Therese Fostervold Mathisen

• Lundberg, Helge Einar; Larsen, Stig; Mathisen, Therese Fostervold; Borgen, Tove Tveitan & Sundgot-Borgen, Jorunn (2026). Propionibacterium cheese and bone turnover in active young adults: a randomized-controlled trial. Journal of Bone and Mineral Metabolism. ISSN 0914-8779. doi: 10.1007/s00774-026-01761-9. Full text in Research Archive Show summary

  Introduction Young physically active individuals exposed to prolonged physiological stress and low energy availability are prone to reduced gonadal steroid protection and increased bone turnover. Nutritional strategies that favor positive bone remodeling balance are of clinical interest. Jarlsberg cheese contains Propionibacterium freudenreichii (PF), which produces vitamin K₂ and 1,4-dihydroxy-2-naphthoic acid (DHNA), compounds with potential favorable effects on bone health. Materials and Methods In this 24-week sex-stratified randomized-controlled trial, 60 young physically active adults engaged in endurance training were allocated to daily intake of either Jarlsberg cheese or a nutritionally comparable control cheese without PF. The primary outcome was change in serum total osteocalcin (tOC). Secondary outcomes were changes in carboxylated osteocalcin (cOC), procollagen type 1 N-terminal propeptide (P1NP), cross-linked C-terminal telopeptide of type I collagen (CTX), P1NP/CTX ratio, lumbar spine bone mineral density (BMD), and trabecular bone score (TBS). Results After 24 weeks, serum tOC was significantly higher in the Jarlsberg group than in controls (38.0 vs. 26.8 ng/mL, p < 0.01). cOC and P1NP/CTX ratio increased in favor of the Jarlsberg group (p = 0.03). Lumbar spine BMD increased in the Jarlsberg group (mean change 0.012 g/cm2, p = 0.03), with a greater increase than in controls (p = 0.05), and TBS showed a positive trend in the Jarlsberg group. Conclusion Daily intake of cheese-containing PF was associated with favorable changes in bone turnover markers and increase in lumbar spine BMD. These findings suggest that PF-fermented cheese may support bone metabolism in young individuals exposed to reduced hormonal protection and high bone turnover.

• Mathisen, Therese Fostervold; Macnaughton, Lindsay; Mountjoy, Margo & Sundgot-Borgen, Jorunn (2026). Implementation gap: a 3-year reality check in body composition monitoring in sport. British Journal of Sports Medicine. ISSN 0306-3674. doi: https:/bjsm.bmj.com/content/early/2026/09/02/bjsports-2026-112287. Full text in Research Archive
• Øistuen, Gina Flugstad; Osborne, John Owen; Sundgot-Borgen, Jorunn; Noordhof, Dionne; Taylor, Madison Y. & Heikura, Ida [Show all 16 contributors for this article] (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. Full text in Research Archive Show summary

  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.

• Sundgot-Borgen, Christine; Sundgot-Borgen, Jorunn & Mathisen, Therese Fostervold (2026). Appearance Pressure, Body Image, and Nutrition Practices in Youth Athletes: Implications for Performance. International Journal of Sports Physiology and Performance (IJSPP). ISSN 1555-0265. doi: 10.1123/ijspp.2025-0687. Full text in Research Archive Show summary

  Elite youth sport (12–19 y of age) exists at the intersection of increasing performance demands, rapid biological development, and growing appearance pressures. For many adolescent athletes, this convergence blurs the distinction between fueling to support performance and manipulating food intake to conform to perceived physique ideals. As cultural and digital body norms intensify through social media engagement, leanness is frequently misconstrued as a marker of success—despite clear evidence that inadequate fueling undermines the physiological and psychological systems required for athletic development.1 A recalibration is needed: nutrition in youth sport must be reframed as a biological prerequisite for growth, adaptation, resilience, sustained enjoyment of sport, and the sustainable development of athletic performance across the developmental years.

• Heradstveit, Siri; Garnweidner-Holme, Lisa; Winje, Brita Askeland; Sundgot-Borgen, Jorunn & Mathisen, Therese Fostervold (2026). Knowledge of Eating Disorders and Relative Energy Deficiency in Sports among Public Health Nurses at Elite Sport Schools. Sage Open Nursing. 12. doi: 10.1177/23779608251407784. Full text in Research Archive
• Mathisen, Therese Fostervold; Mountjoy, Margo & Sundgot-Borgen, Jorunn (2026). Strong Bodies, Unclear Guidelines—Navigating Pregnancy and Postpartum Without Tailored Resistance Exercise Guidelines. Women in Sport & Physical Activity Journal. ISSN 1063-6161. 34(1). doi: 10.1123/wspaj.2025-0112. Full text in Research Archive Show summary

  Objective: This study explored the experiences of female athletes performing heavy resistance exercise during pregnancy and postpartum (REX group) and reflected these against experiences of physically active women not engaging in heavy resistance exercise (REF group). Design: Secondary outcomes from a prospective, longitudinal study following two exercising groups of pregnant women through pregnancy and up to 12 months postpartum. Data were collected via questionnaires and analyzed using inductive content analysis. Results: Thirty-two women were included in the REX group and 17 were in the REF group. Of all participants, 35% reported receiving warnings against their usual training—most often from midwives. Although REX participants typically faced concerns related to heavy resistance exercise, REF participants also reported warnings, particularly about high-intensity exercise. Three key themes emerged from pregnancy responses: “training for two: joy, strength, and sanity through exercise”; “between warnings and worries: pregnant women’s struggle for reliable advice”; and “strength over strain: why resistance training works in pregnancy.” Two themes were identified postpartum: “new priorities, new physique” and “when experts fall silent.” Conclusion: Women training beyond standard health recommendations often encounter concerns from healthcare providers and others. Although the female athletes rely on personal experience, many express doubt and frustration due to the lack of tailored, evidence-based advice. Exercise, especially resistance exercise, was seen as vital for both mental and physical health, particularly when other forms of movement were limited by pregnancy or postpartum symptoms.

• Lundberg, Helge Einar; Larsen, Stig; Sundgot-Borgen, Jorunn & Mathisen, Therese Fostervold (2026). Seasonal changes in energy intake and emerging indicators of energy availability in young elite Nordic skiers. Journal of the International Society of Sports Nutrition (JISSN). 23(1). doi: 10.1080/15502783.2026.2634184. Full text in Research Archive Show summary

  Background Nordic skiing, an energy-demanding endurance sport, may be particularly susceptible to low energy availability (LEA) and relative energy deficiency in sport (REDs). The objective was to examine the nutritional practices and physical symptoms associated with (REDs among young elite Norwegian Nordic skiers during the off-season, with particular emphasis on energy and CHO intake, in the transition from the competitive season to preparation for the subsequent season. Methods Thirty female and thirty male Nordic skiers participated in a 24-week controlled clinical trial. The daily dietary intake variables were carbohydrates (CHO), protein, and calcium (Ca) intake and weekly training hours. The blood variables were vitamin D, total osteocalcin (tOC), procollagen type 1 N-terminal propeptide/cross-linked C-telopeptide type 1-collagen (PINP1/CTX1) ratio, heart rate (HR), resting metabolic rate (RMR), bone mineral density (BMD), lean body mass (LM), visceral adipose tissue (VAT), and body fat percentage (BF%). Results Energy intake increased by 25%, and CHO increased by 14.5% for both sexes during the study, and training volume increased by 41% for female athletes and 83% for male athletes, respectively. There were positive correlations between higher BMD, bone markers, RMR, and LM and negative correlations between VAT and REDs symptoms. VAT was correlated with RMR and bone markers. LM emerged as a key predictor for health variables, explaining variability across multiple REDs markers. Conclusions Nordic skiers seem unable to increase energy intake sufficiently during the preparation period, leading up to the competitive season, as demonstrated by a large discrepancy between changes in energy intake, especially CHO, and exercise volume. The correlations between energy intake and BMD, RMR, VAT, and HR underscore the clinical consequences of insufficient energy intake, which may arise if individuals focus on low body mass and body fat percentage without sufficient knowledge. VAT, tOC, and the P1NP/CTX-ratio are promising indicators for monitoring dietary interventions in individuals with REDs and should be considered in future research on REDs treatment strategies.

