Abstract
Purpose
Although lower body strength and size are often regarded as symbols of masculinity, their relationship to testosterone is unclear. This study aimed to determine the correlation between lower body strength, size, and testosterone levels.
Materials and Methods
Serum testosterone levels, waist circumference, and body mass index (BMI) were measured in 69 men with erectile dysfunction (age >40 years). The circumferences of the thigh and calf were measured, and the muscle strength of the knee joints was evaluated using an isokinetic dynamometer. Patients were classified into three groups according to testosterone levels (group 1, <230 ng/dL; group 2, 230 to 350 ng/dL; group 3, >350 ng/dL). Differences in calf and thigh circumference, bilateral knee extension, and flexion strength between the three groups were investigated using a one-way analysis of variance. Pearson’s chi-square test was used to assess differences in lifestyle habits and underlying diseases. A partial correlation analysis was conducted to determine the association between testosterone levels and lower body size and strength.
Results
There was no difference in BMI among the three groups, but waist circumference was significantly larger in group 1 than in groups 2 and 3. When comparing weight-adjusted values, bilateral thigh circumference showed a significant difference among the three groups. There was also a significant difference between the three groups in the weight-adjusted left calf circumference and in the weight-adjusted right knee extension strength. The partial correlation test showed a significant positive correlation between thigh and calf circumference values adjusted for weight and serum testosterone levels. Weight-adjusted knee extension strength demonstrated a significant positive correlation with serum testosterone levels.
Conclusions
Weight-adjusted thigh and calf circumferences, along with the thigh-to-waist ratio, showed a positive correlation with testosterone levels. Weight-adjusted knee extension strength was positively correlated with testosterone levels. Therefore, a robust thigh and strong lower body are related to testosterone.
Keywords: Anthropometry, Lower extremity, Muscle strength, Testosterone
INTRODUCTION
Testosterone, a major sex steroid hormone in men, influences various physiological aspects of the body, including muscle development, bone density, libido, and sexual performance [1]. Testosterone is recognized for its significant role in the growth and development of muscle mass by promoting protein synthesis in muscle cells, especially in thigh and calf muscles of the lower body [2,3]. Diminished testosterone levels are correlated with increased visceral fat mass [4] and diminished lean body mass and muscle strength [5]. Testosterone replacement in patients with testosterone deficiency significantly improves muscle mass and strength [6]. However, some cross-sectional studies have shown that testosterone levels are not significantly correlated with muscle mass, but rather with fat mass. Muscle strength is not significantly correlated with testosterone levels, but cardiorespiratory fitness is significantly correlated with testosterone levels [7].
Regarding the relationship between lower body strength and testosterone level, Aguirre et al [8] reported a significant positive correlation between knee flexion and extension strength and serum testosterone levels in obese men with a body mass index (BMI) of over 30 and are over 65 years old. However, Ferreira et al [9] concluded that lower body strength was only reduced in the presence of diabetes and that low total testosterone levels were not associated with lower body strength. There are conflicting findings regarding the relationship between lower body strength and testosterone levels, and limited research has been conducted on the relationship between the anthropometric size of the male lower body and testosterone levels. Therefore, this study aimed to ascertain whether the size and strength of the male lower body correlates with testosterone levels.
MATERIALS AND METHODS
1. Ethics statement
The study protocol was reviewed and approved by the Institutional Review Board of Inje University Seoul Paik Hospital (Protocol No. 2021-05-005). Informed consent was obtained from all participants upon enrollment.
2. Participants
Among patients whose serum testosterone levels were assessed at our institution for erectile dysfunction (ED) between March 2021 and December 2022, the data of 69 patients who underwent measurement of the anthropometric size of the lower body and isokinetic knee strength testing were analyzed. In this study, all male participants were a minimum of 40 years of age and reported a persistent inability to achieve or sustain an adequately rigid erection for sexual intercourse for a duration exceeding 6 months. Patients who had trouble participating in isokinetic knee strength testing because of lower extremity joint problems or a history of treatment for hypogonadism were excluded.
