Jose Rojas

Dr. Jose Rojas


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 September 2024 in Nutrients
Verified
Journal Article
Open access
PDF file
JAJose Antonio
Jose Antonio
FPFlavia Fernandes Pereira
Flavia Fernandes Pereira
JCJason Curtis
Jason Curtis
JRJose Rojas
Jose Rojas
CECassandra Evans
Cassandra Evans
Background/Objectives: Sports supplements have become popular among fitness enthusiasts for enhancing the adaptive response to exercise. This review analyzes five of the most effective ergogenic aids: creatine, beta-alanine, nitrates, caffeine, and protein. Methods: We conducted a narrative review of the literature with a focus on the sport supplements with the most robust evidence for efficacy and safety. Results: Creatine, one of the most studied ergogenic aids, increases phosphocreatine stores in skeletal muscles, improving ATP production during high-intensity exercises like sprinting and weightlifting. Studies show creatine supplementation enhances skeletal muscle mass, strength/power, and muscular endurance. The typical dosage is 3–5 g per day and is safe for long-term use. Beta-alanine, when combined with the amino acid histidine, elevates intramuscular carnosine, which acts as a buffer in skeletal muscles and delays fatigue during high-intensity exercise by neutralizing hydrogen ions. Individuals usually take 2–6 g daily in divided doses to minimize paresthesia. Research shows significant performance improvements in activities lasting 1–4 min. Nitrates, found in beetroot juice, enhance aerobic performance by increasing oxygen delivery to muscles, enhancing endurance, and reducing oxygen cost during exercise. The recommended dosage is approximately 500 milligrams taken 2–3 h before exercise. Caffeine, a central nervous system stimulant, reduces perceived pain while enhancing focus and alertness. Effective doses range from 3 to 6 milligrams per kilogram of body weight, typically consumed an hour before exercise. Protein supplementation supports muscle repair, growth, and recovery, especially after resistance training. The recommended intake for exercise-trained men and women varies depending on their specific goals. Concluions: In summary, creatine, beta-alanine, nitrates, caffeine, and protein are the best ergogenic aids, with strong evidence supporting their efficacy and safety.

22 May 2024 in Applied Sciences
Verified
Journal Article
Open access
PDF file
JAJose Antonio
Jose Antonio
CECassandra Evans
Cassandra Evans
FPFlavia Fernandes Pereira
Flavia Fernandes Pereira
HTHena Thakkar
Hena Thakkar
VMViraaj Miriyala
Viraaj Miriyala
JCJason Curtis
Jason Curtis
Background: It has been suggested that supplementation with Tongkat Ali may affect testosterone concentrations; moreover, whether this influences body composition is unclear. Thus, the purpose of this investigation was to determine if four weeks of Tongkat Ali (400 mg daily dose) supplementation affected body composition and salivary free testosterone concentrations. Methods: Thirty-three exercise-trained males (n = 19) and females (n = 14) volunteered for this investigation (mean ± standard deviation: age 33.1 ± 13.0 years; height 171.1 ± 11.3 cm; body mass 77.4 ± 16.8 kg; average total years of training 13.9 ± 13.2; average hours of resistance training/week 4.2 ± 2.5; average hours of aerobic exercise/week 3.4 ± 2.8; average hours of other exercise/week 1.1 ± 2.0). Research participants were pre- and post-tested for body composition (InBody 270), Profile of Mood States (POMS), handgrip strength, and sleep (Pittsburgh Sleep Quality Index [PSQI]). In a subset of the research participants, saliva samples were collected and analyzed for cortisol and free testosterone. The research participants consumed 400 mg of Tongkat Ali or a placebo (rice flour) daily for four weeks. Results: There were no between-group differences (p > 0.05) for body composition (delta score, mean ± SD: lean body mass kg-treatment −0.5 ± 1.9, placebo −0.4 ± 0.7; fat mass kg-treatment −0.5 ± 1.6, placebo 0.3 ± 1.0, % fat treatment −0.1 ± 1.4, placebo 0.5 ± 1.1). Moreover, there were no differences between groups for any additional assessments (e.g., handgrip strength, mood, sleep, and salivary free testosterone and cortisol). Conclusions: Four weeks of supplementation with Tongkat Ali in exercise-trained males and females does not affect body composition, mood, sleep, vigilant attention, handgrip strength, cortisol, and free testosterone.