• Mathisen, Therese Fostervold; Sundgot-Borgen, Jorunn; Macnaughton, Lindsay; Rustaden, Anne Mette; Løkkevik, Inger Johanne & Lundberg, Helge Einar [Show all 7 contributors for this article] (2025). Knowledge of low energy availability in biathlon: Why coaches need more targeted education. Results from a national, cross-sectional study. International journal of sports science & coaching. ISSN 1747-9541. doi: 10.1177/17479541251407845. Full text in Research Archive Show summary

  This study explores the knowledge of coaches working with adolescent biathletes regarding eating disorders (ED), low energy availability (LEA), and Relative Energy Deficiency in Sport (REDs). METHODS: Recruited coaches completed a questionnaire assessing self-reported knowledge (scale 0–10) of ED, LEA and REDs, and secondly by articulating their knowledge (scored by three experts, scale 0–2). RESULTS: Thirty-three coaches participated (mean age 40.6 ± 12.2 years), most without formal coach education (n = 25, 75.8%), and 13 (39.4%) were female. Self-reported knowledge of LEA/REDs was lower than ED knowledge (4.75 ± 2.9 vs. 5.74 ± 2.5; p = 0.02, g = 0.4), with a similar pattern in expert-rated scores (0.72 ± 0.6 vs. 1.12 ± 0.6; p < 0.01, g = 0.8). A regression model explained 45% of variance in self-reported LEA/REDs knowledge, with education level and course participation positively associated, while sex had no significant effect. For expert-rated scores, the model explained 33% of variance, with only course participation significant. For knowledge of guidelines on addressing LEA/REDs concerns self-reported scores were 3.6 ± 2.9, and 4.5 ± 2.9 for ED concerns (p = 0.04, g = 0.4); and expert-assessed scores were 0.7 ± 0.7 and 0.9 ± 0.8 (p = 0.11), respectively. Regression models did not significantly explain variability in these scores CONCLUSION: Biathlon coaches are less aware of LEA/REDs symptoms and less confident in addressing them than symptoms of ED. Importantly, education and course attendance raised knowledge scores, and preferred learning methods were virtual or physical courses with experts over scientific papers.

• Schei, Emilie Alexandra & Mathisen, Therese Fostervold (2025). Sosiale mediers påvirkning på unge voksne med spiseforstyrrelser: en kvalitativ studie. Tidsskrift for Norsk psykologforening (Psykologtidsskriftet). ISSN 0332-6470. doi: 10.52734/JIIG7745. Full text in Research Archive Show summary

  Bakgrunn: Spiseforstyrrelser har økt i forekomst, og behandling kan være krevende. Studier finner sammenheng mellom bruk av sosiale medier (SoMe) og symptomer på spiseforstyrrelser, men vi mangler dybdeforståelse om hvordan SoMe erfares for unge voksne med erfaring med spiseforstyrrelser. Metode: Vi gjennomførte semistrukturerte intervjuer. Deltakere var mellom 20–30 år og hadde erfaring med spiseforstyrrelser og SoMe-bruk. Rekruttering foregikk via SOME. Datamaterialet ble analysert ved refleksiv tematisk analyse. Resultat: Syv deltagere (én mann) med gjennomsnittsalder (SD) 26,4 (4,1) deltok. Det ble identifisert fire overordnede temaer: «Samfunnsmedisin som risikofaktor», som omhandler erfaring med spiseforstyrrelser i et mediesamfunn som legger mye vekt på slanking, «Jeg kan ikke kontrollere det» beskriver erfaring med algoritmer, «Sosiale medier som positiv forsterker» beskriver erfaringer med hensiktsmessig bruk av SoMe i en tilfriskningsprosess, og «Folkeopplysning og utilsiktede konsekvenser» beskriver opplevelsen av SoMe-innhold som opprinnelig er postet med gode intensjoner. Konklusjon: I studien var opplevelser av SoMe koblet til betydningen spiseforstyrrelsen har for den enkelte, og i hvilken sykdomsfase deltagerne befant seg i. Selv om deltagerne tydelig fremhevet negative erfaringer knyttet til SOME-bruk, kom det også frem verdifulle erfaringer når det gjelder å finne støtte i tilfriskningsprosessen. Behandling av spiseforstyrrelser bør adressere bevisst SoMe-bruk.

• Nettum, Vebjørn; Mathisen, Therese Fostervold; Slater, Gary; Seynnes, Olivier R. & Paulsen, Gøran (2025). Lean Body Mass and Maximal Strength Changes during Physique Contest Preparation and Recovery: A Case Series. Performance Enhancement & Health. 14. doi: 10.1016/j.peh.2025.100404. Full text in Research Archive Show summary

  This study aimed to investigate changes in lean body mass (LBM) and maximal strength during preparation for a physique contest season and one month post-season. Three drug-free male physique athletes were observed. Laboratory tests were conducted at various intervals: immediately before starting weight loss, 2 months, 1 month, and 1 week before their first contest, 1 week before their last contest, and 1 month post-season. Body composition was assessed using Dual-energy X-ray absorptiometry (DXA), bioimpedance (BIA), and skinfold (SK) measurements. Muscle thickness (MT) of the elbow flexors and muscle cross-sectional area (CSA) of the vastus lateralis were evaluated via ultrasound. Strength assessments (isometric and isokinetic peak torque) were measured using a dynamometer. Blood biomarkers and dietary intake were also tracked. During the preparation phase, LBM decreased in all athletes: 1.7-5.3 kg (DXA), 4.3-8.5 kg (BIA), and 7.0-9.5 kg (SK). One month into recovery, LBM rapidly increased: 2.5-3.4 kg (DXA), 4.1-4.6 kg (BIA), and 3.4-5.5 kg (SK). Both MT and CSA decreased during preparation but increased during recovery. Maximal strength performance remained within expected day-to-day variation for isometric peak torque and isokinetic peak torque at 60°/s, but isokinetic peak torque at 240°/s exceeded expected variation, only partially restored post-contest. Testosterone levels decreased and sex-hormone binding globulin increased during preparation, with varying recovery. Reductions in LBM, MT, and CSA during caloric restriction were followed by rapid increases post-contest, resulting in negligible net changes from baseline. This provides evidence that highly trained individuals are able to retain contractile tissue during substantial weight loss following a daily caloric deficit of 500 kcal

• Lundberg, Helge Einar; Larsen, Stig; Mathisen, Therese Fostervold & Sundgot-Borgen, Jorunn (2025). Comparison of cheese with and without Propionibacterium freudenreichii subsp. shermanii LMGT 2951 on off-season muscle strength and VO2 max development in Nordic skiers: a randomized clinical trial. Journal of the International Society of Sports Nutrition (JISSN). 22(1). doi: 10.1080/15502783.2025.2566373. Full text in Research Archive Show summary

