What's your hip angle at the top of your pedal stroke?

[Slowman]

I have been given the go ahead to do a bit of light cycling but I have some fairly stringent rules I must obey for the first 6 months so as not to jeopardise my recovery.
1. I can not bend more than 90 degrees at the hip
2. I can not rotate my femur inwards or outwards
3. I can not lift more than 10kg

Rules 2 and 3 above aren't really a risk but 1 could be. I won't be going anywhere near a road bike but I was planning to ride my old hard tail around to keep myself as upright as possible but I am assuming the lower body position on the road bike over an MTB means the pelvis rotates forward and therefore would increase hip flexion angle and possibly risk exceeding 90 degrees. However if you keep the pelvis upright and and bend at the spine it is not so much of a problem but I've never looked into that aspect of my position I just started with the rules of thumb and refined to what I found comfortable and powerful.

Anyone that knows the anatomical nuts and bolts of this have any advice? What is the maximum flexion angle at top of the pedal stroke on a hard tail set up for XC/trail? Anyone know?

 

[spudatm]

Where abouts are you based? i can't answer your questions but i recomend booking an appointment with the
body mechanic
http://www.thebodymechanic.com.au/
I got him to set me up on both my bikes after some injury issues were preventing me from
riding and he was great

 

[akashra]

Personally I would be suggesting you see a professional fitter to see what can be done to accomodate these. There's little point us recommending anyone until we know where you're located. Asking for medical or phyio advice on an online forum is an all-round bad idea.

I would have thought the last one would be the biggest problem, since it's not uncommon for riders to push more than 250kg-f (which is chain-breaking territory for SRAM chains).

 

[Slowman]

Thanks for the suggestions of a professional bike fitters but I do not need such services, so my location does not matter really - but it's God's country

While the question relates to bike fit I just need to know the max hip angle at top dead centre of a typical XC set up. I can take the rest from there. I can work out the stem length, bar rise and sweep angles I'll need if I need to change those things to avoid exceeding my max hip flexion limit.

I just don't feel like paying $200+ just to answer a simple question really. As soon as I'm able I will simply throw my leg over my hard tail and measure the angle myself and make the necessary adjustments from there. This limit is only an artificial limit imposed by the surgeon to reduce any risk of dislocation as I have had my hip resurfaced which means the join capsule has been opened and currently not at full strength until it heals completely. At 6 weeks bone ingrowth into the metal surfaces will have occurred but it is not until 6 months bone ingrowth strength has consolidate enough to allow running, jumping and a return to more extreme activity. So in the meantime these restrictions are in place as a safety measure. My bike fit is fine and at that time I will return to my bikes unaltered, I have pretty much been riding the same position for 30 years with some tweaks along the way as I have aged and even at times developed my strength and flexibility.

Since I weigh 90kg lifting 10kg would give me a combined weight of 100kg, that is the figure my surgeon does not want to exceed on the new joint. I think riding a few bike flat bike paths at a toodling pace I have nothing to worry about. I just want to be able to ride as it is good for my mental health as well as my physical health and it certainly helps recovery.

I guess I should have simply asked what people's hip angles are at top dead centre of their pedal strokes and I've simple confused the issue my mentioning recovery and injury. So, if people wouldn't mind, please throw you leg over and tell me, what's yours?

 

[offthepace]

Have a site I came across one day, bookmarked but not got round to reading further. Hopefully something helpfull.

 

[spudatm]

"I do not need such services, so my location does not matter really - but it's God's country"

Your dead?

 

[Slowman]

...

Your dead?

Time off the bike and out of the water feels like it!

 

[Slowman]

Have a site I came across one day, bookmarked but not got round to reading further. Hopefully something helpfull.

Thanks for that it has a video analysis with marked points and lines showing the angles. Looks like the most acute angle at TDC is roughly 70 degrees ...looks like I'm going to have buy a set of super high rise bars!

 

[longxc]

Thanks for that it has a video analysis with marked points and lines showing the angles. Looks like the most acute angle at TDC is roughly 70 degrees ...looks like I'm going to have buy a set of super high rise bars!

Looking at that video the setup on that bike appears to have a significant amount bar drop compared to the saddle, looks more setup for xc racing.
Another thing to consider that effects hip angle is your height and crank length...for example a 6' rider using 175mm cranks will have a shallower angle(knee will be lower at TDC) at TDC compared to a shorter rider, this is the same with shorter cranks(reduced height that the knee will be at when at TDC).

 

[64ponty]

Why not get on your bike and take a few pics at different crank positions and adjust components as required?

 

[Slowman]

Looking at that video the setup on that bike appears to have a significant amount bar drop compared to the saddle, looks more setup for xc racing.
Another thing to consider that effects hip angle is your height and crank length...for example a 6' rider using 175mm cranks will have a shallower angle(knee will be lower at TDC) at TDC compared to a shorter rider, this is the same with shorter cranks(reduced height that the knee will be at when at TDC).

Yep that's me a 6' rider with 175mm cranks. Ha ha my surgeon said to me to raise my seatpost, it is already at 780mm height from my BB on the road bike and 770mm on the XC bike. Yes because I ride road I tend to have a low XC racing position I try to keep the positions roughly similar allowing for some trade offs for better control and handling etc.

For me the changes will have to be to get me more upright (if required which I suspect is likely) by a combination of, moving the saddle forward, shortening the stem and getting a higher rise in the bars and perhaps more sweep.

 

[bri]

For me the changes will have to be to get me more upright (if required which I suspect is likely) by a combination of, moving the saddle forward, shortening the stem and getting a higher rise in the bars and perhaps more sweep.

Changing the relative position of your hip to the crank centre could produce some problems. If you need to get more upright by shortening and changing stems is not going to work you will need to get a smaller frame with a shorter top tube length (obviously longer seatpost to accommodate the height issue).

It seems to me a pro fit won't cost you $200. And besides, isn't it worth spending a few bucks to prevent causing/aggravating an injury?