Photo Credit: Catherine Smith via enduro-mtb.com
Low Back Pain and mountain bike are like marriage and argument. If your relationship is serious and full time, sooner or later it will happen. And in the same way like in marriage when you get back home and you don’t know why your wife is not talking to you, many times you wonder why you are having back pain. It only happens when you ride your mountain bike. Any other activities are pain-free. Your doctor says your scans are clear too. So what’s going on ? Well, back pain is quite a complicated condition and can have many reasons.

Weak muscles including core, overuse injuries, acute injuries, postural changes, emotional factors, muscle imbalance (even shoulder problems might bring it on), or food, just to name a few. Although all these and other factors might leave you pain-free and switch it on only when you ride the bike, in this article we are going to focus on an otherwise healthy person and common reasons of the lower back pain coming strictly from sitting on the bike saddle.


Quick Anatomy of The Sitting Position

It’s not a secret that sitting, in general, is not really an activity that our backs like. It also does not take a genius to figure out that prolonged bike riding in this position is probably not a very natural activity for our body.

Pressure on the lumbar disc is significantly higher in the sitting position (about 150 kg) than in the standing position, and it further increases while leaning forward. The highest forces that are placed on the disc of the lumbar spine occur when you are in the seated position and leaning forward while bearing weight. This is without any other external forces acting on your spine. Now, imagine the bike scenario when you ride over bumpy terrain with your backpack. Even if these numbers decrease due to the fact that you are leaning on the handlebars, we have to remember that for the spinal load, muscle forces are more relevant than external forces.

Depending on cycling power, the forces in the muscles that span the hip region increase. Higher trunk muscle forces lead to higher spinal forces. They also depend strongly on the location of the centre of mass (CoM) of the upper body. A shift of the centre of mass will require higher back muscle force to keep a stable position, which in turn further leads to higher spinal forces. This position of the CoM of your upper body in relation to the spine will have the strongest effect on the spinal loads. Again, try to picture your body movement when you ride for example enduro trails.



Bike Riding and Possible Causes of Back Pain

If you took a glance at “Quick Anatomy of The Sitting Position” you will easily figure out that it’s not just miles spent pedalling with your ass on the bike saddle. Your lower back forces will further increase due to demands of the rough terrain and different MTB riding styles (Downhill, Enduro, Cross Country). Here are significant factors that might be the answer to why you are having a lower back pain when mountain biking.


1) Incorrect Bike Position

Photo Credit: Trevor Worsey via enduro-mtb.com

Excessive reach, the horizontal distance between the saddle and bars, too upright or cramped position… Incorrect saddle height and bike size (especially when a frame is too large and causes over-reaching), are two most common errors giving riders lumbar problems as well as other injuries like hip or knee pain. Not so obvious errors like crank and stem length and horizontal position of your saddle might also contribute towards the development of lower back pain.


Your shoulders should be relaxed with slightly bent elbows.

Your seat should be at the height so you have very slightly bent knees at the bottom of each pedal stroke and you never force to rock your hips from side to side on the saddle while pedalling.

Saddle, as level as possible, is usually the very efficient position for long cross-country sections. However, setting it at the slight angle might do the trick and allivate back pain in some cases.

Setting your saddle horizontal position will depend a lot on the length of your arms. If you have long arms for your height, you might end up with the saddle set well back. On the other hand, someone with short arms might have to move it forward.

Adjusting stem length and handlebar position will also fine-tune the way you sit over your mountain bike. Many riders solve their lower back pain simply by getting a handlebar with more backsweep or putting the stem up or down by half an inch.

With all these adjustments done the correct way you should be able to maintain the perfectly straight line through your spine.

These are just general rules which are based on efficient pedalling for long cross-country trail riding. Bike fit is complex and very personal, we are all different and you might have to make small adjustments to all these positions to find the optimal comfort for your lower back. Other factors that you will have to consider are: riding style, confidence, personal preferences, or shoes you wear. Identifying an issue yourself by trial and error sometimes can be a lengthy and fruitless process. Going for physio specialising in bike fit might, in the long run, save you time and discomfort.