  Background and objective: Nordic skiers represent a low-impact, weight-sensitive sport and may be inclined to engage in weight-controlling behavior, hence increasing their risk for low energy availability and impairment in health and performance. Jarlsberg cheese (J) is rich in vitamin K₂ from fermentation by Propionibacterium freudenreichii subsp. shermanii LMGT 2951 (Pf) and lactic acid bacteria and increases the osteocalcin (OC) level. Vitamin K is essential for activating OC, which is described to be associated positively with muscle strength, whereas propionic acid bacteria are found to enhance endurance. Except for Pf and its by-products, J and Norvegia (N) cheeses have almost identical nutrient content. The objective of this study was to compare the effects of Jarlsberg and N as potential supplements to training on muscle strength (MS), lean body mass (LBM) and VO2 max. Methods: Thirty female and 30 male Nordic skiers were block randomized 1:1 to either J or N and studied during a 24-week offseason training schedule. The Norvegia group served as a control group. Females and males were treated with 75 and 90 grams/day, respectively. MS by seated pulldown and half-squat, LBM by DXA, and VO2 max were measured at baseline and after the 24 weeks off-season period. Dietary intake and training hours were registered and monitored at baseline and every eight weeks during the study. Results: MS significantly increased in both groups after 24 weeks (p < 0.01). The mean increase difference in MS-upper body favored Jarlsberg by 0.95 kg (95% CI: −0.02–1.46), approaching significance (p = 0.06). No significant difference was found between groups in MS-lower body. LBM and VO2-max both increased significantly in each group (p ≤ 0.05), with no notable differences between groups. Correlation analysis identified LBM as the dominant outcome variable at both baseline and 24 weeks. Endurance training was the dominant input variable and correlated significantly positively both multiply and partially to LBM, (p = 0.04, p = 0.02), respectively. At baseline and 24-weeks sex, endurance training along with OC-level explained 65% and 68% of the LBM variations, respectively. Conclusion: Both Jarlsberg cheese, characterized by its unique Propionibacterium freudenreichii content, and Norvegia cheese, when combined with off-season training, led to increases in LBM, VO₂ max, and MS, with no significant differences observed between groups. However, there was a trend toward greater improvements in MS in the Jarlsberg group. Overall, increases in LBM through structured training appear to be a key driver of gains in both muscle strength and aerobic capacity.

• Sundgot-Borgen, Christine; Sundgot-Borgen, Jorunn; Sølvberg, Nina; Torstveit, Monica Klungland; Mountjoy, Margo & Mathisen, Therese Fostervold (2025). Factors predicting disordered eating and the prevalence of eating disorders in adolescent elite athletes, trained athletes and a reference group: a prospective controlled two-step study. British Journal of Sports Medicine. ISSN 0306-3674. 59(15), p. 1043–1054. doi: 10.1136/bjsports-2024-108808. Full text in Research Archive Show summary

  Abstract Objective To prospectively examine the prevalence of diagnosed eating disorders (ED-diagnosis), ED-symptoms and factors predicting ED-symptoms in three male and female high school student groups: elite athletes, trained athletes and a non-athlete reference group at baseline (T1) and 1-year follow-up (T2). Methods A survey was administered at baseline (T1) (n=1186) and 1-year follow-up (T2) (n=1144) (step-one). Participants classified with ED-symptoms by the Eating Disorder Examination Questionnaire (EDEQ 6.0) at T2 were invited to a diagnostic interview (step-two). Results Prevalence of ED-diagnosis for males and females were 6.9% and 9.3% in elite athletes, 5.9% and 11.2% in trained athletes and 3.0% and 11.9% in references, respectively. No group differences were statistically significant. Male references had more ED-symptoms compared with elite and trained male athletes (EDEQ-global score 0.81 vs <0.55), while elite female athletes had fewer ED-symptoms compared with trained female athletes and female references (EDEQ-global score 1.14 vs >1.59). Trained female athletes increased ED-symptoms over time, whereas elite female athletes consistently had fewer ED-symptoms in comparison. High ED-symptom presentation was predicted by high body mass index and more psychological distress in males, whereas for females, ED-symptoms were predicted by lower resilience, more psychological distress and being a non-athlete reference. Conclusion No statistically significant group differences in the prevalence of ED-diagnosis were observed between elite athletes, trained athletes and a non-athlete reference group. Female elite athletes had fewer ED-symptoms compared with other female groups, and male references had more ED-symptoms compared with male athlete groups. Preventive measures that address psychological resilience and distress should be considered.

• Mathisen, Therese Fostervold; Hubin, Aliaksandr; Mountjoy, Margo & Sundgot-Borgen, Jorunn (2025). Safety of Heavy Resistance Exercise During Pregnancy and Postpartum: A Controlled, Prospective Cohort Study. Women in Sport & Physical Activity Journal. ISSN 1063-6161. doi: 10.1123/wspaj.2025-0010. Full text in Research Archive Show summary

  Objective: To address the knowledge gap on the influence of heavy free-weight resistance exercise on the health of the pregnant athlete and infant. Design: This is a prospective, controlled cohort study with two groups of pregnant women; those engaging in mainly heavy free-weight resistance exercise (REX, n = 33) and those regularly physically active (REF, n = 20). Data originate from eight questionnaires answered prospectively throughout pregnancy and 12 months postpartum. Variables cover exercise routines, pregnancy symptoms and complications, fetal growth, delivery, and mother and infant’s health. Results: Bayesian logistic regression with random and fixed effects identified group membership as a significant predictor of proteinuria, with REX having higher exposure (posterior inclusion probability [PIP] = 1.00; β1 = 197.07, 95% credible interval [CrI] [163.05, 231.08]). Further, Bayesian logistic regression with random and fixed effects confirmed a higher risk of urinary incontinence in the REF group during pregnancy (PIP = 0.98; β1 = −1.17, 95% CrI [−1.89, −0.46]). Gas incontinence was also found more common in the REF group during pregnancy (PIP = 1.00; β1 = −7.62, 95% CrI [−8.68, −6.57]) and postpartum (PIP = 0.91; β1 = −49.39, 95% CrI [−53.57, −45.43]). There were no significant differences in the postpartum period for fecal and urinary incontinence, injuries, infant health outcomes (all PIP < 0.01), or need for assisted delivery (PIP = 0.33). Conclusion: Female athletes experienced in heavy resistance exercise, who continue training during pregnancy and postpartum, do not face increased pregnancy complications. These findings provide evidence supporting safety of such exercise. Yet we highlight the need for a confirmatory study under full clinical supervision.

• Sundgot-Borgen, Jorunn; Torstveit, Monica Klungland; Mathisen, Therese Fostervold & Pensgaard, Anne Marte (2024). Nye retningslinjer for syndromet relativ energimangel i idrett (REDs). Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 144(6), p. 462–462. doi: 10.4045/tidsskr.24.0181. Full text in Research Archive Show summary

  Lav energitilgjengelighet gir dårligere prestasjoner og flere skader. I mange idretter har utøvere et betydelig energibehov for å opprettholde effekten av nødvendig treningsmengde og ønskede konkurranseprestasjoner. Innen idrettsmedisin anvendes uttrykket lav energitilgjengelighet (Low Energy Availability, LEA) for å beskrive en tilstand der energiinntaket er for lavt til å dekke basale energibehov dersom trening tar for mye av energitilførselen. Når eksponeringen for dette er langvarig eller av betydelig størrelse, kalles det problematisk lav energitilgjengelighet (1). Dette vil over tid bidra til ulike negative fysiologiske og psykologiske helse- og prestasjonsrelaterte effekter, en tilstand som omtales som relativ energimangel i idrett (Relative Energy Deficiency in Sport, REDs) (2). Ifølge Den internasjonale olympiske komité (IOC) sin konsensusrapport fra 2023 er relativ energimangel et klinisk diagnostisert, multifaktorielt syndrom karakterisert ved en samling av negative helse- og prestasjonsutfall som følge av eksponering for problematisk lav energitilgjengelighet.