3. Study design and parameters
Patients were categorized based on serum testosterone levels as follows: group 1, <230 ng/dL; group 2, 230 to 350 ng/dL; and group 3, >350 ng/dL. Medical history, alcohol consumption, and smoking habits were recorded, and waist circumference, weight, height, and BMI were measured for each participant. Anthropometric measurements of the lower body involved recording the thickest parts of both the calves and thighs using a tape measure. Lower body muscle strength was assessed using an isokinetic dynamometer (Humac Norm; CSMi) to measure the knee joint extensor and flexor muscle strength. An isokinetic dynamometer is a manual device that controls the movement speed to allow muscles to contract at a constant rate through a defined range of joint motions while resisting a mechanically applied force. The participants were seated in an examination chair to maintain a consistent testing position, aligning the axis of the dynamometer with the anatomical axis of the knee and the lateral epicondyle of the femur. The participants were secured with straps around their thighs, pelvis, and trunk to minimize compensatory movements. Measurements were taken during uniaxial contractions involving successive knee extensions and flexions. The methodology was comprehensively explained to the participants, accompanied by a series of preliminary exercises to ensure complete understanding. The knee’s range of motion for the test ranged from 0° (full extension) to 90°. The participants commenced the exercise with their knees flexed at 90° and initiated movements upon receiving a signal from the examiner. This procedure involved measuring the maximal extension, followed by the maximal flexion at subsequent signals. Each subject executed four repetitions at an angular velocity of 60°/s. Peak torque, quantified in Newtons (Nm), served as the primary metric for analysis. The absolute values of knee extension and flexion strength were subsequently normalized to relative percentages by dividing these values by body weight.
4. Statistical analysis
An one-way analysis of variance was conducted to analyze the data for group differences in BMI, waist circumference calf, and thigh circumferences, and bilateral knee extension and flexion. Pearson’s chi-square test was used to evaluate differences in lifestyle habits and underlying diseases. A partial correlation test was used to examine the relationship among serum testosterone levels, body size, and strength. All statistical analyses were performed using PASW Statistics ver. 18.0 (IBM Corp.). Statistical significance was set at 2-tailed p-values <0.05.
RESULTS
The average age of the 69 men who participated was 59.3 years (40–81 years), and the average serum testosterone level was 305.9 ng/dL (101.6–792.5 ng/dL). Group 1 comprised of 15 people, group 2 comprised of 38 people, and group 3 comprised of 16 people. No significant differences in age were observed among the three groups (Table 1).
Table 1. Comparison of variables between the three groups.
| Group 1 (n=15) | Group 2 (n=38) | Group 3 (n=16) | p-valuea | ||
|---|---|---|---|---|---|
| Age (y) | 60.7±11.37 | 59.5±7.49 | 57.3±11.42 | 0.584 | |
| Comorbidities | |||||
| Number of underlying diseases | 2.53±1.81 | 1.73±1.37 | 1.18±1.10c | 0.018 | |
| Hypertension | 9/15 | 23/38 | 2/16 | 0.004 | |
| Diabetes mellitus | 10/15 | 15/38 | 5/16 | 0.105 | |
| Dyslipidemia | 9/15 | 10/38 | 3/16 | 0.026 | |
| Hepatobiliary disease | 2/15 | 1/38 | 0/16 | 0.142 | |
| Pulmonary disease | 1/15 | 1/38 | 0/16 | 0.537 | |
| Chronic kidney disease | 0/15 | 1/38 | 0/16 | 0.661 | |
| Alcohol | 8/15 | 19/38 | 3/16 | 0.073 | |
| Smoking | 6/15 | 14/38 | 4/16 | 0.629 | |
| Body weight (kg) | 81.6±11.18 | 77.4±12.72 | 73.0±8.76 | 0.129 | |
| Waist circumference (cm) | 101.4±11.18 | 94.4±9.21b | 91.5±7.67c | 0.012 | |
| Body mass index (kg/m2) | 27.5±3.45 | 26.7±4.35 | 25.1±2.98 | 0.228 | |
| Thigh circumference (cm) | |||||
| Right | 49.8±4.31 | 48.2±4.01 | 46.9±3.28 | 0.132 | |
| Left | 49.5±3.99 | 48.0±4.03 | 46.6±3.25 | 0.107 | |
