mobility and hip mobility but at the same good control of the tibia with foot stability and the hips with gluteal strength. For this reason it is my preferred movement to use with people once I have released the stiffness and improved stability at basic individual joints as discussed in the previous step.

Remember how I stated earlier you need to tighten up to loosen up this is how you do it. Technique is everything and you must also take your time with how much volume you use. If you do too much too soon your risk overloading the patella. Even if your technique is perfect. Gradual progressive overload is the secret.

For more detail on the different versions of squats I use read the article – 7 Best squats for bulletproof knees

The one thing the squat lacks however is the demand for alignment of the knee and this is where single leg exercises will provide a greater benefit.

4. Using Single Leg Exercises to Control Knee Alignment

This last part puts all the remaining pieces together and exposes many of the problems with reflex stability which is not to be confused with strength. I find a lot of clients will be able to improve quickly at the squat but will find this much more difficult. Usually I will start with the single leg deadlift before progressing to the more difficult single leg squat. Especially for the person who is in posterior tilt for this movement is the correction to their postural fault. It allows the head of the femur back into the glide deep into the acetabulum as it is meant to for optimal stability and centration of the joint and begins to restore their anterior tilt. For the person with too much anterior tilt I may prefer the single leg squat to begin with.

But the best part of these exercises is they require the foot and hip to work together in harmony to create the perfect alignment at the knee. And once this correct alignment is achieved and becomes an automatic program it reduces the stress on the knee and the patella therefor improving mobility as the body sees no need to create stiffness to protect itself.

There is a lot of moving parts to consider so it can take some time to get right and you will make many mistakes in the learning process. An awesome video to watch below explains all the things you need to look for when performing a single leg movement.

These last two steps of learning the squat and single leg stance exercises are the real secret to improving knee mobility and reducing stiffness in the quads.

You will find some great exercises using the band for resistance in the article - How to isolate the VMO within an integrated movement

Summary

I apologise for the length of this article and the amount of information we covered but you can see how easily we can fall into the trap of stretching and releasing a muscle that really needs to be strengthened and stabilised, not weakened. I made this mistake myself for a long time with my own body and many clients before coming to this realisation. By spending the time to assess where the problems are hiding and putting a plan in place to correct them will ensure you improve your knee mobility and ability to move forever. Make sure you do not skip steps and be careful of how much you volume you add to your corrective training. Too much, too soon will add to the stress of the knee and backfire on you.

The quadriceps are a very unique set of muscles and once you fully understand their purpose and how they work together during movement it is easy to design programs to maintain and develop your strength to do all the things you need in life without pain or limitation. 

For more ideas and information on specific topics I may not have covered in detail be sure to check out our INDEX PAGE on the website that has over 300 of our best articles. These are all sorted into categories for quick reference so you can find what you are after more easily. You can also subscribe to our FREE fortnightly newsletter by clicking here.

If you live in Melbourne and need specific help with your exercise program please feel free to reach out to me for help and we can set you up with your individualised program by clicking the banner below.

About The Author

Nick Jack is owner of No Regrets Personal Training and has over 16 years’ experience as a qualified Personal Trainer, Level 2 Rehabilitation trainer, CHEK practitioner, and Level 2 Sports conditioning Coach. Based in Melbourne Australia he specialises in providing solutions to injury and health problems for people of all ages using the latest methods of assessing movement and corrective exercise.

References:

• Movement - By Gray Cook
• Corrective Exercise Solutions - by Evan Osar
• Complete guide to correcting PFPS - By Dan Pope
• Athletes Acceleration Speed Training & Game Like Speed - by Lee Taft
• Diagnosis & Treatment Of Movement Impairment Syndromes - By Shirley Sahrman
• Low Back Disorders - by Stuart McGill
• Knee Injuries In Athletes - by Sports Injury Bulletin
• The ACL Solution - by Robert G Marx
• Understanding & Preventing Non-Contact ACL Injuries - American Orthopaedic Society For Sports Medicine
• Anatomy Trains - by Thomas Meyers
• Motor Learning and Performance - By Richard A Schmidt and Timothy D Lee
• Assessment & Treatment Of Muscle Imbalance - By Vladimir Janda
• How To Eat, Move & Be Healthy by Paul Chek
• Scientific Core Conditioning Correspondence Course - By Paul Chek
• Advanced Program Design - By Paul Chek
• Twist Conditioning Sports Strength - By Peter Twist
• Twist Conditioning Sports Movement - By Peter Twist
• Twist Conditioning Sports Balance - By Peter Twist