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The Endurance Performance Nerd Alert.
Learn to train smart, run fast, and be strong with Thomas Solomon PhD 
February 2025
This page contains the latest research studies on exercise science and sports nutrition.
Use them to help level up your running performance or coaching practice.
The studies are divided into sub-topics:
sports nutrition,
sports supplements,
recovery (inc. sleep),
athlete health (inc. mental health),
injuries and rehab, and
female athlete physiology,
plus my beer of the month to wash it all down.
I’ve also provided a deeper insight into my four favourite studies of the month. For everything else, you can click on the study title to plunge deep into the full paper and evaluate the authors’ findings. In doing so, aim to be skeptical, not cynical.
My favourite papers this month.
International Society of Sports Nutrition Position Stand: Long-Chain Omega-3 Polyunsaturated Fatty Acids. Jäger et al. (2025 ) J Int Soc Sports Nutr. (click the title to access the full article)
What type of study is this?
- This study is a
position standA position stand is a detailed policy recommendation published by a society that describes a course of action for practice.
What is the authors’ hypothesis or research question?
- The authors aimed to evaluate the impact of long-chain omega-3 polyunsaturated fatty acids (ω-3 PUFAs) on exercise performance, recovery, and brain health, providing evidence-based guidance to athletes and practitioners.
What did the authors do to test the hypothesis or answer the research question?
- This position stand synthesizes findings from a comprehensive literature review. The article summarizes data from multiple studies on healthy and athletic populations, focusing on supplementation with ω-3 PUFAs, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
What did the authors find?
- Athletes may face a higher risk of ω-3 PUFA insufficiency due to dietary inadequacies.
- Diets rich in ω-3 PUFAs or supplements effectively improve ω-3 PUFA levels.
- ω-3 PUFA supplementation enhances endurance capacity and cardiovascular function during aerobic exercise.
- There is no significant evidence that ω-3 PUFA promotes muscle hypertrophy in young adults.
- Combined with resistance training, ω-3 PUFA supplementation can improve strength, dependent on dose and duration.
- ω-3 PUFAs reduce perceived muscle soreness after intense exercise.
- Positive effects on immune cell responses were noted in athletes.
- Prophylactic supplementation offers neuroprotective benefits, especially for athletes at risk of head injuries.
- Improved sleep quality was associated with ω-3 PUFA intake.
- ω-3 PUFAs are recognised as prebiotics; however, research on their effects on gut health in athletes is limited.
- The authors concluded that ω-3 PUFAs hold significant potential for improving performance, recovery, and health outcomes in athletic populations.
What are the strengths of the study?
- The paper includes a comprehensive review of current evidence regarding ω-3 PUFAs.
- Recommendations are based on diverse, high-quality studies, supporting their generalizability.
- The authors highlight practical applications for athletes and coaches.
What are the weaknesses of the study?
- The position stand has an insufficient emphasis on study-specific details such as participant demographics or individual study limitations.
- There is a limited discussion of heterogeneity among the reviewed studies.
- The paper lacks a direct meta-analytical assessment, so the conclusions are not based on a quantified analysis.
How was the study funded and are there any conflicts of interest that may influence the findings?
- The article does not explicitly state funding sources or conflicts of interest.
Are the findings useful in application to training and/or coaching practice?
- Yes → The findings apply to endurance training and coaching. ω-3 PUFA supplementation may improve endurance capacity, recovery, and cardiovascular function, making it a valuable nutritional strategy for athletes.
What is my Rating of Perceived scientific Enjoyment?
-
RP(s)E = 7 out of 10. The paper provides a robust summary of ω-3 PUFA benefits and implications, though it could improve by addressing gaps in individual study data and providing more methodological rigour in synthesising evidence. 
Important: Don’t make any major changes to your habits based on the findings of one study, especially if the study is small (e.g., less than 30 participants in a randomised controlled trial or less than 5 studies in a meta-analysis) or poor quality (e.g., high risk of bias or low certainty of evidence in a meta-analysis). What do other trials in this field show? (Follow the link to explore those trials.) Do they confirm the findings of this study or have mixed outcomes? Is there a high-quality systematic review and meta-analysis evaluating the entirety of the evidence in this field? (Follow the link to explore those reviews.) If so, what does the analysis show? What is the risk of bias or certainty of evidence of the included studies?
