Affiliations: [a] Department of Biomechanics, Kinesiology and Informatics, University of Physical Education, Budapest, Hungary | [b] Fájdalom Ambulancia, Budapest, Hungary | [c] Institute of Sport Sciences and Physical Education, University of Pécs, Pécs, Hungary | [d] Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad, Serbia | [e] Research Institute of Sport Science, University of Physical Education, Budapest, Hungary
Correspondence:
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Corresponding author: János Négyesi, Department of Biomechanics, Kinesiology and Informatics, University of Physical Education, Alkotás 44, 1123 Budapest, Hungary. Tel.: +36 30 522 6227; E-mail:j.negyesi88@gmail.com
Abstract: BACKGROUND: The effects of stretch-shortening cycle (SSC) training are
well-described in the literature but the mechanism of how it changes the
characteristics of the SSC moment-time curve and contraction velocity is
unknown. OBJECTIVE: The purpose of the present study was to investigate the
adaptation mechanisms of the knee extensor contractile properties in
response to a short-term unilateral SSC exercise training. METHODS: Twenty-four subjects (22.9 ± 2.4 years) were randomised to an
experimental or control group. A custom-built dynamometer was used to test
the mechanical properties of the quadriceps muscle. Each subject
participated in the pre-, and post-test session. Subjects in the
experimental group participated in nine training sessions and performed
maximal voluntary stretch-shortening cycle contractions on the dynamometer.
Changes in the knee extensor contractile properties were measured from an
SSC curve. RESULTS: Multivariate analysis of variance (MANOVA) revealed a significant
multivariate effect for the measured variables in relation to group
assignment. SSC exercise training significantly changed concentric moment
(M_{CC}, F_{1,22} = 96.2, p = 0.000), and contraction velocity
(F_{1,22} = 125.6, p = 0.000) resulting in a 29.6% improvement in
concentric peak angular velocity (ω). Stepwise multiple regression
analysis showed that ω was significantly predicted only by M_{CC}
(r = 0.751, p = 0.005). CONCLUSIONS: Short-term unilateral SSC exercise training modifies the
characteristics of the SSC moment-time curve and contraction velocity
through the mechanical adaptation of the knee extensor contractile
properties.
