| 1. |
- Flockhart, Mikael, et al.
(författare)
-
A simple model for diagnosis of maladaptations to exercise training
- 2022
-
Ingår i: Sports Medicine Open. - : Springer. - 2198-9761 .- 2199-1170. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The concept of overreaching and super compensation is widely in use by athletes and coaches seeking to maximize performance and adaptations to exercise training. The physiological aspects of acute fatigue, overreaching and non-functional overreaching are, however, not well understood, and well-defined negative physiological outcomes are missing. Instead, the concept relies heavily on performance outcomes for differentiating between the states. Recent advancements in the field of integrated exercise physiology have associated maladaptations in muscular oxidative function to high loads of exercise training.Method: Eleven female and male subjects that exercised regularly but did not engage in high-intensity interval training (HIIT) were recruited to a 4-week long training intervention where the responses to different training loads were studied. Highly monitored HIIT sessions were performed on a cycle ergometer in a progressive fashion with the intent to accomplish a training overload. Throughout the intervention, physiological and psychological responses to HIIT were assessed, and the results were used to construct a diagnostic model that could indicate maladaptations during excessive training loads.Results: We here use mitochondrial function as an early marker of excessive training loads and show the dynamic responses of several physiological and psychological measurements during different training loads. During HIIT, a loss of mitochondrial function was associated with reduced glycolytic, glucoregulatory and heart rate responses and increased ratings of perceived exertion in relation to several physiological measurements. The profile of mood states was highly affected after excessive training loads, whereas performance staled rather than decreased. By implementing five of the most affected and relevant measured parameters in a diagnostic model, we could successfully, and in all the subjects, identify the training loads that lead to maladaptations.Conclusions: As mitochondrial parameters cannot be assessed without donating a muscle biopsy, this test can be used by coaches and exercise physiologists to monitor adaptation to exercise training for improving performance and optimizing the health benefits of exercise. Clinical trial registry number NCT04753021 . Retrospectively registered 2021-02-12.
|
|
| 2. |
- Flockhart, Mikael, et al.
(författare)
-
Excessive exercise training causes mitochondrial functional impairment and decreases glucose tolerance in healthy volunteers.
- 2021
-
Ingår i: Cell Metabolism. - : Cell Press. - 1550-4131 .- 1932-7420. ; 33:5, s. 957-970
-
Tidskriftsartikel (refereegranskat)abstract
- Exercise training positively affects metabolic health through increased mitochondrial oxidative capacity and improved glucose regulation and is the first line of treatment in several metabolic diseases. However, the upper limit of the amount of exercise associated with beneficial therapeutic effects has not been clearly identified. Here, we used a training model with a progressively increasing exercise load during an intervention over 4 weeks. We closely followed changes in glucose tolerance, mitochondrial function and dynamics, physical exercise capacity, and whole-body metabolism. Following the week with the highest exercise load, we found a striking reduction in intrinsic mitochondrial function that coincided with a disturbance in glucose tolerance and insulin secretion. We also assessed continuous blood glucose profiles in world-class endurance athletes and found that they had impaired glucose control compared with a matched control group.
|
|
| 3. |
- Flockhart, Mikael, et al.
(författare)
-
Reduced glucose tolerance and insulin sensitivity after prolonged exercise in endurance athletes.
