Background: Beetroot juice (BRJ) contains various bioactive compounds suggested to be effective in improving athlete recovery. However, the number of studies evaluating the effects of BRJ on recovery and muscle soreness (MS) indicators in female athletes is limited. Therefore, the present study aimed to determine the effects of BRJ consumption on the performance recovery indicators and MS after exercise-induced muscle damage (EIMD) in female volleyball players. Methods: Twelve young female volleyball players were evaluated in this study. We utilized a randomized, cross-over, and double-blind design during two phases with a 30-day interval (wash-out). During each phase, EIMD was performed first, followed by BRJ or placebo (PLA) supplementation for two days (eight servings of 50 mL). Recovery monitoring of performance indicators and MS was performed after EIMD. The results of wall-sit, V sit and reach (VSFT), vertical jump height (VJH), pressure pain threshold (PPT), and thigh swelling (Sw-T) tests were recorded 48 h after EIMD. Also, the Perceived Muscle Soreness was recorded using the visual analog scale (VAS) 12 (MS-12 h), 24 (MS-24 h), and 48 (MS-48 h) hours after EIMD. Results: The data were analyzed using two-way repeated measures of ANOVA at p < 0.05. Compared to PLA, BRJ supplementation improves wall-sit performance after EIMD (p < 0.05), while reducing Sw-T and perceived muscle soreness (p < 0.05). However, no significant difference was observed between PLA and BRJ in VJH and VSFT performance after EIMD (p > 0.05). Conclusions: Our findings indicate that the consumption of BRJ in female volleyball players can be useful for improving some recovery indicators, such as muscle endurance, perceived muscle soreness, and tissue edema, after EIMD.

Background: The improvement of performance and skill indices of volleyball players can affect their success rate. Therefore, the present study aimed to evaluate the effects of acute caffeine supplementation of varied doses on collegiate volleyball players’ specific performance and skills. Method: This research was a randomized, double-blind, crossover design study in which 15 male volleyball players aged 18 to 25 years participated voluntarily. Participants were randomly placed in three different conditions, including 3 mg of caffeine per kilogram of body weight (C3), 6 mg of caffeine per kilogram of body weight (C6), and a placebo (PLA) with a one-week wash-out period between exercise trials. The supplement was taken 60 min before each exercise session. Ball throwing, hand movement speed, agility, Sargent’s jump and handgrip, and attacking and serving skill tests were measured and analyzed to check the performance and skill of the volleyball players. Results: This study showed a significant increase in agility test in C6 compared with the PLA condition (p = 0.02). Additionally, there was a significant improvement in Sargent’s jump in C6 compared with PLA (p = 0.00) and C6 compared with the C3 condition (p = 0.00). Also, attacking skill significantly increased in C3 compared with PLA (p = 0.00) and C6 compared with the PLA condition (p = 0.00). In addition, there was a significant increase in serving skill for C6 compared with PLA (p = 0.00) and C3 (p = 0.00). However, there were no significant differences in hand movement speed (p = 0.06), left handgrip (p = 0.85), right handgrip (p = 0.47), or medicine ball throwing (p = 0.22) between the three conditions. Conclusions: In conclusion, the findings of the current study suggested that a higher dose of caffeine compared with a lower dose may be more effective in movements requiring lower-body explosive power and the ability to change direction. Also, according to the findings, it seems that caffeine can lead to the improvement of complex skills, such as serving and attacking in volleyball.

While regular exercise training is known to decrease oxidative stress (OS) and enhance antioxidant functions in adults, limited data exist on OS responses in the pediatric population. This study aimed to investigate the effects of high-intensity functional training (HIFT) on oxidative stress and physical performance in adolescent soccer players. In this randomized controlled trial, 20 well-trained adolescent soccer players were divided into HIFT (n = 10) and moderate-intensity soccer technical training (MITT, n = 10) groups. Both groups trained for 8 weeks (3 days/week). Oxidative stress biomarkers (MDA, 8-OHDG, H2O2, GPx, CAT) and physical performance (VO2peak, vertical jump height [VJH], maximal explosive power [MEP]) were assessed pre- and post-intervention. Repeated measure mixed ANOVA (2 × 2) with a significance level of P < 0.05 was used to determine differences between and within subjects. The main effect of interaction was significant for VO2peak, VJH and MEP (P < 0.05). The main effect of interaction was not significant for CAT, 8-OHDG, GPx, H2O2 and MDA (P > 0.05). Following intervention, VO2peak and VJH performance in the HIFT were significantly higher than MITT (P < 0.05). MDA and H2O2 in the HIFT decreased significantly (P < 0.05), but no significant changes were observed in the MITT (P > 0.05). CAT activity decreased significantly (P < 0.05), while GPx activity increased significantly (P < 0.05) in both groups. 8-OHDG did not show significant changes in both groups (P > 0.05). Eight weeks of HIFT did not cause greater OS compared to MITT, while could improve physical performance parameters. These findings suggest that HIFT is a viable and time-efficient training strategy for enhancing athletic performance in youth sports. Trial registration: The present study was a randomized controlled trial (registration number: IRCT20190530043762N1, 25/09/2019, Iran).

Accurate assessment of aerobic capacity is crucial for athlete monitoring. The 30–15 Intermittent Fitness Test (30–15IFT) provides a practical

Objectives: In middle-aged women, the postmenopausal period is associated with increased oxidative, inflammatory, and psychological stress. We intend to investigate the effect of home-based aerobic exercise (HAE) on serum levels of 8-hydroxy-2’-deoxyguanosine (8-C) and the expression of telomerase reverse transcriptase (TERT) in leukocytes of postmenopausal women. Methods: A total of 20 sedentary postmenopausal women who had at least 12 months passed since their last menstruation participated in the study voluntarily. Their Mean±SD age, height, weight, and body mass index (BMI) were respectively 52.4±3.8 years, 161.4±3.7 cm, 74.4±6.8 kg, and 28.6±3.4 kg/m2 . They were randomly divided into two groups: Home-based aerobic exercise (HAE, n=10) and inactive control (CON, n=10). HAE group undertook 4 weeks of home-based aerobic exercise (4 d/wk, intensity: 70%-80% maximal heart rate) with online supervision. Participants’ weight and fasting blood samples (12-h fasting state) were measured and taken before and 48 hours after the intervention. TERT expression in blood leukocytes and serum levels of 8-OHDG were assessed by real-time PCR and ELISA methods, respectively. The collected data were analyzed using mixed (2×2) repeated measure ANOVA and independent samples t-test in SPSS software. A significance level of P<0.05 was considered for all tests. Results: The findings showed that 4 weeks of HAE increased TERT expression significantly compared to the CON (ES=0.40, P<0.05). Although 8-OHDG serum level in the HAE group increased following training compared to pre-training (P0.05). Also, the interaction effect on 8-OHDG was not significant (ES=0.11, P>0.05). In addition, after 4 weeks of HAE, body weight and BMI significantly decreased in the training group compared to the control (P<0.05). Discussion: According to these findings, HEA effectively reduces telomere erosion and improves weight control in postmenopausal women.

Caffeine, a stimulant alkaloid, is one of the most widely consumed supplements worldwide (Barcelos et al., 2020; Faudone et al., 2021; Spriet, 1995). Upon ingestion, caffeine is metabolized in the ...