Do compression garments enhance running performance? An updated systematic review and meta-analysis. Wang et al. (2025 ) J Sport Health Sci. (click the title to access the full article)
What type of study is this?
- This study is a
systematic reviewA systematic review answers a specific research question by systematically collating all known experimental evidence, which is collected according to pre-specified eligibility criteria. A systematic review helps inform decisions, guidelines, and policy. with meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all studies of that treatment.
What is the authors’ hypothesis or research question?
- The authors’ research question was whether wearing compression garments improves running performance, specifically regarding race time, time to exhaustion, and other secondary outcomes like speed, tissue oxygenation, and soft tissue vibration.
What did the authors do to test the hypothesis or answer the research question?
- The systematic review and meta-analysis included 51 randomised controlled trialThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after the exposure to treatment/control. (RCTs), with 899 participants (683 men, 184 women, and 32 undescribed).
- Included studies were retrieved from six databases (e.g., PubMed, Cochrane) up to September 2024.
- The studies primarily assessed primary outcomes of race time and time to exhaustion and secondary outcomes of running speed, submaximal oxygen uptake, and soft tissue vibration.
- The Grading of Recommendations, Assessments, Development, and Evaluation (GRADE) approach was used to assess evidence certainty and risk of bias was evaluated using the Cochrane Risk of Bias 2 tool.
- Included studies spanned both short-distance (10 m–400 m) and long-distance (5 km–marathon) running trials, with various types of compression garments (e.g., tights, stockings, sleeves).
What did the authors find?
- Primary outcomes: Wearing compression garments had no statistically significant effect on race time (SMDStandardised Mean Difference: a standardised measure of the size of an effect of a treatment. = -0.07, 95% confidence intervalA margin of uncertainty — i.e. a plausible range of values within which the true value would be found 95% of the time if the data was repeatedly collected in different samples of people — if the range crosses zero, there is no effect.: -0.22 to 0.09, P=0.40The probability that the result is as or more extreme than that observed under a null-hypothesis. If P is small, the observed difference is big enough to disprove (reject) the null hypothesis. In very basic terms, P = probability that the effect could be explained by random chance and a P-value of less than 0.05 means the results look so promising that there’s only a 1-in-20 (or 5%) chance that they would have occurred if the treatment had no effect at all.) or time to exhaustion (SMD = 0.04, 95% CI: -0.20 to 0.29, p = 0.72). Heterogeneity was low (I² = 0%).
- Secondary Outcomes: No significant effects were found on running speed (SMD = 0.17, p = 0.10) or submaximal oxygen uptake (SMD = -0.02, p = 0.78). A small but statistically significant reduction in soft tissue vibration was observed (SMD = -0.43, 95% CI: -0.70 to -0.15, p < 0.01).
- The authors concluded that compression garments do not provide measurable benefits for running performance (e.g., race time, endurance) but may reduce soft tissue vibration.
What are the strengths of the study?
- The study uses a comprehensive and rigorous methodology, adhering to PRISMA guidelines.
- There is a large sample size pooled from 51 RCTs, increasing statistical powerPower is the probability that one will correctly reject the null hypothesis, i.e., low statistical power leads to a high chance of a false negative (a high chance of failing to detect a meaningful clinical difference)..
- The study uses established quality assessment tools (GRADE and RoB 2).
- The analysis included subgroup analyses based on garment type, race type, and contact surface.
What are the weaknesses of the study?
- Small study sample sizes: Many of the included RCTs had small sample sizes (median = 13 participants).
- Low quality of evidence: Most outcomes had “low” or “very low” GRADE ratings.
- High risk of bias: 75% of the studies had a high risk of bias, mainly due to inadequate randomisation, allocation concealment, or lack of blinding.
- Insufficient data to assess safety or adverse events associated with compression garments.
