Reza Bagheri

1. High-protein diets, typically exceeding 1.5 g·kg−1·d−1, have become popular among athletes and bodybuilders seeking to increase muscle mass, strength, and overall performance [1,2]. These diets ...

Objectives: This secondary exploratory analysis of a randomized, double-blind, placebo-controlled crossover trial developed and compared indices linking administered caffeine dose to habitual intake to characterize variability in performance and side effects in wrestlers. Methods: Seventy-two male wrestlers completed a randomized, double-blind, placebo-controlled crossover trial in which they ingested caffeine (4 mg·kg⁻¹) or placebo 60 min before vertical jump and wrestling-specific testing. Three indices were calculated: DAR, expressing the administered dose as a multiple of the habitual intake; DDI, quantifying the additional caffeine received above habitual intake; and DNI, expressing this additional intake as a proportion of the administered dose. Hierarchical regression models were used to examine whether each index provided incremental explanatory value beyond habitual caffeine intake and absolute caffeine dose. Results: In exploratory hierarchical models adjusted for habitual caffeine intake and absolute dose, DAR was associated with additional explained variance for the change in total throws (ΔR² = 0.249, p < 0.001), the wrestling performance index (ΔR² = 0.321, p < 0.001), the Caffeine Utility Index (ΔR² = 0.160, p < 0.001), and side effect severity (ΔR² = 0.072, p = 0.008), but not for the change in vertical jump performance (ΔR² = 0.004, p = 0.586). DDI provided significant incremental explanatory value for the change in total throws (ΔR² = 0.061, p = 0.027) and the wrestling performance index (ΔR² = 0.067, p = 0.022). Exploratory quadratic analyses identified a theoretical DAR vertex range between 2.25 and 2.81. Conclusions: These findings support DAR as the principal index for prospective evaluation, but they do not establish a dosing prescription. DAR is not intended to replace body-mass-based dosing (mg·kg⁻¹); rather, it provides a complementary reference dimension that should be applied within established safety limits.

1. Skeletal muscle and bone are usually measured as separate compartments, yet in practice they function together as a system that bears and transmits force. Muscle contractions account for much of...

1. Population aging is a major global public health challenge, with preservation of physical function, independence, and cardiometabolic health becoming increasingly important across middle and lat...

Given the widespread use of caffeine among athletes, this meta-analysis quantifies the incidence of acute side effects associated with caffeine supplementation. Despite its well-established performance benefits, evidence on caffeine's side effects remains fragmented, as these outcomes are often reported only as secondary findings. To address this gap, we systematically reviewed and meta-analyzed evidence from randomized controlled trials on acute caffeine-related side effects in athletes. Following PRISMA guidelines, we searched five databases (MEDLINE, Scopus, Web of Science, Embase, Google Scholar) up to July 2025. Eligible studies were randomized controlled trials in athletes aged ≥ 15 years examining acute caffeine ingestion versus placebo with reported side effects. Risk of bias was assessed using PEDro and Cochrane criteria. Data on frequency and magnitude of side effects were pooled using random-effects meta-analyses, with subgroup and dose-response analyses. A total of 48 studies (940 athletes; 63% male, 37% female) were included in the systematic review, of which 38 were eligible for meta-analysis. The mean caffeine dose was 4.9 ± 2.4 mg/kg (range 1.3-12 mg/kg), commonly ingested as capsules or beverages. Compared with placebo, athletes who ingested caffeine self-reported significantly higher odds of headache (Log OR = 0.74, p < 0.001), abdominal discomfort (Log OR = 1.12, p < 0.001), increased feelings of vigor/activeness (classified in this review as a side effect for methodological consistency, although it may also reflect an ergogenic benefit; Log OR = 1.14, p < 0.001), tachycardia (Log OR = 1.47, p < 0.001; > fourfold higher odds compared with placebo), insomnia (Log OR = 1.20, p < 0.001), increased urine output (Log OR = 1.04, p < 0.001), anxiety (Log OR = 1.29, p < 0.001), and nervousness (Log OR = 0.82, p < 0.001). Meta-regression of dose-response effects showed a significant association between caffeine dose and tachycardia (slope = 0.31, p < 0.001), headache (slope = 0.23, p < 0.001), abdominal discomfort (slope = 0.29, p < 0.001), vigor/activeness (slope = 0.18, p < 0.001), increased urine output (slope = 0.28, p < 0.001), and anxiety (slope = 0.37, p < 0.001). Caffeine intake in athletes increases the likelihood of side effects in a dose-dependent manner, with tachycardia, insomnia, abdominal discomfort, and anxiety being the most consistent. Evidence suggests that, compared with high doses (> 6 mg/kg), low to moderate doses (≤ 6 mg/kg) of caffeine may reduce the risk of side effects.

