My husband wakes up with sore legs often. its dull aches from toes to knees and lower back. he thinks its from walking in flip flops. do you agree?

Yes: Flip flops offer no support for your feet and arches. As a result the arches fall or pronate. This creates an imbalance which places more pressure on the inside or medial aspect of both feet. There is more pressure on the toes and there is internal rotation or torque on both knees, hips. This will make hom tip forward when he stands and place more strain on his lower back. Try rainbow sandals.

Probably: Somewhere in the last 5 years or so, flipflops became shoes. Prior to that, they were reserved for their intended purpose, the pool or strange showers. They provide little support and will definitely strain legs and feet. Most of my heel pain patients admit to wearing them frequently. Substitute a good supportive pair of running sneakers and see how he feels in a few weeks.