bfloyd

This is going to sound very strange and I will try my best to describe this in words: I have been experience knee pain located at the back inside corner of both knees. I seen my sports doctor and she diagnosed me with bi-lateral hamstring tendinitis, did the pt stuff, tried lowering saddle, raising saddle, saddle fore / aft, all the while nothing helped. Keep in mind this is on my only bike at the time, a road bike.

Now, I recently just aquired a mountain bike. Probably not best to try a new bike until my pain problem was fixed but I did anyway just the same. When I went for my first ride on the mtb, I was riding pain free! I was so relieved. So, I start to compare the two bikes to find what it is about the mtb that causes no pain. I first notice that the seat tubes are at different angles (lining them up next to each other) although the mfg. sites claim them both to be 73 degrees, and of course the head tubes are different with the mtb at 71 degree and the road bike at 73.5 degrees.

What I found is this; I am using the same saddle on both bikes (WTB Laser V) and noticed that I sit further forward on the saddle on the mtb which is because my body has been used the road bike's steeper seat tube. When I tried to sit further back in the saddle on the mtb, as I do on the road bike, the pain returns. It seems that when I sit in the "scooped" out portion of the saddle (not to be confused with a cut-out saddle with the hole, but scooped as if looking at the saddle from the side) I was fine but when I scooted back on the saddle, sitting more on the portion that raises back up on the back of the saddle, the pain is back. So, I tried to match the same saddle position on the road bike in which I had to slide the saddle all the way back on its rails and sit in the scooped area of the saddle . . . no pain.

So my question is, is there a relation in a certain part of the butt that is linked to the hamstrings at the knee area that could be causing this pain? Perhaps I was straining without realizing when sitting on the back portion of the saddle? Perhaps a flat saddle with no scoop may be better? Though I'm glad I relieved the pain I am still curious as to why . . . Sorry for the long pst and thanks for reading.

cyclezen

interesting, but hard to really define without being there.
another consideration is your hip and torso angle, as defined by the bar reach and height relative to saddle height. changing any of that changes how your pelvis is rotated and what 'parts' are makin contact. course even v-small changes in saddle height will also change those relationships.

Sliding forward of course, causes more weight to be carried by the junk in the middle, as opposed to it all being carried by the sitbones. COurse you don;t really say how far you're moving forward and whether your weight is still (or is ever...) being carried by the sitbones contact patch, or some other parts instead.
it is possible to 'catch' some nerves under the sitbones and have those become irritated, often causing pain down through the upper leg, hamstrings and back of knee(been there on that).
But in my case it was obvious that the damage orginated at the sitbones and just 'extended' down through the legs.
Angle of the seat can have an effect.
maybe experiment with other saddles which might allow a good contact patch for the sitbones without causing the 'irritation'

al least you're onto things which seem to be rooted in the problem. keep workin at it

bfloyd

Thanks. In relation to how I am sitting; the way before when I have the pain, I was sitting more on the butt because I had no pressure on the crotch area as I was sitting on the rear portion of the saddle and the scoop was in front of my crotch. The way I find to sit with no pain is more on the crotch as I feel more pressure there. I feel more pressure on the crotch area because the shape of the saddle has the nose coming back up from the scooped out portion. Of course this coming back upward of the saddle's nose comes up into my crotch area.

I am going to look for a flat saddle and try that . . . maybe easier on the soft area.

Machka 

Yes. The muscle is called the Gracilis. It goes sort of generally from up in the sitbone area down roughly to the knee area.

https://www.rad.washington.edu/atlas2/gracilis.html


Have you also had a look over this page:
https://www.cptips.com/knee.htm

DannoXYZ 

Hmm, there are two variables you're changing here. By sliding forward on the seat, you're reducing the saddle-height AND changing the angle between the hips, knee and pedals. I suspect that it's not saddle-height that's removes the knee pain as you've adjusted that up and down before. So it has to be the fore-aft adjustment of your riding position.

What if you slide the saddle forward so that you are in the same no-knee-pain position, will your crotch be more comfortable with the sit bones on the padding of the saddle?

Otherwise, I suspect somehow your pedal-stroke or some body-positioning is being changed by sitting on the back of the saddle.

bfloyd

Thanks Machka. It looks like the Grac is exactly where the pain is because I get the pain mostly on the inside of the knee where it begins to wrap around and also at times exactly where the Grac ends (as per the photo in the link).

DannoXYZ - Thanks and I did try sliding the saddle forward and sitting more on the cushioned seat area but I still got the same pain once I sat on that rearward portion of the seat. I am still thinking of trying a flat saddle to get off my crotch area.