Background: Overweight women are at increased risk of metabolic dysfunction, muscle loss, and reduced physical function during middle age. Resistance training (RT), combined with a high-protein diet and omega-3 supplementation, may help mitigate these risks; however, their combined effects remain unclear. Objective: To examine whether omega-3 supplementation enhances the effects of RT combined with a high-protein diet on body composition, muscular performance, and selected biochemical markers in overweight women. Methods: Fifty-four overweight women (40–53 years) were randomly assigned to RT plus omega-3 supplementation with a high-protein diet (RO), RT plus placebo with a high-protein diet (RP), or a non-training control group (C). The RT intervention was performed three times per week for 8 weeks. Body composition, muscular performance, and circulating markers related to muscle metabolism and clinical safety were assessed before and after the intervention. Results: Forty-four participants completed the study. Both intervention groups demonstrated significant reductions in body mass and fat mass, alongside increases in skeletal muscle mass (SMM) and improvements in muscular strength, endurance, and power compared with the C group (p < 0.001). Markers related to muscle metabolism improved in both RT groups, with greater changes observed in the RO group. Clinical safety markers remained within normal ranges, with no between-group differences. Conclusions: Eight weeks of RT combined with a high-protein diet effectively improved body composition, muscle function, and anabolic signaling in overweight women. Short-term omega-3 supplementation selectively modulated biochemical markers but did not provide additional improvements in SMM, performance, or clinical safety markers, suggesting that its benefits may be limited without longer-term or higher-dose interventions.

Objectives: This study investigated whether CoQ10 supplementation enhances physical adaptations to high-intensity interval training (HIIT) in muscular strength, power, and physical function in older adults. Method: In a double-blind, randomized controlled trial, 38 adults aged 65–75 were assigned to either a CoQ10 (Females: 8; Males: 11) or placebo (Females: 8; Males: 11) group and completed an 8-week supervised HIIT program. Lower- and upper-body strength (30s 5-repetition chair stand [5XSST], chair standing [30CST], handgrip strength [HGR/L]), balance (single-leg stand [SLS], timed up and go [TUG]), mobility (25-foot walk [25FW]), and aerobic endurance (6-minute walk [6MWT]) were assessed pre- and post-intervention. Results: The CoQ10 group demonstrated significantly greater improvements in 5XSST and 30CST compared to the placebo group (p < 0.05). Both groups showed significant within-group improvements in right and left handgrip strength, SLS, 6MWT, and TUG (all p < 0.001), with no significant between-group differences observed for these outcomes (p > 0.05). No adverse events were reported. Conclusion: While CoQ10 supplementation enhanced improvements in lower-body strength and power, as indicated by the greater gains in 5XSST and 30CST performance compared to the placebo, no between-group differences were observed in TUG, grip strength, or other functional outcomes. This suggests that the performance-related effects of CoQ10 may be more specific to muscular power output and fatigue resistance, rather than general mobility or balance-related tasks. These findings highlight the potential of CoQ10 as a targeted adjunct in exercise for supporting lower-body function and physical performance in older adults.