How was the study funded and are there any conflicts of interest that may influence the findings?
- The study was supported by the National Natural Science Foundation of China and the National Key Research and Development Program of China. The authors declared no competing interests, and funding sources were not involved in study design, analysis, or publication decisions.
Are the findings useful in application to training and/or coaching practice?
- Partially → The findings suggest limited utility of compression garments for improving running performance, with potential application in reducing soft tissue vibration. Coaches and athletes may consider these findings when deciding on their use but should temper expectations regarding performance enhancement.
What is my Rating of Perceived scientific Enjoyment?
-
RP(s)E = 6 out of 10. This paper scores well on methodological rigour and comprehensiveness but is limited by the low quality of included studies and the lack of practical recommendations.
- Important: Don’t make any major changes to your habits based on the findings of one study, especially if the study is small (e.g., less than 30 participants in a randomised controlled trial or less than 5 studies in a meta-analysis) or poor quality (e.g., high risk of bias or low certainty of evidence in a meta-analysis). What do other trials in this field show? (Follow the link to explore those trials.) Do they confirm the findings of this study or have mixed outcomes? Is there a high-quality systematic review and meta-analysis evaluating the entirety of the evidence in this field? (Follow the link to explore those reviews.) If so, what does the analysis show? What is the risk of bias or certainty of evidence of the included studies?
Effects of endurance exercise under hypoxic conditions on the gastric emptying rate and intestinal cell damage. Nomura et al. (2025 ) Eur J Appl Physiol. (click the title to access the full article)
What type of study is this?
- This study is a
randomised controlled trialThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after the exposure to treatment/control. with crossoverCrossover means that all subjects completed all interventions (control and treatment) usually with a wash-out period in between.
What is the authors’ hypothesis or research question?
- The authors hypothesised that endurance exercise under hypoxic conditions would delay the gastric emptying rate and increase intestinal cell damage compared to exercise under normoxic conditions, even when performed at the same relative intensity.
What did the authors do to test the hypothesis or answer the research question?
- The study used a randomised controlled crossover design including 11 healthy, physically active males (mean age: 23.2 ± 1.1 years).
- Participants completed two 60-minute treadmill running trials, one in normoxic conditions (FiO₂: 20.9%) and the other in hypoxic conditions (FiO₂: 14.5%), at 70% of their maximum running velocity (vMax). Trial order was randomised and trials were separated by at least one week.
- Gastric emptying rate was assessed using the ¹³C-sodium acetate breath test after exercise.
- Plasma intestinal fatty acid-binding protein (I-FABP), a marker of intestinal cell damage, was measured before and after exercise.
- Other variables measured included blood glucose, lactate, arterial oxygen saturation (SpO₂), heart rate, and subjective ratings (e.g., nausea).
What did the authors find?
- Gastric Emptying Rate was significantly delayed in hypoxic trials compared to normoxic trials (mean Tmax of 45.5 ± 9.6 minutes vs. 38.5 ± 5.0 minutes, P=0.01The probability that the result is as or more extreme than that observed under a null-hypothesis. If P is small, the observed difference is big enough to disprove (reject) the null hypothesis. In very basic terms, P = probability that the effect could be explained by random chance and a P-value of less than 0.05 means the results look so promising that there’s only a 1-in-20 (or 5%) chance that they would have occurred if the treatment had no effect at all.).
- Plasma I-FABP increased significantly after exercise in both conditions (suggestive of intestinal cell damage) but showed no significant difference between hypoxic and normoxic trials.
- Blood glucose increased after exercise in both conditions without significant differences.
- Blood lactate was significantly higher post-exercise in the hypoxic condition (5.2 ± 2.3 mmol/L vs. 2.9 ± 1.5 mmol/L, P≤0.05The probability that the result is as or more extreme than that observed under a null-hypothesis. If P is small, the observed difference is big enough to disprove (reject) the null hypothesis. In very basic terms, P = probability that the effect could be explained by random chance and a P-value of less than 0.05 means the results look so promising that there’s only a 1-in-20 (or 5%) chance that they would have occurred if the treatment had no effect at all.).
