The stretch-shortening cycle (SSC) revisited: residual force enhancement contributes to increased performance during fast SSCs of human m. adductor pollicis
Accessioned
2016-06-21T19:27:57ZAvailable
2016-06-21T19:27:57ZIssued
2015Subject
concentriceccentric
electrical stimulation
force depression
force enhancement
force redevelopment
muscle
potentiation
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Abstract
The stretch-shortening cycle (SSC) occurs in most everyday movements, and is thought to provoke a performance enhancement of the musculoskeletal system. However, mechanisms of this performance enhancement remain a matter of debate. One proposed mechanism is associated with a stretch-induced increase in steady-state force, referred to as residual force enhancement (RFE). As yet, direct evidence relating RFE to increased force/work during SSCs is missing. Therefore, forces of electrically stimulated m. adductor pollicis (n = 14 subjects) were measured during and after pure stretch, pure shortening, and stretch-shortening contractions with varying shortening amplitudes. Active stretch (30°, x = 161 6°s 1) caused significant RFE (16%, P < 0.01), whereas active shortening (10°, 20°, and 30°; x = 103 3°s 1, 152 5°s 1, and 170 5°s 1) resulted in significant force depression (9–15%, P < 0.01). In contrast, after SSCs (that is when active stretch preceded active shortening) no force depression was found. Indeed for our specific case in which the shortening amplitude was only 1/3 of the lengthening amplitude, there was a remnant RFE (10%, P < 0.01) following the active shortening. This result indicates that the RFE generated during lengthening affected force depression when active lengthening was followed by active shortening. As conventional explanations, such as the storage and release of elastic energy, cannot explain the enhanced steady-state force after SSCs, it appears that the stretch-induced RFE is not immediately abolished during shortening and contributes to the increased force and work during SSCs.Refereed
YesSponsorship
Canadian Institutes of Health Research, the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chair Programma, and the Killan Foundation. Also, the German Research Foundation (DFG), and the Technische Universitat Munchen.Citation
Seiberl, W., Power, G. A., Herzog, W., & Hahn, D. (2015). The stretch‐shortening cycle (SSC) revisited: residual force enhancement contributes to increased performance during fast SSCs of human m. adductor pollicis. Physiological reports, 3(5), e12401.Department
Human Performance LaboratoryFaculty
KinesiologyInstitution
University of CalgaryPublisher
Physiological ReportsPhysiological reports