Kristin Lundanes Jonvik

• Solhaug, E. M.; Ødemark, Hege Nymo; Raastad, Truls; Vikmoen, Olav & Jonvik, Kristin Lundanes (2026). Poor skeleton in the peloton: High prevalence of low bone mineral density and suboptimal vitamin D status in elite male cyclists. Science & sports. ISSN 0765-1597. 41(5-6), s. 463–469. doi: 10.1016/j.scispo.2026.01.012. Fulltekst i vitenarkiv
• Øistuen, Gina Flugstad; Osborne, John Owen; Sundgot-Borgen, Jorunn; Noordhof, Dionne; Taylor, Madison Y. & Heikura, Ida [Vis alle 16 forfattere av denne artikkelen] (2026). Menstrual status and bone health in athletes from different sports – a retrospective analysis. BMC sports science, medicine and rehabilitation. doi: 10.1186/s13102-026-01781-y. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Background Relative energy deficiency in sport (REDs) is linked to low energy availability, menstrual disturbances (MD) and low bone mineral density (BMD; Z-score < -1.0). The prevalence of these symptoms across sports and their interrelationships requires further investigation. This study aimed to 1) investigate the prevalence of severe MD and low BMD among athletes from different sports, 2) compare BMD Z-scores at lumbar spine, total hip and whole-body between regularly menstruating (RM), severe MD and hormonal contraceptive (HC) users, and 3) examine factors related to BMD among endurance athletes, including menstrual status, athletic caliber and sport-specific loading characteristics. Methods Retrospective analysis of cross-sectional data from seven projects included 411 women from 34 sports (endurance: n = 257; non-endurance: n = 154). BMD was assessed using dual-energy X-ray absorptiometry. Menstrual status was defined by the three-step method, cycle tracking or questionnaire, and categorized as RM, severe MD or HC. Endurance sports were further grouped by loading characteristics (very low, low and medium). Results Among non-HC users (51%), the prevalence of severe MD was 37% in endurance, 34% in ball sport and 36% in power- and technical- sports. BMD was not different between menstrual status groups at either lumbar spine ( P  = 0.334), total hip ( P  = 0.079) or whole-body ( P  = 0.164). Endurance athletes had lower lumbar spine BMD Z-scores than non-endurance athletes (-0.0 ± 1.0 vs 1.2 ± 1.2, P  < 0.0001), with a higher prevalence of low BMD (17% vs 2%, P  = 0.015). Total hip BMD Z-scores were lower in endurance than non-endurance athletes (0.6 ± 0.9 vs 1.4 ± 1.2, P  < 0.05 for age < 27). Among endurance athletes, neither loading characteristics nor athletic caliber were associated with BMD. However, endurance athletes with severe MD had lower total hip BMD Z-scores compared to RM athletes ( P  = 0.008) and HC users ( P  = 0.021). Conclusions The prevalence of severe MD did not differ between sport types. Overall, BMD Z-scores did not differ across menstrual status categories. However, endurance athletes had lower BMD, with total hip BMD being lower in those with severe MD. Heterogenous menstrual assessment methods across the projects included in this study may have impacted the results. Future research should integrate comprehensive REDs assessments including detailed data on menstrual status, training history, bone-loading impact and injuries in female athletes from different sports.

• Risvang, Linn Christin; Dijk, Jan Willem van; Baumgart, Julia Kathrin; Rice, Hannah; Liljegren, Anja M.F. & Strøm, Vegard [Vis alle 8 forfattere av denne artikkelen] (2025). High prevalence of low bone mineral density in wheelchair users regardless of sports participation: a cross-sectional analysis of the bonewheel study. European Journal of Applied Physiology. ISSN 1439-6319. s. 1–14. doi: 10.1007/s00421-025-06109-1. Fulltekst i vitenarkiv Vis sammendrag

