Strength vs Size: Key Differences and How to Train for Both Goals

Strength vs Size: Understanding the Key Differences in Training Approaches

In the ongoing debate between strength and size, many lifters believe that lifting heavier weights automatically leads to bigger muscles. It’s a reasonable assumption: after all, the idea that increasing load equals muscle growth often comes with the added perk of hitting new personal bests. However, while lifting heavy weights is essential for building strength, focusing solely on low-rep, heavy training might cause you to miss out on important opportunities for muscle growth. If you’re aiming to build mass, it’s crucial to implement a balanced and thoughtful lifting strategy.

Understanding Muscle Size

Exercise scientist Dr. Mike Israetel has provided valuable insights on the topic of strength versus size in a recent YouTube video. He breaks down the key differences between training for strength and training for muscle size.

Israetel explains that muscle size is defined by the cross-sectional area (CSA) of the muscle. In simple terms, muscle size refers to how large a muscle is when viewed from the side, measured at its thickest point. To track muscle size, methods like MRI scans are used, which can assess muscle width at different points across the body. This measurement helps determine the true size of a muscle.

On a broader scale, size can be approximated by measuring fat-free mass—essentially muscle and bone after subtracting body fat. Tracking changes in fat-free mass and body fat percentage over time can give a clear indication of muscle growth.

What Is Strength?

Unlike size, which is all about muscle volume, strength is a skill: the ability to produce force. The gold standard for measuring strength is through one-rep max (1RM) testing. This is the maximum weight a person can lift for a single repetition of a specific movement, like a squat, bench press, or deadlift.

However, strength isn’t solely about muscle mass. Israetel explains that strength is a product of four main factors:

Muscle Size: Larger muscles have the potential to produce more strength. For example, someone with well-developed pectoral muscles is likely to bench press more than someone with smaller chest muscles.

Muscle Architecture: The way muscles are aligned and how they change based on specific training can also influence strength. For example, training for the bench press can alter the muscle fibers in the chest, triceps, and shoulders, improving performance.

Technique: Proper technique is crucial for lifting the maximum amount of weight. Strength athletes and Olympic weightlifters spend years perfecting their lifting techniques, and even small adjustments can unlock greater force production.

Neural Drive: Neural drive refers to the ability to activate muscles to their fullest potential. Training with maximum effort during lifts can recruit more muscle fibers, increasing strength.

Key Differences Between Strength and Size

Israetel outlines several crucial distinctions between strength and size training:

Muscle-Focused vs. Movement-Focused Techniques: Size training prioritizes maximizing muscle tension, such as focusing on the quads during a high-bar squat. Strength training, on the other hand, is more about optimizing the movement for maximum weight, which often involves using multiple muscle groups for efficiency.

Repetition Range: Size training typically involves a higher rep range (5–30 reps per set), while strength training focuses on fewer reps (4–8 reps per set) with heavier loads.

Relative Effort: In strength training, sets are generally performed with a rate of perceived exertion (RPE) of 7–9, which means tough sets that don’t push you to complete failure. For muscle size, training can occasionally push closer to failure for maximum hypertrophy (muscle growth).

Volume: Strength training usually involves less total volume than hypertrophy (size) training. Strength gains are made by progressively increasing weight over time, whereas size gains often come from more frequent and higher volume training.

Frequency: For strength, only one or two sessions per week should be particularly intense. The rest should focus on technique and lighter weights to allow for recovery. In contrast, hypertrophy training requires all sessions to be intense for optimal muscle growth.

Progression: For size, progression can come from either increasing weight or increasing reps, as long as you’re staying within the optimal rep range (5–30 reps). For strength, progression is mostly achieved by adding weight to the bar, and training is typically done in the 4–8 rep range.

By understanding these fundamental differences between strength and size, you can tailor your training approach to your specific goals—whether you’re focused on increasing your raw power or building muscle mass.