Knee Pain - Bike Fit Fixes

https://vimeo.com/257821553/77ffd33b7e

I recommend that either before or after this section you begin to take a, look at and measure your bike fit. I have a free program on my website. If you're already a member you can simply go start the "Not So Basic Bike Fit" Series. It will walk you through everything you'd need to know to get some accurate and important measurements to properly get a handle on how you interact with your bike.

Potential Bike Fit Fixes for knee pain

It would be impossible to cover every scenario of what might solve a rider’s knee pain, but this doesn’t stop many people from trying to find that one specific cause for their own knee problem. The reason this isn’t more successful is that most bike fit issues aren’t from one single large factor, they’re a handful of factors, some big some very small, but no less important to full resolution of symptoms. It’s for this reason that we’re going to cover many possible remedies and do it in such a way that we address the most common and larger causes but still work our way through the more obscure ones as well. Because in all likelihood, your knee pain will resolve not after we correct one thing, but more than likely two or three changes. If this seems confusing at this point, don’t worry, it will becomes more clear as we go.So here are the changes that most often provide resolution to cycling knee pain:

Raise or lower your saddle

Of course this idea was mentioned in an earlier section, and it bears repeating because most knee issues will need a change of saddle height. Having the wrong saddle height is the easiest way to create an issue for your knees (and certainly other areas, which we’ll get into). Again, it often isn’t the only factor, but it is the most common.Let’s dig deeper into why having your saddle too low or too high can cause trouble.

When the Saddle is Too Low

We’re used to hearing about proper saddle height referenced by the measure of the knee angle at the bottom of the pedal stroke. Determining how straight the knee gets at the bottom of the stroke (6 o’clock position) can go a long way toward determining if saddle height is correct. But tissue on the front of the knee, where most knee discomfort originates, is stressed not at the bottom of the pedal stroke, but at the top. At the top of the stroke, the knee is flexed maximally in the pedal cycle, which stretches the quadricep muscle, quadricep tendon, patellar tendon and increases compressive forces on the patella and sub-patellar cartilage. Because this is where we begin to put real force through the pedals, these tissues are being asked to contract and produce force while being flexed maximally as well. This is a perfect scenario for tearing of tissues to occur as well as compression of the patella into the femur.The lower saddle height is, the more knee flexion occurs at the top of the pedal stroke. Going even a few millimeters below optimal saddle height can strain these tissues and create knee pain. Most cyclists have a narrow range, perhaps 1-3 cm, where saddle height is agreeable to their overall mechanics and problems don’t surface. Go below, or above, this and aches, pains, numbness and other problems will present themselves.

When the Saddle is Too High

Having the saddle too high is certainly less common a problem than too low a saddle, primarily because when a saddle is too high by even a moderate amount it can be difficult to reach the pedals and complete a normal pedal stroke, so riders self-correct rather quickly.

But just as having the saddle a few millimeters too low creates issues so too does having the saddle a couple millimeters too high.The most common presentation of this is pain behind the knee, and for the most part this can be true a lot of the time. With the saddle too high our knee “reaches” for the pedal and is asked to straighten too much which strains the hamstrings and causes pain behind the knee where the hamstrings attach. But in most cases the knee isn’t straightening to its maximal limit - even when a saddle is very high the knee might still be bent 15 or 20 degrees, so why should this cause knee pain when the rider can clearly straighten their knee fully (to zero degrees) when off the bike? In much the same way that too much knee flexion at the top of the pedal stroke can cause front of the knee pain, even when the rider can clearly bend the knee further than this off the bike.

The measurement we’re concerned with this time is the traditional knee extension at the bottom of the pedal stroke measurement. If the saddle is too high, the knee will have to straighten beyond the range that is comfortable/powerful for it and the hamstring will be forced to lengthen or stretch further, under load, which will cause tears in the tissue.The most common tissues involved are the medial, or inside, hamstrings (nominally the semitendinosis, semimembranosis) and often the tendon of these tissues or at least the musculotendinis junction (where the muscle and the tendon meet) are most likely to carry the brunt of the problem.

Why does the bike cause knee pain when we’re not even close to the end range of our motion - at the top and the bottom of our pedal stroke? Because of mechanical factors that go into riding a bike: force production and cadence.As discussed earlier, force production is a major factor at the top of the pedal stroke, and with the front of the knee tissues stretched across the flexed knee this creates the main problem with anterior knee pain.At the bottom of the pedal stroke it’s cadence, and the speed at which our legs are turning, that creates the problem, because at this point we’re asking the hamstrings to lengthen very quickly, and while they’re not a tremendous force production muscle at this point, we are asking them to coordinate the pedal stroke and to do so at a very fast rate. At the bottom of the stroke the hamstrings are playing a large role in the transition of the pedal/foot from moving downward to translating backward. They do this best when the knee is still bent roughly 35 or 40 degrees or more.