- Nausea was significantly greater after hypoxic exercise, but other symptoms (e.g., hunger, bloating) did not differ significantly.
- Endurance exercise under hypoxic conditions impaired gastric emptying but did not exacerbate exercise-induced intestinal cell damage compared to normoxic exercise. The authors concluded that hypoxic exercise might compromise digestive function in the stomach.
What are the strengths of the study?
- Use of a crossover design ensured that participants served as their own controls.
- Hypoxic conditions were carefully simulated using a standardised mask and hypoxic chamber system.
- Comprehensive measurements, including both physiological (e.g., I-FABP, lactate) and subjective data (e.g., nausea), provided a thorough assessment.
What are the weaknesses of the study?
- Sample Size: Limited to 11 participants, which reduces the statistical power of the study.
- Generalisability: Only young, healthy males were included; the findings may not apply to females, older adults, or clinical populations.
- Markers of Intestinal Damage: Only plasma I-FABP was assessed, an indirect marker that may not fully capture intestinal health.
- Lack of Nutritional Factors: Nutritional conditions (e.g., carbohydrate intake) were not evaluated, which could influence the gastric emptying rate and recovery.
How was the study funded and are there any conflicts of interest that may influence the findings?
- The study was supported by research funds from Ritsumeikan University. The authors declared no conflicts of interest.
Are the findings useful in application to training and/or coaching practice?
- Partially → The findings highlight that endurance exercise under hypoxic conditions delays gastric emptying, which could impact nutrient absorption and recovery strategies for athletes training/competing at altitude. Coaches may consider recommending easily digestible foods post-exercise in hypoxic conditions to minimize digestive strain.
What is my Rating of Perceived scientific Enjoyment?
-
RP(s)E = 7 out of 10. The study is well-designed with robust methods and relevant outcomes but is limited by a small sample size and reliance on indirect markers for intestinal damage.
- Important: Don’t make any major changes to your habits based on the findings of one study, especially if the study is small (e.g., less than 30 participants in a randomised controlled trial or less than 5 studies in a meta-analysis) or poor quality (e.g., high risk of bias or low certainty of evidence in a meta-analysis). What do other trials in this field show? (Follow the link to explore those trials.) Do they confirm the findings of this study or have mixed outcomes? Is there a high-quality systematic review and meta-analysis evaluating the entirety of the evidence in this field? If so, what does the analysis show? What is the risk of bias or certainty of evidence of the included studies?
Exploring the use of digital technology for injury prevention and self-management among recreational runners. Walker et al. (2025 ) Phys Ther Sport. (click the title to access the full article)
What type of study is this?
- This study is a
scoping studyA scoping study seeks to understand what people know and/or believe about a topic. The info can help identify areas for future research.
What is the authors’ hypothesis or research question?
- The authors hypothesised that recreational runners frequently use digital technologies to monitor their training but perceive a gap in their usefulness for preventing and managing running-related injuries. They also sought to determine if there was interest in a proposed digital intervention for running-related injury prevention and self-management.
What did the authors do to test the hypothesis or answer the research question?
- A total of 232 recreational runners from Wales, aged 18 years and older, with a mix of male and female participants.
- A quantitative survey conducted online over seven weeks using the Jisc platform. The survey covered six sections including demographics, training habits, running-related injury history, running-related technology use, and opinions on proposed interventions.
- Descriptive statistics and inferential analysis (Pearson’s chi-square and logistic regression) were conducted.
What did the authors find?
- Technology Use: 97% of participants used digital tools to monitor their training, primarily GPS watches (45.1%) and smartphone apps (37.6%).
- Barriers: Many participants felt current technologies do not provide realistic advice for injury prevention or management.
- Demographics and Usage: Younger runners (18–24 years) and those with less experience (3 months–2 years) were more likely to use multiple apps for training. Older runners (55+) were less likely to use any apps.
- Interest in Interventions: 84.5% expressed interest in a proposed intervention. Desired features included: injury prevention advice; self-diagnostic tools; exercises for improving running and recovery; and evidence-based recommendations delivered by healthcare professionals.
