If you are planning on going to Selection I would recommend a ruck that weights at least 60 lbs. The standard was 45 lbs when I went through without water and it is weighed after specific events. If you have access to a beach sand is a great resistance and you will come across that on the road March and land nav or do hills. Both build up leg strength and do it as fast as you can and try to increase speed and difficulty with each evolution.
Read This Next