This one's for the joggers! First, star out with a really big merino sweater (I believe mine was a mens XL, and I wear a medium in workout pants, and a 10 in jeans), and lightly felt it, so that it's still stretchy, but won't unravel when you cut. Now, make the shorts in this tutorial, making the back end pieces slightly bigger than the front pieces if you are using compression shorts as your pattern, like I used for these pants (I didn't do this, wish I would have, but wasn't the end of the world), and making the leg part as long as your sweater will allow. Ok, you should have shorts now.
Now cut the arms off of your sweater, so the tops are straight across. These will be the bottom part of the legs.
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Now take the legs and tuck them inside the bottom of the legs of the shorts, so when you look inside the "tube" you see no seam. Remember that your shorts should still be right sides out at this point.
Now sew 2 seams, 1/4 inch apart, all the way around.
Now you're done! This seam is on the outside, for comfort, and the second stitch around exaggerates the seam, so it ends up looking like shorts over pants, instead of just having a weird seam. I think that if you have a serger, you could serge the legs to the shorts, but since I don't have a serger, I don't know if that would work. If anyone serges the legs on, will you come back and let us know how that turned out?
Here I am in all my running gear. I went out running in this outfit the other day, when it was 40 degrees. Everywhere I had wool (my funky hat tied into a beanie, my runner's mittens, my pants), I was comfortable from start to finish. I had synthetics (my shirt & jacket), I ran hot and cold the whole time. That wasn't a surprise though, since wool is naturally insulating, breathable, and moisture wicking. The added bonus of using wool for running pants, is that you don't have wash them every time, like synthetics, because of their antibacterial properties. After I run, always before I shower, my clothes usually stink [I can't believe I just posted this on the internet], and they go straight into the hamper, but I turned my running pants inside out to air, and the next day they smelled fresh as a daisy!