Thanks for the suggestions, everyone. I tried the runner's loop, but while I play, I am still having significant Achilles tendon pain, mostly in my left Achilles, but the right one is somewhat sore also. I am going to seek medical treatment. I had a foot injury, like plantar fasciitis but inflammation of another tendon on the sole of my foot, in 2019. The rehab included treatment of the calves and Achilles tendons, such as massage, stretching, and ultrasound. I still stretch my calves, although less than I once did. I started stretching them more since I've had the Achilles pain. Unfortunately, that's too late to address this issue. I may try another pair of shoes to see if that helps. I've used the Gel Resolution since Gel Resolution 2 and have liked every successive model, but maybe the 8 doesn't work for my feet.