Brain training, tired calves, and what actually changes for your 100K
11 September 2026 · Seven new publications. Useful signals, important limitations—and no reason to rewrite the training plan.
SYSTEMATIC REVIEW · 11 September 2026
Brain-endurance training: promising, not a new priority
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A review of 10 randomized controlled trials found improved endurance after induced mental fatigue across eight experiments and 275 participants. Results without induced fatigue were inconclusive.
Standardized mean difference 0.82 (95% CI 0.33–1.30); heterogeneity I² = 69%.
Limitations: Running-relevant aerobic evidence comprised only two experiments and 50 participants, with very-low certainty. A standardized effect is not a percentage improvement in race performance.
Do not add cognitive tasks to training on this evidence, particularly during technical running.
Wang et al. · Frontiers in Psychology (opens in a new tab)SMALL EXPERIMENT · 7 September 2026
When calves tire, more work shifts to the knee
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In 12 trained male runners, experimentally reducing plantar-flexor torque approximately 24% shifted positive joint-work contribution away from the ankle and toward the knee. Advanced footwear did not prevent the shift.
Reported joint-work contribution shift: ankle −4%; knee +3%.
Limitations: Fatigue was acutely induced and running lasted only 30 seconds at 10K pace—not the final hours of an ultra.
Keep the existing calf-strength and durability work. This experiment does not establish that calf training prevents late-ultra deterioration.
Primary study · Medicine & Science in Sports & Exercise (opens in a new tab)SMALL RANDOMIZED TRIAL · 10 September 2026
Small drinks can ease thirst and perceived heat strain
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Twelve men completed 90 minutes of cycling plus a 12-km time trial at 35°C. With similar hydration, drinking 25 mL every five minutes produced lower thirst and slightly lower subjective thermal strain than receiving the same volume intravenously. Executive function was unchanged.
Limitations: Small, male-only cycling sample and an artificial intravenous comparison. It does not establish an optimal drinking schedule for an ultra.
Small, frequent drinking opportunities may help comfort in heat. Do not convert the experimental dose into a universal fluid target.
Primary study · Thirst satiation during exercise in the heat (opens in a new tab)CROSSOVER TRIAL · 10 September 2026
Carbohydrate cannot prevent every component of fatigue
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In a double-blind crossover trial of nine men cycling for three hours, approximately 0.7 g/kg/hour carbohydrate maintained blood glucose but did not prevent a decline in rapid eye-movement speed. Measured visual performance remained intact.
Saccade velocity declined 13% in both conditions.
Limitations: Only nine participants; laboratory cycling and eye-movement outcomes cannot establish trail-running safety or ultra performance.
Continue practiced fueling. Do not expect carbohydrate to preserve every cognitive or neural function.
Connell et al. · International Journal of Sport Nutrition and Exercise Metabolism (opens in a new tab)METHODOLOGICAL REVIEW · 9 September 2026
There is no universal running-stability score
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A systematic review of 43 studies found that linear, nonlinear and coordination measures quantify different constructs. Reporting of reliability and processing methods was often incomplete.
Limitations: This review evaluates measurement methods, not a form-retraining intervention. It provides no pooled performance benefit.
Do not turn a stability score or asymmetry value into a universal form target. Keep cues terrain-specific and judge repeated comfort, effort and control.
Systematic review · BMC Sports Science, Medicine and Rehabilitation (opens in a new tab)NARRATIVE REVIEW · 6 September 2026
Recovery nutrition: the fundamentals still lead
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A structured narrative review continued to rank adequate carbohydrate and protein above functional foods for recovery after high-intensity exercise.
Limitations: No pooled effect estimate; evidence for adjunct products was heterogeneous across populations, exercise models and outcomes.
Keep adequate food and recovery fundamentals as the default. This review supplies no reason to add a recovery supplement to the protocol.
Farzana et al. · Food Science & Nutrition (opens in a new tab)Heat monitoring: useful context, not a training controller
4 September 2026 · A new perspective puts wearable data in its proper place: alongside the athlete, the environment and established safety practices.
PEER-REVIEWED PERSPECTIVE · 1 September 2026
Wearable heat monitoring remains supplementary
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The paper reviewed applications ranging from Olympic events to a 200-km desert ultra. Multisensor monitoring may help characterize heat strain, but device validity, sweat-related signal loss, battery failure, individual variability and immature predictive algorithms remain significant limitations.
Limitations: No new intervention trial, participants, effect estimate or evidence that wearable alerts reduce heat illness or improve endurance performance.
Consider heart rate and wearable estimates alongside temperature, pace/RPE drift, symptoms, fluid tolerance and environmental conditions. Do not let a proprietary heat, readiness or physiological-strain score dictate training.
Morrissey et al. · Frontiers in Public Health (opens in a new tab)