Here's a bit more information about the the most often used weight prescriptions on the platform. Whether you're a fan of programming off of a percentage of a 1-rep max or you'd rather assign percentages of difficulty, it's important to understand how the system's algorithms work to allow you to consistently and reliably deliver individualized training.

**The Formula:**

Here is the raw formula for ** %1RME**:

*Weight(reps,1RME) = oneRME*(-3.1631e-05*reps^5 + 0.0022551*reps^4 - 0.058792*reps^3 + 0.66911*reps^2 -5.6984*reps + 104.7705)/100*

The relationship between a user's 1 rep max weight and their X rep max equivalent weight is outlined in the table below.

**% Difficulty:**

If the weight type is set to '% Difficulty', the Xrm value for the exercise is determined using an average of all of the user's completed sets and tests for this exercise. In practice, this means that if you prescribe 5 reps at 80% difficulty, the athlete will be prescribed 5 reps at 80% of their 5RM as defined by the system.

Different factors affect how much each completed set affects this rep-max calculation. Recency, type of set and number of reps are all important--required sets impact the calculation more than worksets, sets completed yesterday affect the calculation more than sets done last month, and sets of 5 reps impact the 5RM calculation more than sets of 10.

Creating individualized programs is never easy. Physiology, level of experience and the rate of progression varies wildly from athlete to athlete and creating programs to challenge and progress athletes can require both constant program updates and repetitive testing. Using percentages of max results is not always the best option for all athletes and practitioners. We understand. That’s why we have created and optimized our algorithm for %Difficulty.

**What is it? **

%Difficulty is our update to the standardized use of %1RM for prescribing weight. It is used to define a prescription that accounts for the relationship between the percentage of the rep max and the number of reps prescribed. Prescribing workouts based on an athlete’s percentages of 1 rep max requires regular testing and varying calculations to determine the correct prescription when assigning 2 or more repetitions. %Difficulty has removed the need for either.

**How would I use %Difficulty rather than %1RME**

Our algorithm determines a correct prescription based off the athlete’s past history and the number of reps as a factor when determining weight. %100 Difficulty is defined as the amount of weight required for the athlete to complete all of the prescribed reps, but no more. For example, an athlete assigned a set of 5 reps at 100% difficulty should be able to complete 5 reps but would not be able to complete a 6th.

This means that 100% difficulty will provide different weight prescriptions when applied to a set of 2, 5, and 10 reps; however, the result will be the same: the weight assigned will allow the athlete to only complete the assigned amount of reps. Our algorithm also accounts for the progression of athletes over the course of their program by consistently updating their prescriptions based on how they interact in the app. If an athlete accomplishes more or less than the prescribed reps or weight, the algorithm will adjust the %difficulty to challenge them accordingly the next time they encounter the same exercise. If you create one program and assign it to multiple athletes, when using % Difficulty, each of your athletes will receive individualized weight parameters based on their previously recorded data. Still not convinced? Here’s how we’ve optimized %Difficulty for EXOS on Bridge.The use of %difficulty allows for coaches to build and for athletes to experience programs that are updating, changing, and evolving as the program progresses.