• Lundberg, Helge Einar; Sundgot-Borgen, Jorunn; Mathisen, Therese Fostervold; Holo, Helge; Whist, Anne Cathrine & Larsen, Stig (2024). Cheese positively affects serum osteocalcin levels, bone turnover markers and bone mineral density in cross-country skiers: a dose-response study. International Journal of Clinical Trials (IJCT). ISSN 2349-3240. 11(2). doi: 10.18203/2349-3259.ijct20240961. Full text in Research Archive
• Garnweidner-Holme, Lisa; Frivold, Yngvild; Max, Gigja; Fjæra, Kristin; Mathisen, Therese Fostervold & Myhrstad, Mari Charlotte Wik (2024). Food and beverage selection in children's sports arenas in Norway: A cross-sectional study. Public Health Nutrition (PHN). ISSN 1368-9800. p. 1–32. doi: 10.1017/S1368980024000818. Full text in Research Archive
• Mathisen, Therese Fostervold; Pettersen, Gunn; Rosenvinge, Jan Harald; Schmidt, Ulrike H. & Sundgot-Borgen, Jorunn (2024). Expectations of a new eating disorder treatment and its delivery: Perspectives of patients and new therapists. International Journal of Eating Disorders. ISSN 0276-3478. 57(3), p. 695–702. doi: 10.1002/eat.24165. Full text in Research Archive Show summary

  Background: A significant number of people with bulimia nervosa (BN) or binge-eating disorder (BED) do not seek professional help. Important reasons include limited knowledge of eating disorders (EDs), feelings of shame, treatment costs, and restricted access to specialized healthcare. In this study, we explored if a novel therapy delivered in a primary care setting could overcome these barriers. We investigated factors such as motivation and expectations and included the patients' and newly trained therapists' perspectives. Method: We interviewed 10 women with BN (n = 2) or BED (n = 8), enrolled in the Physical Exercise and Dietary therapy (PED-t) program, in a Healthy Life Center (HLC) located in a primary healthcare facility. Interview topics discussed were motivations for and expectations of therapy, and the treatment location. In addition, 10 therapists from HLC's were interviewed on their experiences with the PED-t training program and expectations of running PED-t within their service. The semi-structured interviews were analyzed using reflexive thematic analysis. Results: Most patients had limited knowledge about EDs and first realized the need for professional help after learning about PED-t. Patients exhibited strong motivations for treatment and a positive perception of both the PED-t, the new treatment setting, and the therapists' competencies. The therapists, following a brief training program, felt confident in their abilities to treat EDs and provide PED-t. With minor operational adjustments, PED-t can seamlessly be integrated into national HLC service locations. Conclusion: PED-t is an accessible therapeutic service that can be delivered in a primary care environment in a stepped-care therapy model. Public Significance: This study investigates the views and experiences of patients and newly trained therapists of PED-t (Physical Exercise and Dietary therapy), a new program-led primary care therapy for binge-eating spectrum eating disorders. The treatment and the locations for the intervention, that is, local health care centers, were found to be highly acceptable to both patients and therapists, thus PED-t could easily be integrated as a first step into a step-care delivery model.

• Gjestvang, Christina; Mathisen, Therese Fostervold; Bratland-Sanda, Solfrid & Haakstad, Lene Annette Hagen (2024). The Risk of Disordered Eating in Fitness Club Members—A Cross-Sectional Study. Sports. 12(12). doi: 10.3390/sports12120343. Full text in Research Archive Show summary

  Fitness clubs may be environments where abnormal eating behaviors and excessive exercise are socially accepted, potentially putting individuals at risk for disordered eating (DE). This study examined the DE risk prevalence among gym members, comparing body appreciation, exercise motivation, frequency, BMI, and age across DE risk levels, and assessed the associated factors. A sample of 232 gym members (age: 39.6 ± 13.7) completed an online survey measuring DE risk (Eating Disorder Screen for Primary Care (ESP)), body appreciation (Body Appreciation Scale version 2), and exercise motivation (Behavioral Regulation in Exercise Questionnaire-2). One out of five (19.4%) were at risk of DE, while 15.5% and 11.6% reported having secretive eating behaviors and a history of eating disorders, respectively. Body weight impacted self-perception for 62.5% of the respondents. Those at DE risk had a higher mean BMI (26.23 ± 4.36 vs. 24.68 ± 3.61, p = 0.032) with a higher proportion of those with a BMI of 25–29.9 (46.67% vs. 29.41%, p = 0.027) compared to non-at-risk individuals. DE risk was associated with lower body appreciation (3.00 ± 3.60 versus 4.00 ± 3.70, p = ≤0.001), with body appreciation being the only factor associated with DE risk (OR = 0.24, 95% CI = 0.15, 0.39, p = ≤0.001).

• Garnweidner-Holme, Lisa; Wattenberg, Pauline Alise Leganger; Mathisen, Therese Fostervold & Myhrstad, Mari (2024). Adolescents’ experiences with the food selection at the sports arena in the area of Oslo, Norway: A focus group study. Public Health Nutrition (PHN). ISSN 1368-9800. 27(1). doi: 10.1017/S1368980024000181. Full text in Research Archive
• Sundgot-Borgen, Christine; Wisting, Line Norøm; Sundgot-Borgen, Jorunn; Lied, Karoline Steenbuch; Skrede, Jenny Vik & Nilsen, Karoline [Show all 8 contributors for this article] (2024). The “Young Athlete Body Project”—A pilot study evaluating the acceptability of and results from an eating disorder prevention program for adolescent athletes. International Journal of Eating Disorders. ISSN 0276-3478. 57(3), p. 568–580. doi: 10.1002/eat.24140. Full text in Research Archive Show summary

  Background: The high frequency of eating disorders (EDs) in sports speaks of a need for early-stage preventive measures. Objectives: This study evaluated the acceptability of an age, sex, and sports adapted version of the “Body Project” and changes in mental health symptoms. Methods: This noncontrolled pilot study included a class of athletes from 18 sports (N = 73, 13–14 years) at a sport-specialized junior high school in six small-group workshops. We interviewed 34 athletes on program acceptability, and all athletes responded to questionnaires at pretest, posttest, and 6-month follow-up including the Body Appreciation Scale 2–Children, Social Attitudes towards Appearance Questionnaire-4 revised, Eating Disorder Examination Questionnaire Short form-12 modified, and questions about body appearance pressure (BAP). Results: Athletes found the program acceptable and beneficial, but some missed physically oriented activities or did not identify with the focus, particularly boys. There were acceptable levels in mental health constructs before the workshops. There were temporary changes in the percentage of boys experiencing “BAP in society” by −14.8% points (95% CI: −.6 to .0, p = .04), % in total group experiencing “BAP at school” by +11% points (95% CI: .0–.2, p = .05), thinness idealization by girls (g = .6, p = .002) and total group (g = .4, p = .006), and muscularity idealization by boys (g = .3, p = .05) and total group (g = .23, p = .04). Discussion: Athletes experienced benefits from the Young Athlete Body Project. Seeing stabilization in outcomes may mean a dampening of the otherwise expected worsening in body appreciation and ED symptoms over time. Public Significance: Adolescent athletes are at risk for developing EDs. Due to lack of prevention programs for this group, we adapted and evaluated a well-documented effective program, the Body Project, to fit male and female athletes

• Mathisen, Therese Fostervold; Sundgot-Borgen, Jorunn; Rosenvinge, Jan H; Bratland-Sanda, Solfrid; Svendsen, Mette & Pettersen, Gunn [Show all 8 contributors for this article] (2023). Metabolic profile in women with bulimia nervosa or binge-eating disorder before and after treatment: secondary analysis from the randomized PED-t trial. Eating and Weight Disorders - Studies on Anorexia, Bulimia and Obesity. ISSN 1124-4909. 28(1). doi: 10.1007/s40519-023-01567-y. Full text in Research Archive Show summary

  Purpose: Chaotic eating and purging behavior pose a risk to the metabolic health of women with bulimia nervosa (BN) and binge-eating disorder (BED). This study reports on one-year changes in blood markers of metabolic health and thyroid hormones in women with BN or BED attending two different treatments. Methods: These are secondary analyses from a randomized controlled trial of 16-week group treatment of either physical exercise and dietary therapy (PED-t) or cognitive behavior therapy (CBT). Blood samples collected at pre-treatment, week eight, post-treatment, and at 6- and 12-month follow-ups were analyzed for glucose, lipids (triglycerides (TG), total cholesterol (TC), LDL cholesterol (LDL-c), HDL cholesterol (HDL-c), apolipoprotein A (ApoA) and apolipoprotein B (ApoB) lipoproteins), and thyroid hormones (thyroxine (T4), thyroid stimulating hormone (TSH), and thyroperoxidase antibodies). Result: The average levels of blood glucose, lipids and thyroid hormones were within the recommended range, but clinical levels of TC and LDL-c were detected in 32.5% and 39.1%, respectively. More women with BED compared with BN had low HDL-c, and a larger increase over time in TC and TSH. No significant differences occurred between PED-t and CBT at any measurement. Exploratory moderator analyses indicated a more unfavorable metabolic response at follow-up among treatment non-responders. Conclusion: The proportion of women with impaired lipid profiles and unfavorable lipid changes, suggests active monitoring with necessary management of the metabolic health of women with BN or BED, as recommended by metabolic health guidelines.

