Legs feeling tired for the past 10 days, even though I'm not sick, good nutrition, and good sleep ?

I realize re-reading my post that the timeline is a bit weird how I explained it so here's how it went starting from 3x days a week, and average 20-25mpw :

Week 1 : 27mpw - Feeling great

Week 2 : 32 - Feeling great

Week 3 : 35 - Feeling great

Week 4 : 37 - Feeling great

Week 5 : 42 - Feeling wonderful

Week 6 : 35 - Feeling great

Week 7 -35 - Feeling great

Week 8 - 40 - Feeling great

Week 9 - 35 - Feeling off

Week 10 - 30 - Feeling off

Hey friend! I think I may have an answer for you. This isn't problematic unless you're experiencing any sort of injury symptoms. What you're likely suffering from is an often overlooked aspect of physiology known as "muscular tension".

Muscular tension has to do with the reactivity of your muscles. By running a lot of easy/tempo mileage, your muscles tend to lose their reactivity. A remedy for this is max speed development, aka sprinting.

All distance runners need to develop their ability to sprint, not just for the final kick, but because poor max speed will limit your speeds in longer events as well. But to the point: an additional benefit of sprinting is the ability to increase the reactivity of muscles.

Here's what I'd recommend you do: find a moderate incline hill, maybe 50-80 meters long. Sprint for 8 seconds up the hill, then walk down & take two minutes rest. Repeat this for a total of 6 bouts of sprinting.

I would suggest doing this at the start of the run, as your nervous system is most responsive when you're not in a fatigued state. Perform this twice weekly & you'll feel much better in no time.

Best of luck to you!

Happened to me early on, almost same mileage progression as you. Took 4-5 days completely off and came back feeling great and running even stronger. It could just be accumulated fatigue of ramping up for the first time as a newbie.

It takes a lot longer than people think to sustainably build mileage. You can only add 5-10mpw per month. Probably more like 5mpw each month, if low mileage like OP. It takes years to really build it up in a way that is sustainable and allows you to still do hard workouts without feeling super tired. Also make sure to get pace variation in - alternate easy pace one day, recovery pace the next day. Do one fast workout per week - tempo or 10-12 strides, but that's all. The pace variation helps so that you aren't overworking one energy system every day as you build. Let your easy pace slow down a bit as you build, it will come back (and faster) once you hit the peak volume of your build. Good luck.

I never understood the 10% rule.

A newbie hobbyjogger doing 15mpw at 10-11min/mile can "safely" ramp up to 50mpw in 13 weeks?? This is why so many new runners get injured or burned out from being tired af all the time.

Once a newbie can comfortably do 5x3miles each week, I think adding 1 mile/week (or about 4-5 miles/month) sounds about right. That means they would go from 15 to approximately 65 in a year in a very slow, controlled manner. Intuitively and from years of experience that seems about right.

Of this rule may not apply to genetic freaks, people who are already fit from other sports, very slim people, etc.

Yeah, the 10% rule is not good.

Honestly, I think adding 5-10mpw per month is good. Every month, add in 5-10 miles. First week is easy. Second week you are starting to adjust. 3rd week you are finishing adjusting. 4th week you are feeling like you didn't even add any mileage, and you are eager for more. Then repeat. You really have to listen to your body. Mileage limits change as you get older. I struggled to run 45mpw at one time, right now I'm at 60 and it feels easier than 45 did in those days. Good diet, rest, plenty of protein, watching your iron levels is key. And - strength training. The higher your mileage, the more your imbalances and weaknesses will emerge, so you need to stay on to of strength, unless you are a freak like Bill Rodgers who could run 170mpw with no cross training and never got injured. There's a big ego side to building mileage, everyone wants to build to high mileage, but sustaining it is harder. Easy to go out and run 100mpw if you are doing 60mpw, but only for 1 week. It's sustaining the higher volume with quality workouts that's hard. Building mileage is fun because it's an easy breakthrough you can hit every week, but it's a short term thinker's game..

The 10% rule is fine for some people. Everyone's different though.

Way better to actually listen to your body than to decide in advance about some kind of pre-set rate of increase and disregard any form of feedback that your body is giving you. This is why I'm not keen on plans set out that far in advance. You need to see how your body responds to it and how you feel before you make decisions that far out!

OP, why don't you just take some time off and see how you feel? You're saying you went from 3x per week/20 mpw to some weeks 7 days per week/42 mpw. Obviously that's a fairly big increase %-wise. If you feel this tired just take some time off. I don't mean decreasing to 30mpw, I mean taking proper time off for a bit. Having said that, when you train you do feel tired, but there's a difference between the good kind of tiredness (that you do mention) and the kind when you know something is off. It sounds like you think that this is the latter.

dude u need to take like 3 weeks off and retry building the mileage back up way slower. have a professional write u a 16 week plan or something.

100% this. It takes way longer to build mileage than you think. The fatigue accumulates over time. Be patient.

Have you tested for syphilis?