- 2023
-
Ingår i: Acta Physiologica. - : John Wiley & Sons. - 1748-1708 .- 1748-1716. ; 238:4
-
Tidskriftsartikel (refereegranskat)abstract
- AIM: The purpose of this study was to 1. investigate if glucose tolerance is affected after one acute bout of different types of exercise; 2. assess if potential differences between two exercise paradigms are related to changes in mitochondrial function; and 3. determine if endurance athletes differ from nonendurance-trained controls in their metabolic responses to the exercise paradigms.METHODS: Nine endurance athletes (END) and eight healthy nonendurance-trained controls (CON) were studied. Oral glucose tolerance tests (OGTT) and mitochondrial function were assessed on three occasions: in the morning, 14 h after an overnight fast without prior exercise (RE), as well as after 3 h of prolonged continuous exercise at 65% of VO2 max (PE) or 5 × 4 min at ~95% of VO2 max (HIIT) on a cycle ergometer.RESULTS: Glucose tolerance was markedly reduced in END after PE compared with RE. END also exhibited elevated fasting serum FFA and ketones levels, reduced insulin sensitivity and glucose oxidation, and increased fat oxidation during the OGTT. CON showed insignificant changes in glucose tolerance and the aforementioned measurements compared with RE. HIIT did not alter glucose tolerance in either group. Neither PE nor HIIT affected mitochondrial function in either group. END also exhibited increased activity of 3-hydroxyacyl-CoA dehydrogenase activity in muscle extracts vs. CON.CONCLUSION: Prolonged exercise reduces glucose tolerance and increases insulin resistance in endurance athletes the following day. These findings are associated with an increased lipid load, a high capacity to oxidize lipids, and increased fat oxidation.
|
|
| 4. |
- Holmlund, Tobias, et al.
(författare)
-
Energy expenditure in people with motor-complete paraplegia.
- 2017
-
Ingår i: Spinal Cord. - : Springer Science and Business Media LLC. - 1362-4393 .- 1476-5624. ; 55:8, s. 774-781
-
Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN: The present descriptive clinical and laboratory study is cross-sectional in design.OBJECTIVES: The primary aim is to describe and compare resting energy expenditure (REE) and energy expenditure (EE) during different standardized sedentary, non-exercise and exercise activities in people with motor-complete paraplegia (Th7 to Th12.). A secondary aim was to compare men and women.METHODS: Thirty-eight adults (10 women) with SCI, T7-T12 AIS A-B, were recruited. All the data were collected through indirect calorimetry. REE was measured in supine for 30 min after 8 h of overnight fasting. Activity energy expenditure (AEE) for activities was measured for seven minutes during sedentary, non-exercise physical activity (NEPA) and exercise activities.RESULTS: AEE increased four to eight times when engaging in NEPA compared to that in sedentary activities. Men had significantly higher resting oxygen uptake compared to women, 0.19 vs 0.15 l min(-1) (P=0.005), REE per 24 h, 1286 vs 1030 kcal (P=0.003) and EE during weight-bearing activities. However, these became nonsignificant after adjustment for body weight and speed of movement, with a mean resting oxygen uptake of 2.47 ml O2 per kg min(-1) for the whole group (women 2.43 and men 2.57 ml O2 kg(-1) min(-1), P=0.49).CONCLUSIONS: NEPA increases AEE up to eight times compared to sedentary activities. Gender differences in oxygen uptake during both rest and weight-bearing activities were diminished after adjustment for body weight. The mean resting oxygen uptake for the whole group was 2.47 ml O2 kg(-1) min(-1). These results highlight the importance, especially of NEPA, for increasing total daily EE in the target population.
|
|
| 5. |
- Lebedev, Alexander V., et al.
