The 5X5 method of training is designed to build superior strength if done correctly. The way it works is you need to select a compound exercise for each muscle group you train each week per day. For example lets say I train chest on Monday. The compound exercise I choose is the flat bench press. Now what I would do is select a weight I can realistically perform 5 sets of 5 reps with. Yes, you keep the weight the same. You want the weight to be heavy enough so that you're struggling to get the last rep or 2 per set. You want those last 2 sets to take a lot of pushing to do. Get a spotter to help you on any 5X5 lift. When training for strength its about explosiveness so focus on powering the weight up with all your might. a 1-1-1 tempo is best to use when doing 5X5. Be sure to sip water in between sets.