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Metabolic costs of isometric force generation and maintenance of human skeletal muscle.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Russ, David W. Elliott, Mark A. Vandenborne, Krista Walter, Glenn Binder-Macleod, Stuart A. |
| Copyright Year | 2002 |
| Abstract | During isometric contractions, no true work is performed, so the force-time integral (FTI) is often used to approximate isometric work. However, the relationship between FTI and metabolic cost is not as linear. We tested the hypothesis that this nonlinearity was due to the cost of attaining a given force being greater than that of maintaining it. The ATP consumed per contraction in the human medial gastrocnemius muscle (n = 6) was determined by use of (31)P-NMR spectroscopy during eight different electrical stimulation protocols. Each protocol consisted of 8 trains of a single frequency (20 or 80 Hz) and duration (300, 600, 1,200, or 1,800 ms) performed under ischemic conditions. The cost of force generation was determined from the ATP turnover during the short-duration trains that did not attain a steady force level. Estimates of the cost of force maintenance at each frequency were determined by subtracting the ATP turnover during the shorter-duration trains from the turnover during the long-duration trains. The force generation phase of an isometric contraction was indeed more metabolically costly than the force maintenance phase during both 20- and 80-Hz stimulation. Thus the mean rate of ATP hydrolysis appeared to decline as contraction duration increased. Interestingly, the metabolic costs of maintaining force during 20-Hz and 80-Hz stimulation were comparable, although different levels of force were produced. |
| Starting Page | 288 |
| Ending Page | 292 |
| Page Count | 5 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://ajpendo.physiology.org/content/ajpendo/282/2/E448.full.pdf |
| Alternate Webpage(s) | http://ajpendo.physiology.org/content/ajpendo/282/2/e448.full.pdf |
| PubMed reference number | 11788378v1 |
| Volume Number | 282 |
| Issue Number | 2 |
| Journal | American journal of physiology. Endocrinology and metabolism |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | ATP Hydrolysis Adenosine Triphosphate Data Collection Eighty Electric stimulation technique Estimated Fatigue Financial cost Gastrocnemius muscle structure Hertz (Hz) Isometric Contraction Metabolic Process, Cellular Protocols documentation Skeletal muscle structure Swyer-James Syndrome Tetany Tissue fiber Uterine Contraction X-Ray Emission Spectroscopy |
| Content Type | Text |
| Resource Type | Article |
