Fit Transitioning: When Can Transgender Airmen Fitness Test in Their Affirmed Gender?

ABSTRACT

Introduction

Transgender individuals have served openly in the U.S. Military since 2016. Official policies for transgender servicemembers continue to evolve, including approaches to physical fitness testing of transgender servicemembers. There is a paucity of scientific data regarding the effects of gender affirming hormone therapy (GAHT) on athletic performance for the past 24 months of treatment. Identification of expected trends in performance during and after gender transition is essential to allow for the development of appropriate military policy regarding when to assess servicemembers’ fitness by standards of their affirmed gender.

Materials and Methods

We identified Department of the Air Force transgender patients using the Transgender Health Medical Evaluation Unit database and recorded dates of GAHT initiation through a retrospective chart review. We recorded performance values for the Air Force physical fitness test components 1 year before and up to 4 years after GAHT initiation. Performance measures were maximum sit-ups in 1 minute, push-ups in 1 minute, and 1.5-mile run time. Pre- and post-GAHT scores were compared using one-sample T-test to mean scores of Air Force-wide cisgender averages to assess for significant difference between affirmed transgender and cisgender airmen. We then performed the two one-sided test (TOST) procedure for equivalence with upper and lower bounds set at 1 SD from the means for cisgender airmen. Finally, using Z-scores, average transgender group scores were assigned a percentile rank with their respect to affirmed gender throughout the transition process.

Results

Following initiation of GAHT, transgender males demonstrated statistically significant worse performance than cisgender males in all events until 3 years of GAHT. Their average scores would have attained a comfortable passing score within 1 year of GAHT. Transgender females’ performance showed statistically significantly better performance than cisgender females until 2 years of GAHT in run times and 4 years in sit-up scores and remained superior in push-ups at the study’s 4-year endpoint. TOST confirmed equivalence at all points where statistical difference was not demonstrated. Servicemembers approximate their pre-GAHT assigned gender percentile ranking in their affirmed gender in a manner consistent with hypothesis and TOST testing in the push-up event for both transgender males and females and in the 1.5-mile run event for transgender males.

Conclusions

In a sample of Air Force adult transgender patients, athletic performance measures demonstrate variable rates of change depending on the patients’ affirmed gender and differ by physical fitness test component. Based on this study, transgender females should begin to be assessed by the female standard no later than 2 years after starting GAHT, while transgender males could be assessed by their affirmed standard no earlier than 3 years after initiating GAHT.

INTRODUCTION

In 2016, U.S. DoD policy changed to allow open service by transgender servicemembers.^1,2 Since then, many transgender individuals have served honorably in all DoD institutions and proven their suitability for military service. The military health system has facilitated these policy changes by ensuring appropriate healthcare delivery for transgender members.

When patients transition from one gender to another, they are prescribed hormonal medication regimens to facilitate alignment with their affirmed gender, known as gender affirming hormone therapy (GAHT). For transgender males, this is a regimen of testosterone to facilitate masculinizing changes. For transgender females, this is typically medication to block natural testosterone in addition to taking estrogen to facilitate feminization. Many transgender patients also seek surgical procedures in support of their transition including facial plastic surgeries, mastectomy or breast augmentation, genital surgery, or voice surgery.^3,4 The Department of the Air Force provides this care through centralized medical multidisciplinary care team known as the Transgender Health Medical Evaluation Unit (THMEU). This approach ensures access to care for transgender servicemembers, adherence to Air Force policies, and a standardized approach to transgender care.

