Enhanced Blood Supply Through Lower Body Negative Pressure During Slow-Paced, High Load Leg Press Exercise Alters the Response of Muscle AMPK and Circulating Angiogenic Factors

Frontiers in Physiology

Sebastian Gehlert¹  Dajana Parganlija²  Wilhelm Bloch²  Jörn Rittweger³  Frankyn Herrera⁴  Jochen Zange⁴ 

[1] Department for Biosciences of Sports, Institute of Sport Science, University of Hildesheim, Hildesheim, Germany;Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University, Cologne, Germany;Department of Pediatrics and Adolescent Medicine, University of Cologne, Cologne, Germany;Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany;

关键词: resistance exercise;    robotically controlled leg press;    lower body negative pressure;    muscle perfusion;    physiological responses;    AMPK;   

DOI  :  10.3389/fphys.2020.00781

来源: DOAJ

【 摘 要 】

Lower body negative pressure (LBNP) is an established method of simulating the gravitational effects of orthostasis on the cardiovascular system during space flight or at supine body position on Earth. We hypothesized that LBNP added onto leg press exercise would promote leg muscle perfusion, stimulate oxygen consumption, and modify acute molecular responses. Eighteen subjects performed fifteen slow-paced concentric (4 s) and eccentric contractions (4 s) without or with 40 mmHg LBNP. Force corresponding to 6% of the one-repetition maximum (1-RM) at knee flexion gradually increased to 60% 1-RM within the first half of the range of motion, thereafter remaining constant. AMPK and P-AMPK protein expression was determined in biopsies of vastus lateralis. Venous blood samples were used to measure angiogenic factors. Physiological responses to LBNP included an elevated EMG amplitude, higher heart rate and doubling of the cardiac output compared to control (p < 0.001). Muscle total hemoglobin was increased by around 20 μmol/l vs. control (p < 0.001), accompanied by decreasing tissue oxygen saturation and elevated oxygen uptake (p < 0.05). MMP-2 levels were reduced, and the ratio of P-AMPK to AMPK elevated after exercise with LBNP (p < 0.05). MMP-9 similarly increased in both groups, whereas endostatin was only elevated in the control group (p < 0.05). Our results indicate facilitated peripheral blood supply and higher oxygen exploitation leading to activation of the energy sensor AMPK and differential regulation of angiogenic factors involved in muscle tissue remodeling and capillary growth. Simulating orthostasis with LBNP might promote beneficial structural adaptations of skeletal muscles during resistance exercise and contribute to future exercise countermeasures achieving increased muscle strength and endurance during space flight.

【 授权许可】

Unknown