Abstract
ltra-endurance running presents significant physiological demands, with adequate nutri- tional intake being critical for optimal preparation, performance, and recovery. However, athletes of this sport often consume an insufficient diet. Semi-structured interviews were conducted virtually with ten recreational ultra-endurance runners (age mean±standard deviation 46±12 years; eight male, two female), all with experience competing in ultra- endurance events, to explore their ultra-endurance experience, dietary intake, nutrition knowledge, and gastrointestinal symptom management. Interviews were transcribed verbatim and thematically analysed in accordance with the COM-B model and the Theo- retical Domains Framework. Themes were defined under each of the three COM-B model components: Capability: (1) knowledge and skills, (2) the intention–behaviour challenge; Opportunity: (1) facilitators and barriers to optimal nutrition, (2) information sourcing and learning; and Motivation: (1) drivers of nutrition behaviours, (2) risk perceptions’ influence on fuelling strategies. Participants demonstrated strong psychological capability, that is, awareness of nutrition’s importance, yet limited behavioural regulation to translate this knowledge into practice. Nutrition strategies were largely self-directed, relying on peers and social media over professional support. Fear of gastrointestinal symptoms and time pressures further shaped dietary decisions. These findings emphasise the importance of evidence-based nutrition guidance to support performance and recovery while minimising gastrointestinal symptom risk. For practitioners and self-coached athletes, recommen- dations should reflect the practical realities and competing demands of ultra-endurance runners’ daily lives and be feasible within real-world settings. Keywords:ultra-endurance running; sports nutrition; gastrointestinal symptoms; nutrition behaviours; COM-B model 1. Introduction Ultra-endurance running, a term often used interchangeably with ultra-marathon running or ultra-running, is a form of endurance exercise defined by
symptom risk. For practitioners and self-coached athletes, recommen- dations should reflect the practical realities and competing demands of ultra-endurance runners’ daily lives and be feasible within real-world settings. Keywords:ultra-endurance running; sports nutrition; gastrointestinal symptoms; nutrition behaviours; COM-B model 1. Introduction Ultra-endurance running, a term often used interchangeably with ultra-marathon running or ultra-running, is a form of endurance exercise defined by either distance or duration. The former describes an ultra-endurance run exceeding the well-known typ- ical marathon length of 26.2 miles/42.2 km, while the latter defines an ultra-endurance run as a single bout of exercise that exceeds six hours in duration [1]. Events may be single- or multi-stage, with varying levels of self-sufficiency required. For example, in wholly self-sufficient events, participants must carry all required nutrition for the entire race, while semi-supported events offer intermittent refreshment points with food and hydration, and fully supported events provide frequent, organised nutritional provision. Sports2026,14, 109 https://doi.org/10.3390/sports14030109
Sports2026,14, 109 2 of 19 Additionally, the challenging nature of these events may be further exacerbated by rough terrain and harsh environmental conditions [2]. On a global scale, there has been a dy- namic increase in ultra-endurance running event participation over the past 25 years, from approximately34,401 totalannual ultra-endurance running event participants in 1996 to 611,098 in 2018 [3,4]. Though serious adverse effects are uncommon, long-term health implications of ultra- endurance running include cardiovascular, respiratory, and musculoskeletal complications. For example, prolonged, high-volume running places significant stress on bones, muscles, joints, and connective tissues which, when coupled with inadequate nutrition, may con- tribute to osteoarthritic changes [5]. Additionally, gastrointestinal symptoms (GIS) are a prominent issue for ultra-endurance runners. These range from mild symptoms, such as belching and flatulence, to more severe discomfort, such as nausea and vomiting [6]. A range of intrinsic and extrinsic factors may exacerbate these. The former, intrinsic factors, include disorder or disease, internal bacterial composition (e.g., the gut microbiome), di- etary intake, and nutrition strategies employed. Conversely, the latter, extrinsic factors, comprise variables such as exercise type, exercise duration, and surrounding environmental conditions [7–9]. Despite the significant importance of adequate nutrition and hydration practices for ultra-endurance athletes’ health and