Biomechanical Classification of Exercises

You are currently exploring the Fundamentals Library, which is designed to provide a basic overview of the topics that are covered in other longer articles. This article is a part of the Exercise Selection section.

Why Classify Exercises?

When we program exercises, we always organize them in the larger context. Typically, in traditional training programs, exercises are grouped into training sessions. These sessions then form a micro-cycle (often a training week).

Because training sessions and weeks are focused on specific goals, we need to know how much of the specific stimulus and also how much fatigue the exercises we perform bring, as well as which areas they target.

To make this matter easier to organize, we can divide exercises into categories based on their rough mechanics, using some basic principles. This simplifies the process of counting volume and iterating programs based on feedback.

Functional Classification of Exercises

In the context of resistance training, the functional way I like to classify exercises is into compound and isolation exercises. Sometimes the terminology used is based on the number of joints involved in the exercise, where we have polyarticular and monoarticular exercises. In practice, they mean the same thing.

It's important to note that compound and isolation exercises are not about the number of joints involved, but the number of anatomical muscle groups that can be limiting factors. For example, in a pull up, elbow flexors and shoulder extensors are potential limiting factors. On the other hand in a bicep curl, only elbow flexors could be classified as a limiting factor.

Just because there is no motion in a joint, doesn't mean it can't be a limiting factor, and vice versa - just because there is movement in a joint doesn't mean it has to be the limiting factor.

Picture an exercise like planche press to handstand - even though there is no motion occurring in the elbow, it still has to withstand a large amount of torque, and it could be a limiting factor.

A front lever raise is in my book also a compound exercise. Despite the fact that we are technically only moving in the shoulder joint, we still have to stabilize other joints with a lot of torque. This is not the same situation as the Lat Prayer exercise, which is highly isolated when it comes to shoulder extension component.

This division is primarily about classifying exercises based on stimulus and fatigue. It can be very useful for counting volume as well as comparing exercises in terms of specificity. Here is the full classification:

• Compound Exercises (Polyarticular)
  • Upper Body Exercises
    • Push
      • Vertical (Upward)
      • Horizontal
      • Vertical (Downward)
    • Pull
      • Vertical
      • Horizontal
    • Other
      • Mid Section Focused
      • Push + Pull
      • Adduction
  • Lower Body Exercises
    • Squat
    • Hinge/Thrust
• Isolation Exercises (Monoarticular)
  • Neck
  • Upper Back
  • Rotator Cuff
  • Pecs
  • Lats
  • Anterior & Middle Deltoids
  • Triceps
  • Elbow Flexors
  • Anterior Forearm
  • Posterior Forearm
  • Abdominals
  • Spinal Erectors
  • Quads & Hip Flexors
  • Gluts
  • Hip Adductors
  • Hamstrings
  • Calves
  • Tibialis Anterior

In compound exercises, the division is more mechanical. Pulling and pushing exercises will be fairly self-explanatory. Pulling will be based on shoulder extension, while pushing will be based on shoulder flexion (in the spectrum between sagittal and transverse planes).

Depending on the direction of the force vector, the exercise can be further classified into vertical and horizontal. It is important to note that, especially for push exercises, we must specify whether the vector direction is upward or downward (because, for example, dips and overhead presses are completely different exercises, despite both being “vertical push”).

Exercises in the "other" category are the most difficult to program. These are exercises that involve many different muscles. For example, the V-sit is an exercise that works the posterior deltoid and upper back, but also has a tremendous core component.

On the other hand, we may have something that includes muscles associated with both pushing and pulling movements. One such example is the human flag, where one arm pushes and the other pulls. A similar example might be ring muscle ups or assisted reverse muscle ups.

Finally, there are exercises that achieve the same effect by focusing on shoulder adduction - an anatomical movement that targets pecs and lats as well as triceps and biceps - depending on the details of the exercise.

Lower body exercises are simply divided into squatting and hinging/pushing movements. In squatting, our knees bend significantly and typically move forward in relation to the ankle or they remain in the same position. The hinging movement is typically focused on the movement in the hip (extending it back to neutral) and our knee never moves forward. In the thrusts, we basically perform a hinging motion, but with a bent knee, usually fixed in a narrow range of angles.

For isolation exercises, I think it is better to look at things topographically. After all, these types of exercises are almost always performed to target a specific muscle and don't require as much specificity in terms of movement pattern coordination. For this reason, I don't divide these exercises anatomically by function (like curls, flys, etc.).

It is worth noting that exercises in this category can have different variations within them. Exercises for elbow flexors may be more brachioradialis focused, exercises for calves may target the medial or lateral compartment to a greater extent, exercises for hamstrings may target different heads and distal or proximal regions by varying between knee flexion and hip extension. However, the exercise in a given category will always be close to other exercises of that type and can be counted together, for example, in the context of training volume.

Additional Classification of Exercises

Additionally, exercises mentioned above can be split based on their biomechanics to:

• Static
• Dynamic (Lifting Based)
• Dynamic (Lowering Based)

As well as:

• Unilateral (single limb)
• Bilateral (both limbs)

As well as:

• Lengthened Focused
• Mid Range Focused
• Contracted Focus

The way I look at this is as an additional level of precision in describing the type of exercise. The basic functional classification will still give us the most insight, but if we can add these on top, we really have a system that captures and organizes most exercises.

Examples

The following examples show the classification on multiple levels. Each one of them is separated by a different color: