{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,2,21]],"date-time":"2025-02-21T14:09:29Z","timestamp":1740146969711,"version":"3.37.3"},"reference-count":50,"publisher":"Public Library of Science (PLoS)","issue":"6","license":[{"start":{"date-parts":[[2023,6,16]],"date-time":"2023-06-16T00:00:00Z","timestamp":1686873600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID04045\/2020"],"award-info":[{"award-number":["UID04045\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID04045\/2020"],"award-info":[{"award-number":["UID04045\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID04045\/2020"],"award-info":[{"award-number":["UID04045\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>The importance of the muscle-tendon complex in sport and for activities of everyday living is well recognised. The free oscillation technique is frequently used to determine the musculo-articular \u201capparent\u201d stiffness (obtained from vertical ground reaction force) and other parameters. However, an in-depth understanding of the muscle-tendon complex can be gained by separating the muscle (soleus) and the tendon (Achilles tendon) components and studying the \u201ctrue\u201d stiffness for each of these components (by considering the ankle joint moment arms), which can be valuable in improving our understanding of training, injury prevention, and recovery programs. Hence, this study aimed to investigate if muscle and tendon stiffness (i.e., \u201ctrue\u201d stiffness) are similarly affected by different impulse magnitudes when using the free-oscillation technique. Three impulse magnitudes (impulse 1, 2 and 3), corresponding to peak forces of 100, 150 and 200 N, were used to estimate the stiffness of the ankle joint in 27 males, using multiple loads (10, 15, 20, 25, 30, 35, and 40 kg). A significant decrease (<jats:italic>p<\/jats:italic> &lt; 0.0005) was found in musculo-articular \u201capparent\u201d stiffness (29224 \u00b1 5087 N.m<jats:sup>-1<\/jats:sup>; 27839 \u00b1 4914 N.m<jats:sup>-1<\/jats:sup>; 26835 \u00b1 4880 N.m<jats:sup>-1<\/jats:sup>) between impulses 1, 2 and 3 respectively, when loads were collapsed across groups. However, significant differences (<jats:italic>p<\/jats:italic> &lt; 0.001) were only found between the median (Mdn) of impulse 1 (Mdn = 564.31 (kN\/m)\/kN) and 2 (Mdn = 468.88 (kN\/m)\/kN) and between impulse 1 (Mdn = 564.31 (kN\/m)\/kN) and 3 (Mdn = 422.19 (kN\/m)\/kN), for \u201ctrue\u201d muscle stiffness, but not for \u201ctrue\u201d tendon stiffness (Mdn = 197.35 kN\/m; Mdn = 210.26 kN\/m; Mdn = 201.60 kN\/m). The results suggest that the musculo-articular \u201capparent\u201d stiffness around the ankle joint is influenced by the magnitude of the impulse applied. Interestingly, this is driven by muscle stiffness, whereas tendon stiffness appears to be unaffected.<\/jats:p>","DOI":"10.1371\/journal.pone.0286847","type":"journal-article","created":{"date-parts":[[2023,6,16]],"date-time":"2023-06-16T17:23:21Z","timestamp":1686936201000},"page":"e0286847","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Free-oscillation technique: The effect of the magnitude of the impulse applied on muscle and tendon stiffness around the 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