The Swedish School of Sport and Health Sciences
Not a member yet
3569 research outputs found
Sort by
Molecular Regulators of Muscle Mass and Mitochondrial Remodeling Are Not Influenced by Testosterone Administration in Young Women.
No full textTestosterone (T) administration has previously been shown to improve muscle size and oxidative capacity. However, the molecular mechanisms underlying these adaptations in human skeletal muscle remain to be determined. Here, we examined the effect of moderate-dose T administration on molecular regulators of muscle protein turnover and mitochondrial remodeling in muscle samples collected from young women. Forty-eight healthy, physically active, young women (28 ± 4 years) were assigned in a random double-blind fashion to receive either T (10 mg/day) or placebo for 10-weeks. Muscle biopsies collected before and after the intervention period were divided into sub-cellular fractions and total protein levels of molecular regulators of muscle protein turnover and mitochondrial remodeling were analyzed using Western blotting. T administration had no effect on androgen receptor or 5α-reductase levels, nor on proteins involved in the mTORC1-signaling pathway (mTOR, S6K1, eEF2 and RPS6). Neither did it affect the abundance of proteins associated with proteasomal protein degradation (MAFbx, MuRF-1 and UBR5) and autophagy-lysosomal degradation (AMPK, ULK1 and p62). T administration also had no effect on proteins in the mitochondria enriched fraction regulating mitophagy (Beclin, BNIP3, LC3B-I, LC3B-II and LC3B-II/I ratio) and morphology (Mitofilin), and it did not alter the expression of mitochondrial fission- (FIS1 and DRP1) or fusion factors (OPA1 and MFN2). In summary, these data indicate that improvements in muscle size and oxidative capacity in young women in response to moderate-dose T administration cannot be explained by alterations in total expression of molecular factors known to regulate muscle protein turnover or mitochondrial remodeling
Age-related differences in white matter microstructure measured by advanced diffusion MRI in healthy older adults at risk for Alzheimer’s disease
No full textNeurite orientation dispersion and density imaging (NODDI) is an advanced diffusion imaging technique, which can detect more distinct microstructural features compared to conventional Diffusion Tensor Imaging (DTI). NODDI allows the signal to be divided into multiple water compartments and derive measures for orientation dispersion index (ODI), neurite density index (NDI) and volume fraction of isotropic diffusion compartment (FISO). This study aimed to investigate which diffusion metric—fractional anisotropy (FA), mean diffusivity (MD), NDI, ODI, or FISO—is most influenced by aging and reflects cognitive function in a population of healthy older adults at risk for Alzheimer’s disease (AD). Age was significantly associated with all but one diffusion parameters and regions of interest. NDI and MD in the cingulate region adjacent to the cingulate cortex showed a significant association with a composite measure of Executive Function and was proven to partially mediate the relationship between aging and Executive Function decline. These results suggest that both DTI and NODDI parameters are sensitive to age-related differences in white matter regions vulnerable to aging, particularly among older adults at risk for AD
The interrelationship between physical activity intensity, cardiorespiratory fitness, and executive function in middle-aged adults : An observational study of office workers.
No full textBACKGROUND: Previous evidence supports a beneficial effect of physical activity on executive function across the whole lifespan. Yet, the interrelationships of the intensities of physical activity, cardiorespiratory fitness, and executive function require further investigation in adults. AIM: Using unfiltered accelerometry data and high-resolution intensity classification, we sought to estimate the associations of physical activity with cardiorespiratory fitness and executive function in adult office workers. METHODS: We included 343 full-time office workers (mean age: 42.41 years, range of age: 36-49 years). Executive function was assessed using Stroop, Trail making tests (part-B), and 2-back tests, and a composite score was produced to reflect the general executive function performance. Physical activity was assessed using the Actigraph GT3X+-monitor, worn by each participant for seven days at the hip. Raw accelerometry data were processed by the 10 Hz frequency extended method and divided into 22 intensity bins and sleep time. Cardiorespiratory fitness was estimated using the submaximal Ekblom-Bak cycle ergometer test. Data were analyzed using partial least squares regressions. RESULTS: In adults, cardiorespiratory fitness was closely correlated with a wide range of absolute physical activity intensity patterns. A higher level of executive function in adults was associated with both higher absolute physical activity intensities and cardiorespiratory fitness, which was independent of age, sex, and education levels. A very weak association between intensities, fitness, and executive function was observed in high-fit adults. Among low-fit adults, although a positive association started already toward the upper end of moderate intensity, there still appeared to be an association between intensities, cardiorespiratory fitness, and executive function. That is, cardiorespiratory fitness may mediate the association between absolute physical activity intensities and executive function up to a certain level. CONCLUSION: The maintenance of executive function in adulthood was related to both physical activity intensities and cardiorespiratory fitness, while their interrelationship was not equal across fitness levels. It is highly recommended to consider the cardiorespiratory fitness level in future studies that focus on executive functions in aging as well when designing individualized physical activity training programs.This research was funded by the Knowledge Foundation (Grant Nos. 20160040 and 20210002) and by the following companies: ICA-gruppen, Intrum, SATS, Elixia, Monark Exercise, and Itrim Sweden.</p
Associations of impulsivity, hyperactivity, and inattention with nonsuicidal self-injury and suicidal behavior : longitudinal cohort study following children at risk for neurodevelopmental disorders into mid-adolescence.
