Brain training, tired calves and what changes for a 100K
· 2 min read
First published:
Research through: 11 September 2026
Seven publications offered useful but limited signals on mental fatigue, calf fatigue, drinking comfort, carbohydrate, stability measures, the microbiome and recovery nutrition. None justified rewriting the training plan.
Selected historical recovery; not an exhaustive account of all research published that week.
Topics: Training, Recovery
Finding
A review of 10 randomized trials reported benefits after induced mental fatigue, but running-specific evidence was small and effects without induced fatigue were inconclusive.
Limitations: Heterogeneity was high and running-relevant evidence had very low certainty.
Evidence level: Emerging evidence
Finding
In 12 trained male runners, acute plantar-flexor fatigue shifted some joint-work contribution from the ankle toward the knee.
Limitations: Fatigue was induced experimentally and running lasted only 30 seconds at 10K pace.
Evidence level: Emerging evidence
Finding
In 12 men exercising in heat, small frequent drinks reduced thirst and slightly reduced perceived heat strain compared with the same fluid volume given intravenously.
Limitations: Cycling in a laboratory with an artificial comparator does not establish an optimal ultra drinking schedule.
Evidence level: Emerging evidence
Finding
In 9 men cycling for 3 hours, carbohydrate maintained blood glucose but did not prevent a decline in rapid eye-movement speed.
Limitations: The small cycling study and its neural measure do not establish trail-running safety or ultra performance.
Evidence level: Emerging evidence
Finding
Across 43 studies, running-stability measures fell into linear, nonlinear and coordination-based approaches that describe different movement constructs.
Limitations: The review compared methods, not form-retraining interventions, and found no universal best score.
Evidence level: Moderate evidence
Finding
A post-hoc comparison of 2 runners from a 217-km mountain race is hypothesis-generating and cannot estimate a causal microbiome effect on performance.
Limitations: Two selected cases, confounding and unmeasured diet make causal interpretation unreliable.
Evidence level: Emerging evidence
Finding
A narrative review continued to place adequate carbohydrate and protein ahead of functional foods for recovery after high-intensity exercise.
Limitations: There was no pooled effect estimate and evidence for adjunct products was heterogeneous.
Evidence level: Practice-informed
Interpretation
Keep the established plan: conversational effort, practiced fueling, small frequent drinking opportunities when useful, calf durability work and terrain-specific form cues. Do not add cognitive tasks, microbiome interventions or a recovery supplement from these findings.