• Mathisen, Therese Fostervold; Pettersen, Gunn; Rosenvinge, Jan H; Schmidt, Ulrike H. & Sundgot-Borgen, Jorunn (2023). Effectiveness and acceptability of the physical exercise and dietary therapy in a healthy life center. International Journal of Eating Disorders. ISSN 0276-3478. 56(10), p. 1931–1940. doi: 10.1002/eat.24020. Full text in Research Archive Show summary

  Objective: The high burden of eating disorders (EDs) and limited availability of treatment speaks of a need to explore new avenues for treatment delivery. To understand if new treatment avenues are helpful and acceptable to patients, we investigated the effectiveness of Physical Exercise and Dietary Therapy (PED-t) in participants with bulimia nervosa or binge-eating disorder, and acceptability when the PED-t was implemented in a Healthy Life Center in a municipal primary healthcare service. Method: Exercise physiologists and one dietitian were trained in ED literacy and to run PED-t, before screening women for eligibility. Effectiveness (n = 16) of PED-t and participants' experiences (n = 8) were evaluated by a mixed methods study design. Results were analyzed by relevant statistics and reflexive thematic analysis. Results: Of 19 eligible participants, 16 completed treatment. At post-treatment, the Eating Disorder Examination Questionnaire global score, binge-eating frequency, and symptoms of depression were lower, and nine (56% of completers) were in remission. Participants' treatment experiences were classified into two overarching themes: “competence” and “emotional support.” Participants reported high acceptance for PED-t, the local venue and group format, and felt that PED-t provided them with coping tools and increased mental strength. However, many also spoke of an unmet need to address emotional eating. Discussion: Findings point to a potential for making an effective ED therapy more accessible, and that participants find the local low-threshold delivery within a group-format helpful. With small adjustments, the PED-t could emerge as a promising first-line treatment for bulimic EDs. Public Significance Statement: Limited access to treatment for EDs, patients' high barriers to help-seeking, and the high rates of limited efficacy from psychotherapy speak of a need to explore new therapies and avenues for delivery. In this study, we build on findings from a controlled ED treatment trial and replicate the beneficial effects and find a high patient acceptance of “physical exercise and diet therapy” implemented in a real, non-clinical setting.

• Mathisen, Therese Fostervold; Sundgot-Borgen, Jorunn & Sundgot-Borgen, Christine (2023). Nutrition and eating disorders in youth sport. In Armstrong, Neil & Mechelen, Willem van (Ed.), Oxford Textbook of Children’s Sport and Exercise Medicine. Fourth Edition. Oxford University Press. ISSN 9780191926556. p. 691–707. doi: 10.1093/med/9780192843968.001.0001. Full text in Research Archive

View all works in NVA

• Storheil, Elina Louise Karlsen & Mathisen, Therese Fostervold (2026). Behandlinga gir betre effekt enn psykolog: Nå vekker resultata oppsikt – NRK Østfold – Lokale nyheter, TV og radio. [Internet]. Nrk Østfold. Full text in Research Archive Show summary

  Nina Nagele sleit med overeting og følte at hjelpa frå helsevesenet ikkje fungerte. Så bytte ho ut psykologstolen med tunge vekter – og resultata slår tradisjonell terapi.

• Mathisen, Therese Fostervold (2026). Physical Activity in the Treatment of Eating Disorders: A Mixed-Methods Study of Current Practice in Norway. doi: https:/nedsconference.com/wp-content/uploads/2026/05/NEDS-abstract_TFM_SP.pdf. Full text in Research Archive
• Mathisen, Therese Fostervold; Collin, Emelie; Rosling, Pia & Glenthøj, Louise Birkedal (2026). Thematic Seminar - New Treatment Methods: PED-t for EDs – Long-Term Outcomes and Exploring How It Works. Full text in Research Archive Show summary

  Thematic Seminars during the NEDS Conference 2026

• Laursen, Kristin Engløkken Mainitz; Mathisen, Therese Fostervold & Vestre, Jan Christian (2026). Helse, Spiseforstyrrelse | Verdensnyhet i Fredrikstad: Ny behandling mot spiseforstyrrelser. [Internet]. Fredrikstad Blad. Full text in Research Archive Show summary

  I et helt liv har Camilla Lind (40) slitt med spiseforstyrrelser. Nå er hun bedre enn hun noen gang har vært.

• Mathisen, Therese Fostervold (2026). Distriktsnyheter Østlandet - NRK TV. [TV]. NRK Østlandssendingen. Full text in Research Archive
• Gutterup, Maud & Mathisen, Therese Fostervold (2026). Nytt behandlingstilbud mot spiseforstyrrelser: – Har vært livsendrende. [Internet]. Fredrikstad Blad. doi: https:/www.f-b.no/spiseforstyrrelse-fredrikstad/v/80-59-40257. Full text in Research Archive Show summary

  Fredrikstad er først i verden med å tilby en ny lavterskel behandlingsmetode for spiseforstyrrelser, med fokus på veiledet trening og kosthold via Frisklivssentralen.

• Sundgot-Borgen, Jorunn; Mathisen, Therese Fostervold & Merryweather, Alice (2026). Body Composition and Mental Health Concerns in Athletes. doi: https:/promiseconference.co.uk/view-program/. Full text in Research Archive Show summary

  Potential Mental Health Implications of Assessing Body Composition in Athletes; Assessment of Body Composition in Athletes: Best Practices and Pitfalls; The Athlete Voice

• Sundgot-Borgen, Jorunn; Mathisen, Therese Fostervold & Stensrud, Eva Berg (2026). Preventing body dissatisfaction progressing to eating disorders. doi: https:/promiseconference.co.uk/view-program/. Full text in Research Archive Show summary

  This workshop provides an evidence-based and practice-oriented overview of how to prevent body dissatisfaction, disordered eating, and eating disorders among athletes. It integrates knowledge on risk factors with applied prevention strategies and emphasizes interdisciplinary collaboration across sport medicine, psychology, nutrition, and coaching.

• Mathisen, Therese Fostervold (2026). Hvordan spiser norsk ungdom? – hvordan kan vi fremme matro og kroppsaksept? Full text in Research Archive
• Mathisen, Therese Fostervold (2026). Måling og veiing i ungdomsidretten – når, hvorfor og er det alternativer? Full text in Research Archive
• Mathisen, Therese Fostervold; Sundfør, Tine Mejlbo & Borchsenius, Cathrine (2026). Kostholdsråd, Trening | Om kosthold og fysisk aktivitet: Dette er ikke vrøvl! Full text in Research Archive Show summary

  Det er med en viss uro vi leser FB Livsstil-intervjuet med overlege, spesialist og leder for hjertemedisinsk forskningsgruppe, der det fremsettes flere påstander om kosthold og fysisk aktivitet som ikke er i tråd med etablert kunnskap.