| Calf circumference (cm) | |||||
| Right | 39.2±3.76 | 37.5±2.89 | 36.1±1.73c | 0.015 | |
| Left | 38.8±3.79 | 37.1±2.76 | 36.0±1.66c | 0.025 | |
| Thigh circumference/weight (cm/kg)d | |||||
| Right | 58.9±0.07 | 63.1±0.06 | 65.5±0.07c | 0.023 | |
| Left | 58.7±0.07 | 62.8±0.06 | 65.0±0.07c | 0.027 | |
| Calf circumference/weight (cm/kg)d | |||||
| Right | 46.3±0.05 | 49.1±0.05 | 50.4±0.05 | 0.067 | |
| Left | 45.9±0.05 | 48.7±0.05 | 50.3±0.05c | 0.046 | |
| Thigh circumference/waist (%) | |||||
| Right | 49.3±0.04 | 51.3±0.04 | 51.5±0.04 | 0.245 | |
| Left | 49.1±0.04 | 51.1±0.04 | 51.1±0.04 | 0.242 | |
| Calf circumference/waist (%) | |||||
| Right | 38.7±0.03 | 39.9±0.03 | 39.6±0.03 | 0.483 | |
| Left | 38.9±0.03 | 39.5±0.03 | 39.5±0.03 | 0.780 | |
| Calf/thigh circumference (%) | |||||
| Right | 78.7±0.03 | 77.8±0.04 | 77.1±0.04 | 0.483 | |
| Left | 78.3±0.03 | 77.6±0.04 | 77.5±0.04 | 0.780 | |
| Knee extension strength (Nm) | |||||
| Right | 137.1±37.52 | 138.2±34.24 | 144.8±29.98 | 0.777 | |
| Left | 148.3±31.40 | 134.1±27.28 | 143.4±29.56 | 0.234 | |
| Knee flexion strength (Nm) | |||||
| Right | 69.4±21.90 | 66.0±18.64 | 63.2±18.69 | 0.686 | |
| Left | 69.6±24.44 | 66.4±20.33 | 62.3±17.27 | 0.620 | |
| Knee extension strength/weight (Nm/kg)d | |||||
| Right | 165.3±38.25 | 181.4±40.98 | 202.3±42.41c | 0.050 | |
| Left | 178.5±26.72 | 179.2±35.75 | 200.3±42.88 | 0.126 | |
| Knee flexion strength/weight (Nm/kg)d | |||||
| Right | 83.4±20.15 | 86.6±27.06 | 87.1±24.28 | 0.905 | |
| Left | 81.6±24.63 | 86.8±27.31 | 86.0±22.38 | 0.811 | |
Values are presented as mean±standard deviation.
Patients were classified into three groups according to testosterone levels (group 1, <230 ng/dL; group 2, 230 to 350 ng/dL; group 3, >350 ng/dL).
ap-value derived from the analysis of variance between the three groups. bStatistically significant difference between groups 1 and 2 in the post-hoc analysis. cStatistically significant difference between groups 1 and 3 in the post-hoc analysis. dDisplayed as the original value multiplied by 100.
There was a significant difference in the number of comorbidities between the three groups (p=0.018), with group 1 having a significantly higher number of comorbidities than group 3, wherein a significantly higher incidence of hypertension and dyslipidemia was present (p=0.004, p=0.026). BMI showed no significant difference; however, waist circumference showed a significant difference (p=0.012), wherein the waist circumference of group 1 was significantly larger than that of groups 2 and 3 (p=0.041, p=0.012; Table 1).
The comparison between the three groups exhibited a significant difference in calf circumference (p=0.015, p=0.025). Group 1 had the thickest calf circumference, and group 1 had a significantly larger calf circumference than group 3 (p=0.011, p=0.019). There were no differences in knee extension and flexion strengths among the three groups. The comparison of bilateral thigh circumference adjusted for body weight showed a significant difference among the three groups (p=0.023, p=0.027), with group 3 having a larger value than group 1 (p=0.019, p=0.023). When calf circumference was adjusted for body weight, the values also increased from group 1 to 3. There was a significant difference among the three groups in the comparison of the left calf circumference adjusted for body weight (p=0.046). The weight-adjusted left calf circumference in group 3 was significantly larger than that in group 1 (p=0.039). The comparison of thigh and calf circumferences corrected for waist circumference did not show a significant difference among the three groups. There was no significant difference in the thigh-to-calf circumference ratio among the three groups. It demonstrated no marked differences between the three groups in bilateral knee extension and flexion strength; however, when comparing weight-adjusted values, there was a notable difference in right knee extension strength between the three groups (p=0.05), with group 3 having significantly greater strength than group 1 (p=0.041; Table 1).
