| Content Provider |
World Health Organization (WHO)-Global Index Medicus |
| Author |
Krainski, Felix Hastings, Jeffrey L. Heinicke, Katja Romain, Nadine Pacini, Eric L. Snell, Peter G. Wyrick, Phil Palmer, M. Dean Haller, Ronald G. Levine, Benjamin D. |
| Description |
Author Affiliation: Krainski F ( Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas); Hastings JL ( Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas); Heinicke K ( Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas); Romain N ( Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas); Pacini EL ( Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas); Snell PG ( University of Texas Southwestern Medical Center at Dallas, Dallas, Texas); Wyrick P ( Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas); Palmer MD ( Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas); Haller RG ( Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas); Levine BD ( Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas) |
| Abstract |
Exposure to microgravity causes functional and structural impairment of skeletal muscle. Current exercise regimens are time-consuming and insufficiently effective; an integrated countermeasure is needed that addresses musculoskeletal along with cardiovascular health. High-intensity, short-duration rowing ergometry and supplemental resistive strength exercise may achieve these goals. Twenty-seven healthy volunteers completed 5 wk of head-down-tilt bed rest (HDBR): 18 were randomized to exercise, 9 remained sedentary. Exercise consisted of rowing ergometry 6 days/wk, including interval training, and supplemental strength training 2 days/wk. Measurements before and after HDBR and following reambulation included assessment of strength, skeletal muscle volume (MRI), and muscle metabolism (magnetic resonance spectroscopy); quadriceps muscle biopsies were obtained to assess muscle fiber types, capillarization, and oxidative capacity. Sedentary bed rest (BR) led to decreased muscle volume (quadriceps: -9 ± 4%, P < 0.001; plantar flexors: -19 ± 6%, P < 0.001). Exercise (ExBR) reduced atrophy in the quadriceps (-5 ± 4%, interaction P = 0.018) and calf muscle, although to a lesser degree (-14 ± 6%, interaction P = 0.076). Knee extensor and plantar flexor strength was impaired by BR (-14 ± 15%, P = 0.014 and -22 ± 7%, P = 0.001) but preserved by ExBR (-4 ± 13%, P = 0.238 and +13 ± 28%, P = 0.011). Metabolic capacity, as assessed by maximal O2 consumption, (31)P-MRS, and oxidative chain enzyme activity, was impaired in BR but stable or improved in ExBR. Reambulation reversed the negative impact of BR. High-intensity, short-duration rowing and supplemental strength training effectively preserved skeletal muscle function and structure while partially preventing atrophy in key antigravity muscles. Due to its integrated cardiovascular benefits, rowing ergometry could be a primary component of exercise prescriptions for astronauts or patients suffering from severe deconditioning. |
| File Format |
HTM / HTML |
| ISSN |
87507587 |
| e-ISSN |
15221601 |
| Journal |
Journal of Applied Physiology |
| Issue Number |
12 |
| Volume Number |
116 |
| Language |
English |
| Publisher |
American Physiological Society |
| Publisher Date |
2014-06-15 |
| Publisher Place |
United States |
| Access Restriction |
Open |
| Subject Keyword |
Discipline Physiology Bed Rest Adverse Effects Physiology Muscle, Skeletal Ergometry Exercise Therapy Head-down Tilt Knee Leg Physiopathology Muscular Atrophy Resistance Training Weightlessness Weightlessness Countermeasures Weightlessness Simulation Randomized Controlled Trial Research Support, Non-u.s. Gov't |
| Content Type |
Text |
| Resource Type |
Article |
| Subject |
Physiology Physiology (medical) Sports Science |
