There are many ways to design programs for your clients. One of the most important factors of a program is periodization. You may choose to use linear, undulating, or nonlinear periodization, but what are these and how do you know which one to use for your clients?
We’ll start with the basic linear periodization. This is the model that’s been around the longest. A typical linear program looks like this:
Weeks 1–4: 3 X 12
Weeks 5–8: 3 X 10
Weeks 9–12: 4 X 8
That makes your 12-week macrocycle. I wouldn’t recommend this for too many people, as it isn't as effective as other methods and it can lead to a plateau in strength gains.
The next periodization method, undulating, has become the most popular of the three and is probably similar to what most of you do with your clients. An 
undulating program can be done daily or weekly depending on how you do your exercises and how many times a week your client may train with you. For example, if you have a person who is dedicated and may be training for competition lifting or another sport, you may be able to do daily undulation. What that means is if you bench one day of the week, you may do three sets of ten. Then if you do bench again on day three of the same week, you may do four sets of eight. Typically, daily undulation works best with a four-day workout week so that you hit all the main lifts twice in the week. This is why daily undulation is utilized more for competition lifters.
Weekly undulation may be more suitable for the general population. This is where you may hit one main lift (bench, squat, press, deadlift, or clean) every workout of the week instead of doing multiple main lifts in one day. Here's what this looks like...
In week one, you would do three sets of twelve. In week two, you would do three sets of ten, and in week three, you would do four sets of eight. Your client’s goals would determine what week four looks like. If he wants to get strong, week four may have four sets of six or a five, three, one type set up. If the goal is more endurance or hypertrophy, you may deload that week and go back to three sets of twelve. You just have to plan your microcycles if you want them to be three or four weeks long and base it off your client’s goals.
You may wonder what you should do if you only see your client twice a week. Well, don’t make it too complicated. Stick to the same plan. Just draw it out over two weeks. For example, I have many people who only train with me twice a week. So what I do is:
Week 1
Squat, 3 X 12
Bench, 3 X 12
Week 2
Deadlift, 3 X 12
Press, 3 X 12
Week 3
Squat, 3 X 10
Bench, 3 X 10
Week 4
Deadlift, 3 X 10
Press, 3 X 10
Week 5
Squat, 4 X 8
Bench, 4 X 8
Week 6
Deadlift, 4 X 8
Press, 4 X 8
This isn't ideal to reach the ultimate strength potential in a client, but let's face it—the 40- and 50-year-old moms just want to be stronger than they are, not compete in Strongman competitions or MMA. This type of program will get them to their goals. Another added benefit of this style is we can hit the main lifts early for strength and then do cardio training afterward and all within an hour.
Undulating periodization also allows for a period of deloading, which will help to decrease the chance of a plateau effect. The plateau effect can happen more easily in the linear program. This type of periodization program is a more balanced program, so you can train muscle endurance/hypertrophy, strength/hypertrophy, raw strength, and power all with weekly undulation whereas linear periodization is usually just limited to training one energy system.
Last is nonlinear periodization. This has been a program that has flown under the radar for quite a few years and is slowly starting to get some publicity. It's still relatively new to me because I have only read a book and a few articles on it and have just recently began a program following nonlinear periodization. From what I know and have experienced, it seems like a great program to follow for your clients who are athletes or are very fit and active. I became intrigued by it when I was working at the collegiate level and feel it would work best within the sports realm.
With nonlinear periodization, you focus on one energy system per day. This is where you really need to get specific in your client’s goals and find out what he wants to achieve. If he wants to increase strength and cardio, then you would focus one day completely on strength building and the next day completely on cardio. I've designed a few programs based off this system. One I designed was intended for pitchers on a baseball team. With this program, examine the needs base, like always, and calculate what’s needed for that position. For baseball pitchers, they need power, strength, and power endurance. So their three lifting days primarily focused on those three energy systems. You also have to periodize according to the season if you're working with athletes. You still want to develop the energy systems in the order of aerobic/hypertrophy, hypertrophy/strength, strength/power, and strength/power/power endurance (if power endurance is necessary). Ideally, you want to be on strength and power/power endurance in-season.
