Soreness in shoulders during rucking may indicate strengthening, but excessive weight or poor form can lead to injury.

“if your shoulders are sore right then you know decrease the weight or if it's if it's a good sore then that's them getting stronger yeah I always find that in the winter I just rock less because I it's for whatever reason I I enjoy the heat more so I have less motivation to go out in the winter and I always find that when I really ramp up volume in this Summer that first week I feel it in the shoulders again yeah but as you said it it's easy to distinguish a good sore from a bad sore”