Key words: Body composition; Physical fitness.

Why is this study important?

The inclusion of transgender athletes in competitive sports has sparked significant dialogue and controversy. This study is crucial as it addresses the gap in data regarding exercise performance, body composition, and health-related parameters of transgender athletes, specifically transgender women (TW), compared to cisgender women (CW), and cisgender men (CM) volleyball players (1). Understanding these differences can inform policies and practices to ensure a fair and inclusive sport environment.

How was the study conducted?

This cross-sectional study was conducted in São Paulo, Brazil, involving 23 amateur volleyball players: 7 TW, 8 CW, and 8 CM. Participants were matched by age, body mass index (BMI) and level of activity according to the International Physical Activity Questionnaire. The study assessed various parameters, including body composition, blood biomarkers, handgrip strength, countermovement jump height, squat jump height, and maximum oxygen consumption (V̇O2max).

Participants underwent a series of tests. Initially, they answered questionnaires, performed blood tests and body composition assessment.  Vertical jump tests were performed at the athletes’ training sites to ensure ecological validity. The volunteers consumed a standardized meal before performing muscle strength and cardiorespiratory tests carried out in an exercise physiology laboratory

What were the study’s findings?

The study revealed several key findings:

1. Body Composition and Biomarkers: Transgender women and cisgender women had similar levels of estradiol, testosterone, and hemoglobin, while cisgender men had significantly higher levels of testosterone and hemoglobin. Lean body mass was lower in transgender women compared to cisgender men but similar to cisgender women. Fat mass did not differ significantly between transgender and cisgender women, but cisgender men had higher lean body mass.
2. Exercise Performance: In terms of exercise performance, transgender women showed lower handgrip strength, countermovement jump height, and squat jump height compared to cisgender men, but these measures did not differ significantly between transgender and cisgender women. Specifically, transgender women exhibited similar physical capabilities to cisgender women in these areas. However, cisgender men outperformed both groups in these performance metrics. Maximum oxygen consumption (V̇O2max) was also lower in transgender women compared to cisgender men but similar to cisgender women, indicating comparable aerobic capacity between transgender and cisgender women.
3. Health Parameters: The study found no significant differences in sleep quality or dietary intake between transgender and cisgender women. However, cisgender men had higher energy intake and lower sleep duration compared to both transgender and cisgender women. 

Key conclusions and practical implications

The study suggests that transgender women volleyball players have similar exercise performance and health parameters to cisgender women but lower than cisgender men. These findings highlight the need for further research to understand the impact of gender-affirming hormone therapy on athletic performance and to develop inclusive sports policies. Promoting fair competition while ensuring the inclusion of transgender athletes requires a nuanced understanding of these differences. The study also underscores the importance of considering various health parameters, such as sleep quality and dietary intake

Further research with larger sample sizes and diverse sports disciplines is needed to build on these findings and inform evidence-based policies.

Authors: Leonardo Alvares

References

1. Alvares LA, Dos Santos Quaresma MV, Nakamoto FP, Santos LM, Navarro LS, Navarro GS, Orozco BMM, Sá BMC, Achkar GB, Marques CG, Barbosa RCC, Ferreira RES. Body composition, exercise-related performance parameters and associated health factors of transgender women, cisgender women and cisgender men volleyball players. Br J Sports Med. 2025 Feb 18:bjsports-2024-108601. doi: 10.1136/bjsports-2024-108601. Epub ahead of print. PMID: 39965884. 

Text based on data from the TOP (Transgender Observational Protocol) study.