DoD policy currently states that fitness standards applied to transgender members should align with their gender marker in the Defense Enrollment Eligibility Reporting System.^5,6 Exceptions to policy (ETPs) are also available, but obtaining individual ETPs creates additional administrative burdens to command and individual airmen. The ongoing appropriate evolution of Air Force policy remains the ultimate standard in military operations.⁷

Under 2021 guidance, all transgender servicemembers starting hormone therapy may seek a fitness exemption for a period of 6 months with re-evaluation every 6 months.⁵ These policies, while flexible, lend unnecessary confusion and paperwork to the already complex transition process and are based on scarce evidence of the true impact of hormone therapy on a member’s ability to perform their fitness assessment. They also add the concern that a member’s overall health and conditioning may be impacted if they are not being held to any physical fitness test (PFT) standard at all for that period.⁷ It is prudent for policymakers to ensure that servicemembers have a gender marker change when they have fully transitioned but also at the time that they are fit to pass the fitness assessment in their affirmed gender. The right balance with this policy will maintain maximum force fitness with minimal unnecessary medical reviews and waivers for a transgender patient who is fit to serve.

Transgender athletics research thus far has focused on documenting physiological changes. Transgender males improve in most aspects of physical performance on GAHT, while transgender females experience deteriorating performance.⁸ Transgender females experience increases in fat mass on GAHT.⁹ While transgender males experience gains in lean mass, transgender females will have less lean body mass after 4 years of GAHT.¹⁰ There are also changes in muscle cross-sectional area, with transgender males making gains and transgender females demonstrating losses.¹¹ Maximal strength tests show mixed results depending on the modality used.^8,11,12 It is impossible to say how these changes translate to real-life athletic performance over time given the lack of research on this topic. The precise timing of when performance approximates that of an individual’s affirmed, rather than assigned, gender is poorly understood.^13–15 The military’s fitness testing programs offer an opportunity to better understand this because of the standardized process through which it is administered at specific intervals and the advantage of a cisgender comparison group.

This article expands on previously published data by Roberts et al. which documented a cohort of 75 transgender airmen’s fitness testing following up to 2 years of GAHT.¹ The focus of this previous analysis was to examine when transgender athletes might gain (in the case of transgender males) or lose (in the case of transgender females) a competitive advantage relative to the field of their affirmed gender during the follow-up period. Using simple hypothesis testing, they found that transgender males retained no advantage after 1 year of GAHT compared to cisgender males and transgender females retained a significant athletic advantage compared to cisgender females after 1 year of GAHT.

With continuing follow-up, we were able to establish a larger cohort of 374 patients followed for up to 4 years of GAHT to discuss in this article. Our focus is not to discuss competitive advantage but to address the question of unified and evidence-based fitness testing policy for a growing number of transgender servicemembers. We seek to provide evidence to guide commanders and policymakers about transgender airmen’s fitness assessments during gender transition. This is a fundamentally different question as military fitness testing aims to set a standard above which individuals demonstrate basic physical performance capabilities and maximize medical readiness, rather than quantifying the ceiling of human performance in a cohort.

Additionally, readers will note that the resulting performance timelines when servicemembers initiate GAHT differ between transitioning genders. There are several reasons for this. First, the parameters between genders differ in that transgender females should be assessed by the female standard once they are likely to fail the male standard including the failure of any single event, whereas transgender males should be assessed by the male standard once they are likely to be able to pass that standard.⁷ Second, limited prospective evidence has shown that advantageous increases to muscle mass and hemoglobin are mostly induced in the first 12 months of testosterone initiation for transgender males, whereas the time course of reduction in muscle bulk among transgender females has shown progressive loss for up to 36 months.^13–15

METHODS

For this study, we identified Air Force transgender patients using the Air Force’s centralized THMEU case management database. GAHT initiation date was recorded, as well as scores for the Air Force PFT (AFPFT) components in the year before and up to 4 years following GAHT initiation. Scores were categorized by year after GAHT initiation. Additional data gathered for this study included the servicemember’s military rank and duty status, GAHT regimen, as well as the dates of any gender-affirming surgical procedures performed during the study’s follow-up period.