wellbeing, previous research has observed that this population often fails to meet intake recommendations [10–12]. In addition, a systematic review by Janiczak et al. [13] found athletes’ nutrition knowledge, a factor associated with their nutritional intake, to be low. The International Society of Sports Nutrition provides dietary recommendations and considerations for training and competing in ultra-endurance runs (see Table S1 in the Supplementary Material) [14]. Guidelines are defined as intake per hour, with energy, carbohydrates, and protein recommended at 150–400 kilocalories, 30–50 g, and 5–10 g, respectively. Regarding the optimal sourcing of these, athletes are advised to experiment with various foods and to take into consideration their individual food palatability, tolerances, and preferences. Though these recommendations exist, ultra- endurance athletes have been reported to favor other athletes’ experiences, opinions, and recommendations over those of qualified nutrition personnel, highlighting the influence of social opportunity and motivational factors on nutrition
the optimal sourcing of these, athletes are advised to experiment with various foods and to take into consideration their individual food palatability, tolerances, and preferences. Though these recommendations exist, ultra- endurance athletes have been reported to favor other athletes’ experiences, opinions, and recommendations over those of qualified nutrition personnel, highlighting the influence of social opportunity and motivational factors on nutrition behaviours [15]. Little is known about the real-life experiences of ultra-endurance runners. Existing research investigating these athletes is often quantitative in nature, monitoring values such as blood biomarkers [11]. Previous reviews highlight the need to better understand food choice, nutrition knowledge, and diet quality using appropriate methods, as well as the challenges athletes face when translating recommendations into practice [16,17]. These gaps suggest potential deficits in the capability, opportunity, and motivation factors described in the COM-B model, yet no research has explicitly examined these mechanisms in ultra-endurance runners [18,19]. The COM-B model is a framework proposing three components—capability (C), opportunity (O), and motivation (M)—that are essential for a behaviour (B) to occur and can be used to guide intervention development (Figure S1 in the Supplementary Material). Capability refers to an individual’s physical and psychological capabilities to engage in a behaviour, such as their physical functional status and psychological skills and intentions. Opportunity encompasses their physical opportunities, such as available free time, and social opportunities, such as peer support. Lastly, motivation includes an individual’s automatic and reflective motivation. The former, automatic motivation, includes habits and emotional reactions, while the latter, reflective motivation, includes evaluation of experiences and future planning [20,21]. This model has been used to explore experiences, as well as barriers and facilitators, to physical activity and nutrition practices in both sport https://doi.org/10.3390/sports14030109
Sports2026,14, 109 3 of 19 and non-sport populations [11–14]. However, this theory has yet to be incorporated into research on ultra-endurance runners [22–24]. Conversely, the Theoretical Domains Framework (TDF) is a theoretical framework that provides a lens through which to view the cognitive, affective, social, and environmental influences on behaviour. This framework consists of 33 theories of behaviour and behaviour change which have been clustered into 14 (originally 12) domains (see Table S2 in the Supplementary Material for examples of TDF domains and their constructs) [25,26]. Initially developed specifically to identify influences on health professional behaviour related to the implementation of evidence-based recommendations, the TDF was extended to explore other areas where behaviour change is important, such as physical activity engagement and nutrition practices [27,28]. Recognising the lack of theory-informed research in ultra-endurance running popu- lations, the present study sought to gain an in-depth understanding of ultra-endurance runners’ lived experiences of nutrition behaviours and GIS management. Using the COM- B model and TDF, this study aimed to identify behavioural determinants, barriers, and enablers influencing the adoption of evidence-based nutrition practices. 2. Materials and Methods 2.1. Study Design This research involved conducting individual interviews with ultra-endurance run- ners, with resulting transcripts thematically analysed in accordance with the Braun and Clarke [29,30] methodology for conducting qualitative investigations. Figure S2 in the Supplementary Material provides a visual overview of the research process. 