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- Oxfeldt, Mikkel, et al.
(författare)
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Low Energy Availability Followed by Optimal Energy Availability Does Not Benefit Performance in Trained Females
- 2024
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Ingår i: Medicine & Science in Sports & Exercise. - : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 56:5, s. 902-916
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Short periods of reduced energy availability are commonly undertaken by athletes to decrease body mass, possibly improve the power-to-mass ratio, and enhance physical performance. Our primary aim was to investigate the impact of 10 d of low energy availability (LEA) followed by 2 d of optimal energy availability (OEA) on physical performance parameters in trained females. Second, physiological markers at the whole-body and molecular level related to performance were evaluated. Methods: Thirty young trained eumenorrheic females were matched in pairs based on training history and randomized to a 10-d intervention period of LEA (25 kcal.fat-free mass (FFM)(-1).d(-1)) or OEA (50 kcal.FFM-1.d(-1)) along with supervised exercise training. Before the intervention, participants underwent a 5-d run-in period with OEA + supervised exercise training. After the LEA intervention, 2 d of recovery with OEA was completed. Participants underwent muscle biopsies, blood sampling, physical performance tests, body composition measurements, and resting metabolic rate measurements. A linear mixed model was used with group and time as fixed effects and subject as random effects. Results: Compared with OEA, LEA resulted in reduced body mass, muscle glycogen content, repeated sprint ability, 4-min time-trial performance, and rate of force development of the knee extensors (absolute values; P < 0.05). Two days of recovery restored 4-min time-trial performance and partly restored repeated sprint ability, but performance remained inferior to the OEA group. When the performance data were expressed relative to body mass, LEA did not enhance performance. Conclusions: Ten days of LEA resulted in impaired performance (absolute values), with concomitant reductions in muscle glycogen. Two days of recovery with OEA partially restored these impairments, although physical performance (absolute values) was still inferior to being in OEA. Our findings do not support the thesis that LEA giving rise to small reductions in body mass improves the power-to-mass ratio and thus increases physical performance.
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| 2. |
- Oxfeldt, Mikkel, et al.
(författare)
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Low energy availability reduces myofibrillar and sarcoplasmic muscle protein synthesis in trained females
- 2023
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Ingår i: Journal of Physiology. - : John Wiley & Sons. - 0022-3751 .- 1469-7793. ; 601:16, s. 3481-3497
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Tidskriftsartikel (refereegranskat)abstract
- Low energy availability (LEA) describes a state where the energy intake is insufficient to cover the energy costs of both exercise energy expenditure and basal physiological body functions. LEA has been associated with various physiological consequences, such as reproductive dysfunction. However, the effect of LEA on skeletal muscle protein synthesis in females performing exercise training is still poorly understood. We conducted a randomized controlled trial to investigate the impact of LEA on daily integrated myofibrillar and sarcoplasmic muscle protein synthesis in trained females. Thirty eumenorrheic females were matched based on training history and randomized to undergo 10 days of LEA (25 kcal.kg fat-free mass (FFM)(-1).day(-1)) or optimal energy availability (OEA, 50 kcal.kg FFM-1.day(-1)). Before the intervention, both groups underwent a 5-day 'run-in' period with OEA. All foods were provided throughout the experimental period with a protein content of 2.2 g kg leanmass(-1).day(-1). A standardized, supervised combined resistance and cardiovascular exercise training programme was performed over the experimental period. Daily integrated muscle protein synthesis was measured by deuterium oxide (D2O) consumption along with changes in body composition, resting metabolic rate, blood biomarkers and 24 h nitrogen balance. We found that LEA reduced daily integrated myofibrillar and sarcoplasmic muscle protein synthesis compared with OEA. Concomitant reductions were observed in lean mass, urinary nitrogen balance, free androgen index, thyroid hormone concentrations and resting metabolic rate following LEA. These results highlight that LEA may negatively affect skeletal muscle adaptations in females performing exercise training.
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| 3. |
- Valaker, Irene, et al.