- Statistical Associations: Less experienced runners were more likely to express interest in the intervention (P≤0.05The probability that the result is as or more extreme than that observed under a null-hypothesis. If P is small, the observed difference is big enough to disprove (reject) the null hypothesis. In very basic terms, P = probability that the effect could be explained by random chance and a P-value of less than 0.05 means the results look so promising that there’s only a 1-in-20 (or 5%) chance that they would have occurred if the treatment had no effect at all.). However, no significant predictors (e.g., age, gender) were identified for technology use variables.
- The authors concluded that there is a strong need for evidence-based, tailored digital interventions for injury prevention and self-management among recreational runners.
What are the strengths of the study?
- Large Sample Size: The study surveyed 232 participants, offering robust descriptive insights.
- Relevance: Addresses a common issue (running-related injuries) with potential practical implications.
- Stakeholder Engagement: Explored user preferences for digital intervention content.
What are the weaknesses of the study?
- Survey Limitations: Closed-question format limited the depth of insights into runners' preferences and behaviours.
- Generalisability: Conducted exclusively in Wales, which may limit the broader application to other populations.
- Sample Composition: Underrepresentation of elite runners or those running at higher weekly mileage limits insights into these groups.
- No Qualitative Data: The lack of qualitative follow-up restricts the understanding of the nuanced reasons behind runners’ attitudes.
How was the study funded and are there any conflicts of interest that may influence the findings?
- The study was funded by Knowledge Economy Skills Scholarships (KESS2), supported by the Welsh Government and European Social Funds. The authors declared no conflicts of interest.
Are the findings useful in application to training and/or coaching practice?
- Yes → The proposed interventions could aid coaches and practitioners in developing personalised, evidence-based advice to help reducing injury risks and improve training outcomes.
What is my Rating of Perceived scientific Enjoyment?
-
RP(s)E = 6 out of 10. The study thoroughly explores a relevant issue and offers actionable insights but is limited by its focus on a single geographic area, a lack of high-training volume runners, and a lack of qualitative data that would garner deeper insights.
- Important: Don’t make any major changes to your habits based on the findings of one study, especially if the study is small (e.g., less than 30 participants in a randomised controlled trial or less than 5 studies in a meta-analysis) or poor quality (e.g., high risk of bias or low certainty of evidence in a meta-analysis). What do other trials in this field show? (Follow the link to explore those trials.) Do they confirm the findings of this study or have mixed outcomes? Is there a high-quality systematic review and meta-analysis evaluating the entirety of the evidence in this field? (Follow the link to explore those reviews.) If so, what does the analysis show? What is the risk of bias or certainty of evidence of the included studies?
All the other interesting papers I found this month are below.
You can dig in and evaluate the authors’ findings by clicking on the titles to access the full papers.
Learn to critically evaluate each paper using the framework I used for my favourite papers. 
Sports nutrition and hydration.
International Society of Sports Nutrition Position Stand: Long-Chain Omega-3 Polyunsaturated Fatty Acids. Jäger et al. (2025 ) J Int Soc Sports Nutr. Sports supplements.
Ergogenic Benefits of β-Hydroxy-β-Methyl Butyrate (HMB) Supplementation on Body Composition and Muscle Strength: An Umbrella Review of Meta-Analyses. Bideshki et al. (2025 ) J Cachexia Sarcopenia Muscle. Does Creatine Supplementation Enhance Performance in Active Females? A Systematic Review. Tam et al. (2025 ) Nutrients. Recovery (including sleep).
Do compression garments enhance running performance? An updated systematic review and meta-analysis. Wang et al. (2025 ) J Sport Health Sci. Athlete health (including mental health).
