Upper Body Assistance Work: How to Build the B Series

Assistance exercises should do more than fill the second half of a training session.

In this episode of Between 2 Racks, the KILO Crew explains how to build the upper body B Series and the reasoning behind every major programming decision within it.

The discussion begins with the role of the B Series in developing strength, hypertrophy, muscular balance, and sufficient weekly exposure. Stéphane explains how the 90-degree principle emerged from analyzing training outcomes and how it can be used to organize pressing angles across a session, mesocycle, macrocycle, and training year.

The crew then breaks down the B2 exercise, including how horizontal rows, leaning 45-degree pulldowns, and vertical pulling variations complement the work performed in the A Series. They also discuss grip width, hand position, exercise selection, equipment limitations, and why the effects of an exercise must be considered across the entire training week.

Finally, the episode covers tempo and loading. You will learn when tempo should be strictly followed, when a controlled natural rhythm is enough, and how to progress B Series loading across a three-week mesocycle. The crew also explains why the A Series demands an athlete’s approach while the B Series allows the trainee to put on a bodybuilder’s hat and train closer to concentric failure.

This episode is a detailed look at the difference between writing workouts and designing training programs.

Better assistance work begins with better reasoning.

To learn the entire system, enroll in KILO's Program Design Course and begin your journey to earning your Level 1 Certification.

00:00 Intro to upper body B Series

00:19 Defining the role of the B Series

01:04 Building muscular balance and pairings

01:39 Origin of the 90° Principle

09:27 Applying the principle across mesocycles

11:03 Why it helps novice trainees

12:19 B2 exercise selection philosophy

14:08 Rotating primary and assistance exercises

19:34 Choosing B2 exercise types

29:31 Dumbbell row vs seated row

38:44 Tempo philosophy for B Series

44:32 Loading and training to failure

47:51 Tracking progressive overload

50:17 Two sets vs more sets to failure

52:14 Course reference and wrap up