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Evidence indicates that master athletes have higher concentration of Sirtuin 1 (Sirt1), lower body fat (BF), and greater activity of the hypothalamic–pituitary–gonadal axis in comparison to untrained peers. However, no published data have demonstrated possible mediation effect of Sirt1 in the interaction of BF and testosterone in this population. Therefore, this study compared and verified possible associations between Sirt1, BF, fat mass index (FMI), testosterone, luteinizing hormone (LH), and testosterone/luteinizing hormone (T/LH) ratio in middle-aged master athletes (n = 54; 51.22 ± 7.76 years) and control middle-aged peers (n = 21; 47.76 ± 8.47 years). Venous blood was collected for testosterone, LH, and Sirt1. BF was assessed through skinfold protocol. Although LH concentration did not differ between groups, master athletes presented higher concentration of Sirt1, testosterone, and T/LH ratio, and lower BF and FMI in relation to age-matched nonathletes. Moreover, Sirt1 correlated positively with testosterone and T/LH ratio, negatively with BF, and was not significantly correlated with LH (mediation analysis revealed the effect of BF on testosterone is mediated by Sirt1 and vice versa; R2 =.1776; p =.032). In conclusion, master athletes have higher testosterone, T/LH ratio, and Sirt1, and lower BF and FMI in relation to untrained peers. Furthermore, Sirt1 was negatively associated with BF and positively associated with testosterone and T/LH ratio. These findings suggest that increased circulating Sirt1, possibly due to the master athlete's training regimens and lifestyle, exhibits a potential mediation effect on the interaction between endocrine function and body composition. [ABSTRACT FROM AUTHOR]

Purpose: We compared the adaptive responses to supramaximal high-intensity interval training (HIIT) individualized according to anaerobic speed reserve (ASR), the 30-15 Intermittent Fitness Test (VIFT), and velocity associated with maximum oxygen uptake (MAS) to determine which approach facilitates more identical adaptations across athletes with different profiles. Methods: Thirty national-level basketball players (age = 28.4 [5] y; body mass = 88.9 [6.3] kg; height = 190 [4.8] cm) were randomly assigned to 3 training groups performing 2 sets of 4, 6, 8, 6, 8, and 10-minute runs (from first to sixth week, respectively), consisting of 15-second running at Δ%20ASR (MAS + 0.2 × ASR), 95%VIFT, and 120%MAS, with 15 seconds recovery between efforts and a 3-minute relief between sets. Results: All 3 interval interventions significantly (P <.05) enhanced maximum oxygen uptake ( V ˙ O 2 max), oxygen pulse ( V ˙ O 2 / HR), first and second ventilatory threshold (VT1 and VT2), cardiac output ( Q ˙ max ), stroke volume, peak and average power output, testosterone levels, and testosterone-to-cortisol ratio following the training period. Different values of interindividual variability (coefficient of variation) for the percentage changes of the measured variables were observed in response to HIITASR, HIITvIFT, and HIITMAS for V ˙ O 2 max (8.7%, 18.8%, 34.6%, respectively), V ˙ O 2 / HR (9.5%, 15.0%, 28.6%), VT1 (9.6%, 19.6%, 34.6%), VT2 (21.8%, 32.4%, 56.7%), Q ˙ max (8.2%, 16.9%, 28.8%), stroke volume (7.9%, 15.2%, 23.5%), peak power output (20%, 22%, 37.3%), average power output (21.1%, 21.3%, 32.5%), testosterone (52.9%, 61.6%, 59.9%), and testosterone-to-cortisol ratio (55.1%, 59.5%, 57.8%). Conclusions: Supramaximal HIIT performed at Δ%20ASR resulted in more uniform physiological adaptations than HIIT interventions prescribed using VIFT or MAS. Although hormonal changes do not follow this approach, all the approaches induced an anabolic effect. [ABSTRACT FROM AUTHOR]

Androgen deprivation therapy (ADT) forms the cornerstone in the treatment of advanced prostate cancer. However, by suppressing testosterone ADT results in a decrease of skeletal muscle mass. In this narrative review, we explore the magnitude and mechanisms of ADT-induced muscle mass loss and the consequences for muscle strength and physical performance. Subsequently, we elucidate the effectiveness of supervised resistance exercise training as a means to mitigate these adverse effects. Literature shows that resistance exercise training can effectively counteract ADT-induced loss of appendicular lean body mass and decline in muscle strength, while the effect on physical performances is inconclusive. As resistance exercise training is feasible and can be safely implemented during ADT (with special attention for patients with bone metastases), it should be incorporated in standard clinical care for prostate cancer patients (starting) with ADT. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of supraphysiologic administration of testosterone in an early and late model of implant osseointegration in rat tibiae. Materials and Methods: A total of 40 rats were randomly allocated into four groups (n = 10/group), which were divided according to the type of experiment and time of osseointegration: (1) vehicle (14 days), (2) testosterone (14 days), (3) vehicle (42 days), and (4) testosterone (42 days). Testosterone cypionate (7.5 mg/kg) administration started 4 weeks before implant placement, and the injections were performed daily until euthanasia. Machined-surface titanium implants (2.2 mm in diameter and 4 mm high) were placed bilaterally in the tibia of animals 28 days after the first testosterone injection. At days 14 and 42 after implant placement, euthanasia was performed and the tibiae were harvested to perform biomechanical evaluation and histomorphometric analysis of bone-to-implant contact (BIC%) and bone between the threads (BBT%). Results: There was no statistical difference in the removal torque of the implants between the groups treated with the vehicle (control group) or testosterone (P > .05). At 14 days of osseointegration, the BIC% and BBT% did not differ between vehicle or testosterone groups (P > .05), while at 42 days, both the BIC% and BBT% were significantly reduced by testosterone compared to the vehicle group (P < .05). Conclusions: Testosterone cypionate in supraphysiologic dose impaired late-phase osseointegration in rat tibiae. [ABSTRACT FROM AUTHOR]