A one rep (repetition) max is considered the most weight you can lift one time, with a specific lift. It is very important to know what your 1 rep max is for each lift because development of performance, strength, and power is based on that max. Strong and Steady CrossFit centers part of their workouts off your 1 rep max depending on what we are trying to focus on for that day: Performance, Strength, or Power. Throughout the monthly programming, our goal is to focus on all three of these areas consistently and appropriately.
Through research, we know that to develop muscle performance or hypertrophy of the muscle (increase in muscle mass) we need to lift at 60-70% of our 1 rep max, 3+ sets, and at 5+ repetitions. Although this will increase the size of the muscle, it will not necessarily make the muscle stronger or more powerful. However, this is the foundation to work from, so most of our workouts will be in this area. Research also shows that to develop muscle strength (how much force your muscles can produce, how much weight you can lift, or how much resistance you can overcome) we need to lift at 70-85% of our 1 rep max, 2-4 sets, and 3-6 repetitions. Finally, to develop power of the muscle (the ability to use strength quickly) we need to lift at 85%+ of our 1 rep max, 1-3 sets, and 1-3 repetitions.
You will notice that Strong and Steady CrossFit strives to have two heavy days a week, where we try to find our 1 rep max; or focus on strength and power based off our 1 rep max, on a specific lift. One of our goals is to work on our 1 rep max every 2 months or so, within each of the basic lifts.