Strength vs Hypertrophy

Much debated, here's a breakdown and the differences of the two styles of programming in a easy to review list.

The main question we see with weight-training is: What is happening differently to the muscle that it causes you to develop greater strength in some cases, but greater "mass" in other hypertrophy/bodybuilding routines?

When lifting for hypertrophy, some strength development will occur. Additionally, the counter is true as well, lifting for strength will result in some "mass development".

General Rules

  • 1-5 reps primarily develop strength, with more impact on muscle size and none on endurance.
  • 6-12 reps develop a balance of strength, muscle size and endurance.
    • Many strength-based programs follow some form of 5 rep variants. While hypertrophy routines seem to fall in approximately 12 rep range.

The main factors that are lead to muscular hypertrophy are mechanical tension, muscular damage and metabolic stress.

  • Lifting for strength can physically tear the cell membrane of the muscle cell. Heavy negatives damage myosin heads, leading to their eventual repair. The neurons controlling the muscles will increase in firing rate, synchronicity, and extent of muscle fibers recruited in response to strength training.
  • Hypertrophy training involves a greater release of metabolic byproducts and hormones than strength training, which in turn cause a change in the local environment.  The muscle cells release pro-inflammatory cytokines which are thought to be an important part of recovery after intense training. Myonuclei (muscle stem cells) are also activated by factors such as growth hormones, which carry out the normal activities involved in protein synthesis to create the myofilaments (actin and myosin) and any other proteins needed.

To conclude the two previous points: Strength adaptations tend to be more neural, while hypertrophy adaptations tend to be more muscular in nature.

Basic guidance from the ACSM is that gains in both strength and size result from using a resistance equivalent to 60 – 80% of your 1 rep max.

  • This varies depending on training age, with novice-to-intermediate strength trainees being recommended to use a load of 60 – 70% of 1RM, while more advanced trainees being recommended to use >80% of 1RM 

Data shows that multiple working sets generated significantly greater increases in strength than single sets and where the workout programs were of longer duration. So basically, a 4 week program that schedules multiple sets for each exercise will generate better results in strength gains than an 8 or 12 week program with single set or low volume workouts.

  • For the total-reps, biomechanical variables were greater in the hypertrophy workout in comparison with the power and strength workouts, mainly due to the sheer difference in volume.
  • Relative load is generally the main determinant of all mechanical responses, but the interaction of volume and load determines the overall mechanical responses to multiple repetitions and overall workout stimulus.

Hypertrophy workouts may be superior for gaining muscular size because the slightly lower relative load allows a greater total volume to be performed, which maximizes the appropriate aspects of muscular tension.

The total force exerted over the course of high-volume hypertrophy workouts is considerably higher than that during strength workouts. To avoid overuse injury, it is likely advisable to gradually ramp up volume rather than to switch directly from low-volume to high-volume training.

The differences between how reps/weights/training effects growth of the muscle cells is highly debated and far from resolved. While the weightlifting community generally promotes the idea that the number of reps affects one or the other, it’s far from conclusive.