2.2. Ethics This project was granted ethical approval by the Research Sub-Committee of the Academic Council of Atlantic Technological University. An email outlining the nature of the research, eligibility criteria, and researchers’ contact details was initially distributed to relevant organisations and personnel. Individuals who contacted the researcher were sent a participant information sheet via email offering more details on the research, what it entailed, and the confidential nature of the data resulting from each interview. Consent was obtained from each participant prior to their partaking in a 1-1 digital interview with the researcher. All information was anonymised to protect the participants from identification. 2.3. Recruitment Between January and June 2023, running organisations, clubs, and event organisers in Ireland were contacted and
what it entailed, and the confidential nature of the data resulting from each interview. Consent was obtained from each participant prior to their partaking in a 1-1 digital interview with the researcher. All information was anonymised to protect the participants from identification. 2.3. Recruitment Between January and June 2023, running organisations, clubs, and event organisers in Ireland were contacted and provided with study information and the author’s contact details. They were asked to share this information with their networks. A purposive sam- pling strategy was employed to target specific individuals with relevant ultra-endurance running experience. Snowball sampling was also used, whereby participants could recom- mend other athletes who met the inclusion criteria set for this investigation. These criteria were as follows: 18 years of age or older, any gender, healthy, living in Ireland, having any degree of running experience and having previously completed an ultra-endurance running event, considering themselves an “ultra-endurance runner”, having any history of GIS, and fluency in English. The exclusion criteria were as follows: diagnosed with a medical condition, pregnant or lactating currently or within the previous year, or having suffered an injury which halted the ability to run currently or within the previous year. https://doi.org/10.3390/sports14030109
Sports2026,14, 109 4 of 19 2.4. Data Collection and Analysis The interviews were conducted virtually via Microsoft Teams and were semi- structured and iterative in their design, with questions based upon a previously devel- oped and validated questionnaire by Scrivin et al. [31], which is freely available online asSupplementary Materialto their publication. The lead researcher was integrated into a team with extensive experience in qualitative analysis, receiving training, participating in regular team discussions throughout the study, and keeping notes of research activities. Question responses were used to gather insight into nutrition’s role for ultra-endurance runners before, during, and after ultra-marathon events. Each participant was presented with questions regarding their experiences, which were broadly categorised into the follow- ing topics: (1) athlete history, (2) nutrition knowledge and sourcing, (3) the role of nutrition pre-, during- and post-ultra-endurance activity, and (4) GIS awareness and management. The audio recordings of each interview were transcribed verbatim and subsequently cross- referenced with the original audio to ensure accuracy. The resulting document consisted of n = 10 individuals’ interview transcripts (interview duration as mean±standard deviation: 31±11 min). The resulting data were reviewed and analysed in line with the Braun and Clarke recommended methodology for qualitative analysis, with themes subsequently mapped to the COM-B model and TDF to identify behavioural determinants, barriers, and enablers influencing nutrition practices [20,21,25,26]. This methodology comprised six key phases: (1) Familiarisation: transcriptions were read and re-read to become immersed and familiar with the data; (2) Initial Coding: succinct labels or “codes” were generated that captured and portrayed the critical information in the interviews; (3) Constructing Themes: the codes were examined and broader patterns were identified; (4) Review- ing and Refining Themes: the initial themes generated were checked against the coded data to ensure accurate reflection of information, with edits being made where necessary; (5) Defining and Naming Themes: each identified pattern or theme was given a name to represent it truly; and (6) Writing Results: the data extracts were woven together and linked to their most relevant theme, then discussed. The analysis was conducted from a realist/essentialist epistemological position, aiming to report