  Purpose Wheelchair users are at increased risk of low bone mineral density (BMD). While BMD varies by sport among Paralympic athletes, it remains unclear whether sports participation protects against low BMD in the impaired population. This study compared BMD at several skeletal sites between sports-active and non-sports-active wheelchair users. Methods This study presents cross-sectional analyses of adult (18–60 years) wheelchair users with non-progressive impairments recruited for a subsequent multi-site intervention study. BMD and body composition were measured with dual-energy X-ray absorptiometry. Low BMD was defined as Z-score <–1.0. Multiple linear regression models assessed differences between sports-active (≥ 1 year organised; ≥3 training hours per week) and non-sports-active participants, and associations with impairment and exercise characteristics, and body composition. Results Sixty-three wheelchair users (age 37 ± 11 years; 41% female; 48% sports-active; 49% with acquired impairments) were included. Low BMD was prevalent in 33%, 81% and 77% at the spine, hip and femoral neck, respectively. Low BMD at the hip was less prevalent in sports-active compared to non-sports-active (p = 0.013), without differences in any BMD Z-score models (all p > 0.05). Acquired impairments was positively associated with lumbar spine BMD (p = 0.034), while full-time wheelchair use was negatively associated with femoral neck BMD (p = 0.036). Impairments and SCIM scores were associated with hip BMD (both p < 0.05). Conclusion Notably high prevalences of low BMD was found in this study, particularly at the hip and regardless of sports participation. Impairments and ambulatory ability appear the most influential on BMD. Targeted exercise interventions for bone health are warranted in this population.

• Weijer, Vera C. R.; Jonvik, Kristin Lundanes; Dam, Lotte Van; Risvang, Linn; Plasqui, Guy & Sandbakk, Øyvind Bucher [Vis alle 9 forfattere av denne artikkelen] (2024). Energy Requirements of Paralympic Athletes: Insights from the Doubly Labeled Water Approach. Medicine & Science in Sports & Exercise. ISSN 0195-9131. 56(5), s. 963–971. doi: 10.1249/MSS.0000000000003379. Fulltekst i vitenarkiv Vis sammendrag

  Purpose: Advanced insight in energy requirements of Paralympic athletes is imperative for optimizing their nutritional counseling. Given the lack of accurate data on total daily energy expenditure (TDEE) of Paralympic athletes, this study aimed to assess energy expenditure and nutritional intake of a large cohort of Paralympic athletes, across different sports and disabilities. Methods: In this cross-sectional study, 48 Dutch and Norwegian Paralympic athletes (19 male/29 female) with various disabilities, competing in Para cycling, wheelchair tennis, wheelchair basketball, Para Nordic skiing, and alpine skiing participated. TDEE was assessed by the gold standard doubly labeled water method over a 14-d period, resting metabolic rate by ventilated hood indirect calorimetry, energy intake by three unannounced 24-h dietary recalls, body composition by dual-energy x-ray absorptiometry, and exercise training duration by a training log. Results: Mean TDEE was 2908 ± 797 kcal·d−1, ranging from 2322 ± 340 kcal·d−1 for wheelchair basketball players to 3607 ± 1001 kcal·d−1 for Para cyclists. Regression analysis identified fat-free mass, exercise duration, and the presence of a spinal cord disorder as the primary predictors of TDEE, explaining up to 73% of the variance in TDEE. Athletes’ energy intake (2363 ± 905 kcal·d−1) was below their TDEE, whereas their body mass remained constant, indicating underreporting. Carbohydrate intake (4.1 ± 1.9 g·kg−1 body mass) was low, even when considering underreporting, whereas protein intake (1.8 ± 0.6 g·kg−1 body mass) was relatively high. Conclusions: Paralympic athletes display moderate- to high-energy expenditure, varying across sports and individuals. Much of the variation in TDEE can be attributed to individual differences in fat-free mass and exercise duration. This study establishes the benchmarks for energy requirements of Paralympic athletes, serving as the foundation for future dietary guidelines within this population.

• Weijer, Vera C.R.; Dijk, Jan-Willem van; Dam, Lotte van; Risvang, Linn; Bons, Judith & Raastad, Truls [Vis alle 8 forfattere av denne artikkelen] (2024). Do Paralympic athletes suffer from brittle bones? Prevalence and risk factors of low bone mineral density in Paralympic athletes. Bone Reports. 21. doi: 10.1016/j.bonr.2024.101767. Fulltekst i vitenarkiv Vis sammendrag

  Background: Bone health may be a concern in Paralympic athletes, given the presence of multiple risk factors predisposing these athletes to low bone mineral density (BMD). Objective: We aimed to assess the prevalence of low BMD among Paralympic athletes participating in various sport disciplines, and to identify potential risk factors for low BMD. Conclusions: In this cohort of Paralympic athletes, low BMD is mainly present at the hip, and to a lesser extent at the whole-body and lumbar spine. The most prominent risk factors for low BMD in Paralympic athletes are related to mechanical loading patterns, including wheelchair use, the type of sport, and body mass.