11 January 2023 in Research Directs in Strength and Performance
Verified
Journal Article
Open access
PDF file
JRJose Rojas
Jose Rojas
VMVeronica Mekhail
Veronica Mekhail
CECassandra Evans
Cassandra Evans
JAJose Antonio
Jose Antonio
Introduction: Delayed onset muscle soreness (DOMS) is a common condition characterized by muscle stiffness, pain, and inflammation following intense or unaccustomed exercise. Despite its prevalence, the underlying mechanisms of DOMS remain unclear. This study aimed to investigate the effects of collagen supplementation on tissue repair and pain associated with DOMS in exercise-trained individuals. Methods: Fourteen exercise-trained men (n=7) and women (n=7) were enrolled in a randomized, counterbalanced, crossover trial. Participants were assigned to either a whey protein group (n=8) or a collagen protein group (n=6). Each participant consumed 40g of their respective protein supplement daily for four consecutive days. Peak soreness was assessed using self-reported ratings and algometer measurements. Statistical analysis included independent samples t-tests and Levene's test for equality of variances. Results: The analysis revealed no significant difference in peak soreness between the whey protein and collagen protein groups at the 24-hour time point (t(12) = 1.33, p = 0.208). Both groups experienced a decrease in peak soreness over the 24-hour period, but the reduction was not statistically different between the groups. No significant differences were observed in other variables measured. Conclusions: These findings suggest that collagen protein supplementation did not significantly reduce peak soreness associated with DOMS compared to whey protein supplementation in exercise-trained individuals. While collagen supplementation has shown potential benefits in tissue repair and joint health, further research is needed to explore its specific effects on DOMS. Larger studies with different dosages and participant populations are warranted to obtain a more comprehensive understanding of collagen's impact on muscle soreness and tissue repair.

26 September 2026 in Nutrients
Verified
Journal Article
Open access
PDF file
CECassandra Evans
Cassandra Evans
SHSusan Hewlings
Susan Hewlings
JGJacqueline Goodrich
Jacqueline Goodrich
VBVictoria Burgess
Victoria Burgess
JTJaime Tartar
Jaime Tartar
AMAlexis Madelyn-Adjei
Alexis Madelyn-Adjei
Background: Executive function is a critical component of cognitive health that supports goal-directed behavior, attentional control, and cognitive flexibility. These processes are sensitive to aging and lifestyle factors and may be modifiable through nutritional strategies. Hericium Erinaceus (lion’s mane; LM) is an edible mushroom containing bioactive compounds shown to stimulate neurotrophins such as brain-derived neurotrophic factor (BDNF), suggesting potential cognitive benefits. Methods: This pilot, proof-of-concept study examined the effects of four weeks of daily LM supplementation on executive function and circulating plasma BDNF in healthy adults. Participants (n = 10) were healthy adults (18–55 years) and consumed 2 g/day of a certified organic LM supplement composed of mycelial biomass and fruiting body for 28 days. Executive function was assessed using the NIH Toolbox Flanker Inhibitory Control and Attention Test and the dimensional change card sort (DCCS) test. Plasma BDNF concentrations were measured using a quantitative ELISA. Paired-samples t-tests were used to assess changes from pre to post, and effect sizes were calculated using Cohen’s d. Results: No statistically significant differences were observed in executive function or plasma BDNF following supplementation (p > 0.05). However, small-to-moderate effect sizes were observed for flanker inhibitory control and attention (Cohen’s d = 0.48), DCCS (Cohen’s d = 0.25) and plasma BDNF (Cohen’s d = 0.31), suggesting modest improvements from baseline. Conclusions: The results of this small, pilot, proof-of-concept study demonstrate, within the confines of this study, that LM is safe and well tolerated in healthy adults. The small-to-moderate effects on cognitive function combined with the modest increase in plasma BDNF suggest a promising signal for LM supplementation that warrants further investigation in larger and longer-term randomized double-blind placebo-controlled studies.