• Sundgot-Borgen, Jorunn & Mathisen, Therese Fostervold (2026). LEA and Eating Disorders in Sport. Full text in Research Archive Show summary

  About Eating Disorders in sport; symptoms, causes and how to address your concern

• Mathisen, Therese Fostervold (2026). Trenings- og kostholdsterapi som behandling av spiseforstyrrelser. - Vi tilgjengeliggjør behandling for bulimiske SPF. Full text in Research Archive Show summary

  En presentasjon av effektene fra behandlingen mot spiseforstyrrelser; PED-t

• Cumming, Kristoffer Toldnes & Mathisen, Therese Fostervold (2026). Aktivitetsmedisin i helsetjenestene. Full text in Research Archive Show summary

  Om hvordan fysisk aktivitet kan anvendes for å bidra til økt funksjonsevne og selvstendighet hos en aldrende befolkning

• Mathisen, Therese Fostervold (2026). To train or not to train; that shouldn't be the question. Full text in Research Archive Show summary

  Et foredrag om effekter av bedrest, og fordelen av fysisk aktivitet i behandling - også ved spiseforstyrrelser

• Kaste, Anders Moen & Mathisen, Therese Fostervold (2026). Mobil­bruk og spise­forstyrrelser: – Algoritmene driver oss, og de er vanvittig sterke. [Internet]. Forskning.no. doi: https:/www.forskning.no/barn-og-ungdom-mobiltelefon-skjerm/mobilbruk-og-spiseforstyrrelser-algoritmene-driver-oss-og-de-er-vanvittig-sterke/2643047. Full text in Research Archive Show summary

  Unge vil heller bli inspirert av unge med store muskler eller veldig slank kropp enn professor på 50, sier professor.

• Mathisen, Therese Fostervold (2026). "Strong Bodies, Unclear Guidelines" – navigating pregnancy and postpartum without tailored resistance exercise guidelines. Full text in Research Archive Show summary

  Introduction: Recommendations for physical activity during pregnancy are insufficiently specific for highly trained athletes, particularly with regard to resistance exercise. This study explored the experiences of athletes performing heavy free-weight resistance exercise during pregnancy and postpartum (REX group), and reflected these against experiences of pregnant trained athletes not engaging specifically in heavy free-weight resistance exercise (REF group). Materials and Methods: This is secondary outcomes from a prospective, longitudinal study following two exercising groups of pregnant women. Data were collected via questionnaires and analyzed using inductive content analysis. Results: Thirty-two women were included in the REX group and 17 in the REF group. Totally 35% reported receiving warnings against their usual training; most often from midwives. While REX participants typically faced concerns related to heavy resistance exercise, REF participants also reported warnings, particularly about high-intensity exercise. Three key themes emerged from pregnancy responses irrespective of group: “Training for Two: Joy, Strength, and Sanity Through Exercise”, “Between Warnings and Worries: Pregnant Women’s Struggle for Reliable Advice”, and “Strength Over Strain: Why Resistance Exercise Works in Pregnancy”. Two themes were identified postpartum: “New Priorities, New Physique” and “When Experts Fall Silent”. Conclusion: Women training beyond standard health recommendations often encounter concerns from healthcare providers and others. Although they rely on personal experience, many express doubt and frustration due to the lack of tailored, evidence-based advice. Exercise, especially resistance exercise, was seen as vital for both mental and physical health, particularly when other forms of movement were limited by pregnancy or postpartum symptoms.

• Mathisen, Therese Fostervold (2026). REDs is prevalent in young biathletes– a need for awareness among sports medicine practitioners. Full text in Research Archive Show summary

  INTRODUCTION: Relative Energy Deficiency in Sport (REDs) arises from low energy availability (LEA) and can impair both physical and mental health in athletes. This study examines REDs symptoms, physical and mental health in three biathlete age cohorts at the start of the season and explores association with end-of-season competition results. METHOD: This national cross-sectional study recruited biathletes 16-20 years of age to respond to a digital survey on demographic, including validated health symptom questionnaires, and a clinical diagnostic interview if eating disorders (EDs) were indicated. Additionally, athletes ≥18 years were invited to lab-measurements (blood work, resting metabolic rate, -heart rate and -blood pressure, body composition and bone mineral density). RESULTS: A total of 72 athletes were included (55% females) with mean (SD) age 17.8 (1.4), tier level 2.7 (0.9), and training volume of 13.3 (3.3) hours per week. Additionally, 28 athletes (43% females) participated in lab-measurements. Frequency of REDs symptoms was 32%, clinical EDs was 6%, depression 15%, low BMD 4%, low RMR X, bradycardia 3%, hypotension 7%, and incontinence 4%. Few of these symptoms overlapped, but REDs symptoms were more prevalent in females and increased by age. Association with end-of-season competitive results will be analyzed and presented. CONCLUSION: Symptoms of health issues were prevalent in young biathletes and increase the risk of mental and physical clinical diagnoses. Competence within the sports medicine support team to recognize and address symptoms of REDs and health issues is essential for initiating early interventions, and prevent potential early career termination.

• Sundgot-Borgen, Jorunn & Mathisen, Therese Fostervold (2026). Hva er REDs, årsaksforhold, identifisering og konsekvenser, for trenere. Full text in Research Archive Show summary

  Om risikofaktorer og årsaker til REDs, symptomer og konsekvenser.

• Mathisen, Therese Fostervold (2026). Trenerrollen og kunnskap om REDs, hva vet vi? Full text in Research Archive Show summary

  Om treneres kunnskap om REDs og spiseforstyrrelser i idretten, basert på en publikasjon.

• Sundgot-Borgen, Jorunn & Mathisen, Therese Fostervold (2026). Hva er REDS, årsaksforhold, identifisering og konsekvenser. Full text in Research Archive Show summary

  Om risikofaktorer og årsaker til lav energitilgjengelighet og relativ energimangel i idretten (REDs), samt symtpomer og konsekvenser

• Mathisen, Therese Fostervold (2026). Hva opplever helsesykepleierne at de trenger av kunnskap. Full text in Research Archive Show summary

  En kort gjennomgang av funn fra studien vår om kunnskap hos helsesykepleiere om spiseforstyrrelser og REDs

• Horwood, Kennedy-Anne & Mathisen, Therese Fostervold (2026). Dancers and researchers push for health over thinness in the dance studio | The Chronicle. [Internet]. The Chronicle. doi: https:/chronicle.durhamcollege.ca/2026/03/dancers-and-researchers-push-for-health-over-thinness-in-the-dance-studio/. Full text in Research Archive Show summary

  Article about changing the culture in dance that idealizes the thin body ideal. Based on two previous publications exploring mental health in professional dance students, and evaluating the outcomes from an intervention aimed at increasing mental health literacy in professional dance students.

• Mathisen, Therese Fostervold; Sundgot-Borgen, Jorunn & Holmlund, Heidi (2025). «Ta din del av krafttaket for positiv energi» -forebygging av kroppsmisnøye i idretten. Full text in Research Archive Show summary

  Webinar med fokus på hva idretten gjør bra, hva den gjør lite bra, og hva den trenger gjøre mer av for å forebygge kroppsmisnøye og spiseforstyrrelser

• Mathisen, Therese Fostervold (2025). Nye retningslinjer for veiing og måling -Vekt og kroppssammensetning i idretten - hva, hvem og hvorfor? Full text in Research Archive Show summary

  Fagforedrag om de nye retningslinjer for måling av kroppssammensetning i idretten ved den Internasjonale Olympiske Komite (IOC), samt bakgrunnen for dette

• Mathisen, Therese Fostervold (2025). Ung utøver i 2025– om vekst, prestasjon, SOME og REDs. Full text in Research Archive Show summary

  Fagseminar-foredrag om risikoforhold for spiseforstyrrelser og relativ energimangel (REDs) i idretten

• Mathisen, Therese Fostervold (2025). Trening mot depresjon? Full text in Research Archive Show summary

  En litteraturgjennomgang av effektene fra fysisk aktivitet i behandling av depresjon, og en teorigjennomgang av hvordan vi kan forstå slike effekter utfra nevrobiologi, psykososiale teorier eller ren atferdsmestring.