ensure accurate reflection of information, with edits being made where necessary; (5) Defining and Naming Themes: each identified pattern or theme was given a name to represent it truly; and (6) Writing Results: the data extracts were woven together and linked to their most relevant theme, then discussed. The analysis was conducted from a realist/essentialist epistemological position, aiming to report the participants’ lived experi- ences as they described them. Coding was both inductive and deductive, with initial codes generated from the data, while subsequent organisation and interpretation were guided by the COM-B model and TDF domains. Themes were defined at a latent level, capturing underlying meanings and behaviours in participants’ accounts. A coding journal and theme development were developed by the first author, T.R., with these then discussed and agreed upon by the research team. The first author, T.R., conducted and transcribed each interview and analysed the results. The research team, E.D. and L.R., developed themes and sub-themes and subsequently reviewed them. Any disagreements were resolved through a research team group discussion. 2.5. Reflexivity and Data Management The lead researcher’s background in sports nutrition and prior experience with ultra- endurance runners were acknowledged as both a strength, in terms of interpretative sensitivity, and a potential source of bias. Reflexivity was maintained through journaling, peer debriefing, and collaborative theme discussions. Coding was documented in a journal; themes were reviewed and refined collaboratively. Theory and investigator triangulation were employed in the present study. We acknowledge that member checking and systematic negative case analysis were not performed and highlight this as a limitation. Further questioning was carried out, when necessary, in order to draw out more information from the participants. Recruitment continued until data saturation was reached, defined as the point at which no new themes or sub-themes were identified from additional interviews. https://doi.org/10.3390/sports14030109
Sports2026,14, 109 5 of 19 3. Results A total of n = 10 ultra-endurance runners participated (eight males, two females; age of those who disclosed: mean±standard deviation 46±12 years, range29–79 years;Table) . Participants varied in ultra-endurance experience), enabling exploration of nutrition be- haviours through the COM-B framework and TDF. Table 1.Participant characteristics (participants were given the choice not to disclose their age). Participant Number Gender Age 1 Female Not disclosed 2 Male 45 3 Male 49 4 Male 29 5 Male 39 6 Female 46 7 Male 39 8 Male 70 9 Male Not disclosed 10 Male 54 Analysis of resulting interview transcripts resulted in the identification of six overar- ching themes, mapped to the components of the COM-B model and linked to their relevant domains of the TDF. These were: Capability: (1) knowledge and skills, (2) the intention- behaviour challenge; Opportunity: (1) facilitators and barriers to optimal nutrition, (2) information sourcing and learning; and Motivation: (1) drivers of nutrition be- haviours, (2) risk perceptions’ influence on fuelling strategies (see Figure S3 in the Supplementary Material). Tables S3 and S4 in the Supplementary Material offer detailed contextual information on participants’ running backgrounds, nutrition knowledge, in- formation sources, fuelling practices, gastrointestinal symptom management strategies, and commonly included or avoided foods, beverages, and supplements before and during ultra-endurance events. 3.1. Theme 1: Capability The first component of the COM-B model, capability, refers to an individual’s capacity to engage in a behaviour. This encompasses both their physical abilities, such as fitness level, and psychological abilities, such as mental state and knowledge, to perform a be- haviour and achieve the desired outcome. This aligns with the psychological capability component of the TDF, reflecting the athletes’ knowledge and skills necessary to enact effective nutrition behaviours. Two themes relating to participants’ capability became evident through analysing interview data. These were (1) nutrition knowledge and skills, and (2) the intention–behaviour challenge. 3.1.1. Sub-Theme 1: Knowledge and Skills Participants reported moderate self-perceived nutrition knowledge (scores 5–8/10, mean ~6.5), demonstrating awareness of energy, carbohydrate, fluid, and salt intake. Most participants reported eating and drinking ad hoc during training and
