Sildenafil citrate, a potent and selective inhibitor of phosphodiesterase type-5, is used clinically to treat erectile dysfunction and pulmonary arterial hypertension. We investigated the effect of sildenafil citrate on brain central fatigue through serotonin (5-hydroxytryptamine, 5-HT) synthesis after exhaustive swimming exercise in rats. The rats in the sildenafil citrate-treated groups received sildenafil citrate orally once a day for 14 consecutive days at respective dosage. On the 14 days after starting experiment, each animal was submitted to swimming test with intensity equivalent to overload. The exhaustion was defined as a state in which coordinated movements did not return to the water surface for breathing within 10 sec. Immunohistochemistry for 5-HT, tryptophan hydroxylase (TPH), and western blot for serotonergic type 1A (5-HT1A) receptor and 5-HT transporter (5-HTT) were performed. Exhaustive swimming exercise increased 5-HT and TPH expressions in the dorsal raphe and sildenafil citrate suppressed 5-HT and TPH expressions in the exhaustive swimming exercise rats. Exhaustive swimming exercise increased 5-HT1A receptor and 5-HTT expressions in the dorsal raphe and sildenafil citrate suppressed 5-HT1A receptor and 5-HTT expressions in the exhaustive swimming exercise rats. The significant suppressing effect appeared in the 20-mg/kg sildenafil citrate. Sildenafil citrate might be proposed as a potential ergogenic aid through anticentral fatigue.

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The aim of the current study is twofold. First, a preliminary analysis was conducted to discover the important factors in terms of preparing for life after retirement across different South Korean age groups (i.e., the 30s, 40s, and 50s). In this process, the level of importance and the statistical significance of the group difference were confirmed based on the ANOVA results. Second, a stepwise regression technique was utilized, as the main analysis, to explore the association between the preparation for life after retirement factors and perceived quality of life. One-way ANOVA analysis results indicated that there were significant differences between age groups in terms of leisure activities, psychological health, physical health, and emotional health factors (p < 0.001). No difference in factors pertaining to family relationships, finances, and social relationships was observed. Furthermore, the stepwise regression analysis results entail that financial stability and psychological health proved to be the most dominant factors associated with quality of life regardless of age. While the family relationship was an important factor for the 40s group, the 50s group perceived emotional health as an important factor that relates to their quality of life. In essence, it is important to provide educational programs and materials that are readily accessible to individuals preparing for retirement to promote successful preparation toward retirement and improving quality of life.

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Background: Taekwondo athletes with lateral chronic ankle instability (LCAI) may experience difficulties with proprioception and ankle muscle strength. After surgery, a conventional rehabilitation exercise program can be ineffective, as it may not restore proprioception or muscle strength and, thus, result in minimal improvement. Objective: This study aimed to assess the effects of an ARE program following MBO on the proprioception, isokinetic strength, and endurance of ankle. Methods: Thirty athletes diagnosed with LCAI underwent MBO. They were divided into the ARE group (n=15) and the control group (CON, n=15). The ARE group performed early ARE exercises six times per week for 4 weeks. The parameters applied to test ankle muscle strength were angular speed of 30°/sec and 180°/sec (inversion: Inv. and eversion: Eve., respectively). Proprioception was measured as being able to sense a joint position of 15° of Inv. and 5° of Eve. Results: Significant differences were observed between the ARE and CON groups in ankle strength 30°/sec (Inv.: p<0.001, Eve.: p<0.001), 180°/sec (Inv.: p<0.001, Eve.: p<0.001), and proprioception at 15° (Inv.: p<0.001) and 5° (Eve.: p<0.001). Conclusions: We recorded significant short-term effects from early ARE in Taekwondo athletes with LCAI after MBO. The results provide reference data for the sports rehabilitator or ATC in evaluating the rehabilitation phase and informing patients about expectations after MBO in terms of performance status and the timing of return to sports. Level of evidence III; Therapeutic studies–Investigation of treatment outcomes - Case-control Study.