2) Tightnesses, Weakness, Imbalances of Particular Muscle Groups and Areas of The Body

Photo Credit: Catherine Smith via enduro-mtb.com


#Mobility / Flexibility

Tightness in the hip flexors, hamstrings, gluteal or piriformis muscles is quite common in regular bike riders. This often leads to increased lateral pelvic movement and conversely makes the lower back work harder to compensate and eventually results in lower back pain. Decreased hip mobility can also cause other injuries including knee pain and Iliotibial band syndrome.

#Weak Core Muscles

Core muscles are a very important factor playing a big role in segmental stabilization. A weak core can leave your lower back as the vulnerable weak point during your riding which more likely than not will lead to the pain in this area.

#The Muscles Fatigue

Your postural muscles fatigue just like any other muscles. When you tire your lower back and trunk muscles, they will stop supporting your joints and begin to struggle to hold your position. Additionally, they also may be forced to take on extra load to compensate for your leg weakness. Yes, weakening of your calf and thigh muscles can have an unexpected effect on other groups of muscles, including those in your back. Your knees can begin to splay in or out and the more your leg position moves away from the vertical, the worse your back posture will become.


Tight, weak or imbalanced body parts are often neglected by many cyclists and mountain bikers. However, working on your core just with very small and precise rehabilitative movements to target a small muscle group in isolation, or just stretching your hip and hamstrings might not be enough to remedy the problem. The key is to look at the body as a whole. A general all over mobility routine, multi-joint, muscle groups functional type exercises and sport specific fitness and conditioning are the solutions here. Our body (especially lower back) loves the movement. Gymnastics strength and conditioning can be of a great value here. But I’m going to leave this topic for another article.

3) Back Pack

Photo Credit: Trevor Worsey via enduro-mtb.com

Going out for a long day ride to very isolated areas often requires carrying a bunch of essentials such as bike repair kits, sufficient food, hydration, additional clothing, first aid or even an Emergency Shelter. These all can add up to a backpack often weighing in excess of 10 kg.

When you ride, the position of a backpack places most of the load through your mid-back (thoracic spine). It makes the lumbar segment act as a suspension between the pelvis, hips, and the mentioned heavily loaded thoracic spine. The lower back in this scenario has to do incredibly hard work to maintain its own neutral position. The structures of the surrounding soft tissue like tendons, ligaments and muscles will eventually become overloaded and will result in back pain.


Rethinking your backpack strategy can help. Backpacks with hip/waist pockets, small saddle bag for your spares and tools, road style tops with back pockets, transferring some water to bottle cages… all these and other strategies can help spread the load and reduce the load off your back.


4) Climbing Technique

Photo Credit: Schpytzyo / mountainbike.nl

Yes, I know. Staying seated in the saddle when climbing is much more efficient. But, it also additionally increases strain on your lower back. Add a heavy bag to your climbs and the numbers go up even higher. Remember that you are probably not a professional racer. Even on flat rides, get into the habit of standing out of the saddle regularly to stretch your back. Regular standing can help your back since the spine will be in a more neutral position.

In the beginning, I mentioned that with increasing cycling power, the forces in the muscles that span the hip region increase and lead to higher spinal forces. This also means that reducing pedal forces by keeping a slightly easier gear and therefore pedalling at higher cadence can further help alleviate problems in the lower back.



Although the lower back pain in mountain biking and generally in cycling is a quite common thing, don’t accept it as the norm. Try to fix your relationship somehow. Many times back problems take longer to resolve than expected and may be complicated by a number of different factors, but in most cases they are fixable. If fixing your existing marriage does not work, you might have to get divorced and start a new relationship. But hey, You will have a new bike :)

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