Knees going weak

[dabac]

Hi guys,

I have some issues with my knees due to old overexertion injuries. To try to improve things I've switched to shorter cranks (from 175 to 170), and just about gotten religious about keeping the cadence up.
I take my stretching exercises pretty seriously too.
This seemed to improve things for maybe about a year, but these last weeks I've begun to feel as if the knees are losing strength.
And it's really in the knees, the actual joint, not the muscles. Not exactly painful, more like the soreness you get from working out a little too hard.

Any suggestions?
Time to schedule a MRI?
Chalk it up to ageing?
Stock up on the anti-inflammatory or sell of the bikes?
Any special keywords to mention to the doc?
Training hints/routines that might help?

Cheers,

 

[jhuskey]

It never hurt to seek a professional opinion and some times they can help, unfortunately age does tend to increase the risk of arthritis and that nagging dull pain or pressure you feel under the knee caps.The Meniscus gets irritated or is simply wearing out.
I find that a hot tub also helps. Consider that cycling is much easier on the knees than running or maybe tennis or handball and you can always back off the routine just a little.

 

[dabac]

...that nagging dull pain or pressure you feel under the knee caps.

That's pretty close too.

....The Meniscus gets irritated or is simply wearing out.

I messed mine up well and proper several years ago. In my theory it's that old issue that keeps on raising its ugly head.

...Consider that cycling is much easier on the knees than running..

Less impact, sure. But when running on the flat the knees don't have to take much strain when bent, something which is pretty much unavoidable when riding a bike.

.....and you can always back off the routine just a little.

What? noo...

The thing that got me wondering this time is that riding with the long cranks and lower cadences I felt strong, but got very sore and tender after riding. Shorter cranks and higher cadences has me feeling kinda powerless while riding, but less soreness after.
It'd be interesting to know if this is a consequence of the change in riding, or merely because that's where the state of my knees are at this point in life.
If it was due to the unintentional change in training that the change in riding has brought about, then maybe there's something I can add/adapt in my programme to improve thjings again.

 

[Serious Chris]

Higher cadence is always better for avoiding knee stress, as well as other reasons, so if switching to a shorter crank has you feeling pain free; I say keep with it. The whole feeling less/more powerful tends to be a placebo effect so I wouldn't read into it very much. Besides, how powerful do you feel when your knees keep you from riding the bike?

 

[davereo]

Hi guys,

I have some issues with my knees due to old overexertion injuries. To try to improve things I've switched to shorter cranks (from 175 to 170), and just about gotten religious about keeping the cadence up.
I take my stretching exercises pretty seriously too.
This seemed to improve things for maybe about a year, but these last weeks I've begun to feel as if the knees are losing strength.
And it's really in the knees, the actual joint, not the muscles. Not exactly painful, more like the soreness you get from working out a little too hard.

Any suggestions?
Time to schedule a MRI?
Chalk it up to ageing?
Stock up on the anti-inflammatory or sell of the bikes?
Any special keywords to mention to the doc?
Training hints/routines that might help?

Cheers,

How often are you riding? Over use could also be an issue. All the questions you have should be raised with your doctor.

 

[frenchyge]

The thing that got me wondering this time is that riding with the long cranks and lower cadences I felt strong, but got very sore and tender after riding. Shorter cranks and higher cadences has me feeling kinda powerless while riding, but less soreness after.

For the same power output, a higher cadence means lower torque and less force on the knees. Higher cadences can be used with either longer or shorter cranks. 10% higher cadence means 10% lower force on the knees. Ok.

Shorter cranks reduce the leverage on the crank arm, which means that *more* force would be required in order to supply given torque. Not necessarily better for the knees, since force is higher. Using 170mm cranks requires 3% more force be applied by the leg as compared to 175mm cranks.

Shorter cranks put the pedal lower at the top of the stroke, and the knee is flexed slightly less at that point. If the seat were raised by 5mm when you switched cranks (to keep the same distance to the bottom of the circle), then your foot relative to the seat will be 10mm lower at the top of the circle, which should be better for the knee by keeping the leg straighter.

Not that it matters *why* your knees feel better, but shorter cranks both work for and against that result, while raising cadence is all good.

 

[lanierb]

Any suggestions?

I would suggest two things:
(1) See a really good professional fitter to make sure your bike fit is good. Ask around before you go anywhere. (I can recommend someone near Boston if that works for you and yes it's even worth flying in.) It's expensive (usually a few hundred dollars) but it's worth more than a good bike IMO.
(2) See a doctor.
There are lots of different types of knee trouble that can result from lots of different things and there's pretty much no way we're going to be able to help. Most of us couldn't help much even if you were standing in front of us, let alone over the internet.