Most training programs will keep the variables set for a period of 4 weeks. This means the sets, reps and exercise selection will stay the same for a month. There is nothing wrong with this and this style of training is backed by a lot of research. In fact, most of my programs are designed this way. It follows a more traditional linear periodization.
But for a lot of people, following the same workouts for 4 weeks creates some boredom, and they need changes in their workouts more frequently – it keeps the motivation level high. Some trainers will continually changes exercises, or create crazy looking exercises just to be different, or worse, not have any plan at all.
Other well-known strength coaches will use a non-linear or undulated style of periodization where the training variables change each workout so they hit a hypertrophy (increase in lean mass), strength and power style workout every week.
I’m a pretty conservative guy, and my philosophy is to stick with very basic, compound exercises that work a lot of muscle fibers, and get very good at the technique in those lifts. Better technique allows you to lift more weight, leading to more strength, power, and muscle. I kind of look at it as “exercise specialization”. Any professional that is well-known and makes a lot of money is a specialist, not a generalist. They pick one thing and become very good at it. So my repertoire of exercises is relatively small compared to many other coaches and trainers. (Not that I’m against it, or that I won’t add exercises when necessary, just my view).
As far as a typical undulated periodization, I like to keep my workouts short and split movement patterns up between two or three alternating workouts. In order to make sure all movements were hit each workout, would make the workouts longer than I would want. It’s not impossible to do, but that’s for another post.
So my solution is to change the variables every week, or every two weeks. An example program that follows this is my Ultimate Strength Training Manual. With typical monthly cycles, a sample plan and it’s phases might look like this (with sample sets and reps in brackets):
Month 1: Adaptation (2-3×12)
Month 2: Hypertrophy (3×8)
Month 3: Strength (3×6)
Month 4: Power (3×4)
By changing the variable each week, it becomes this:
Week 1: Adaptation (2-3×12)
Week 2: Hypertrophy (3×8)
Week 3: Strength (3×6)
Week 4: Power (3×4)
Having an Adaptation week every month acts somewhat as an unloading week, keeping you fresh and recharged, ready to hit new goals.
Further, following a plan like this allows you to look forward to a new phase every week, and you can set personal bests in each phase every month, rather than every four months. (You should always compare PBs to a similar phase, set and rep scheme). This way, boredom is less likely to set in, and setting PBs more often helps keep you motivated. Nothing is more motivating than seeing success and results.