When the factors that correlated with testosterone levels after adjusting for age were examined using partial correlation analysis, testosterone levels decreased significantly as the body weight, waist circumference, and BMI increased (p=0.002, p=0.000, p=0,005; respectively). A thicker calf circumference was associated with lower testosterone levels (p=0.002, p=0.008), and weight-adjusted calf circumference was positively correlated with testosterone levels (p=0.009, p=0.002). A thicker thigh circumference was associated with lower testosterone levels (p=0.042, p=0.035), and weight-adjusted thigh circumference and waist circumference-corrected thigh circumference exhibited a positive correlation with testosterone levels (p=0.001, p=0.001, p=0.045, p=0.049). The thigh-to-calf circumference ratio showed an increase in testosterone levels as the relative thigh thickness increased without statistical significance. Weight-adjusted bilateral knee extension strengths positively correlated with testosterone levels (p=0.008, p=0.040); however, knee flexion strength was not significantly correlated with testosterone levels (Table 2).
Table 2. Correlation between serum testosterone level, anthropometric data, and knee strength.
| Variable | Testosterone | |
|---|---|---|
| r | p-value | |
| No. of comorbidities | -0.212 | 0.101 |
| Weight | -0.394 | 0.002* |
| Waist | -0.434 | 0.000* |
| Body mass index | -0.353 | 0.005* |
| Thigh circumference, right | -0.261 | 0.042* |
| Thigh circumference, left | -0.270 | 0.035* |
| Calf circumference, right | -0.390 | 0.002* |
| Calf circumference, left | -0.336 | 0.008* |
| Thigh circumference/weight, right | 0.411 | 0.001* |
| Thigh circumference/weight, left | 0.408 | 0.001* |
| Calf circumference/weight, right | 0.330 | 0.009* |
| Calf circumference/weight, left | 0.384 | 0.002* |
| Thigh circumference/waist, right | 0.258 | 0.045* |
| Thigh circumference/waist, left | 0.253 | 0.049* |
| Calf circumference/waist, right | 0.147 | 0.259 |
| Calf circumference/waist, left | 0.216 | 0.094 |
| Calf/thigh circumference, right | -0.194 | 0.135 |
| Calf/thigh circumference, left | -0.063 | 0.630 |
| Knee extension strength, right | -0.009 | 0.943 |
| Knee extension strength, left | -0.127 | 0.328 |
| Knee flexion strength, right | -0.062 | 0.635 |
| Knee flexion strength, left | -0.141 | 0.278 |
| Knee extension strength/weight, right | 0.334 | 0.008* |
| Knee extension strength/weight, left | 0.264 | 0.040* |
| Knee flexion strength/weight, right | 0.186 | 0.150 |
| Knee flexion strength/weight, left | 0.114 | 0.381 |
Partial correlation analyses with age as a confounding factor were performed.
r: Pearson correlation coefficient.
*p<0.05.
DISCUSSION
In this study, dividing patients into three groups based on testosterone levels revealed a notably higher comorbidity incidence in group 1. Testosterone, a critical regulator of metabolic homeostasis, affects various physiological processes such as endothelial function, inflammation, and glucose metabolism [10]. It exerts a protective effect on pancreatic β-cells by modulating inflammation through the androgen receptor [11]. Notably, low serum testosterone levels are significantly associated with insulin resistance and the development of type 2 diabetes [12]. Furthermore, low testosterone levels are strongly correlated with metabolic syndrome, including hypertension and hyperlipidemia [13]; serve as predictors of cardiovascular events, such as stroke and transient ischemic attacks; and are associated with increased cardiovascular and overall mortality [14]. Testosterone levels also affect body composition, exhibiting an inverse relationship with body weight, fat content, BMI, waist circumference, and waist-to-hip ratio [15]. This study found significant negative correlations between testosterone levels and weight, BMI, and waist circumference, wherein waist circumference displayed a marked statistical difference between groups. A previous study highlighted the strong association between waist circumference and serum testosterone levels in men, particularly with testosterone supplementation in testosterone-deficient patients. Reduction in waist circumference was the only factor that was significantly associated with increased testosterone levels [6].