How do I know I need to change saddle height?

What metric or test can we use to determine if a saddle height change is in order? There’s more than one way to go about this.You could use a calculator, like the LeMond method where you take your true inseam and multiply it by .883. The usefulness and accuracy of these formulaic methods is often inversely related to how easy they are to use. They might get some people relatively close to their proper saddle height but because they lack sensitivity in regards to individual differences in strength and flexibility among other things, they just don’t cut it most of the time.

The simplest way to get proper saddle height and include some aspect of personal mobility is to measure using an old trick of pedaling backwards with your heel on the pedal. I have an article I wrote on this subject -- namely what the easiest method to determine proper saddle height is. Put your heel on the pedal and pedal slowly backwards -- your knee should straighten fully (or nearly so) when doing this but not at the expense of your hips. Your hips shouldn’t rock back and forth over the saddle and your heel should remain in contact with the pedal the whole time. Move slowly and have a friend check your movement if you’re not sure.

Sometimes it’s hard to tell how much your hips are rocking. You could also video yourself doing this in order to check your hip motion.Is this the most accurate method of determining saddle height? No, absolutely not, but among the very simple methods, I find this one to be the best.

There are definitely more complex ways -- as I mentioned above, I have a free program that teaches anyone how to use basic video motion capture technology that we all have through our phones, tablets, GoPros and other devices how to do a basic bike fit assessment of proper saddle height. Even in the hands of someone who has never done it before, this can yield good results and shed a lot of light on how a rider moves over their bike. It takes more time and a little planning, but the results are significantly better -- additionally we can use the video to investigate other aspects of the bike fit and potentially solve more problems.

Either of these methods can go a long way toward showing you how low (or high) your saddle is. For instance, if you use the heel on the pedal method and you can easily pedal backwards keeping your heel in contact with the pedal and at the bottom of the pedal stroke your knee is still bent a lot, you know that you have a long way to go and should raise your saddle a bit more. If your knee is only bent slightly then perhaps you just raise a small amount at a time.How much is “a small amount”? And what constitutes a large adjustment? When I’m performing a bike fit, and I believe my client is pretty close to their ideal saddle height I may raise it only 3-4 millimeters, but if they’re further off I might adjust about 4-5 times that -- perhaps 20-30 millimeters (or right around an inch). On occasion I do get someone in that’s a huge amount off -- the equivalent of doing the heel-on-the-pedal test where the knee remains bent 20° or more at the bottom of the stroke -- and I have to raise their saddle 75-100 mm (3-4 inches). A good rule of thumb is to start smaller than you think -- err on the side of caution. You can always raise the saddle more later and in my experience it’s easier to undershoot the mark and slowly work your way up (or down) to the proper height than it is to bounce drastically back and forth between too high and too low.

Get your hips back

As with so much on the bike, balance is important. I don’t mean in the “making sure you don’t fall over” or training wheels idea of balance strictly, although this is important. I mean making sure we have the right amount of weight on our hands, our butt, and our feet. Also, we need to consider muscular balance so that the muscles are working together in the right proportions to most effectively support and propel us. No other place is so important for this as in the hips. Making sure the hips are positioned properly will ensure both of these things happen. We need to have the hips a safe amount behind the feet so that we have good balance of weight distribution between the butt and the hands as well as making sure that the large muscles on the back side of the hips and butt, called the gluteals, are put in a position to do their share of the work.

Of course their are many muscles that do work to turn our pedals but the lion’s share of our power is driven by the gluteals and the quadriceps. Having the proper balance between these two muscle groups is key. If the hips are too far forward, often this fosters dominance of the quadriceps over the gluteals because with the hips further over the feet, it can make it difficult to activate the large muscles of the glutes. Take as an example performing a squat two different ways:

First standing upright squat down allowing your knees to move in front of your feet as you descend versus performing a squat where you keep the knees even with or slightly behind your toes. When you allow your knees to track in front of your feet the quads will predominantly activate whereas if you keep your weight back more, the hip and glute muscles are noticeably more engaged.How far back the hips need to be is determined by more than just leg or femur length. Trunk and hip stability, pelvic angle, flexibility, saddle type, and bar position are just a few of the factors involved and so each individual will truly be different where their hips will be balanced.How does this cause knee trouble? When the hips are misplaced, and the glute/quad balance is upset it is more often the case that the quads are doing more and the glutes are doing less than they should. This over-activity in the quads simply leads to more strain being placed through the quad muscle, quad tendon, patellar tendon and the sub-patellar cartilage. When the quads are over-used, then all of the problems associated with the too high/too low saddle height issue are magnified. Quads dominant and the saddle too low is a recipe for disaster of course.Quads dominant and the saddle a little too high can still create front of the knee problems -- however other problems like calf, achilles and toes/foot problems become even more common since the rider is more likely to “reach” for the pedals with the ankle, feet, and toes and strain these tissues on the lower half of the posterior (backside) chain. We’ll dig into this further as we discuss more of the secondary effects in a section coming up.

