The Full Range Fallacy

We have been engineered to believe that a complete repetition requires a full lockout and a peak contraction. This is known as full range of motion or Full ROM. While this standard is useful for judging powerlifting competitions, it appears to be suboptimal for hypertrophy.

New research indicates that the mechanical tension required for growth is not distributed evenly throughout the rep. It is concentrated in the first half of the movement where the muscle fibers are elongated.

The Gastrocnemius Data

A 2023 study published in the Journal of Strength and Conditioning Research isolated this variable in the calf muscles. Researchers split forty-two women into three distinct groups to perform calf raises. One group used the full range. One group used only the initial range. The deep stretch. The third group used only the final range. The peak contraction.

The training lasted for eight weeks. The results heavily favored the stretched position. The group training in the initial lengthened range saw a 15.2% increase in muscle thickness for the medial gastrocnemius. The group using the full range of motion saw only a 6.7% increase.

The data for the group focusing on the squeeze was even worse. They achieved only a 3.4% increase. This implies that adding the top half of the rep actually diluted the efficacy of the exercise. The lengthened partials were more than double the effectiveness of the full range.

The Quadriceps Data

This phenomenon is not unique to the calves. A parallel study examined the quadriceps during knee extensions. Participants were randomized into groups performing full range, initial range, or final range repetitions.

The pattern repeated itself. The group performing partial repetitions in the initial lengthened phase demonstrated greater relative hypertrophy in specific muscle regions than any other group. At 70% of femur length, the lengthened group outperformed everyone.

Crucially, the group performing the shortened partials. The squeeze: achieved results similar to the control group. This means that training only the top half of the leg extension produced almost no structural change compared to doing nothing at all.

The Mechanism of Tension

The biological driver here is the length-tension relationship. When a muscle is loaded while lengthened, it experiences passive tension from elastic elements like titin. This additive mechanical stress signals a need for rapid repair and reinforcement.

When you lock out a weight or focus on the squeeze, the muscle fibers shorten and overlapping filaments reduce the potential for force production. You are doing work, but you are not creating the specific mechanical signal required for maximum hypertrophy.

The Protocol: Engineered Range

Optimization requires us to discard tradition when the data contradicts it. The bottom of the movement is the point of maximum opportunity.

To optimize for hypertrophy you must prioritize the stretched position. Do not waste energy fighting for a peak contraction that yields diminishing returns. Keep the tension in the bottom half of the movement. If you are performing calf raises or leg extensions, avoid the lockout. Iterate through the stretch.

Summary Data

  • The Calf Input: Comparison of Initial ROM (lengthened) versus Final ROM (shortened) and Full ROM.
  • The Calf Output: Initial ROM generated 15.2% growth versus 6.7% for Full ROM and 3.4% for Final ROM.
  • The Quad Input: Comparison of knee extension angles showing 0 to 65 degrees is superior to full extension.
  • The Quad Output: Lengthened partials promoted greater relative hypertrophy than all other configurations.
  • The Failure: Shortened partials in the quadriceps produced results statistically similar to the non-training control group.