Muscle mass, which is a source of strength, is typically assessed by measuring the cross-sectional area (CSA) of the muscle using dual x-ray absorptiometry (DEXA) scan or magnetic resonance imaging (MRI). However, these procedures are uncomfortable, expensive, and difficult to achieve patient cooperation. Therefore, in this study, we used anthropometric indices that can be easily measured. Various studies have shown that anthropometric indices can be used as markers of muscle mass and can predict the presence of diseases, such as hypertension, dementia, and cancer [16,17].
The clinical value of the anthropometric calf and thigh circumferences measured in our study has been validated in several studies. Hodgkiss and McCarthy [18] found that thigh circumference in adult men was strongly correlated with skeletal muscle mass, particularly at normal and overweight levels, and more so than in obese men. This may be due to the greater influence of fat mass on thigh circumference in obese individuals. For these reasons, our study adjusted calf and thigh circumferences for weight. These circumstances may be helpful in diagnosing sarcopenia. A Korean study of individuals aged 70 to 84 suggested a cutoff value of less than 35 cm for calf circumference in men for diagnosing sarcopenia [19]. A similar Indonesian study proposed cutoff values of 34 cm for calves and 49 cm for thighs for diagnosing sarcopenia [20]. Another study on older adults demonstrated a significant correlation between thigh muscle volume, as measured by MRI, thigh circumference, and physical functions such as quadriceps muscle power. This study developed a regression equation to estimate the actual thigh muscle mass, incorporating factors such as age, sex, weight, and thigh circumference [21]. These studies indicated a significant correlation between thigh and calf circumferences and lower body muscle mass. Given the pivotal role of testosterone in muscle development, we anticipated a favorable correlation between muscle mass and serum testosterone concentrations. However, our study revealed a significant negative correlation between calf circumference and serum testosterone levels through a partial correlation analysis. In a prior study [7] that examined men with ED, no significant correlation between skeletal muscle mass and serum testosterone levels were found. Only fat-related parameters demonstrated negative correlation with serum testosterone levels. In this study, we re-evaluated this correlation with serum testosterone levels using weight-adjusted values of the calf and thigh circumferences. This analysis revealed a significant positive correlation between the adjusted circumferences and serum testosterone levels. The uncorrected measurements of thigh and calf circumference, which include fat components besides muscle mass, likely contributed to their negative correlation with serum testosterone. The negative correlation of calf/thigh ratios with serum testosterone levels suggests a stronger association between increased thigh circumference and higher testosterone levels than that of the calf circumference. One-way analysis of variance, which categorized participants into three groups based on testosterone levels, revealed significant differences in calf circumference between the groups. Group 1, which had the lowest testosterone levels, had significantly thicker calves than group 3, implying a greater impact of fat mass on the calf than on the thigh in Korean men aged >40 years. However, when calf and thigh circumferences were adjusted for waist circumference, corrected thigh circumference exhibited a noteworthy positive correlation with serum testosterone levels. Yeo et al [7] reported a significant negative correlation between waist circumference and serum testosterone levels. Additionally, waist circumference is most closely related to increased serum testosterone during treatment [6]. The findings of this study, wherein thigh circumference adjusted for waist circumference was significantly correlated with serum testosterone levels, further underscore the relationship between fat mass and waist circumference.
Our study purposed to evaluate the relationship between lower body strength and testosterone levels, as well as lower body size. Various methods, such as the standing long jump and one rep max maximum squat [22,23] measure lower body muscle strength and power. However, these methods involve substantial upperbody engagement, including the back and abdominal muscles, and may pose risks to older participants. In contrast, assessing knee flexion and extension strength using an isokinetic dynamometer offers a safe, reliable, and reproducible option for older individuals that accurately reflects the strength of lower extremity muscles.