(författare)
-
Effects of daily L-dopa administration on learning and brain structure in older adults undergoing cognitive training : a randomised clinical trial
- 2020
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Cognitive aging creates major individual and societal burden, motivating search for treatment and preventive care strategies. Behavioural interventions can improve cognitive performance in older age, but effects are small. Basic research has implicated dopaminergic signalling in plasticity. We investigated whether supplementation with the dopamine-precursor L-dopa improves effects of cognitive training on performance. Sixty-three participants for this randomised, parallel-group, double-blind, placebo-controlled trial were recruited via newspaper advertisements. Inclusion criteria were: age of 65–75 years, Mini-Mental State Examination score >25, absence of serious medical conditions. Eligible subjects were randomly allocated to either receive 100/25 mg L-dopa/benserazide (n = 32) or placebo (n = 31) prior to each of twenty cognitive training sessions administered during a four-week period. Participants and staff were blinded to group assignment. Primary outcomes were latent variables of spatial and verbal fluid intelligence. Compared to the placebo group, subjects receiving L-dopa improved less in spatial intelligence (−0.267 SDs; 95%CI [−0.498, −0.036]; p = 0.024). Change in verbal intelligence did not significantly differ between the groups (−0.081 SDs, 95%CI [−0.242, 0.080]; p = 0.323). Subjects receiving L-dopa also progressed slower through the training and the groups displayed differential volumetric changes in the midbrain. No statistically significant differences were found for the secondary cognitive outcomes. Adverse events occurred for 10 (31%) and 7 (23%) participants in the active and control groups, correspondingly. The results speak against early pharmacological interventions in older healthy adults to improve broader cognitive functions by targeting the dopaminergic system and provide no support for learning-enhancing properties of L-dopa supplements in the healthy elderly. The findings warrant closer investigation about the cognitive effects of early dopamine-replacement therapy in neurological disorders. This trial was preregistered at the European Clinical Trial Registry, EudraCT#2016-000891-54 (2016-10-05).
|
|
| 6. |
- Lännerström, Johan, et al.
(författare)
-
Effects of Plyometric Training on Soft and Hard Surfaces for Improving Running Economy.
- 2021
-
Ingår i: Journal of Human Kinetics. - : Sciendo. - 1640-5544 .- 1899-7562. ; 79:1, s. 187-196
-
Tidskriftsartikel (refereegranskat)abstract
- The present study investigated the effects of plyometric jump training on hard and soft surfaces on running economy (RE), maximal oxygen uptake (VO2max), running performance and the rate of force development in orienteers. Nineteen orienteers (11 women and 8 men, body mass 61.1 ± 7.3 kg, age 21 ± 5.8 yrs) were randomly stratified based on sex, age, VO2max and RE to plyometric jumping training (8 sessions over 4 weeks) on either a hard or a soft surface. RE, VO2max and running performance were assessed on a treadmill and outdoor on- and off-trail loops. Moreover, ground reaction forces and force development were assessed during a one leg drop-jump test. The training intervention led to an overall 2-7% improvement in treadmill and off-trail RE, independent of the jumping surface and running velocity assessed. These improvements were not explained by force development during drop jump tests, which remained unchanged following the intervention. The changes in time-trial performance were associated with changes in RE. Plyometric training improved RE with no difference between the hard or the soft training surface and improved RE was also independent of the running speed assessed. Furthermore, improved running performance was associated with changes in RE after the intervention.
|
|
| 7. |
- Schaumberg, Katherine, et al.
(författare)
-
The Science Behind the Academy for Eating Disorders' Nine Truths About Eating Disorders
- 2017
-
Ingår i: European eating disorders review. - : WILEY. - 1072-4133 .- 1099-0968. ; 25:6, s. 432-450
-
Forskningsöversikt (refereegranskat)abstract
- ObjectiveIn 2015, the Academy for Eating Disorders collaborated with international patient, advocacy, and parent organizations to craft the Nine Truths About Eating Disorders'. This document has been translated into over 30 languages and has been distributed globally to replace outdated and erroneous stereotypes about eating disorders with factual information. In this paper, we review the state of the science supporting the Nine Truths'. MethodsThe literature supporting each of the Nine Truths' was reviewed, summarized and richly annotated. ResultsMost of the Nine Truths' arise from well-established foundations in the scientific literature. Additional evidence is required to further substantiate some of the assertions in the document. Future investigations are needed in all areas to deepen our understanding of eating disorders, their causes and their treatments. ConclusionsThe Nine Truths About Eating Disorders' is a guiding document to accelerate global dissemination of accurate and evidence-informed information about eating disorders. Copyright (c) 2017 John Wiley & Sons, Ltd and Eating Disorders Association.
|
|
