Well, your post got me to thinking.
Desi has sinking hiney syndrome as well. And his gait is very stiff, too. I prayed for winter to end as he was slipping
on the ice so badly. However, the warmer it's gotten, the worse his hiney-sink. This has been the first really warm weekend
here, and once it's over 70F Desi is begging for a/c. He's always been very heat intolerant. As in, he pants if it's over 50.
Over 60, he pants like a freight train. Over 70, it's like he thinks he's in a frying pan. This afternoon, we went for a
quickie pee walk, and he didn't even make it a block before he was sinking, we headed back to the house, & I was afraid we
weren't going to make it. Now that he's cooled off, his sinkage is much better. I don't know why the warm weather would
affect his weak rear, so your post made me wonder if it was the stress of being too hot. And stress is stress is stress.......
just my own wandering thoughts.