The AFPFT performance measures at the time of the study were maximum number of push-ups and maximum number of sit-ups in 1 minute and a 1.5-mile run time.⁶ PFT tests are administered in a standardized fashion at the individual unit level across the Air Force. Testing is required biannually for performers who score from 75 to 90 and annually in the case of an “excellent” score over 90. Failing scores require retesting in 3 months. Servicemembers may receive waivers from their physicians not to test specific components of the fitness test due to injury. We calculated aggregate scores using scoring tables released for testing on January 1, 2022, for ages 25-29 (Table I).⁷

TABLE I.

Mean Scores by Component with Estimate Total Test Scores

Transgender males
	Male cisgender	Pre-GAHT	1-year GAHT	2-year GAHT	3-year GAHT	4-year GAHT
Number of scores		292	93	50	17	17
Number of subjects		131	63	46	25	5
Push-ups (SD)	54 (9)	37.5 (9)a	45.5(13)	48.4 (14)	56.6 (9)	62.1 (14)
Sit-ups (SD)	52 (8)	50 (8)	54.2 (7)	54.4 (8)	58.5 (10)	59 (8)
1.5-mile run (SD)	11:59 (1:33)	13:50 (2:08)	13:14 (2:15)	12:48 (1:48)	11:29 (1:39)	12:33 (1:02)
Total score, male standard	90.9	80.2	87.2	89.5	93.9	94
Total score, female standard	97.5	93	95.6	96.5	98.5	97
Transgender females
	Female cisgender	Pre-GAHT	1-year GAHT	2-year GAHT	3-year GAHT	4-year GAHT
Number of scores		456	106	42	26	11
Number of subjects		223	93	61	40	15
Push-ups (SD)	30 (10)	49.9 (10)	43.4 (10)	39.3 (9)	38.5 (13)	35.3 (7)
Sit-ups (SD)	41 (8)	52.6 (7)	49.4 (8)	48.1 (8)	45.6 (10)	44.4 (10)
1.5-mile run (SD)	14:36 (1:51)	12:00 (4:38)a	13:15 (1:52)	13:51 (1:53)	13:51 (3:12)	14:34 (2:13)
Total score, female standard	86	97.5	94.2	92.4	91	70.6
Total score, male standard	66	90.1	83.5	80.4	78	54

This table shows mean scores of each component at each phase of GAHT with standard deviations, as well as aggregate scores from these means calculated using the 2022 AFPFT standards for airmen aged 25-29. Bolded scores denote that no statistical difference was noted when compared with affirmed cisgender means using one-tailed T-test with P < .05.

^a

denote those scores that were considered non-equivalent to affirmed cisgender means by TOST analysis with upper and lower bounds set at 1 SD around the mean. The number of scores and number of individuals tested is analyzed is also noted at each endpoint. When multiple scores were attained in each period they were averaged for analysis. A score of 75 is a passing score.

Mean pre- and post-GAHT scores were separated by affirmed gender and categorized by year after initiation. If multiple scores were available in a given year, they were averaged for analysis. These were then compared by one-sample T-test to mean scores of Air Force-wide cisgender averages for servicemembers aged 20-30 to demonstrate where no significant difference could be found between affirmed transgender and cisgender airmen.¹⁶ This analysis evaluated the data sets for the prevalence or absence of a statistical difference—and where a difference is not found—it is not appropriate to conclude that equivalence between score groups exists.¹⁷

Additional analysis for equivalence was performed using the two one-sided test (TOST) procedure with upper and lower bounds for comparison set at 1 SD from the mean for cisgender average scores to assess for equivalence between affirmed gender and cisgender scores to capture the middle 50% of cisgender performances. This type of statistical analysis allows us to appropriately reject the presence of a statistically significant effect of difference between groups. The analysis allows us to set upper and lower equivalence bounds based on the smallest effect size of interest, which are chosen as above to adequately represent 50% of the comparison sample size and provide a confirmatory test for initial hypothesis testing (Table I).¹⁷

Finally, to illustrate progression with respect to peer airmen, we utilized a Z-score calculation using the normally distributed Air Force-wide cisgender averages to identify the percentile ranking of the transgender mean among those of their assigned gender before GAHT. This percentile is then compared with a percentile ranking among those in their affirmed gender at different time points following the initiation of GAHT (Fig. 3).

