The American College of Sports Medicine (ACSM) has published an expert consensus statement addressing the biological basis of sex differences in athletic performance. The main goal of the statement, which focuses primarily on adult male and female athletes, is to contribute to the public dialogue by providing the latest scientific knowledge and subject matter expertise on the sex differences in athletic performance, while assisting with evidence-based solutions and ensure an equitable and fair solution for all. The statement has implications for adult athletes at every age.

Key findings include: 

- Biological sex is a determinant of athletic performance: adult males are faster, stronger, more powerful than females because of fundamental sex differences in anatomy and physiology dictated by sex chromosomes.

- Before puberty, sex differences in athletic performance are minimal. Significant differences emerge at puberty (around age 12) due to anabolic effects of testosterone in males. Testosterone levels rise 20-30-fold in males during puberty and are 15 times higher in males than females by age 18.

- Direct and indirect effects of testosterone during male puberty include increased skeletal muscle mass due to larger muscle fiber cross-sectional area, especially fast, type II fibers; lower percentage body fat; higher hemoglobin concentration and mass; larger ventricular mass (heart) and cardiac volumes; larger airways and lungs; greater body height; and longer limbs.

- Adult males are stronger, more powerful, and faster than females of similar age and training status. The sex difference in athletic performance where endurance or muscular power is required is roughly 10%-30% depending on the event.

- Past and present studies of athletic performance, acute exercise and exercise training involve the testing of more males than females or fail to distinguish between the sexes. Consequently, less is known about the physiology of female athletes than males, the limits of their athletic abilities, and the acute and adaptive response of females to exercise and training.

-The rate of improvement in athletic performance of women has exceeded that of men in the last 100 years across a multitude of sports as women have gained access to training, equipment, facilities, and opportunities.

“It should be noted that ACSM acknowledges that there are gaps in the data and further research is needed to address them,” said  lead author, Sandra Hunter, PhD. “A major step toward closing the knowledge gap is to include more and equitable numbers of women to that of men in mechanistic studies that determine any of the sex differences in response to an acute bout of exercise, exercise training and athletic performance.”

This consensus statement is the first in a series of three ACSM pronouncements on the topic of sex differences and transgender athletes.

To read the abstract of the consensus statement, published in Medicine & Science in Sports & Exercise, click here