Effects of daily static stretch training over 6 weeks on maximal strength, muscle thickness, contraction properties, and flexibility

Tim Wohlann; Konstantin Warneke; Martin Hillebrecht; Astrid Petersmann; Alexander Ferrauti; Stephan Schiemann

doi:10.3389/fspor.2023.1139065

Effects of daily static stretch training over 6 weeks on maximal strength, muscle thickness, contraction properties, and flexibility

Front Sports Act Living. 2023 Apr 17:5:1139065. doi: 10.3389/fspor.2023.1139065. eCollection 2023.

Authors

Tim Wohlann¹, Konstantin Warneke¹, Martin Hillebrecht², Astrid Petersmann^{3

4}, Alexander Ferrauti⁵, Stephan Schiemann¹

Affiliations

¹ Institute for Exercise, Sport and Health, Leuphana University, Lüneburg, Germany.
² University Sports Centre, Carl von University of Oldenburg, Oldenburg, Germany.
³ University Institute for Clinical Chemistry and Laboratory Medicine, University Medicine Oldenburg, Oldenburg, Germany.
⁴ Institute for Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany.
⁵ Faculty of Sports Science, Ruhr University Bochum, Bochum, Germany.

Abstract

Purpose: Static stretch training (SST) with long stretching durations seems to be sufficient to increase flexibility, maximum strength (MSt) and muscle thickness (MTh). However, changes in contraction properties and effects on muscle damage remain unclear. Consequently, the objective of the study was to investigate the effects of a 6-week self-performed SST on MSt, MTh, contractile properties, flexibility, and acute response of creatine kinase (CK) 3 days after SST.

Methods: Forty-four participants were divided into a control (CG, n = 22) and an intervention group (IG, n = 22), who performed a daily SST for 5 min for the lower limb muscle group. While isometric MSt was measured in leg press, MTh was examined via sonography and flexibility by functional tests. Muscle stiffness and contraction time were measured by tensiomyography on the rectus femoris. Additionally, capillary blood samples were taken in the pretest and in the first 3 days after starting SST to measure CK.

Results: A significant increase was found for MSt (p < 0.001, η ² = 0.195) and flexibility in all functional tests (p < 0.001, η ² > 0.310). Scheffé post hoc test did not show significant differences between the rectus femoris muscle inter- and intragroup comparisons for MTh nor for muscle stiffness and contraction time (p > 0.05, η ² < 0.100). Moreover, CK was not significantly different between IG and CG with p > 0.05, η ² = 0.032.

Discussion: In conclusion, the increase in MSt cannot be exclusively explained by muscular hypertrophy or the increased CK-related repair mechanism after acute stretching. Rather, neuronal adaptations have to be considered. Furthermore, daily 5-min SST over 6 weeks does not seem sufficient to change muscle stiffness or contraction time. Increases in flexibility tests could be attributed to a stretch-induced change in the muscle-tendon complex.

Keywords: contraction time; hypertrophy; maximal strength; muscle damage; muscle stiffness; static stretching.

Grants and funding

This publication was funded by the German Research Foundation (DFG).