Some good-ol' fashioned man-porn.
Training with low reps constantly gets tiring. Endless sets of 3s and 5s might boost your strength for some time; yet after a while, the body becomes adapted to the same stress, and you find yourself stuck on a plateau. What's the answer? Why, some good-ol' fashioned bodybuilding, bro! By which I mean, multiple sets of 6 to 10 reps, training each muscle group twice a week, minimum. Ideally, you should do a two month hypertrophy program, then switch to two months of strength-building, then finally peak for a month to discover your new maxes, according to bodybuilder/strength coach Mike Isratel (link). Powerlifter Greg Nuckols (link) also recommends this sort of approach. After all, the more muscle mass you have, the more strength potential you'll develop. Just check out some of the top raw powerlifters, Dan Green for instance:
Damn-near as jacked as Arnold in his prime.
So how should you structure a bodybuilding program with a powerlifting focus? Obviously you want to still use the squat, deadlift, and bench press for much of your training. However, instead of working on increasing your one rep max (and ego), you'll focus on developing the primary movers of those respective lifts (so the quads, hamstrings, glutes, pectorals, shoulders, triceps, and spinal erectors, namely), though during this time, you can also work building supporting muscles groups like your biceps and lats. Variation is key, since you'll want to expose your muscles to different stressors (the ol' muscle confusion bro-science, which has a little merit). Below is a sample program designed for someone with the following maxes: 300 lbs bench press, 400 lbs squat, and 500 lbs deadlift.
Sunday: Bench press 225 for 4 sets of 6 (75 percent of 1 rep max). This is your heavy bench day. Also do 4 sets of 10 dumbbell flies, followed by dumbbell rows for 4 sets of 8 and dumbbell shoulder presses for 4 sets of 8. Add five lbs to your bench weights each week, while adding one rep to your assistance exercises.
Monday: Deadlift 3 sets of 10-8 reps with 295 lbs (just under 60 percent of 1 rep max). Why only three sets? Well, it's because the deadlift sucks! Honestly, this workout is harder than it looks. You're going to be doing a lot of squatting, which will affect how much you pull. Just add ten lbs each week. Also do 3 sets of 10 dumbbell stiff-legged deadlifts. Keep those legs stiff and work on the hammy stretch. The weight doesn't matter that much, just add sets each week.
Wednesday: Low bar squat with belt 250 lbs for 4 sets of 10 (a little over 60 percent of max). Practicing your competition form with high reps will pay off in the long run. Try to keep rest times down for added challenge. Do 4 sets of 10 pistol squats afterwards. Once again, the weight doesn't matter, you're just trying to fatigue your squatting muscles. Follow with close grip bench press 185 lbs (60 percent of max) for 4 sets of 10, followed by biceps curls/triceps extension superset for 4 sets of ten. Add ten lbs to the squats each week, and five lbs to the bench press.
Friday: Bench press 4 sets of 8 with 205 lbs (just under 70 percent of max). Follow with 5 sets of 8-12 reps of the following exercises, supersetted if you wish: dumbbell curls, pressdowns, pulldowns, and side laterals. Add five lbs each week to bench press.
Saturday: High bar squat, no belt. 225*8, 235*8, 245*8, 250*8. Keep pushing that top set each week, by ten lbs: increase warm up sets if you feel like it. For assistance, do weighted step ups 4 sets of 10, followed by side leg raises.
After four weeks, do a deload on the fifth, and then start again. After eight weeks, you should transition to a strength program. I'll post one in the future.