Kay, A. D. and Blazevich, A. J. (2009) Moderate-duration static stretch reduces active and passive plantar flexor moment but not Achilles tendon stiffness or active muscle length. Journal of Applied Physiology. 106, pp. 1249-1256. 8750-7587.
| Item Type: | Article |
|---|---|
| Abstract: | The effects of static stretch on muscle and tendon mechanical properties and muscle activation were studied in fifteen healthy human volunteers. Peak active and passive moment data were recorded during plantar flexion trials on an isokinetic dynamometer. Electromyography (EMG) monitoring of the triceps surae muscles, real-time motion analysis of the lower leg, and ultrasound imaging of the Achillesmedial gastrocnemius muscle-tendon junction were simultaneously conducted. Subjects performed three 60-s static stretches before being retested 2 min and 30 min poststretch. There were three main findings in the present study. First, peak concentric moment was significantly reduced after stretch; 60% of the deficit recovered 30 min poststretch. This was accompanied by, and correlated with (r _ 0.81; P _ 0.01) reductions in peak triceps surae EMG amplitude, which was fully recovered at 30 min poststretch. Second, Achilles tendon length was significantly shorter during the concentric contraction after stretch and at 30 min poststretch; however, no change in tendon stiffness was detected. Third, passive joint moment was significantly reduced after stretch, and this was accompanied by significant reductions in medial gastrocnemius passive muscle stiffness; both measures fully recovered by 30 min poststretch. These data indicate that the stretching protocol used in this study induced losses in concentric moment that were accompanied by, and related to, reductions in neuromuscular activity, but they were not associated with alterations in tendon stiffness or shorter muscle operating length. Reductions in passive moment were associated with reductions in muscle stiffness, whereas tendon mechanics were unaffected by the stretch. Importantly, the impact on mechanical properties and neuromuscular activity was minimal at 30 min poststretch. |
| Uncontrolled Keywords: | triceps surae; force deficits; tissue mechanics; electromyography |
| Subjects: | Q Science > QP Physiology > QP301 Exercise and sports physiology |
| Creators: | Kay, Anthony D and Blazevich, Anthony J |
| Publisher: | American Physiological Society |
| Faculties, Divisions and Institutes: |
University Faculties, Divisions and Research Centres - OLD > Faculty of Health & Society > Sports, Exercise & Life Sciences University Faculties, Divisions and Research Centres - OLD > Research Centre > Institute of Health and Wellbeing > Centre for Physical Activity and Chronic Disease Faculties > Faculty of Health & Society > Sports, Exercise & Life Sciences Research Centres > Centre for Health Sciences and Services Research Centres > Centre for Physical Activity and Life Sciences |
| Date: | 29 January 2009 |
| Date Type: | Publication |
| Page Range: | pp. 1249-1256 |
| Journal or Publication Title: | Journal of Applied Physiology |
| Volume: | 106 |
| Language: | English |
| ISSN: | 8750-7587 |
| Status: | Published / Disseminated |
| Refereed: | Yes |
| URI: | http://nectar.northampton.ac.uk/id/eprint/2114 |
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