Does Body Build Predict Training Response?

Researchers examined whether a person’s somatotype (ectomorph, mesomorph, or endomorph) was predictive of muscle and strength gains. They found that somatotype was a weak predictor of training response.

Overview

• What did they test? Researchers put 40 untrained young adult men on a 9-week resistance training program. At the beginning of training, they were classified into their somatotype (ectomorph, mesomorph, or endomorph). The researchers looked at muscle hypertrophy and strength responses, and whether these were related to somatotype.
• What did they find? Greater baseline mesomorphy (i.e., more natural muscularity) was only weakly associated with hypertrophy and strength outcomes. 
• What does it mean for you? A person’s body build is not a good predictor of whether he will be a strong responder to resistance training. For example, some ectomorphs could respond very well, while some mesomorphs may not. Don’t let your natural body build discourage you from seeing where a solid training and nutrition program might take you.

What’s the Problem?

Somatotype is a popular method to classify your body build. It was first popularized in the 1940s, and divides people’s body types into one of three classifications:

1. Ectomorph. A person with a narrow frame and minimal body fat and musculature. We often think of ectomorphs as naturally skinny people. I would consider myself in that category.
2. Mesomorph. A naturally muscular person with broad shoulders and narrow waist.
3. Endomorph. A person with a large skeletal frame and higher level of body fat.

People may also fall into a combination of these categories For example, someone might be an ecto-mesomorph. We might even consider that these categories operate more on a continuum rather than thinking them as nice neat categories that any person could fit into.

It’s been thought for a long time that mesomorphs have a greater capacity to respond well to resistance training, with superior improvements in size and strength. There is evidence that a person’s somatotype may be related to their baseline strength. For example, mesomorphs have significantly higher 3-RM squats and bench presses than ectomorphs 1. However, just because your somatotype might be related to your baseline strength or muscle doesn’t mean it’s related to how you respond to a training program. There hadn’t been a study to date that has investigated how somatotype might impact training response, until now. In a recent preprint that has yet to be peer-reviewed, a group of scientists, primarily from Brad Schoenfeld’s Applied Muscle Development Lab in New York, investigated the impact of somatotype on strength and hypertrophy during a resistance training program. Let’s take a look at it.

Purpose

The purpose of this study was to examine the relationship between baseline somatotype and subsequent gains in muscle size and performance.

Hypothesis

The researchers hypothesized that greater baseline mesomorphy would be associated with greater muscle hypertrophy and performance adaptations, and that people with a predominantly mesomorphic phenotype would show greater adaptations than non-mesomorphs. Also, they hypothesized that people with greater African genetic ancestry would be associated with higher mesomorphy, based on other unpublished research from the same lab showing greater baseline muscularity in men of African descent compared to European descent 2.