Several studies have reported an association between testosterone levels and knee strength measured using an isokinetic dynamometer. Aguirre et al [8] observed this correlation in frail, obese patients aged >65 years with an average BMI of 37.0, while measuring isokinetic knee extension and flexion strength in a hip-flexed position (120°). They found that testosterone levels were positively correlated not only with knee flexion and extension strength but also with total body strength, physical performance, and aerobic fitness. Ferreira et al [9] investigated a similar association in male patients aged 18 to 65 years. They compared non-type 2 diabetes mellitus (T2DM) individuals, T2DM patients with low testosterone levels, and T2DM patients with normal testosterone levels by measuring concentric knee extension and flexion strength. While testosterone levels varied significantly across these groups and T2DM markedly reduced knee strength, the study found no significant difference in knee strength between the low and normal testosterone groups. Additionally, the correlation analysis revealed no significant relationship between testosterone levels and knee strength.
In our study, serum testosterone was significantly correlated with weight-adjusted knee extensor strength, but not with knee flexor strength. This may stem from the difference in muscle mass between the knee extensors (rectus femoris, vastus medialis, intermedius, and lateralis) and flexors (semimembranosus, semitendinosus, biceps femoris, gracilis, sartorius, gastrocnemius, plantaris, popliteus). The knee extensors are known to have greater muscle mass and strength, with MRI showing their CSA muscle volume to be more than 93% larger than that of the flexors, and their maximum isometric force is 135% greater than the knee flexors [24,25]. A systematic review of the effects of testosterone treatment on muscle strength and physical function revealed that testosterone treatment was moderately effective in increasing knee extensor strength but not significantly effective in increasing knee flexor strength [26]. This suggests that testosterone has more impact on the knee extensors than flexor muscles.
Our study had several limitations. First, the analyzed participants were of a relatively limited size. Out of 69 subjects, only 38 were in group 2, and the other groups had less than 20 subjects; therefore, statistical power may be lacking. Second, symptom questionnaires such as the International index of erectile function and Aging Male's Symptoms scale were not administered to assess erectile function or hypogonadal symptoms. A questionnaire survey would provide further insight into the correlation between symptom severity and lower body size and strength. Third, we did not measure the participants’ muscle mass. Specific muscle volumes can be measured with a fairly high degree of accuracy using MRI or DEXA scans [27,28], and bioelectrical impedance analysis can also provide an overview of the lower body muscle mass. Further information can be obtained by correlating muscle volume measurements with anthropometric indices.
Despite these limitations, this study included relatively older patients (mean age of 59 years) with ED and was able to note the clinical significance of anthropometric measurements of the lower body, which are relatively simple to perform and do not require costly testing and also confirmed that, among knee strength parameters, which is a representative parameter of lower body strength, extension strength is more closely related to serum testosterone than flexion strength.
CONCLUSIONS
The size of a man’s lower body, particularly the weight-adjusted thigh and calf circumferences, along with the thigh-to-waist ratio, demonstrated a positive correlation with serum testosterone levels. Therefore, it may be possible to estimate low testosterone levels from simple lower body anthropometric measurements without special equipment or tests. In particular, thigh circumference is likely to be more useful than calf circumference for anthropometric measurements. In terms of lower body strength, weight-adjusted knee extension strength was positively correlated with testosterone levels. Therefore, a robust and strong lower body is associated with serum testosterone levels.
Acknowledgements
None.
Footnotes
Conflict of Interest: The authors have nothing to disclose.
Funding: None.
- Conceptualization: MGP.
- Data curation: MGP, DK.
- Formal analysis: MGP, JKY.
- Investigation: MYC, DK, MGP.
- Methodology: MYC, DK, MGP.
- Writing – original draft: MGP, TYP.
- Writing – review & editing: MGP, TYP.
Data Sharing Statement
The data analyzed for this study have been deposited in HARVARD Dataverse and are available at https://doi.org/10.7910/DVN/KLKMXH.