• Weijer, Vera C.R.; Jonvik, Kristin Lundanes; Dam, Lotte van; Risvang, Linn; Raastad, Truls & Loon, Luc J.C. van [Vis alle 7 forfattere av denne artikkelen] (2024). Measured and Predicted Resting Metabolic Rate of Dutch and Norwegian Paralympic Athletes. Journal of the Academy of Nutrition and Dietetics. ISSN 2212-2672. 125(2), s. 217–227. doi: 10.1016/j.jand.2024.05.010. Fulltekst i vitenarkiv Vis sammendrag

  Background: Although resting metabolic rate (RMR) is crucial for understanding athletes’ energy requirements, limited information is available on the RMR of Paralympic athletes. Objective: The aim of this study was to determine RMR and its predictors in a diverse cohort of Paralympic athletes and evaluate the agreement between measured and predicted RMR from both newly developed and pre-existing equations. Design: This cross-sectional study, conducted between September 2020 and September 2022 in the Netherlands and Norway, assessed RMR in Paralympic athletes by means of ventilated hood indirect calorimetry and body composition by means of dual-energy x-ray absorptiometry. Participants: Sixty-seven Paralympic athletes (male: n = 37; female: n = 30) competing in various sports, with a spinal cord disorder (n = 22), neurologic condition (n = 8), limb deficiency (n = 18), visual or hearing impairment (n = 7), or other disability (n = 12) participated. Main outcome measures: RMR, fat-free mass (FFM), body mass, and triiodothyronine (T3) concentrations were assessed. Statistical analyses: Multiple regression analyses were conducted with height, FFM, body mass, sex, T3 concentration, and disabilities as potential predictors of RMR. Differences between measured and predicted RMRs were analyzed for individual accuracy, root mean square error, and intraclass correlation. Results: Mean ± SD RMR was 1386 ± 258 kcal/d for females and 1686 ± 302 kcal/d for males. Regression analysis identified FFM, T3 concentrations, and the presence of a spinal cord disorder, as the main predictors of RMR (adjusted R2 = 0.71; F = 50.3; P ＜ .001). The novel prediction equations based on these data, as well as pre-existing equations of Chun and colleagues and Nightingale and Gorgey performed well on accuracy (＞60% of participants within 10% of measured RMR), had good reliability (intraclass correlation ＞0.78), and low root mean square error (≤141 kcal). Conclusions: FFM, total T3 concentrations, and presence of spinal cord disorder are the main predictors of RMR in Paralympic athletes. Both the current study’s prediction equations and those from Chun and colleagues and Nightingale and Gorgey align well with measured RMR, offering accurate prediction equations for the RMR of Paralympic athletes.

• Jonvik, Kristin Lundanes; King, Michelle; Rollo, Ian; Stellingwerff, Trent & Pitsiladis, Yannis (2022). New Opportunities to Advance the Field of Sports Nutrition. Frontiers in Sports and Active Living. 4. doi: 10.3389/fspor.2022.852230. Fulltekst i vitenarkiv Vis sammendrag

  Sports nutrition is a relatively new discipline; with ~100 published papers/year in the 1990s to ~3,500+ papers/year today. Historically, sports nutrition research was primarily initiated by university-based exercise physiologists who developed new methodologies that could be impacted by nutrition interventions (e.g., carbohydrate/fat oxidation by whole body calorimetry and muscle glycogen by muscle biopsies). Application of these methods in seminal studies helped develop current sports nutrition guidelines as compiled in several expert consensus statements. Despite this wealth of knowledge, a limitation of the current evidence is the lack of appropriate intervention studies (e.g., randomized controlled clinical trials) in elite athlete populations that are ecologically valid (e.g., in real-life training and competition settings). Over the last decade, there has been an explosion of sports science technologies, methodologies, and innovations. Some of these recent advances are field-based, thus, providing the opportunity to accelerate the application of ecologically valid personalized sports nutrition interventions. Conversely, the acceleration of novel technologies and commercial solutions, especially in the field of biotechnology and software/app development, has far outstripped the scientific communities' ability to validate the effectiveness and utility of the vast majority of these new commercial technologies. This mini-review will highlight historical and present innovations with particular focus on technological innovations in sports nutrition that are expected to advance the field into the future. Indeed, the development and sharing of more “big data,” integrating field-based measurements, resulting in more ecologically valid evidence for efficacy and personalized prescriptions, are all future key opportunities to further advance the field of sports nutrition.