• Mathisen, Therese Fostervold (2025). Gruppebasert aktivitetstilbud. Full text in Research Archive Show summary

  Presentasjonen setter fokus på fysisk aktivitet og helseeffekter, med spesifikt fokus på effekten av gruppetilbud, for å stimulere etablering av flere gruppetilbud innen fysioterapitjenesten i kommunen.

• Mathisen, Therese Fostervold (2025). Frisklivssentralen i Fredrikstad – Et målrettet svar på lokale folkehelseutfordringer og høye helseutgifter. Full text in Research Archive Show summary

  Norge har betydelige sosiale helseforskjeller. Personer med alvorlige psykiske lidelser og/eller rusproblemer er særlig utsatt, har dårligere somatisk helse og langt lavere forventet levealder.

• Ulvevadet, Maria; Mathisen, Therese Fostervold; Gjestvang, Christina; Stensvold, Dorthe Berg & Kristiansen, Ingrid (2025). - Det er skummelt. [Journal]. Internett. doi: https:/www.dagbladet.no/sport/det-er-skummelt/83776109?fbclid=IwY2xjawN18SlleHRuA2FlbQIxMQABHp0Ga4CqB8sdjlOOT_FykCEX4Mh_zPJ5rzFg_z2hpYK0OAMjiTZ3xMNyu3dy_aem_jPSKKocHIQv4zBN3tNZ5Xw. Full text in Research Archive Show summary

  Fire fagpersoner kommenterer treningstrender for 2025, lansert av ACSM.

• Mathisen, Therese Fostervold (2025). Den tredje konferansen om Trening som Medisin. doi: https:/psykiskhelse.no/hit-for-livet-trening-som-medisin-2/. Full text in Research Archive Show summary

  Konferansier for nasjonal konferanse om Trening som medisin for personer med psykiske- eller rusutfordringer, i regi av Rådet for Psykisk Helse og Rusfeltets Hovedorganisasjon. Konferansen holdes i sammenheng med det faglige nettverket for høyintensiv trening som medisin. https://www.youtube.com/shorts/NGJhDj_EXew

• Mathisen, Therese Fostervold (2025). Trygt å trene hardt i graviditeten? doi: https:/www.facebook.com/hiofnorge/posts/i-anledning-forskningsdagene-b%C3%B8d-noen-av-forskerne-v%C3%A5re-i-forskergruppen-aktivit/1191933386293533/. Full text in Research Archive Show summary

  Kvinner som trener hard styrketrening opplever mangelfull kunnskap hos helsepersonell, og lite tilgjengelig dokumentert kunnskap, om hvor trygt det er å fortsette hard styrketrening når man blir gravid. Kan man risikere spontanabort? Kan man igangsette fødsel for tidlig? Kan man skade fosteret? Kan man selv pådra seg permanente skader som delte magemuskler eller bekkenledd-skader? I denne presentasjonen får du innsikt i hvordan det gikk med en stor gruppe godt trente kvinner under deres graviditet og første barselår når de ønsket opprettholde sine egne, tøffe styrketreningsrutiner.

• Mathisen, Therese Fostervold (2025). Fra fellesskap til press: Gruppekultur og risiko for kroppsmisnøye i idrett. doi: https:/www.frid.no/post/fredrikstadidrettens-idrettsseminar-2025-gruppedynamikk-i-idretten. Full text in Research Archive Show summary

  Via sosiale teorier forklares det hvordan kroppsmisnøye og spiseforstyrrelser kan oppstå i en gruppe dersom den interne kulturen ikke bevisst styres i riktig retning.

• Mathisen, Therese Fostervold; Hubin, Aliaksandr; Mountjoy, Margo & Sundgot-Borgen, Jorunn (2025). Safety of Heavy Resistance Exercise During Pregnancy and Postpartum: A Controlled, Prospective Cohort Study. doi: https:/scs.academy/scs-annual-meeting/. Full text in Research Archive Show summary

  Objective: To address the knowledge gap on the influence of heavy free-weight resistance exercise on the health of the pregnant athlete and infant. Design: This is a prospective, controlled cohort study with two groups of pregnant women; those engaging in mainly heavy free-weight resistance exercise (REX, n = 33) and those regularly physically active (REF, n = 20). Data originate from eight questionnaires answered prospectively throughout pregnancy and 12 months postpartum. Variables cover exercise routines, pregnancy symptoms and complications, fetal growth, delivery, and mother and infant’s health. Results: Bayesian logistic regression with random and fixed effects identified group membership as a significant predictor of proteinuria, with REX having higher exposure (posterior inclusion probability [PIP] = 1.00; β1 = 197.07, 95% credible interval [CrI] [163.05, 231.08]). Further, Bayesian logistic regression with random and fixed effects confirmed a higher risk of urinary incontinence in the REF group during pregnancy (PIP = 0.98; β1 = −1.17, 95% CrI [−1.89, −0.46]). Gas incontinence was also found more common in the REF group during pregnancy (PIP = 1.00; β1 = −7.62, 95% CrI [−8.68, −6.57]) and postpartum (PIP = 0.91; β1 = −49.39, 95% CrI [−53.57, −45.43]). There were no significant differences in the postpartum period for fecal and urinary incontinence, injuries, infant health outcomes (all PIP < 0.01), or need for assisted delivery (PIP = 0.33). Conclusion: Female athletes experienced in heavy resistance exercise, who continue training during pregnancy and postpartum, do not face increased pregnancy complications. These findings provide evidence supporting safety of such exercise. Yet we highlight the need for a confirmatory study under full clinical supervision.

• Mathisen, Therese Fostervold (2025). Viktige bevegelser: betydning av trening for psykisk helse . doi: https:/www.nih.no/om/aktuelt/hva-skjer/2025/kvinner-i-bevegelse-og-idrett-.html. Full text in Research Archive Show summary

  En redegjørelse for forklaringsmodeller om hvordan fysisk aktivitet kan bidra til bedre psykisk helse (nevrobiologi, psykososiale teorier, atferdsmessige endringer), og eksempel ved å vise til resultater fra PED-t (behandling med fysisk aktivitet for spiseforstyrrelser).

• Sveen, Ole; Mathisen, Therese Fostervold; Husebye, Birgitte Nordahl & Cumming, Kristoffer Toldnes (2025). Trygt å trene – forskningsbaserte erfaringer og anbefalinger til ulike behov – Fakultet for helse, velferd og organisasjon – Høgskolen i Østfold. doi: https:/www.hiof.no/hvo/om/aktuelt/arrangementer/2025/trygt-%C3%A5-trene. Full text in Research Archive Show summary

  Trening er viktig for helsa di, uansett hva slags form eller helsemessige utfordringer du måtte ha. Sammenhengen mellom fysisk aktivitet, helse og trygg trening. 

