I wish I knew, Tom. For years, I used to use 9-10 lb. basses on 4-5 hour gigs with a 2 inch Ernie Ball strap and never had so much as a twinge. All of a sudden I hit 40 and my shoulder would kill me after about 15 minutes. Then I bought every wide and padded strap on the market trying to alleviate it, but nothing worked entirely. There were three that actually made it better, the Slapstrap, the Levy's MSS24 4 1/2" padded strap, and the Planet Waves strap that Justin's using now. Everything else was money down the drain. But the only thing that really truly worked for me was moving to a lighter bass. I can usually take a Precision, but most Jazz basses are right out. And now my main bass is a modified P-Lyte, which I can play all night without soreness. I felt like a bit of a wuss using one, but since Justin said Trent uses one, I don't feel so bad now