Two themes relating to participants’ capability became evident through analysing interview data. These were (1) nutrition knowledge and skills, and (2) the intention–behaviour challenge. 3.1.1. Sub-Theme 1: Knowledge and Skills Participants reported moderate self-perceived nutrition knowledge (scores 5–8/10, mean ~6.5), demonstrating awareness of energy, carbohydrate, fluid, and salt intake. Most participants reported eating and drinking ad hoc during training and events, guided by feelings of hunger and thirst. Knowledge of supplements and medication to support performance was also evident. Over half (n = 7) of participants included salt tablets in their https://doi.org/10.3390/sports14030109
Sports2026,14, 109 6 of 19 event nutrition protocols; however, they were often ingested ad hoc, primarily dependent on when participants believed they were becoming dehydrated. P6: “when you’re running, you get like white salt, kind of encrusting your face, and that’s a sign that you need to take on your salts as well. So these are things you learn”. Many participants were aware of nutrition strategies that they could employ in the lead-up to an event, though many admitted they “tried to eat a lot of carbs. . . . . . didn’t really have a proper approach” (P4) and would instead generally aim to eat “a couple of days before. . . . . . be eating pastas and pizza’s and stuff like that” (P5). This demonstrates a gap between reflective motivation and procedural capability, whereby athletes understand what should be done but struggle to consistently implement structured strategies, relying instead on intuitive, experiential decision-making. Instead, they found themselves oftentimes “nibbling a little bit more” (P2) in the run-up to an event. Additionally, this time was often coupled with switching to leaner meats such as chicken and turkey, while simultaneously making intentional efforts to “avoid loads of sugar, biscuits, chocolate, sweets” (P4). The latter, in particular, was in an attempt to avoid GIS and feeling “a bit off . . . . . . iffy on a run” (P4). During events, the majority (n = 9) of participants typically relied on high-sugar, fast- acting carbohydrate products including gels, flapjacks, jellies, and drinks. The exception to this, P3, avoids food before running, stating that he had been “doing it for years. . . and there’s no science to prove that I’m doing wrong” (P3). This participant considered himself “fairly knowledgeable” on nutrition, noting he has “enough confidence for [his social media account sharing nutrition information and recommendations]”. P3: “I try not to eat about four hours before any runs. If it was a race I won’t eat at all before”. For those who did fuel during events, eating and drinking periods were separated by timing, often approximately every 30 to
on nutrition, noting he has “enough confidence for [his social media account sharing nutrition information and recommendations]”. P3: “I try not to eat about four hours before any runs. If it was a race I won’t eat at all before”. For those who did fuel during events, eating and drinking periods were separated by timing, often approximately every 30 to 60 min, or distance, whereby food and fluid were ingested after specific distances. For example, one participant explained, “I would have practiced ok every 40 min. I have to take on some nutrition and then after every hour and a half I try and have something more substantial like uh, small bit of a sandwich” (P5). One participant considered themselves extremely regimented with regard to planning their during-event nutrition and timing their food and fluid intake, noting he “had the spreadsheet with all my foods and with how many carbs, how many calories, what each portion would weigh, because I had to carry it in my bag” for the Marathon des Sables self-sufficient event (P10). However, this participant had a background in sport science with a previous career in sport. In contrast, post-event nutrition was often undervalued, with many participants demonstrating limited knowledge of its importance for recovery. One participant, who originally began running as a weight-loss strategy, explained that they tried not to indulge after an event as “you don’t wanna be like piling on the weight afterwards” (P6). Here, the focus was on weight management rather than optimising nutrient intake for recovery. This suggests that although athletes may be aware of fuelling strategies for supporting event preparation, performance, and recovery, knowledge of specific evidence-based pro- tocols and their reasoning is often lacking, leaving participants at risk of inadequate nutrition intake. An outlier within the sample was one participant who, after discussions with a friend who was a sports nutritionist, avoided eating at all prior to and during events, a strategy they termed “running on empty” (P3). They believed that “food is sometimes poison, even the good food”, and that carrying food and liquids would expend energy better used
Description
This study explores nutrition practices among ultra-endurance runners in Ireland.