Like the commenter below, I initially ordered the Red set of StretchCordz, being a pretty experienced Master's swimmer. It is very hard to do a lot of reps or extended sets with this level of resistance. I switched up to Green, and now I am much happier. TeamAquatic processed the exchange without any hassle, so thank you for that!
I ordered these as I like to think I am pretty strong though I am 5’3”. They provide somewhat more resistance than I would like So I definitely can’t do many reps. Doing 1 arm at a time is ok. Trying to do alternating arms at the same time is very difficult for me with this resistance as it seems to require more core stabilization than I can generate. I think green would have been a better fit for me but I am enjoying using these ones. I took off 1 star because the resistance of the red one isn’t optimal for me ( but that really is my own fault)