Bicycle Tutor

My feet start to go numb about 45 min's into a ride. What could be the problem and how can I correct it?

It could be a number of things. If you stopped for a minute, would the numbness go away?

Remember you use your feet differently on the bike than in walking or running. A lot more to guess would be on how the numbness happens.

Some things to think on:
1. What kind of shoes do you use? Improper support will cause problems.
2. How do you put your feet on the pedals?
3. What kind of posture do you have on the bike? Numbness can occur when some nerves in the legs are pinched. You might try checking your seat height and handlebar height.

But truthfully, all we can do is guess on this, without actually watching you on the bike.

Yea, the numbness goes away after I'm off the bike a few mins. and get some blood flow going.

The shoes feel okay and I use speedplay pedals, so I do have some side to side movement.

Could be my saddle.

Hi, I'm a physical therapist and have knowledge in the area of nerve dysfunction. What you describe is likely caused by transient ischemia (fancy term for temporary lack of blood flow) of the nerve. The first place to start would be foot position over the pedals. I would try a slight shift of your foot forward on the pedal or a slight shift in or out, but only one adjustment at a time. If this doesn't help, or causes other problems in the foot/hip/knee/low back, then the next thing would be to consider semi-custom insoles in your shoes to improve support and foot position. Many good bike shops will have these.

If you have recently purchased new shoes, they might be too snug, causing a compression of the interdigital nerves of the foot., but your comments make this sound unlikely.

There is the possibility this could be related to your low back, but that wouldn't be my first thought. You would have other symptoms as well, such as back pain, posterior hip pain, radiating/burning pain down the leg. These symptoms would also likely be aggravated doing other daily activities, beside riding.

Let me know if you have any other questions.

Mike

I have a similar problem but it seems related to blood flow in my feet, as making sure I keep my toes moving helps. Having said that, I do have a disc in my back that causes some of the symptoms that apilopo talks about (I'm a tall male in my mid-40s, don't we all have bad backs?).

I was wondering, in case it's my shoes, where in the foot are the "interdigital" nerves. Are they along the top? If there is anywhere my shoes may be causing a problem, it is there.

The interdigital nerves are between your metatarsals. Which brings the next obvious question, "What are the metatarsals?" If you begin from the tips of your toes and travel toward the ankle, the toes will end and the metarsals will begin. There are 5 of them (one for each toe). They are analogous to the bones in the palm of your hand.

In the space between metatarsals run the interdigital nerves. So they are not really on top or on bottom.
One of the problems, of course, with clipless pedals is that they have a small surface area. So the rider is putting all their force through one small area of the foot. This leads to excessive pressure and decreased blood flow. A good shoe and insole will help to distribute the pressure evenly across the width of the forefoot, rather than concentrating the pressure in one small area.

As stated previously, if the shoes are too tight, then you will be getting compression from the sides as well as from the bottom, compounding the problem.

Your cleat position will also have an effect. I am playing with this right now, as I have some new SPD shoes/cleats/pedals. 30 minutes and all of my toes were numb. I moved the cleat and will try it later today to see how it goes. This is were experimentation is needed.

Mike

Thanks Mike, I'll try adjusting my cleats and see if that works.

FYI, I rode 45 minutes yesterday after moving my cleats around and had almost no numbness. A little more of a tweak and I hope to be all set.

Mike

Since we have a physical therapist in the house, I thought I might ask this question along the same general line as the original post. What about a numb arm while on the bike, along with some shoulder pain on the back? Could anything be done to address that?

Skyguy - The shoulder and back pain sounds like the handlebars are too narrow. I have the same problem on one of my bikes that is meant for someone shorter than me(6'1). I'm assuming the numbness in your arm is probably related.

Skyguy,
Where is the numbness, specifically? The whole arm? Just a portion? If it is in the hand, which fingers are affected? Is the shoulder pain really in the shoulder or is more in the shoulder blade? Specifics help.

The great thing about the human body is that certain principles apply everywhere. Skeletal muscle is skeletal muscle, whether it is in the the foot or the head. Bone is bone, whether it is the humerus or the tibia. With that said, numbness happens because of nerve damage. It can be caused by direct compression, reduced blood flow, excessive vibration, or laceration (believe me, you don't want a lacerated nerve; sucks hard!).

Regarding biking, the most likely culprits are direct compression and/or vibration. The most common nerve compressions are of the ulnar nerve at the wrist (numbness in the pinkie and ring finger) the pudendal nerve (numbness of the special parts) and the interdigital/intermetatarsal nerves (described above). Vibration contributes/exacerbates the problem.

I am not a bike fitting expert, but there are a few things I can say for certain. 1) all humans are built differently. Therefore, what works for most people may not work for you. However, starting with some of the "rules of thumb" is a good place to start. A good bike set up is worth the money. 2) even with a well set up bike, frequent changes of hand position is important. Getting out of the saddle every 10-15 minutes is also important.

If you have a job that involves a lot of repetitive use of the hands (typing, using a screw gun, writing) or vibration (construction, manufacturing) you are probably set up to have numbness while biking. Imagine 2 cups. One is half full and the other is 90% full. An overflowing cup = numbness. The 90% full cup is like the person who works doing data entry or on a line manufacturing parts. Add just a little more water and the cup overflows. If your cup is only half full, it takes a lot more water to cause the cup to overflow. The amount of hands-on work I do with people causes me to have a baseline level of nerve irritation (my cup is 90% full). I have to change hand position a lot and I should probably look at my set up and tweak it.

Mike

Quote:Where is the numbness, specifically? The whole arm? Just a portion? If it is in the hand, which fingers are affected? Is the shoulder pain really in the shoulder or is more in the shoulder blade? Specifics help.

It hasn't happened in a little while, but usually it's enough numbness when it does happen that I can't keep a good grip on the handlebar. My biggest problem though is soreness in the shoulder between the spine and the shoulder blade. I think it's probably related more to other things.

But most of what I have done for fitting my bike has been things that I've figured out over time with pain happening during rides and whatever. Much of my leg problems I had went away when I got the seat high enough so my legs could spin freely without any pressure (the seat works its way down when I ride, but that's more a technical issue).

Of course, the problem in that came that my seat is now about 2" higher than the handlebars (I have them raised to maximum height). As a result, I can't really reach them comfortably without either locking my elbows hard (causing pain) or bending my elbows and feeling like laying over the handlebars (which I've found no troubles with in certain instances - I have a set of bars that stick out from the handlebar and grab, doing that when I take hills or don't have to turn/brake). Of course, sometimes I grab the handlebars with the ends of my fingers to try and gain a little bit of comfort.

I know much of this is my fitness level - I started from a pretty bad place on average in biking. But much of it too, I'm sure, is not getting a proper form and fit for the bike when I ride it.

There's always some progress somewhere, though, and I'm thankful for the progress I have seen. Thanks for your thoughts.

I'm guessing the shoulder blade pain begins as a dull ache but can progress to a burning pain if you don't do something about it? It might also happen when sitting with poor posture or when on the computer for a long period. This is fairly typical muscle overuse pain. Luckily it has a relatively easy solution. Remove stress from the painful muscle. Typically, strengthening of some upper back muscles, stretching of the pecs, and a little better postural awareness will do it.

Try this: lay on your stomach with your forehead supported on one forearm. Place the other arm overhead, about 45 degrees away from your head (if you had both arms in this position, you would look like the letter "Y" when viewed from above).

From here, lift the arm straight toward the ceiling, about 3-5 inches. You should feel your shoulder blade glide down and in toward the spine.

Hold 5 seconds and repeat for 2-3 sets of 10. It is good for upper back strengthening and pec stretching.
Mike