References
- 1.Cunningham GR, Matsumoto AM, Swerdloff R. Low testosterone and men’s health. J Clin Endocrinol Metab. 2004;89:E2. doi: 10.1210/jc.2003-031866. [DOI] [PubMed] [Google Scholar]
- 2.Wolfe R, Ferrando A, Sheffield-Moore M, Urban R. Testosterone and muscle protein metabolism. Mayo Clin Proc. 2000;75 Suppl:S55–S59. discussion S59-60. [PubMed] [Google Scholar]
- 3.Ferrando AA, Tipton KD, Doyle D, Phillips SM, Cortiella J, Wolfe RR. Testosterone injection stimulates net protein synthesis but not tissue amino acid transport. Am J Physiol. 1998;275:E864–E871. doi: 10.1152/ajpendo.1998.275.5.E864. [DOI] [PubMed] [Google Scholar]
- 4.Woodhouse LJ, Gupta N, Bhasin M, Singh AB, Ross R, Phillips J, et al. Dose-dependent effects of testosterone on regional adipose tissue distribution in healthy young men. J Clin Endocrinol Metab. 2004;89:718–726. doi: 10.1210/jc.2003-031492. [DOI] [PubMed] [Google Scholar]
- 5.O'Donnell AB, Travison TG, Harris SS, Tenover JL, McKinlay JB. Testosterone, dehydroepiandrosterone, and physical performance in older men: results from the Massachusetts male aging study. J Clin Endocrinol Metab. 2006;91:425–431. doi: 10.1210/jc.2005-1227. [DOI] [PubMed] [Google Scholar]
- 6.Park TY, Choi MY, Kim DS, Yeo JK, Rajasekaran M, Park MG. Correlation analysis between hypogonadal symptoms and changes in body composition and physical fitness after testosterone treatment in men with testosterone deficiency. World J Mens Health. 2024;42:178–187. doi: 10.5534/wjmh.220274. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Yeo JK, Cho SI, Park SG, Jo S, Ha JK, Lee JW, et al. Which exercise is better for increasing serum testosterone levels in patients with erectile dysfunction? World J Mens Health. 2018;36:147–152. doi: 10.5534/wjmh.17030. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Aguirre LE, Jan IZ, Fowler K, Waters DL, Villareal DT, Armamento-Villareal R. Testosterone and adipokines are determinants of physical performance, strength, and aerobic fitness in frail, obese, older adults. Int J Endocrinol. 2014;2014:507395. doi: 10.1155/2014/507395. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Ferreira JP, Leal AMO, Vasilceac FA, Sartor CD, Sacco ICN, Soares AS, et al. Decreased muscle strength is associated with proinflammatory cytokines but not testosterone levels in men with diabetes. Braz J Med Biol Res. 2018;51:e7394. doi: 10.1590/1414-431X20187394. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Berg WT, Miner M. Hypogonadism and metabolic syndrome: review and update. Curr Opin Endocrinol Diabetes Obes. 2020;27:404–410. doi: 10.1097/MED.0000000000000582. [DOI] [PubMed] [Google Scholar]
- 11.Zitzmann M. Testosterone deficiency, insulin resistance and the metabolic syndrome. Nat Rev Endocrinol. 2009;5:673–681. doi: 10.1038/nrendo.2009.212. [DOI] [PubMed] [Google Scholar]
- 12.Rao PM, Kelly DM, Jones TH. Testosterone and insulin resistance in the metabolic syndrome and T2DM in men. Nat Rev Endocrinol. 2013;9:479–493. doi: 10.1038/nrendo.2013.122. [DOI] [PubMed] [Google Scholar]
- 13.Garcia-Cruz E, Piqueras M, Huguet J, Perez-Marquez M, Gosalbez D, Peri L, et al. Hypertension, dyslipidemia and overweight are related to lower testosterone levels in a cohort of men undergoing prostate biopsy. Int J Impot Res. 2012;24:110–113. doi: 10.1038/ijir.2011.55. [DOI] [PubMed] [Google Scholar]
- 14.Yeap BB. Androgens and cardiovascular disease. Curr Opin Endocrinol Diabetes Obes. 2010;17:269–276. doi: 10.1097/MED.0b013e3283383031. [DOI] [PubMed] [Google Scholar]