• Mathisen, Therese Fostervold (2025). Veier 13-åringer. [TV]. Nrk Dagsrevyen. Full text in Research Archive
• Mathisen, Therese Fostervold (2025). Fotballklubber ber 13-åringer om å veie seg. [TV]. NRK Østfold Distriktsnyheter. Full text in Research Archive
• Mathisen, Therese Fostervold (2025). Body Composition Assessment in Athletes: Why? When? How? Association between body composition and performance. Full text in Research Archive
• Mathisen, Therese Fostervold & Macnaughton, Lindsay (2025). Best Practice Guidelines for Body Composition Assessment: 8 steps. Full text in Research Archive
• Mathisen, Therese Fostervold (2025). The Ethical Dilemma: Does it truly enhance health and performance? -Best practice recommendation for body composition assessment in sport. Full text in Research Archive
• Pilskog, Hanne Eik; Mathisen, Therese Fostervold & Häbler, Camilla (2025). Flipped/Flopped classroom og leselogger. Full text in Research Archive
• Mathisen, Therese Fostervold; Mollandsøy, Sunniva; Bruset, Kristina Aasen; Stedal, Kristin; Bergestuen, Bent Egil & Drilen, Tove Langlo (2025). Forebygging og lavterskeltilbud forsvinner. Full text in Research Archive
• Mathisen, Therese Fostervold; Bratland-Sanda, Solfrid & Carlsen, Jørund Wessel (2025). Norske fotballklubber ber 13-åringer veie seg: – Blir kvalm av å høre det. [Internet]. NRK.no. Full text in Research Archive
• Mathisen, Therese Fostervold (2025). Eating Disorders in Sport. Full text in Research Archive
• Mathisen, Therese Fostervold (2025). Utvikling og implementering av en ny behandlingsmetode for spiseforstyrrelser i kommunehelsetjenesten. Full text in Research Archive
• Mathisen, Therese Fostervold (2025). Erfaringsseminar for PED-t terapeuter. Full text in Research Archive
• Mathisen, Therese Fostervold; Enoksen, Eystein & Stigum, Elisabeth (2025). Løpeguide: Slik forbereder du deg til konkurranseløp. [Internet]. VG Vektklubb. Full text in Research Archive
• Mathisen, Therese Fostervold (2025). – Jeg tenkte at det er nesten sånn at du kan klare HVA som helst! Full text in Research Archive
• Mathisen, Therese Fostervold & Øgar, Sindre (2025). Veier barn på 11 år for å finne biologisk alder. [Internet]. VG.no. Full text in Research Archive
• Mathisen, Therese Fostervold & Hamre, Iris Katrine (2025). Åtvarar mot drastisk «spytte-grep»: – Ikkje formålstenleg for nokon. [Internet]. NRK.no. Full text in Research Archive
• Mathisen, Therese Fostervold (2024). Bakgrunn for, utvikling av og resultater fra PED-t. Full text in Research Archive
• Mathisen, Therese Fostervold; Sundgot-Borgen, Jorunn; Torstveit, Monica Klungland & Dasa, Marcus Småvik (2024). Strategier for primær forebygging (The Young Athlete Body Project + IOC Guidelines for Body Comp Management) in seminar: Preventing & treatment of REDs. Full text in Research Archive
• Mathisen, Therese Fostervold; Sundgot-Borgen, Jorunn; Hubin, Aliaksandr & Mountjoy, Margo (2024). Kan vi anbefale kvinnelige utøvere å trene tung frivekts-styrketrening under graviditet og barseltid? Full text in Research Archive
• Mathisen, Therese Fostervold (2024). Aktivitetsmedisin - Psykt bra for deg! Full text in Research Archive
• Mathisen, Therese Fostervold; Grøndal, Beate & Gomnæs, Heidi (2024). Kan det bli for mye Cottage Cheese? [Radio]. Morran i Østfold, NRK radio. Full text in Research Archive
• Mathisen, Therese Fostervold (2024). PED-t instruktørkurs. Opplæring om spiseforstyrrelser og behandlingsmetoden Physical Exercise and Dietary Therapy. Full text in Research Archive
• Mathisen, Therese Fostervold & Macnaughton, Lindsay (2024). Best Practice Recommendations for body composition assessment – Making a Paradigm Shift. Full text in Research Archive
• Mathisen, Therese Fostervold & Sundgot-Borgen, Jorunn (2024). Idrettens ignoranse koster liv. Full text in Research Archive
• Mathisen, Therese Fostervold (2024). Treningsavhengighet - er det så farlig? Full text in Research Archive
• Mathisen, Therese Fostervold & Jarlsbo, Rønnaug (2024). Tilbyr kontroversiell behandling for personer med spiseforstyrrelser. [Internet]. Fagbladet nettsider. Full text in Research Archive
• Mathisen, Therese Fostervold (2024). PED-t instruktørkurs. Opplæring om spiseforstyrrelser og behandlingsmetoden Physical Exercise and Dietary Therapy. Full text in Research Archive
• Mathisen, Therese Fostervold & Sundgot-Borgen, Jorunn (2024). REDs – Suboptimal ernæring. Treatment of energy availability. REDsCAT2 – tool for health personnel. Full text in Research Archive
• Mathisen, Therese Fostervold & Jarlsbo, Rønnaug (2024). Flere kan få gratis hjelp mot denne spiseforstyrrelsen: – Kjører ganske hardt. [Internet]. Fagbladet nettsider. Full text in Research Archive
• Torstveit, Monica Klungland; Mathisen, Therese Fostervold; Pensgaard, Anne Marte & Sundgot-Borgen, Jorunn (2024). Oppdatert kunnskap om syndromet REDs (Relative Energy Deficiency in Sport). Verdt å vite for helsepersonell i idretten. Tidsskrift for Norsk Idrettsmedisin. Full text in Research Archive
• Mathisen, Therese Fostervold; Sundgot-Borgen, Jorunn & Sandholt, Ragna Kristine (2024). Rasar mot Norges idrettsforbund etter rapport: – Dette er alvorleg. [Internet]. Nrk.no. Full text in Research Archive
• Mathisen, Therese Fostervold & Johansen, Frode Ramstad (2024). The Impact of Apps Designed to Reduce Food Waste: can it help Improve Healthy Eating, and reduce Financial Expenses and Personal Food Waste? Full text in Research Archive
• Mathisen, Therese Fostervold; Kristiansen, Siw Carina & sivertzen-oksmo, Heidi (2024). 5 om dagen - hva og hvordan om frukt og grønt. [Radio]. Nrk Østfold "morran". Full text in Research Archive
• Gaarder, Jorun; Mathisen, Therese Fostervold; Sundgot-Borgen, Jorunn & Martinsen, Marianne (2024). Refser idrettstopper: - Meler sin egen kake. [Internet]. Dagbladet. Full text in Research Archive
• Mathisen, Therese Fostervold (2024). Kroppssammensetning i idretten. Grunn til bekymring? Nye retningslinjer fra IOC. Full text in Research Archive
• Mathisen, Therese Fostervold (2024). Vi behandler bulimiske spiseforstyrrelser med trening- og kostholdsterapi. Full text in Research Archive
• Mathisen, Therese Fostervold & Nustad, Kaia Hauge (2023). Forsker: Erstatt proteinpulver med dette. [Journal]. Dagbladet +. Full text in Research Archive
• Mathisen, Therese Fostervold (2023). NKS skaper muligheter: ny behandling av spiseforstyrrelser. Full text in Research Archive
• Mathisen, Therese Fostervold & Ulvang, Vegard (2023). Debatt om 5 mil for kvinner, Holmenkollenstafetten. [Radio]. Nrk.no. Full text in Research Archive
• Mathisen, Therese Fostervold & Bjerke, Ylva Lie (2023). Bruker styrketrening i behandling av spiseforstyrrelser. [Internet]. Demokraten. Full text in Research Archive
• Mathisen, Therese Fostervold & Sundgot-Borgen, Jorunn (2023). Forebygging og behandling av spiseforstyrrelser i idrett. In Sandbakk, Øyvind Bucher; Solli, Guro Strøm & Staff, Hanne Cesilie (Ed.), Den kvinnelige idrettsutøveren. Fagbokforlaget. ISSN 9788245036930. p. 221–232. Full text in Research Archive
• Mathisen, Therese Fostervold & Syvertsen, Tuva Bakke (2023). Hedda (22) skal konkurrere i biknifitness: -Jeg har lyst å gjøre noe som ikke så mange andre gjør. [Internet]. Moss Avis. Full text in Research Archive

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