There are multiple ways to design the nonlinear program. You can fill in your exercises however you like. For my “experiment” using nonlinear, I'm currently blending a nonlinear method with undulating periodization. For example, my training program is as follows:
Week 1
Hypertrophy, 3 X 10
Power, 3–4 X 5
Strength, 3–4 X 5
Week 2
Hypertrophy, 3 X 8
Power, 4–5 X 3
Strength, 4–5 X 3
Week 3
Hypertrophy, 4 X 6
Power, 5, 3, 1 +
Strength, 5, 3, 1 +
Then I deload in week four, following the same template as week one. I also do all my main strength lifts on my strength days—squat, bench, and deadlift. I don't recommend this for anyone in a competitive season or a younger person because that is a lot of stress for your body to take on in one day.
This style has facets from daily undulation, weekly undulation, and nonlinear as well as the 5, 3, 1 template. I've had great results with strength gains thus far and am finishing up my eighth week. I set up a friend with a similar style and he has also had great results through four weeks of training this way. He's hitting PRs nearly every week. I know it isn't scientific and it isn't consistent throughout a year, but I’m hoping to find out. I’ll let you know in 44 more weeks.
There is much information here and you may be stuck wondering how to determine what the best periodization scheme is for your client. It all goes back to 
your client’s goals for training. Most people's goals are to improve cardio and lose weight. A linear program would be fine for this, but it still isn't my first recommendation. Why? These are usually people you may see twice a week, maybe three if you’re lucky, and that isn't taking into account missed workouts. Trying to use a daily undulating type workout for these people wouldn't work very well because you may end up only seeing them once a week anyway. I still wouldn’t recommend a straight linear type periodization either because it isn't as effective as weekly undulation. Honestly, would you want to do the same weights for four weeks straight? Didn’t think so. You’d get bored and so would your clients!
If your client’s goals are to build strength, an undulating program is definitely the way to go. Usually people with these goals are typically experienced or at least are interested in gaining more experience. He will more likely be able to follow an undulating program. A study done in 2002 (1)compared undulating programming to linear programming. The group that worked out using a daily undulating program design found an increase in their bench press by 28.78 percent while the linear group found an increase of only 14.37 percent. The linear group in this study changed their loads every four weeks. This study was done over a 12-week period. That being said, you can see why if your client’s goal is to build strength, an undulating program may be the best way.
While it may be best to use a daily undulating program, it may still be difficult given your client’s schedule and availability. You may choose to follow the weekly undulating program mentioned above. In the study mentioned above, they didn't find any significant differences in circumference measurements between the linear group and the undulating group. However, most of the time, when a client wants to build mass, he also wants to gain strength, so I recommend an undulating program.
As mentioned earlier, a nonlinear program is typically a program specific to athletes. It isn't that people in the general public couldn’t handle a program of this format. They just usually don't need to develop their energy systems as an athlete would. Most of the general population is looking for strength and cardio to help them lose weight. An undulating program as mentioned above can do very well in that regard.
Another reason nonlinear works well with athletes is because it's meant to be flexible around athletes’ demanding schedules of practice and games. If you're 
around or have been around collegiate level sports and above, you know that schedules can change very quickly. Not only that, but you can't control what they do in practice. The coach may make them run sprints for 30 minutes before he ships them into your training session. The nonlinear program is designed to work around challenges like that.
To learn more about the nonlinear program design, check out William Kraemer and Steve Fleck's book called Optimizing Strength Training: Designing Nonlinear Periodization Workouts. You can find it online pretty cheap. If anything else, it’ll help give you some more ideas and variations, which always helps to keep clients’ interest. And no, I’m not a salesman of any kind for the book. I’m just a big advocate for reading and learning new things.
Now that you’re just a piece of paper away from being an expert in program designing (sarcasm), pick the periodization style that best fits your client’s goals and your style of training!
References
- Rhea M, Ball S, Phillips W, Burkett L (2002) A Comparison of Linear VS Undulating Periodized Programs with Equated Volume and Intensity for Strength. Journal of Strength and Conditioning 250–55.