Since there are so many disadvantages of carrying too much weight, the solution must be to discuss how to reduce the burden.
1. Choose a lightweight backpack with an excellent carrying system.
2. After the load is reduced, you can also wear lighter shoes, thereby saving more energy and walking more gracefully on the journey.
3. For those who like photography or climbing, you can carry more professional equipment while the weight of other equipment is reduced.

Having said so much, you may not understand one point: the carrying is the whole of a backpack, not a backboard or adjusted shoulder straps and lumbar support. The carrying is equal to the entire backpack! That is to say, any point that can cause your use experience is considered a burden, and it is not determined by a simple system.
In fact, the padding, accessories, maximum load and even your packing skills are all part of the backpack. If 80% of a good carrying experience depends on the backpack, the remaining 20% ​​is up to you. If you don't adjust it properly according to your body, even the best backpack will be uncomfortable for you.