RESULTS

The sample included 374 patients, 146 transgender males and 228 transgender females, with a mean age of 26 at GAHT initiation (Supplemental Table S1). Twenty-eight patients completed follow-up to 4 years of GAHT (Table I, Supplemental Table S1).

Transgender Males

Before GAHT, transgender males demonstrated better performance compared to cisgender females in push-ups, sit-ups, and run times. Compared with cisgender males, they performed inferiorly in all events. Following initiation of GAHT, transgender men showed no statistical difference from cisgender men in the sit-up event at 1 year while push-ups and run times took 3 years to cease demonstrating statistically significant difference (Table I). This is demonstrated graphically in Fig. 1.

FIGURE 1.

Transgender male performance after GAHT initiation.

For percentile rankings, transgender males approach their pre-GAHT percentile ranking among cisgender females in their affirmed gender in a time pattern consistent with hypothesis testing in the push-up and 1.5-mile run time (Fig. 3). This can be appreciated as these airmen reach their pre-GAHT ranking at the same point as hypothesis testing ceases to demonstrate a difference between transgender and cisgender athletes in a particular event. In the sit-up event, the analogous percentile was reached 2 years after hypothesis testing initially failed to demonstrate a significant difference.

Using mean PFT component scores, we calculated the hypothetical average score on an entire test by each gender standard (Table I). Transgender males are high athletic performers before GAHT, and their hypothetical average score before therapy was a very low passing score in their affirmed gender. This includes no individual component failures by the male standards. There were increases in performance thereafter.

For transgender males, results of TOST analysis showed non-equivalence to cisgender females only in the push-up event before GAHT because of superior performance.

Transgender Females

Before GAHT, transgender females demonstrated poorer performance in push-ups compared to cisgender males but were not significantly different in sit-ups or run times. Compared with cisgender females, they demonstrated better performance in all events. Following initiation of GAHT, transgender females performed significantly better than cisgender females at 1 year in all tested events (Table I). Mean performances over time are noted in Fig. 2.

FIGURE 2.

Transgender female performance after GAHT initiation.

FIGURE 3.

Transgender percentile ranked performance.

Transgender female’s performance showed almost no statistical difference from cisgender females at 4 years of GAHT in the sit-up event. They did continue demonstrate statistical superiority in maximum push-ups during the study’s 4-year follow-up period. In run times, transgender females were no longer statistically different from cisgender females after 2 years of hormone therapy (Table I).

With respect to overall PFT scores, transgender females demonstrate an immediate decline in performance at the initiation of GAHT and demonstrate a very low passing score on the male standard after 2 years of therapy. This includes no individual component failures by the female standards. Scores and performance continue to decline thereafter (Table I, Fig. 2).

For transgender females, results of TOST analysis showed non-equivalence with cisgender females only in the run event before GAHT, demonstrating superior performance. In all other events and time points, transgender females demonstrated equivalence with cisgender females.

When assessing percentile ranking, transgender females do not arrive at their pre-GAHT cisgender percentile ranking in the push-up event, and this is consistent with hypothesis testing. They also do not arrive at their ranking in the sit-up event, and this differs from hypothesis testing which shows no significant difference between cisgender and transgender athletes at the 4-year mark. In the 1.5-mile run event, transgender females achieved their pre-GAHT ranking only after 4 years of therapy, which is a later time point compared to hypothesis testing.