No full textBACKGROUND: The knowledge of how the separate Attention-Deficit/Hyperactivity Disorder (ADHD) subdimensions (impulsivity, hyperactivity, and inattention) are associated with nonsuicidal self-injury (NSSI) and suicidal behavior (SB) is limited. The objective of this study was to investigate the associations of childhood ADHD subdimensions with NSSI and SB in children at risk of neurodevelopmental disorders (NDDs; including ADHD). METHODS: The sample (N = 391) included twin pairs where at least one twin screened positive for at least one NDD or common comorbidity at age 9 or 12. Data on ADHD subdimensions was collected through a telephone interview with a caregiver/legal guardian at age 9 or 12, and data on NSSI and SB was collected through an in-person clinical assessment at age 15. The associations between the ADHD subdimensions and NSSI or SB were tested in three different models: (1) univariable, (2) together with the other ADHD subdimensions, and (3) in a confounder-adjusted model including other NDD symptoms in addition to ADHD subdimensions, for NSSI and SB separately. RESULTS: A total of 32 (8.2%) adolescents reported life-time engagement of NSSI, and 18 (4.6%) SB. Childhood impulsivity was associated with SB and childhood inattention with NSSI, in all models. Hyperactivity was not meaningfully associated with any of the outcomes. CONCLUSION: Impulsivity and inattention, but not hyperactivity, may be of particular importance in understanding SB and NSSI. Brief screening for impulsivity and inattention in childhood could facilitate detection of children vulnerable to NSSI and SB and indicate valuable information for preventive and intervention strategies.Published erratum:Ojala O, Kuja-Halkola R, Bjureberg J, Ohlis A, Cederlöf M, Norén Selinus E, Lichtenstein P, Larsson H, Lundström S, Hellner C. Correction: Associations of impulsivity, hyperactivity, and inattention with nonsuicidal self-injury and suicidal behavior: longitudinal cohort study following children at risk for neurodevelopmental disorders into mid-adolescence. BMC Psychiatry. 2023 Nov 21;23(1):864. doi: 10.1186/s12888-023-05338-y. Erratum for: BMC Psychiatry. 2022 Nov 3;22(1):679. PMID: 37990195; PMCID: PMC10664592.</p
Revisiting perfectionism in high-level ballet : A longitudinal collective instrumental case study
No full text‘’There was a lot of football involved, and I think that’s when my identity was created’’ : A study about retired male football players, early specialization and athletic identity.
No full textThe aim of this study was to investigate different experiences of retired football players who went through an early specialization, in which way it affected their athletic identity and retirement, and how they have dealt with it. The research questions were: · What are Swedish footballers’ experiences of early specialization in relation to athletic identity? · How do early specialized Swedish footballers reflect on athletic identity after career termination? To answer the research questions, a qualitative method with semi-structured interviews were used. Six male retired football players were recruited through a convenience sample. The participants were between 20-30 years old and have been retired for more than a year. Within this study, an inductive thematic analysis was conducted. The interviews and the thematic analysis resulted in four segments, which are part of their football journey. These are: 1) Early specialization- At the start of their career until they reached youth football, 2) Career- from youth football to a senior level, 3) Retirement- Right before and after career termination, 4) Athletic identity- Journey through their careers. Within each segment, there are categorized themes with the participants reflections of their experience throughout football. The results within this study shows that athletic identity starts growing within the early specialization segment, through the career and gets encountered with complications through retirement within the retired footballer. Early specialized footballers who identify stronger with their athletic-self have a harder time transitioning out of football. Further research should consider studying early specialization's relationship with athletic identity in football since no studies are found investigating the matter.
