Dídac Navarro-Martínez

Exogenous ketone supplementation has emerged as a potential ergogenic strategy for trained and physically active individuals, prompting increasing research into its effects on exercise performance and metabolism. This systematic review evaluated the effects of ketone supplementation on athletic performance, metabolic variables, and physiological responses in trained and physically active populations. Searches were conducted in EBSCOhost, PubMed, and Web of Science following PRISMA 2020 guidelines. Peer-reviewed controlled studies published between 2018 and December 2025 were included. Twenty-six studies met the eligibility criteria. Ketone supplementation consistently increased circulating β-hydroxybutyrate concentrations and modified glucose, lactate, and acid–base balance. Effects on exercise performance were heterogeneous, with some studies reporting improvements in time-trial performance and cognitive function, whereas others found no benefit or even impaired performance. Co-ingestion with sodium bicarbonate attenuated metabolic acidosis and occasionally enhanced performance outcomes. Ketone supplementation also influenced cardiorespiratory responses and fluid regulation, and may promote muscular angiogenesis during periods of training overload. Overall, current evidence remains heterogeneous and does not support definitive conclusions regarding ergogenic efficacy, which appears to depend on exercise intensity, participant characteristics, supplementation protocols, and co-ingestion strategies.

Background: Plantar pressure analysis provides insight into load distribution at the foot–pedal interface during cycling; however, its modulation by pedaling power, cadence, and overuse injury status remains poorly understood by professional cyclists. It is unclear whether common overuse injuries, such as Achilles tendinopathy, patellofemoral pathology, and iliotibial band syndrome, are associated with distinct plantar loading patterns. This study aimed to characterize plantar pressure distribution in elite cyclists and determine how power, cadence, and injury status influence this pattern. Methods: Professional cyclists completed a single integrated protocol using a high-resolution in-shoe pressure system. Plantar forces were recorded across nine anatomical regions and grouped into the transverse and longitudinal segments of the foot. Three phases were included: absolute power manipulation (100 and 200 W), cadence manipulation (80 and 100 rpm) at fixed power, and an ecological combined protocol using relative power (1.5 and 3 W·kg⁻¹) with individualized cadence. The cyclists used their habitual bike setups. Participants were classified into the non-pathological (NP), AT, PFP, or ITBS groups. Mixed repeated-measures ANOVAs were used to analyze the effects of power, cadence, zone, foot, and injury status. Results: The plantar pressure distribution was consistently dominated by the medial forefoot. Increasing the absolute power from 100 to 200 W increased the maximal plantar pressures by 84.74% (p < 0.001), whereas increasing the cadence from 80 to 100 rpm at a fixed power increased the pressures by 15.90% (p = 0.003). Under individualized conditions, increasing relative power from 1.5 to 3 W·kg⁻¹ increased pressures by 39.59% (p < 0.001), whereas cadence had no global main effect but significantly altered the regional pressure distribution (p < 0.001). Injury groups showed pathology-specific deviations, including higher overall pressures and asymmetry in Achilles tendinopathy, bilateral asymmetry in patellofemoral pathology, and asymmetric loading patterns in iliotibial band syndrome. Conclusions: Power is the main determinant of plantar pressure, and cadence modulates load distribution. Overuse injuries induce pathology-specific pressure patterns, supporting plantar pressure analysis for injury prevention and performance optimization in athletes.