Why percentage systems don’t work in strength coaching

Strength Sensei CP


Because of the success of Russian weightlifters, many American coaches design workouts using percentages of their maximum results. While it makes sense for weightlifting, percentages are not practical, even when using high-tech software systems.

Before getting into how I determine how much weight to use for a set, let’s look at three reasons why percentage systems are ineffective:

  1. Strength Levels are Unpredictable.How much weight you can lift in a specific exercise can vary as much as 20 percent during the day. In the morning, you might be able to bench press 200 pounds, but in the evening, you might struggle with 180. Having to use light weights in the evening would reduce the strength training effect.

This variation in strength levels is especially problematic during test days, as percentage systems are based upon maximum results. Using our bench press example, depending on the time of day the test occurs, the weight prescribed in future workouts can be too heavy or too light.

Another issue is that some days you simply have bad days. Maybe you cannot perform your best on test day because you didn’t get enough sleep the night before testing, ate some bad cheese, or have a minor illness? Whatever the cause, the weights prescribed based on those maxes will be too light to achieve an optimal training effect.

  1. Muscle Fiber Types Vary.How well someone performs on a 1-repetition max test is influenced by their muscle fiber type. Let’s say we have two individuals who can bench press 200 pounds, and one person is predominately slow-twitch and the other fast-twitch. The workout program might determine that someone at that strength level should bench press 180 pounds for four repetitions. An individual with predominated slow-twitch muscle fibers might perform 6 reps with that weight and someone with predominately fast-twitch fibers may only be able to perform 2 reps. Again, for one individual, the weight based on a percentage of a 1-repetitions maximum (1RM) is too light, and for the other, too heavy.

Expanding on this topic, muscle fiber types vary with individual muscles. For example, the two major calf muscles are the gastrocnemius and the soleus. The gastrocnemius is predominantly fast-twitch and is most activated when the leg is straight, and the soleus is predominantly slow-twitch and is most activated when the leg is bent. A percentage system would need to have different conversion formulas for each muscle to prescribe the most appropriate weights.

Even if two trainees have the same maximum result in the squat, the number of reps each can perform will vary based on each individual’s muscle fiber composition. (All photos by Miloš Šarčev)


  1. Percentage Formulas Vary with the Exercises.One popular percentage conversation formula says to add one repetition for every 2.5 percentage decrease in weight. For example, someone who can perform 100 pounds for one rep in an exercise should be able to perform 3 reps with 95 pounds and 5 reps with 90 pounds. Although this may work for simpler movements such as a triceps pushdown or a biceps curl, it would be too challenging to perform 5 reps in the clean and jerk with 90 percent of a 1RM with decent technique.

Rather than percentages, let the repetitions determine the load for each exercise. For example, a workout for someone who can bench press 200 pounds might prescribe 5 sets of 5 reps after warm-up. After a warm-up, your first workout set might be 150 pounds. If you make all five reps, you would increase the weight for the next set; if you didn’t make all five reps, you would reduce the weight. This way, you are always performing the optimal number of reps for the specific strength training quality you are trying to improve (such as relative strength or absolute strength).

One last point — I like to give a range of repetitions for each set. So rather than 3 x 5, I might prescribe 3 x 4-6. This approach increases the total effort of the trainee, rather than having to use lighter weights on the previous sets to ensure they can reach the goal number of reps on the last set. As an example, rather than using 175 pounds for 3 sets of 5, with only the last set being to failure, the trainee might perform 180 pounds for 6 reps, 5 reps, then 4 reps.

In summary, percentage systems have their place in weightlifting, where the sport is the barbell. For those who simply want to get bigger or stronger, they should train harder and smarter by letting the reps determine the load!

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