Exercising on the edge: mitochondrial and metabolic responses to intense training
No full textExercise and exercise training induces several physiological adaptations that increase the oxidative capacity of the muscles and improve glucose regulation. While the positive metabolic adaptations and effects on glucose regulation after exercise and exercise training have been extensively studied, negative outcomes have not. This thesis aims to address these questions and investigate possible negative effects of intensified training on mitochondrial parameters and glucose regulation. In two separate interventions, we studied these outcomes after progressive exercise training, and after different intensities of exercise. Mitochondrial respiration was assessed in muscle biopsies taken from m. vastus lateralis 14 hours after exercise and oral glucose tolerance tests were performed at the same time point. In paper I, we demonstrate that there is an upper limit of training load that can be tolerated without the manifestation of negative outcomes. After administrating almost daily sessions of high-intensity interval training, mitochondrial function and glucose control were impaired. In paper II, we used mitochondrial function as a novel biomarker of maladaptive training loads and constructed a diagnostic model that can be used for the early detection of maladaptations to exercise training. In paper III, we further demonstrated that endurance-trained athletes can have decreased glucose tolerance and increased insulin resistance the day after three hours of continuous cycling whereas these responses were not accentuated in healthy controls. Our results indicate that a metabolic switch in favor of lipid metabolism is the probable cause of this phenomenon. In paper IV, we briefly commented on a publication that described changes in whole-body VO2 responses to work rates in the athlete with the highest recorded VO2max. We provided arguments that the observed changes in VO2 and gross efficiency can in part have their origin in the mitochondria. We here combine measurements in muscle tissue with physiological measurements in an applied context. Using this integrated approach, we investigated the effects of intensified training on health-related and performance outcomes, thereby presenting insights into what maladaptations to exercise can constitute. We hope that our results and conclusions can help to further understand the complex relationship between exercise and health and to guide athletes and coaches to optimize training outcomes
Studier av natur och hälsa närmar sig grönskans mysterier
No full textArtikeln belyser utvecklingen inom forskningen om natur och hälsa, och pekar på behovet av att i framtida studier av fysisk aktivitet och hälsa inkludera natur i livsmiljön som en "confounder", på samma sätt som man har med kön, ålder och socioekonomi. Projekt gröna miljöe
Monitoring mental distress in Para athletes in preparation, during and after the Beijing Paralympic Games 2022 : A 22 week prospective mixed-method study.
No full textIt is common in elite sport to monitor athletes' training load, injuries and illnesses, but mental distress is rarely included. An improved understanding of the epidemiology of mental distress among elite Para athletes and how their coaches perceive such monitoring would allow us to better develop and implement preventive measures. The purpose of this study was therefore to (1) prospectively describe elite Para athletes' mental distress, before, during and after the Beijing Paralympic Games (Paralympics Games 22 = PG22); and to (2) gain a better understanding of if and potentially how awareness of athletes' mental distress changed, through weekly monitoring, and influenced how coachers perceive athletes' mental distress and if they accounted for this before, during and after PG22. A mixed-method study design was used, in which prospective mental distress (depression and anxiety) data were collected weekly from 13 [Swedish] elite Para athletes in preparation, during and after PG22. Data were screened and evaluated weekly by a physiotherapist and a sports psychologist, and coaches also received weekly reports. A focus-group interview with the coaches were conducted post Paralympics to address coaches' awareness about mental distress and athlete health monitoring in Parasport. For data analyses, descriptive statistics was used for the quantitative data and a content analysis was conducted for the qualitative data. The results reveled the following proportion of datapoints indicating symptoms of anxiety and depression: before PG22 (15.8 and 19.1%); during PG22 (47.6 and 38.2%); and after PG22 (0 and 11.8%). The qualitative results indicated that coaches perceived athlete health monitoring as helpful for increasing their awareness of mental distress, and as a useful tool to initiate support for their athletes as well as improving their coaching. In summary, this cohort of elite Para athletes reported a high proportion of mental distress during the Winter Paralympic Games in Beijing. The results also show that it is important and feasible to monitor Para athletes' mental distress to detect and manage early symptoms of mental distress
Normative values and changes in range of motion, strength, and functional performance over 1 year in adolescent female football players : Data from 418 players in the Karolinska football Injury Cohort study.
No full textOBJECTIVE: To study normative values of range of motion (ROM), strength, and functional performance and investigate changes over 1 year in adolescent female football players. DESIGN: Cross-sectional. PARTICIPANTS: 418 adolescent female football players aged 12-17 years. MAIN OUTCOME MEASURES: The physical characteristic assessments included (1) ROM assessment of the trunk, hips, and ankles; (2) strength measures (maximal isometric and eccentric strength for the trunk, hips, and knees, and strength endurance for the neck, back, trunk and calves), and (3) functional performance (the one-leg long box jump test and the square hop test). RESULTS: Older players were stronger, but not when normalized to body weight. Only small differences in ROM regarding age were found. ROM increased over 1 year in most measurements with the largest change in hip external rotation, which increased by 6-7° (Cohen's d = 0.83-0.87). Hip (d = 0.28-1.07) and knee (d = 0.38-0.53) muscle strength and the square hop test (d = 0.71-0.99) improved over 1 year. CONCLUSIONS: Normative values for ROM and strength assessments of neck, back, trunk, hips, knees, calves and ankles are presented for adolescent female football players. Generally, fluctuations in ROM were small with little clinical meaning, whereas strength improved over 1 year