I have a muscle issue that has been affecting me for a while (15+ years). As I get older it seems like it's getting worse.

If I ride at an easy pace, I'm OK for relatively long rides (30-50 miles). If I use my muscles with anger - hard efforts, climbing, sprints - my muscles start to lose power quickly. After a short while - minutes sometimes - I get to where I can't do any more efforts at all and on one long ride (70) I had to stop and rest for 15 minutes before I could continue.

I am 50 now and it seems like it gets worse every year.

I also get cramps fairly easily and have to monitor my electrolytes closely, but no amount of mineral eases the power problem.
I also get 'micro cramps' called Fasciculation which don't really hurt but are very odd.

I have larger muscle mass than most cyclists and obviously have lots of fast twitch. I don't lose sprints (amateur .

I have been to the sports doc and got all the tests and they say "you're fine". Part of the doc's take I feel is that I'm older, I don't have any real competitive future and I should just be OK with being healthy. I get it.
But still, I like to race and do OK at least. I like to go on longer rides with friends and not have to have them wait for me. It's a 1st world problem but would love to see if there's a supplement or ______? that I could take that would get me back to something normal.

thanks

What, how much, and when do you eat before, during, and after a bike ride? What is your normal diet? What's your guess at the distribution of the 3 macros: protein, carbs, and fat?

I assume you've read the wiki on Fasciculation and have, working with your doctor, eliminated all but the benign causes, including CPT2.

Depending the answer to those questions, it could still be a training problem. This has nothing to do with age, believe me. That's BS from someone who's not worked with older athletes. I'm 71 and still ride double centuries, etc. at a good pace.

I'll make a couple recommendations.

If you aren't riding at least 100 miles/week try increasing your volume. I find that 150 miles/week is a good number for reliable cycling performance.

Do strength training if you don't already. Read this thread: https://www.bikeforums.net/training-n...e-athlete.html

Do first ventilation threshold (VT1) training. This is easier to do and very effective. It's best if you have a trainer or rollers or access to a lot of flat road with no stops. On a geared road bike, warm up gradually and then add power until you start to breathe deep and fast. Then back off until the fast breathing ceases and you are only breathing deeply and at a rate which allows you to easily recite the alphabet in one out-breath.

Play around with this, gradually increasing effort until faster breathing starts and then backing off until it eases back to the alphabet ("conversational") pace. You'll find that the pace (VT1) just below faster breathing is very distinct. If you have a heart rate monitor or power meter, note that HR and/or power. That number will be fairly consistent at the VT1 pace.

Once you have your VT1 figured out, ride for at least an hour at that steady pace, trying really hard not to go over it. Don't eat during that period. If you start to feel light-headed like you need to eat, or if your HR increases or power or speed decreases at that VT1 pace during the hour, you need a lot more training at that level. If you can hold that pace for over an hour without changes to your HR, speed, or power, that's not the problem! If you can't, train at that level for at least 3 hours/week for 2-3 months. If you can hold it easily, on to the next idea:

Start doing zone 5 intervals once or twice a week. If you're racing or doing group rides on the weekend, then only once/week. Find a long relatively steady hill and, after warming up, climb at a zone 5 pace* for 8 minutes. If you can't hold 8 minutes, then for as long as you can hold it. You should do 3-4 repeats of the same duration, but watch how high you climb each time. When you can't climb as high as you did the last time, quit and go home at an endurance (VT1) pace.

*Zone 5 pace is above VT2, about the same as lactate threshold or FTP. To find your second ventilation threshold (VT2), on a long climb gradually increase your pace through deep breathing, through deep, fast breathing, through really fast deep breathing, until all you can do is pant. When you start to pant, that's above VT2 and just where you want to be for these intervals.

And no matter how the rest of it goes, the zone 5 training is always a good idea. For most folks it eliminates cramping on long hard rides.

I did notice that you asked about supplements. One of my standard sayings is "Supplements are a feather. Training is the hammer." Not to say they don't work. Your reply to the diet question might shed light on whether and what supplements might help.

This past summer, my first summer cycling, I had steadily increased volume and intensity and felt I peaked in July. Then it seemed everything got harder and my legs always felt fatigued. I was riding 3-5 days a week and never took off from riding more than 3 days in a row. In Nov. I took a 24 hr urine test to check my amino's and I was very low on over half of the essentials. I was also very low on magnesium. I took a week off the bike, and started supplementing my protein macro % with a protein powder, once a day when off the bike and twice on a ride day. I have since done very little on road training but lots on the rollers and my recovery feels better. In the spring I will do another test. Hopefully I didn't damage myself from August through October and lose any gains made. Looks like protein% might need to be higher for endurance athletes than some might suggest.

Could it be as simple as that you're not conditioned for sustained effort above a low threshold?

Consider altering your training and mixing in more medium/high effort for longer intervals. Or look for some long shallow hills to climb.

Runners are divided into three classes, sprinters, milers, and marathoners. None can do very well in classes other than their own, so no reason cyclists should be any different.

Find yourself a coach in your cycling group, and train with the specific goal of raising your range at speed.

Yes, that's also my experience, especially for older athletes. For some idiotic reason, protein "requirements" are expressed as minimums. Like sure, oh yeah, I want to make sure I get only the minimum of the most important nutrients. So many people think that the minimum requirements are the maximum they should get, lest their liver go south or some such silliness.

Are the symptoms all over, or in isolated spots?

Did your doctor actually say you're fine, as in "there's nothing wrong with you at all"?

Or did he actually say, "I've checked out your symptoms and good news- you don't have ALS or some other fatal, progressive neuromuscular disease. I have no treatment to offer you, this is just something you have to live with by avoiding the precipitating activities"?

Do you actually race in formal bike races? Or is your desire to be able to chase down stop signs with your friends?

Some people are pure sprinters and can't realistically perform well at endurance events. Maybe you're one of those types who'd shine at the track doing 3 min long races.

Are you a vegan ??...Being low in essential amino acids and other important nutrients is very common in people who follow strict vegan diets...It's very difficult to be an athlete on a vegan diet, very few people can do it successfully.

thanks for the replies all

Just to clarify and respond to some:
I am a sprinter so yes, I shouldn't necessarily be "good" at a distance race or ride. I live in Boulder and have been on the usual program of long rides up canyons since I moved here (age 37). Even though I've never been much of a performer (my bike-racer wife would have to wait for me at the top usually), I have noticed that the issues with me doing long stuff and climbing simply gets worse and worse every year - to the point of it being painful - literally and figuratively.

I have been in the gym more in the last few years in order to get better at track racing but I still like to do crits on occasion. Last crit I did in 2016, I couldn't finish - very frustrating. My muscles are getting bigger and stronger and this fact could be contributing, maybe. I get the sensation that when I go for a 1,500+ watt effort that my muscles comply but then say "ok, done".

As far as the doctor goes, we did around 30 blood tests and a pee test. All came back nominal for anything 'wrong'. I'm willing to bet that if I had a million $ to throw at him and find the cause, we'd turn up something in my muscles or Krebs cycle or ??? that points to the problem. Here's the dilemma right? - what value is it for a penta-genarian to get to the root of something that is obviously a unique and 'personal' problem in order for that old guy to be able to finish a crit? Not much truthfully, but still!

Thanks again for the input.