Breaking Down the Components of a Rep
Before diving into how we perform our reps, it’s important to understand the three fundamental types of muscle contractions that occur during a lift:
1.) Concentric Contraction
Concentric contraction is the muscle action most people picture when thinking about muscle engagement. In this process, the muscle shortens as it exerts force. This is generally the “up” portion of the rep. For example, during the upward phase of a bicep curl, when you lift the weight from your waist to your chest, the concentric contraction occurs. Although this is the contraction that most people envision, it actually generates the least amount of force compared to other contraction types.
2.) Isometric Contraction
In an isometric contraction, the muscle generates force without changing its length. Imagine trying to lift a chair that’s firmly anchored to the ground. Despite your efforts, the chair doesn’t move, but your muscles are still working hard. In the weight room, this translates to holding a weight in a fixed position, typically at the top of a rep, where you pause after the concentric phase and before the eccentric phase begins. Even without movement, your muscles are forcefully contracting to generate tension. This type of contraction is also known as a “hold.”
3.) Eccentric Contraction
Although often overlooked, the eccentric contraction is in my opinion the most crucial part of a rep. This phase occurs when the muscle lengthens while contracting. For example, during a bicep curl, it’s the controlled lowering of the weight from your chest back down to your waist. It’s essential to manage the descent rather than simply letting gravity do the work. Known as the “negative” phase, this is where the majority of muscle breakdown occurs. You’re also capable of generating more force during this phase than any other phase, which increases muscle tension and further increases breakdown, both key drivers of muscle growth. Additionally, eccentric contractions allow you to overload your muscles beyond what you could lift concentrically. For example, when you can no longer perform a full concentric rep, you can cheat the weight up and focus on a slow, controlled negative for even more stimulus on your muscles.
Rep Counting and Cadence
Now that we understand the phases of muscle contraction, let’s discuss how to count reps to achieve the ideal cadence for maximizing hypertrophy. While there are benefits to varying the cadence, this discussion focuses on maximizing muscle growth. It’s important to note that some exercises start with an eccentric phase (e.g., squats, bench press), while others begin with the concentric phase (e.g., pull-ups, bicep curls). Although the cadence remains consistent, the counting method varies slightly.
For both types of exercises, we aim for a 1-1-2 or 1-1-3 cadence; referring to concentric-isometric-eccentric phases.
- Exercises Starting with the Eccentric Phase (e.g., Bench Press):
Perform 2 seconds on the way down (eccentric), 1 second hold at the bottom (isometric), and 1 second on the way up (concentric). - Exercises Starting with the Concentric Phase (e.g., Bicep Curl):
Perform 1 second on the way up (concentric), 1 second hold at the top (isometric), and 2 seconds on the way down (eccentric).
Despite the different starting points, the cadence is still defined by the durations of each phase rather than the order in which they occur.
The goal is to achieve a total time under tension (T.U.T) of at least 30-60 seconds per set, but ideally between 45-60 seconds. For example, 8 reps at a 1-1-3 cadence provide 40 seconds of T.U.T, while 12 reps at a 1-1-2 cadence yield 48 seconds of T.U.T.
Conclusion
Understanding the distinct phases of muscle contraction and how to effectively count and time your reps are fundamental for maximizing hypertrophy. By focusing on the proper execution of each contraction type and adhering to the optimal rep cadence, you can significantly enhance muscle growth and overall progress. Remember, the eccentric phase is your best friend if you want to put on mass and break plateaus. Experiment with the 1-1-2 or 1-1-3 cadences to find what best suits your training needs and goals. I personally prefer higher reps (10+) and a 1-1-2 cadence because I feel like I can take my sets closer to failure that way. Always aim for a total time under tension that challenges your muscles and pushes them to failure. Apply this knowledge consistently in your workouts, and you’ll likely see substantial improvements in both your performance and physique. Now go get your ass in the gym!