How do I know I need to get my hips back?So how can we figure out if our hips are misplaced? There are a few ways to look at this, and I prefer the more functional on the bike test that we’ll go over second. But first, many bike fitters use the Knee Over Pedals Spindle (KOPS) rule. KOPS is the idea of lining your knee up directly over the pedal spindle while the pedal is the forward (or 3 o’clock) position. The problem is that this just doesn’t hold biomechanical water. In many circumstances the knee will fall somewhere generally over the pedal in this position but this isn’t strictly a requirement for good power output or healthy knees.

There is a false idea that if your knee falls in front of the pedal spindle then this will place extra strain through the extensor tendons of the knee and create front of the knee pain. While it is possible for this to happen, it depends on a few other things happening -- the knee being in front by itself won’t cause knee trouble. Just ask any triathlete who rides on a steep seat angled bike. Triathletes knees often fall many centimeters in front of the pedal spindle and few experience knee pain as a result.The KOPS test is done by dropping a plumb line from the front of the knee and adjusting the saddle fore/aft until the plumb line bisects the pedal spindle. There are many problems with this test: First, there is little agreement about what part of the knee should fall directly over the spindle. Should we be dropping the plumb line from the front of the kneecap? The tibial tuberosity? Center of rotation for the knee? These are just three of the ways that are out there as a “rule” and they all produce significantly different positions on the bike. So if the KOPS method isn’t the way to go, how should we figure out saddle position? I prefer the functional balance test I went into detail in a previous YouTube video. This test can help you figure out where you are the best balanced and generating power equally through the large leg muscles.

One individual might have their knees a couple centimeters further back or forward relative to another cyclist.An extremely important thing to keep in mind for this test is that your saddle’s fore/aft and tilt may be perfect but you still might fail this test. How? You may not be sitting on the correct part of the saddle. The most common cause of this is when the handlebars are set too long and/or low which will tend to draw the pelvis forward on the saddle. This usually results in saddle discomfort too because the pelvis is resting on a narrower portion of the seat putting pressure on the soft tissue of the perineum. So if you have knee pain, and you’re considering whether you need to get your hips back, if you also have saddle discomfort then you’ll want to look at handlebar reach and drop (in the next section) as a potential piece of the puzzle.

Change handlebar position

Now that we’ve covered the importance of hip position, the issue of handlebar placement will make more sense. A rider could have their saddle height set perfectly and also placed exactly in the correct spot behind their feet but still have poor quad/glute balance and it usually happens due to the wrong bar position.When our handlebar is placed too long/low or too short/high it creates the wrong posture for our upper body. The shoulder and trunk’s flexibility and stability will be compromised and the pelvis will be pulled out of position. The most common scenario for this is when the handlebar is placed too far away and/or is too low for the mechanics of the individual. The upper body and trunk will compensate as much as they can, to reach the bar but inevitably some of the compensation will occur in the pelvis - usually in the form of it tilting forward or sliding forward more than it ought to. This misplaces the hips and we get all the problems discussed above.It should be noted that while less common it is quite possible that having a too short or high a reach to the bar will create the same problem. With the bar placed too high or short, the upper body and torso will be “cramped” or restricted in its ability to assume its most powerful length which will also affect pelvic posture and hip position.It’s significantly more common to have athletes need to be shortened or raised in their bar position though so we’ll focus predominantly on that.

Wedge the Cleats

So far we’ve discussed mostly fore/aft or what I call X-Y changes. When viewing riders from the side, moving the seat or bars up or down (Y-axis) or shorter/longer (X-axis) but now we’re going to address our first medial-lateral or Z-axis movement. We’re all familiar with seeing the knees of some riders move in and out towards or away the bike frame. This side to side movement is common and not always a result of anything happening at the knee. In fact it’s much more common for it to be driven by the hip or the foot/ankle. The knee is what we call a “slave” joint because it’s trapped between the hip and feet and its motion is largely driven by these joints above and below it.

We’ve addressed some of the bike fit changes that address some issues at the hip (above) and we’ll get into more exercise-based interventions for the hips that can also help to correct aberrant hip motor patterns that may be causing trouble for the knees in a later section, but this next fix of using cleat wedges is meant to mainly make up for issues arising through the feet and ankles.How our feet line up - what their static posture is - as well as how they move are important drivers of knee movement. Much of the population has some degree of forefoot varus - meaning the forefoot (the toes and the bones behind them, the metatarsals) will rest in an unweighted position such that if you were sitting on a table with your feet dangling in the air, the bottom of your feet in the fore region would be angled slightly towards each other. On the bike, visualize this as our feet resting in the shoes with the big toe and the inside of the forefoot sitting slightly raised up relative to the little toe and the outside of the foot.For most riders, the amount of forefoot varus they have isn’t a problem and doesn’t need extra correcting. In fact many cycling shoes are built with a small amount of forefoot varus in the sole already which is a testament to how common this posture is.The movement of the foot and ankle are also important. In cycling, because the front half of the foot is where most of the action is happening, the mobility of the toes, the metatarsals and the arch or mid-foot are the primary drivers of problems. The more movement we have through the foot, the more likely it is to cause a problem that needs to be addressed. A cyclist could have a very neutral forefoot, as far as varus positioning goes, but with extra forefoot and arch mobility, this can grow into a problem that needs to be corrected.So what happens? How does this forefoot varus position lead to problems at the knees? The forefoot begins in varus during the recovery portion of the pedal stroke when there is less weight placed through it. The inside of the foot (the big toe and its metatarsal) will lift up or unweight slightly from the bottom of the shoe. Then when the power phase begins that big toe and inside portion of the foot has to regain solid contact with the bottom of the shoe because in order to effectively complete the power portion of the pedal stroke the force should finish through the big toe. To make contact the foot and ankle will compensate by rolling inward - this causes the tibia to rotate inward as well which will then drive the knee in toward the top tube of the bike.To control this motion, we have a choice of putting a wedge under the cleat or under the foot itself. The wedge will be oriented such that the fat part of it is to the inside of the foot. The wedge tilts the cleat down on the inside, but since it still has to make contact with the pedal in a flat orientation, this has the opposite effect on the foot -- it lifts the inside (medial side) of the shoe up, which is exactly how the forefoot is aligned in a varus posture. The forefoot gets to stay in its desired position throughout the pedal stroke and so the forefoot, midfoot and ankle joints don’t need to roll inward to compensate and the knee then tracks in a more vertical path with less side-to-side motion.

Move Cleats Back

This isn’t a widely considered solution to knee pain, but one I find often ends up being part of the equation. To understand why, we need to understand what happens to our mechanics as the cleats are moved fore or aft. Cleats more forward:

More toe-down posture through the pedal stroke

Greater ankle range of motion

Increased foot and calf muscle involvement

More likely to inhibit the glute muscles

Cleats further back:

Flatter foot posture (less toe-down)

Less ankle motion

Less foot and calf muscle involvement

More facilitative to glute muscle involvement

It’s this final point of glute activation of course that is the primary issue. The two different methods of squatting we discussed above apply in the exact same way here. The more we allow our knees to drift in front of our feet as we squat, the more weight we’ll be bearing on our toes and forefoot which correlate with increased quadricep dominance. When we squat keeping our knees equal to or behind our toes, more pressure is borne through the back of the foot and less through the toes/forefoot, correlating with increased gluteal involvement.While the cleats don’t need to be all the way back on the shoe, there is significantly lower overall risk when erring on the side of further back than further forward.

Shorten Cranks

This is a knee pain solution whose time has come due. For years the component manufacturers have limited our crank selection to mostly to the 170-175 mm range with a few exceptions slightly more or less than this. This “nearly one size fits all” method is severely problematic though as many athletes are finding their mechanics are much better with much shorter cranks, especially when knee pain is involved.What do shorter cranks do? It’s important to first understand that no matter what length crank you have, your saddle height can be properly set to have the right amount of knee extension for you as an individual, at the bottom of the pedal stroke. If you have 175 mm cranks your saddle height would be set one place, and then if you changed to 200 mm cranks we would simply lower your seat height to get the same amount of knee extension at the bottom of the stroke. Easy.The problem arises with crank length at the top of the pedal stroke. While your knee extension may be perfect at the bottom of the stroke, the longer your crank is the more your knee is bent, or flexed, at the top of the pedal stroke. That longer crank just lifts your foot higher and requires more hip and knee flexion in the 12 o’clock position. This increased knee flexion can have all the detrimental effects that we saw from simply having your saddle too low -- increased stretching of the quads, quad tendon, patellar tendon, an increase in sub-patellar cartilage compression, etc -- and resultant knee pain.For many athletes who struggle with knee pain, moving from a 172.5 mm crank to a 155 mm or 160 mm crank decreases the amount of knee flexion they experience at the top of the pedal stroke enough to relieve these tissues and their knee pain.