Effects of endurance exercise under hypoxic conditions on the gastric emptying rate and intestinal cell damage. Nomura et al. (2025 ) Eur J Appl Physiol. Effects of Short-Term Low Energy Availability on Metabolism and Performance-Related Parameters in Physically Active Adults. Nolte et al. (2025 ) Nutrients. Exercise interventions to improve bone mineral density in athletes participating in low-impact sports: a scoping review. Florvåg et al. (2025 ) BMC Musculoskelet Disord. Relative Energy Deficiency in Sport-Multidisciplinary Treatment in Clinical Practice. Meyer et al. (2025 ) Nutrients. A Preliminary Study of Nutrients Related to the Risk of Relative Energy Deficiency in Sport (RED-S) in Top-Performing Female Amateur Triathletes: Results from a Nutritional Assessment. Langa et al. (2025 ) Nutrients. The relationship between quality of sports friendships and mental health in Chinese junior high school students: the bidirectional chain mediating effects of sport motivation and exercise adherence. Li et al. (2025 ) BMC Public Health. Injury and rehab.
Exploring the use of digital technology for injury prevention and self-management among recreational runners. Walker et al. (2025 ) Phys Ther Sport. Self-reported injury in ultra-endurance participants with a focus on knee injuries: An exploratory cross-sectional comparative study of running, cycling, and triathlon. Weir et al. (2025 ) Phys Ther Sport. Incidence, severity, and risk factors for injuries in female trail runners - A retrospective cross-sectional study. Goodrum et al. (2025 ) Phys Ther Sport. Does high-intensity running to fatigue influence lower limb injury risk? Rice et al. (2025 ) J Sci Med Sport. Female athlete physiology and sex differences.
A Preliminary Study of Nutrients Related to the Risk of Relative Energy Deficiency in Sport (RED-S) in Top-Performing Female Amateur Triathletes: Results from a Nutritional Assessment. Langa et al. (2025 ) Nutrients. Incidence, severity, and risk factors for injuries in female trail runners - A retrospective cross-sectional study. Goodrum et al. (2025 ) Phys Ther Sport. Are we asking the right questions? Female athletes' perspectives on the menstrual cycle in sport. van et al. (2025 ) Psychol Sport Exerc. Sex differences in exercise-induced arterial hypoxemia and pulmonary edema following high-intensity exercise in highly trained endurance athletes. Hind et al. (2025 ) Physiol Rep.
And, to help you wash down the latest evidence, here's a snifter from my recent indulgence...
My beer of the month.
Mucho Mucho Citra.
Brewed by Basqueland Brewing (Hernani, Spain).
New England Hazy IPA.
8% ABV.
A little bitter, a little hoppy, and a little boozy. Tasty but needs a fresh citrusy kick to be mucho mucho tasty.
RP(be)E(r)(Rating of Perceived beer Enjoyment)
7 out of 10
Access to education is a right, not a privilege:
Equality in education, health, and sustainability is important to me. I was lucky to be born into a social welfare system where higher education was free. Sadly, that is no longer true. Consequently, to provide access to exercise science and sports nutrition education to folks from all walks of life, I publish freely accessible high-quality exercise science and nutritional science content. This nerd alert newsletter is part of that offering. You can find more free educational resources from me, Thomas Solomon PhD, at veohtu.com.
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Empower yourself to train smart.
Be informed Stay educated Think critically.
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Disclaimer: I occasionally mention brands and products but it is important to know that I am not affiliated with, sponsored by, an ambassador for, or receiving advertisement royalties from any brands. I have conducted biomedical research for which I have received research money from publicly-funded national research councils and medical charities, and also from private companies, including Novo Nordisk Foundation, AstraZeneca, Amylin, A.P. Møller Foundation, and Augustinus Foundation. I’ve also consulted for Boost Treadmills and Gu Energy on their research and innovation grant applications and I’ve provided research and science writing services for Examine — some of my articles contain links to information provided by Examine but I do not receive any royalties or bonuses from those links. These companies had no control over the research design, data analysis, or publication outcomes of my work. Any recommendations I make are, and always will be, based on my own views and opinions shaped by the evidence available. My recommendations have never and will never be influenced by affiliations, sponsorships, advertisement royalties, etc. The information I provide is not medical advice. Before making any changes to your habits of daily living based on any information I provide, always ensure it is safe for you to do so and consult your doctor if you are unsure.