Kay, A. D., Rubley, B., Talbot, C., Mina, M. A. and Blazevich, A. J. (2014) Six weeks of maximal eccentric knee extensor training affects muscle-tendon mechanics and muscle damage. Other presented to: 19th Annual Congress of the European College of Sport Science (ECSS 2014), 2014-07-01 - 2014-07-04.
| Item Type: | Conference or Workshop Item (Other) |
|---|---|
| Abstract: | Introduction: Strength training can influence muscle-tendon mechanics and architecture, and provide a protective effect from exercise-induced muscle damage; however more data are required describing the specific influence of eccentric training. Therefore, the aims of the present study were to examine the effect of 6 weeks of maximal eccentric knee extensor training on these properties. Methods: Thirteen recreationally active participants (age = 28.3 ± 1.7 yr, mass = 73.5 ± 14.6 kg, height = 1.7 ± 0.1 m) volunteered for the study after giving written informed consent; ethical approval was granted from the University of Northampton. Training was performed twice weekly and consisted of 5 sets of 12 repetitions of 3-s maximal knee extensor isokinetic eccentric contractions at 30°·s-1 from 180° to 90° knee extension. Maximal isometric and eccentric knee extensor moment, range of motion (ROM), stretch tolerance, VL thickness and fascicle angle, and tendon and muscle-tendon unit (MTU) stiffness were measured using isokinetic dynamometry and real-time ultrasonography before and after the training. Creatine kinase (CK) concentration and delayed onset muscle soreness (DOMS) were also measured before and 24 h after a 20-min downhill run (16° decline). Results: A significant increase in isometric (21.6%; p<0.05) and eccentric (28.1%; p<0.01) strength, ROM (6.6°; p<0.01), stretch tolerance (83.6%; p<0.01), VL thickness (7.8%; p<0.01) and fascicle angle (9.2%; p<0.01) was found after training; changes in VL thickness and fascicle angle were strongly correlated (r=0.96: p<0.01). While no change was found in MTU stiffness (slope of the passive moment curve) using dynamometry (-5.8%; p=0.45), ultrasound data revealed a significant increase in VL tendon stiffness (8.7%; p<0.01). Although CK concentration after downhill running increased significantly before (103.2%; p<0.01) and after (42.1%; p<0.05) training, the increase in CK was significantly lower following the training (p<0.05), with subjects also reporting minimal DOMS within the knee extensors. Discussion: The substantial increases in strength were accompanied by increases in both muscle size and pennation. Moreover, significant increases in ROM and stretch tolerance were observed, indicating a dual benefit to the eccentric training. An increase in tendon stiffness was observed, which will likely impact muscle-skeleton force transfer, and ultimately influence movement capacity. However, importantly this was not accompanied by a change in whole MTU stiffness, suggesting that MTU measurements may miss tissue-specific adaptations. Finally, the attenuated CK and DOMS response after training has clear implications for both muscular performance and injury risk. Contact: tony.kay@northampton.ac.uk |
| Creators: | Kay, Anthony D, Rubley, B, Talbot, Chris, Mina, M A and Blazevich, Anthony J |
| Faculties, Divisions and Institutes: |
Faculties > Faculty of Health & Society > Sports, Exercise & Life Sciences Research Centres > Centre for Physical Activity and Life Sciences |
| Date: | 1 July 2014 |
| Date Type: | Publication |
| Journal or Publication Title: | 19th Annual Congress of the European College of Sport Science (ECSS 2014) |
| Event Title: | 19th Annual Congress of the European College of Sport Science (ECSS 2014) |
| Event Dates: | 2014-07-01 - 2014-07-04 |
| Place of Publication: | NLD |
| Event Type: | Other |
| Language: | English |
| Status: | Published / Disseminated |
| Refereed: | Yes |
| Related URLs: | |
| URI: | http://nectar.northampton.ac.uk/id/eprint/11428 |
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