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Beaumont, A., Sculthorpe, N., Hough, J. 
ORCID: 0000-0001-6970-5779, Unnithan, V. and Richards, J.,
2018.
Global and regional left ventricular circumferential strain during incremental cycling and isometric knee extension exercise.
Echocardiography: a Journal of Cardiovascular Ultrasound and Allied Techniques.
ISSN 1540-8175
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Abstract
Background: The objective of this study was to investigate left ventricular (LV) circumferential strain responses to incremental cycling and isometric knee extension exercises.
Methods: Twenty-six healthy male participants (age = 30 ± 6 years) were used to study LV global (GCS) and regional circumferential strain at the apex (ACS) and base (BCS) during incremental cycling at 30% and 60% work rate maximum (Wmax) and short-duration (15 seconds contractions) isometric knee extensions at 40% and 75% maximum voluntary contraction (MVC) using two-dimensional speckle tracking echocardiography.
Results: During cycling (n = 22), GCS increased progressively from rest to 60% Wmax (−22.85 ± 3.26% to −29.87 ± 2.59%, P < .01). ACS increased from rest to 30% Wmax (−26.29 ± 4.84% to −36.84 ± 6.94%, P < .01) and then remained unchanged to 60% Wmax (−40.72 ± 4.06%, P = .068). BCS decreased from rest to 30% Wmax (−19.41 ± 2.79 to −17.51 ± 4.66%, P = .05) and then remained unchanged to 60% Wmax. During isometric knee extension (n = 23), GCS decreased from rest to 40% MVC (−22.63 ± 3.46 to −20.10 ± 2.78%, P < .05) and then remained unchanged to 75% MVC. Similarly, BCS decreased from rest to 40% MVC (−19.21 ± 2.58% to −13.55 ± 3.45%, P < .01) and then remained unchanged, whereas ACS did not change with exercise intensity (rest, −26.05 ± 5.34%; 40% MVC, −26.64 ± 4.53% and 75% MVC −27.22 ± 5.34%, all P > .05).
Conclusion: Global circumferential strain increased stepwise during incremental cycling, mediated by the apex with trivial changes at the base. In contrast, GCS decreased during the isometric knee extension to 40% MVC and then plateaued, due to decreased BCS as ACS was maintained. A novel finding is that the GCS response appears to be exercise modality dependant and is the consequence of region-specific changes.
| Item Type: | Journal article | ||||
|---|---|---|---|---|---|
| Publication Title: | Echocardiography: a Journal of Cardiovascular Ultrasound and Allied Techniques | ||||
| Creators: | Beaumont, A., Sculthorpe, N., Hough, J., Unnithan, V. and Richards, J. | ||||
| Publisher: | Wiley on behalf of the International Society of Cardiovascular Ultrasound | ||||
| Date: | 16 April 2018 | ||||
| ISSN: | 1540-8175 | ||||
| Identifiers: |
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| Rights: | © 2018 Wiley Periodicals, Inc. | ||||
| Divisions: | Schools > School of Science and Technology | ||||
| Record created by: | Jill Tomkinson | ||||
| Date Added: | 20 Jul 2018 15:39 | ||||
| Last Modified: | 16 Apr 2019 03:00 | ||||
| URI: | https://irep.ntu.ac.uk/id/eprint/34125 |
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