- 15.Gates MA, Mekary RA, Chiu GR, Ding EL, Wittert GA, Araujo AB. Sex steroid hormone levels and body composition in men. J Clin Endocrinol Metab. 2013;98:2442–2450. doi: 10.1210/jc.2012-2582. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Hsu KH, Shih CP, Liao PJ. Waist-to-thigh ratio is a predictor of internal organ cancers in humans: findings from a cohort study. Ann Epidemiol. 2013;23:342–348. doi: 10.1016/j.annepidem.2013.04.004. [DOI] [PubMed] [Google Scholar]
- 17.Liao PJ, Lin TY, Ting MK, Peng TI, Chiou WK, Chen LH, et al. Chest width, waist circumference, and thigh circumference are predictors of dementia. Int J Geriatr Psychiatry. 2018;33:1019–1027. doi: 10.1002/gps.4887. [DOI] [PubMed] [Google Scholar]
- 18.Hodgkiss A, McCarthy HD. Thigh circumference measurement as a potential marker of leg skeletal muscle mass – cross sectional study in a U.S. population age 39–69 years. Proc Nutr Soc. 2017;76(OCE1):E14 [Google Scholar]
- 19.Kim S, Kim M, Lee Y, Kim B, Yoon TY, Won CW. Calf circumference as a simple screening marker for diagnosing sarcopenia in older Korean adults: the Korean Frailty and Aging Cohort Study (KFACS) J Korean Med Sci. 2018;33:e151. doi: 10.3346/jkms.2018.33.e151. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Mienche M, Setiati S, Setyohadi B, Kurniawan J, Laksmi PW, Ariane A, et al. Diagnostic performance of calf circumference, thigh circumference, and SARC-F questionnaire to identify sarcopenia in elderly compared to Asian Working Group for Sarcopenia's Diagnostic Standard. Acta Med Indones. 2019;51:117–127. [PubMed] [Google Scholar]
- 21.Chen BB, Shih TT, Hsu CY, Yu CW, Wei SY, Chen CY, et al. Thigh muscle volume predicted by anthropometric measurements and correlated with physical function in the older adults. J Nutr Health Aging. 2011;15:433–438. doi: 10.1007/s12603-010-0281-9. [DOI] [PubMed] [Google Scholar]
- 22.Castro-Piñero J, Ortega FB, Artero EG, Girela-Rejón MJ, Mora J, Sjöström M, et al. Assessing muscular strength in youth: usefulness of standing long jump as a general index of muscular fitness. J Strength Cond Res. 2010;24:1810–1817. doi: 10.1519/JSC.0b013e3181ddb03d. [DOI] [PubMed] [Google Scholar]
- 23.Lindberg K, Solberg P, Bjørnsen T, Helland C, Rønnestad B, Thorsen Frank M, et al. Strength and power testing of athletes: a multicenter study of test-retest reliability. Int J Sports Physiol Perform. 2022;17:1103–1110. doi: 10.1123/ijspp.2021-0558. [DOI] [PubMed] [Google Scholar]
- 24.Narici MV, Roi GS, Landoni L. Force of knee extensor and flexor muscles and cross-sectional area determined by nuclear magnetic resonance imaging. Eur J Appl Physiol Occup Physiol. 1988;57:39–44. doi: 10.1007/BF00691235. [DOI] [PubMed] [Google Scholar]
- 25.Overend TJ, Cunningham DA, Kramer JF, Lefcoe MS, Paterson DH. Knee extensor and knee flexor strength: cross-sectional area ratios in young and elderly men. J Gerontol. 1992;47:M204–M210. doi: 10.1093/geronj/47.6.m204. [DOI] [PubMed] [Google Scholar]
- 26.Nam YS, Lee G, Yun JM, Cho B. Testosterone replacement, muscle strength, and physical function. World J Mens Health. 2018;36:110–122. doi: 10.5534/wjmh.182001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Lester RM, Ghatas MP, Khan RM, Gorgey AS. Prediction of thigh skeletal muscle mass using dual energy x-ray absorptiometry compared to magnetic resonance imaging after spinal cord injury. J Spinal Cord Med. 2019;42:622–630. doi: 10.1080/10790268.2019.1570438. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Segal NA, Glass NA, Baker JL, Torner JC. Correcting for fat mass improves DXA quantification of quadriceps specific strength in obese adults aged 50-59 years. J Clin Densitom. 2009;12:299–305. doi: 10.1016/j.jocd.2008.11.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data analyzed for this study have been deposited in HARVARD Dataverse and are available at https://doi.org/10.7910/DVN/KLKMXH.