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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. |
- Petersen, Astrid H., et al.
(författare)
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The effect of exercise on the absorption of inhaled human insulin via the AERx insulin diabetes management system in people with type 1 diabetes
- 2007
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Ingår i: Diabetes Care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 30:10, s. 2571-2576
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE - This study investigated the effect of moderate exercise on the absorption of inhaled insulin via the AERx insulin diabetes management system (iDMS). RESEARCH DESIGN AND METHODS - in this randomized, open-label, four-period crossover, glucose clamp study 23 nonsmoking subjects with type I diabetes received a dose of 0.19 units/kg inhaled human insulin followed in random order by either 1) no exercise (NOEX group) or 30 min exercise starting, 2) 30 min after dosing (EX30), 3) 120 min after dosing (EX120), or 4) 240 min after dosing (EX240). RESULTS - Exercise changed the shape of the free plasma insulin curves, but compared with the NOEX group the area under the curve for free plasma insulin (AUC(ins)) for the first 2 h after the start of exercise was unchanged for EX30 and EX240, while it was 15% decreased for EX120 (P < 0.01). The overall insulin absorption during 6 and 10 h after dosing was 13% decreased for EX30 (P < 0.005), 11% decreased for EX120 (P < 0.01), and unchanged for EX240. Exercise.), while the time to C-max was 22 min did not influence the maximum insulin concentration (C-max) earlier for EX30 (P = 0.04). The AUC for the glucose infusion rate (AUC(GIR)) for 2 h after the start of exercise increased by 58% for EX30, 45% for EX120, and 71% for EX240 (all P < 0.02) compared with the NOEX group. CONCLUSIONS - Thirty minutes of moderate exercise led to unchanged or decreased absorption of inhaled insulin via AERx iDMS and faster C-max for early exercise. Thus, patients using AERx iDMS can adjust insulin dose as usual independent of time of exercise, but they should be aware of the faster effect if exercising early after dosing.
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