(författare)
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Adaptation and psychometric properties of the Norwegian version of the heart continuity of care questionnaire (HCCQ)
- 2019
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Ingår i: BMC Medical Research Methodology. - : BioMed Central. - 1471-2288. ; 19, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Continuity of cardiac care after hospital discharge is a priority, especially as healthcare systems become increasingly complex and fragmented. There are few available instruments to measure continuity of cardiac care, especially from the patient perspective. The aim of this study was (1) to translate and adapt the Heart Continuity of Care Questionnaire (HCCQ) to conditions in Norway, and (2) to determine its psychometric properties in self-report format administered to patients after percutaneous coronary intervention (PCI). Methods: The HCCQ was first translated into Norwegian from the original English version, following a widely used cross-cultural adaptation process. Data were collected before hospital discharge and in a follow-up after 2months. To assess psychometric properties, a confirmatory factor analysis (CFA) was performed and three aspects of construct validity were evaluated: structural validity, hypotheses testing and cross-cultural validation. Internal consistency of the HCCQ subscales was calculated using Cronbach's alpha, while intra-class correlation (ICC) was used to assess test-retest reliability. Additionally, socio-demographic and patient-reported data were collected to correlate with HCCQ scores. Results: Of those included at baseline, 436 (76%) completed the questionnaires after 2months. CFA suggested that the fit of the HCCQ data to a 3-factor model was modest (RMSEA = 0.11, CFI = 0.90, TLI = 0.90). However, convergent validity was satisfactory, based on existing research. Internal consistency was good, as indicated by its Cronbach's alphas: total continuity of care (0.95); informational (0.93), relational (0.87), and management (0.89) continuity. The ICC for the total HCCQ score was 0.80 (95% CI [0.71, 0.87] p<0.001). As indicated by negative care experiences (rated as 1 or 2 on the five-point scale), patients seemed to have limited knowledge about medical treatment, lifestyle modification and follow-up after PCI. Participation in cardiac rehabilitation and longer consultations with the general practitioner after hospital discharge were positively correlated with better continuity of care. Conclusions: Implementation of the HCCQ will likely support healthcare providers and researchers in identifying problem areas of continuity of cardiac care and in evaluating interventions aimed at improving continuity of care.
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| 4. |
- Valaker, Irene, et al.
(författare)
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Continuity of care and its associations with self-reported health, clinical characteristics and follow-up services after percutaneous coronary intervention
- 2020
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Ingår i: BMC Health Services Research. - : BioMed Central. - 1472-6963. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Complexity of care in patients with coronary artery disease is increasing, due to ageing, improved treatment, and more specialised care. Patients receive care from various healthcare providers in many settings. Still, few studies have evaluated continuity of care across primary and secondary care levels for patients after percutaneous coronary intervention (PCI). This study aimed to determine multifaceted aspects of continuity of care and associations with socio-demographic characteristics, self-reported health, clinical characteristics and follow-up services for patients after PCI. Methods: This multi-centre prospective cohort study collected data at baseline and two-month follow-up from medical records, national registries and patient self-reports. Univariable and hierarchical regressions were performed using the Heart Continuity of Care Questionnaire total score as the dependent variable. Results: In total, 1695 patients were included at baseline, and 1318 (78%) completed the two-month follow-up. Patients stated not being adequately informed about lifestyle changes, medication and follow-up care. Those experiencing poorer health status after PCI scored significantly worse on continuity of care. Patients with ST-segment elevation myocardial infarction scored significantly better on informational and management continuity than those with other cardiac diagnoses. The regression analyses showed significantly better continuity (P <= 0.034) in patients who were male, received written information from hospital, were transferred to another hospital before discharge, received follow-up from their general practitioner or had sufficient consultation time after discharge from hospital. Conclusion: Risk factors for sub-optimal continuity were identified. These factors are important to patients, healthcare providers and policy makers. Action should be taken to educate patients, reconcile discharge plans and organise post-discharge services. Designing pathways with an interdisciplinary approach and shared responsibility between healthcare settings is recommended.
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