How bad will it be running after 3-4 weeks off?

Don't stress from 3-4 weeks. You've done other things to remain active. I recently had a hamstring strain and was off for ~3 weeks. My first track workout back was faster and easier than pre-injury. Often, slightly prolonged breaks allow for fuller recovery of the energy systems that we tax so much and often. There is some literature on such breaks helping with output from the faster end of the fast-twitch muscle fiber population.

OP, I had to take 6 weeks off earlier this year (spring) due to a stress fracture, and also did a lot of swimming and elliptical/biking while out of commission. The act of running wasn't that difficult upon returning, but my body was sore as hell for about a week. I am older, though (37). If you are younger, you might pop right back into it without much trouble.

I also came back hot with my first run being a 7 miler at 6:45 pace. I met a friend to run and just acted natural. The run itself was no problem, but I couldn't walk down the stairs the next morning. Same feeling you might get after racing a marathon. Took one day off midway through the week due to the soreness (swam and did elliptical instead), but after about a week things were back to normal.

You won't be sharp or at your best, but that is fine. Just be glad you stayed active and fit during the time off.

How long until I'm able to work back up to my normal mileage? Within a week or two, or will it take longer than that?

Oh my God... you have a hamstring strange and you are Pool running!!! That is literally the worst thing you can do as well as biking.

Don't worry because I didn't know this either :) I had a hamstring strain and because I didn't realise it was the pool running, biking and elliptical that was preventing my injury from healing and making it worse, I ended up tearing my tendon (grade 2) at the attachment to the bone. It has taken me 7 months so far and I am still in a minor discomfort. But I can run very easy. Before this I was running 65 miles a week average.

So how I treated mine from unbearable pain to what now is a little uncomfortable is NOTHING that creates a dragging sensation OR the motion of running. For example you are using you hammy to pull a pedal, pull you through the water or pull the elliptical/ x-trainer round. Stop that because it will only aggravate it further.

ICE has been the only thing that has saved me! A bag of crushed ice works wonders. DRY NEEDLING is something I have found very useful as well as sports massage, foam rolling, and cross friction massage/ trigger point with the foam roller.

3 weeks really is not a long time to have out for a hammy, you would have lost barely any fitness at all trust me. For cross training I found that pull buoy swimming helped me massively as to not use your legs but still get your HR up. After all my time off I returned to running shortly and of course, I felt a little less fit but not half as much as I was expecting :)

Don't panic- there are ways around it if you really want it. I thought mine would never go and I proved everyone wrong! Good luck

G

^^^^

Not bad at all

OP Can you walk fine? Up hills or stairs? I went through the high hamstring issues which usually take much longer to get rid of and walking long distances and backwards walking on the treadmill with inclines helped give me exercise time. You can really get into some pretty good efforts on the treadmill on inclines and it all probably helped with muscle imbalances.

Eliptical works too. Recumbent bike machine is better than upright.

What kind of hamstring strain did you have?

My PT told me that I'd be okay to cross train doing whatever didn't hurt, and pool running doesn't hurt. I have a high hamstring strain, right near my glutes.

How was your return to running? Did you come back after 4 weeks? Yes I am bumping this thread 3 years later. I have a high hamstring strain right now.