DISCUSSION

Statistical Methods: Establishment of Equivalence with Affirmed Gender

The combined methods of hypothesis and equivalence testing as noted above create a superior analytical model to demonstrate performance equivalence where it may exist between two groups that goes beyond hypothesis testing. As noted in Figs. 1-2, performance scores for 50% of the cisgender populations show overlap in many events. In our study, the combination of null hypothesis testing with equivalence testing can help clarify incremental changes in performance when transgender athletes are compared with both their assigned and transitioning gender groups.¹⁷

Where transgender athletes are found to be statistically equivalent to as well as not statistically different from the performance of their affirmed gender, we can confidently state that transgender performance has approximated that of the cisgender group. This occurs for transgender males in the sit-up event at 1 year, run event, and push-up events at 3 years of GAHT and for transgender females in the 1.5-mile run event at 2 years of therapy and sit-ups at 4 years. Transgender females did not demonstrate equivalence in the push-up event during the study’s follow-up period. Further consideration must be given with respect to total PFT scoring to determine fitness testing timelines.

Additional confirmatory analysis using percentile rankings is demonstrated in Fig. 3. This allows another aspect of consideration for when performance was equivalent as an assessment of percentile ranking among an affirmed gender’s peers. In some events, this analysis acts as confirmatory to the previous tests: both push-up events and the transgender male run time. Yet, in other events, we note that percentile rank equivalence is achieved more slowly than hypothesis testing.

Transgender Males

Transgender males showed improvements in performance across all PFT events after initiation of GAHT. This is an expected result given the known anabolic and performance-enhancing effects of testosterone.^13,14,18 Of the 146 transgender males in our study, the most common regimen utilized was injected testosterone cypionate by 106 participants, injected testosterone ethanoate by three participants, with the other 37 utilizing topical testosterone gel or patch. We surmise that this may be a higher rate of topical testosterone use than the civilian population, as this formulation is more costly, but this regimen is preferred for servicemembers to remain deployable. We also note that this group had a high rate of gender-affirming surgical procedures during the study follow-up, with mastectomy being the most performed procedure in 65 participants. This may slow gains in performance over time as individuals are unable to complete training regimens or fitness tests while recovering from surgery.

An important finding is also that transgender males have a high level of fitness with respect to cisgender females before transition; i.e., they perform better in all events than cisgender females before transition. However, the model does suggest that most transgender males undergoing in-service transition should be capable of comfortably passing the male standard PFT after 3 years of masculinizing hormone therapy based on demonstrating a loss of significant difference with cisgender males in all events and indicating equivalence with cisgender males in two of three events. Aggregate scores noted in Table I comfortably support this conclusion. Furthermore, the percentile rankings wherein transgender males are likely to attain similar ranking relative to their peers within 3 years support this conclusion in the push-up and run events (Fig. 3).

Transgender Females

Transgender females demonstrate declining performance following initiation of GAHT. This is consistent with previous studies documenting loss of muscle mass and aerobic endurance.^8,15 However, the timing of individual changes to different PFT components illustrates the heterogeneous nature of changes that transgender females undergo over time.

At the 2-year mark, they cease demonstrating statistically different performance to females in the 1.5-mile run event—a marker for aerobic fitness. After 4 years, the sit-up event also lost significant difference as a marker of core strength and endurance, around when muscle area changes are maximized.^11,15 In this study, push-ups never stopped demonstrating a significant difference. This may illustrate innate anthropometric changes that occur because of assigned gender puberty such as larger upper body muscle mass and smaller lower body fat mass. These may change more slowly or not at all. The percentile ranking model is confirmatory in this event.

Transgender females only approximate cisgender female performance in two of three events, the run and the sit-up event, at 4 years. Percentile ranking adaptation lags in both of these events compared with hypothesis testing (Fig. 3). However, declines in performance following GAHT initiation prevent transgender women from obtaining a passing score on the male standard throughout their transition (Table I). A failure in any single event results in a failure of the entire test. Transgender females are likely to fail the male PFT standard around 2 years of therapy, suggesting a fitness ETP or change of gender marker to ensure use of female standards should occur by then.

Military-Specific Considerations

There are a few additional considerations unique to this data set. First, we recognize that all fitness testing in the study was completed before scoring standard changes in 2022. These changes included lower minimum component and total scores, smaller age group brackets, higher point values for similar performances, as well as the option to complete alternative testing components.⁶ It is difficult to say how these changes would motivate performance on the individual level. We recognize that we have used a previous performance compared to a current metric and the effect of this change is unknown.

