I've been doing puppy dog pose regularly as well as hero pose. The reason is that my thoracic spine and knees are two areas that could use good bit of improvement. Some interesting changes have resulted in my body over the past several days.
My sternum is no stranger to popping and becoming open with a good back bend first thing in the morning. This morning, though, it was caught in a weird place. My higher up. After some light floor stretching, I stood up, took a back bend and it popped back open. It felt less like the sternum was stuck and more like the intercostal muscles at the top of the rib cage. One way or the other, I lengthened then settled back into an only muscle pattern during sleep but the new feeling of tightness and release just serves to indicate that change is indeed occurring daily.
As for my knees, there has been significantly less popping in my "trick knee" - my left knee. My gait and alignment have been off since I was a kid and I have sustained multiple ankle injuries in both ankles so its no wonder my knees make clicks and pops. Over time my right knee has stopped all the noise but the lateral ligaments in my left knee have been worrying me lately. Hero pose seems to have helped greatly though. In the last few days my "trick knee" has fallen silent. Additionally, the peroneus muslces along the outside calf on both of my legs are feeling very stretched. Again, my calves have been brutally tight after years of sports, sport-related injury and not stretching. Good things are afoot (or knee or calf).