Se alle arbeider i NVA

• Risvang, Linn Christin; Strøm, Vegard; Dijk, Jan-Willem van; Rice, Hannah; Sandbakk, Øyvind Bucher & Bovim, Lars Peder Vatshelle [Vis alle 10 forfattere av denne artikkelen] (2025). Investigating the Effects of a High-Load Resistance Training Program on Bone Health in Wheelchair Users (the BoneWheel Study): Protocol for a Randomized Controlled Trial. doi: 10.2196/70125. Fulltekst i vitenarkiv Vis sammendrag

  Background: Low mechanical loading of the bones of wheelchair users leads to low bone mineral density (BMD) and increased risk of bone fractures and associated complications. High-load resistance training of the upper body is one way to achieve mechanical loading of the lumbar spine and the hip bones. In addition, maintaining good nutritional status with key nutrients for bone remodeling, that is, vitamin D and calcium, is important for bone accrual. Objective: This study aims to investigate the effect of 24 weeks of high-load resistance training combined with nutritional optimization on lumbar spine BMD. Secondary objectives are to investigate the effects of the intervention on (1) bone and physical health parameters, such as bone turnover blood markers, nutritional status, body composition, and maximal muscular strength, as well as (2) exercise motivation and mental health. Methods: In this randomized controlled trial, we aimed to include 60 wheelchair users with nonprogressive impairments. Participants were randomly allocated to 24 weeks of either (1) high-load resistance training and nutrition optimization or (2) nutrition optimization only, stratified by sex and sport activity status. The training program consisted of 3 weekly sessions comprising 6 exercises periodized in low-, moderate-, and high-load phases. The nutritional optimization aimed to ensure sufficient intake of protein, vitamin D, and calcium. BMD and body composition; maximal muscular strength; and nutritional, physical, and mental health status were assessed at baseline, midpoint, and postintervention visits. Furthermore, follow-up assessments of a subgroup were conducted at 6 to 18 months after the intervention. This protocol was approved by the Regional Committee for Medical and Health Research Ethics South-East, Norway. Results: Recruitment occurred between November 2022 and 2023. A total of 68 wheelchair users were screened for eligibility, of whom 45 (66%) were enrolled and allocated to one of the study groups (n=24, 53% training group; n=21, 47% control group). At the midpoint and postintervention visits, 36 (n=17, 47% and n=19, 53%, respectively) and 33 (n=14, 42% and n=19, 58%, respectively) participants were assessed, respectively. Analysis of the data collected at the screening visit commenced in spring 2024, while analyses of data collected at the baseline and retest visits began in autumn 2024. Publication of the results of this study is expected by the end of 2025. Conclusions: This protocol presents the first randomized controlled trial of a high-load resistance training intervention in wheelchair users, focusing on bone, physical, and mental health. The results will contribute to new knowledge in exercise science for this population and generate novel hypotheses for future studies.

• Baumgart, Julia Kathrin; Jonvik, Kristin Lundanes; Severin, Anna Cecilia; Hrozanova, Maria & Solli, Guro Strøm (2023). Parautøveren. I Sandbakk, Øyvind Bucher; Solli, Guro Strøm & Staff, Hanne Cesilie (Red.), Den kvinnelige idrettsutøveren. Fagbokforlaget. ISSN 9788245036930. Fulltekst i vitenarkiv
• Bieniek, Daniel; Jonvik, Kristin Lundanes; Stormoen, Kristiane; Lekhal, Samira; Mathisen, Therese Fostervold & Sundfør, Tine Mejlbo [Vis alle 9 forfattere av denne artikkelen] (2022). Flertallet av nordmenn tror fagpersoner er uenige om hva som er sunt. Det stemmer ikke. Fulltekst i vitenarkiv

Se alle arbeider i NVA