Deltoids Sore

I have long lamented the fact that my deltoids never get sore. The fronts get a little tight sometimes after a big bench press session, but they never get sore. I have tried and tried and tried to make them sore. I have done lateral raises until I grew mentally fatigued with the process and quit. I have done upright rows and upright rows and upright rows until it was time to do something else.

I have laid out kettle bells and dumbbells across the back yard and gone up and down the line working those muscles, trying to make them hurt. They get tired, but the next day there is never soreness. 

The only time they ever got sore was when I was playing around with overhead squats. Huh? Yeah, just playing around and the next day it was wow!

Then, late Friday afternoon, my deltoids grew sore. What's going on? I asked myself. The tough swim this morning? Nah. The weights yesterday? Nah. Nothing unusual, except. . .

I did some overhead dumbbell walks. This is the second time I have done them and I did not get sore the first time. But this time, I went farther, 390 feet, with 15 pound dumbbells overhead. The delts and the rotator cuff muscles are constantly contracting, reacting, adjusting to keep the weights centered, overhead, balanced. That's the only thing it could be. I did do some tough swimming Friday morning and that may or may not have contributed to the soreness. I just know that next week, I will be doing more walking with dumbbells. It builds shoulder stability.