In competitive athletics, some have suggested creating a separate transgender category, and the THMEU has considered this possibility for transitioning servicemembers. There are several flaws with this model. First, transition timelines differ significantly between individual depending on the number and type of surgical procedures required for transition. These surgeries also impact a servicemember’s ability to complete fitness testing during their transition. There are not yet enough data to create normative scores for transgender patients. Finally, the current ETP model allows commanders of fitness-exempted servicemembers to keep a close eye on their servicemembers during the transition process and provide optimal support.

Limitations

It is important to recognize the limitations of this study and analysis. First, this analysis does not contribute to the ongoing discussion of the inclusion criteria for transgender athletes in cisgender sporting competition, and that is not the aim of this paper. The question of retained advantage relative to the field in transitioning transgender female athletes is an exceedingly difficult one to answer with available statistical data, as demonstrated by the intricacy of results in this article regarding transgender females’ fitness changes over time.

This analysis, like many in the transgender literature, suffers from many methodological issues including a small sample size and uncontrolled for lifestyle variables that could affect physical fitness such as different exercise regimens, body mass index, and access to fitness equipment during Coronavirus lockdowns of 2020. Recent literature regarding transgender individuals’ fitness practices shows mixed factors contributing consistent physical training including an overall lack of trans-inclusive spaces but also individual’s desire for gender-specific body changes that can be achieved in the gym, and these criteria should be considered in future analyses without specific training programs.¹⁹

In this design, there is also concern for survivorship bias. Most of our subjects did not complete 4-year follow-up because of recent start dates of GAHT, but many of them had also left the military before receiving 4 years of GAHT. We are unable to account for the performance of dropout subjects because they were no longer in the military or receiving care within the military health system. This might skew our data in several ways. For example, perhaps, individuals who continue military service display a higher level of physical fitness or have better access to healthcare than those who leave. Our data are unable to distinguish between the career servicemember who might have more external motivation to stay fit versus the young airman wanting to separate after an initial enlistment. Number of scores analyzed at each data point is noted in Table I. Servicemembers with poor scores are also tested more frequently, but data points achieved within a single analysis timeframe were averaged for analysis.⁷

Improvements to a future design might include a longitudinal control group without GAHT or more standardized GAHT and exercise regimens, both of which would contribute well to a randomized controlled trial model but whose methods may be unethical or unfeasible.

CONCLUSIONS

As transgender individuals receive more opportunities to serve, policy development regarding fitness testing should consider their unique physiology. Commanders can advocate for their transgender troops at the unit level as well. Currently, the process of obtaining individual fitness ETPs can be burdensome and a unified policy would better support both troops and command. To this end, our data support that transgender males should be held to the male standard no earlier than 3 years after GAHT initiation and transgender females should be afforded the female standard no later 2 years after GAHT initiation.

ACKNOWLEDGMENTS

None.

SUPPLEMENTARY MATERIAL

Supplementary Material is available at Military Medicine online.

FUNDING

This study received no funding.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflicts of interest.

CLINICAL TRIAL REGISTRATION

None.

INSTITUTIONAL REVIEW BOARD

This study was approved by the Wilford Hall Ambulatory Surgical Center’s Institutional Review Board.

INSTITUTIONAL ANIMAL CARE AND USE COMMITTEE (IACUC)

Not applicable.

DATA AVAILABILITY

The data that support the findings of this study are available on request from the corresponding author.

INSTITUTIONAL CLEARANCE

Institutional clearance approved.

Author notes

Preliminary findings from this research have been previously presented in short abstract form at the Society for Adolescent Health and Medicine Annual Meeting 2022.

The views expressed in this material are those of the authors and do not reflect the official policy or position of the U.S. Government, the DoD, or the Department of the Army.