{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T18:25:06Z","timestamp":1793125506217,"version":"4.5.0"},"reference-count":34,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2019,10,17]],"date-time":"2019-10-17T00:00:00Z","timestamp":1571270400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2019,10,17]],"date-time":"2019-10-17T00:00:00Z","timestamp":1571270400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004243","name":"Prinses Beatrix Spierfonds","doi-asserted-by":"publisher","award":["grant number W.OR 14-21"],"award-info":[{"award-number":["grant number W.OR 14-21"]}],"id":[{"id":"10.13039\/501100004243","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["J NeuroEngineering Rehabil"],"published-print":{"date-parts":[[2019,12]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>To improve gait, persons with calf muscle weakness can be provided with a dorsal leaf spring ankle foot orthosis (DLS-AFO). These AFOs can store energy during stance and return this energy during push-off, which, in turn, reduces walking energy cost. Simulations indicate that the effect of the DLS-AFO on walking energy cost and gait biomechanics depends on its stiffness and on patient characteristics. We therefore studied the effect of varying DLS-AFO stiffness on reducing walking energy cost, and improving gait biomechanics and AFO generated power in persons with non-spastic calf muscle weakness, and whether the optimal AFO stiffness for maximally reducing walking energy cost varies between persons.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Thirty-seven individuals with neuromuscular disorders and non-spastic calf muscle weakness were included. Participants were provided with a DLS-AFO of which the stiffness could be varied. For 5 stiffness configurations (ranging from 2.8 to 6.6\u2009Nm\/degree), walking energy cost (J\/kg\/m) was assessed using a 6-min comfortable walk test. Selected gait parameters, e.g. maximal dorsiflexion angle, ankle power, knee angle, knee moment and AFO generated power, were derived from 3D gait analysis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      On group level, no significant effect of DLS-AFO stiffness on reducing walking energy cost was found (\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u20090.059, largest difference: 0.14\u2009J\/kg\/m). The AFO stiffness that reduced energy cost the most varied between persons. The difference in energy cost between the least and most efficient AFO stiffness was on average 10.7%. Regarding gait biomechanics, increasing AFO stiffness significantly decreased maximal ankle dorsiflexion angle (\u2212\u20091.1\u2009\u00b1\u20090.1 degrees per 1\u2009Nm\/degree,\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0&lt;\u20090.001) and peak ankle power (\u2212\u20090.09\u2009\u00b1\u20090.01\u2009W\/kg,\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0&lt;\u20090.001). The reduction in minimal knee angle (\u2212\u20090.3\u2009\u00b1\u20090.1 degrees,\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u20090.034), and increment in external knee extension moment in stance (\u2212\u20090.01\u2009\u00b1\u20090.01\u2009Nm\/kg,\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u20090.016) were small, although all stiffness\u2019 substantially affected knee angle and knee moment compared to shoes only. No effect of stiffness on AFO generated power was found (\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u20090.900).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The optimal efficient DLS-AFO stiffness varied largely between persons with non-spastic calf muscle weakness. Results indicate this is caused by an individual trade-off between ankle angle and ankle power affected differently by AFO stiffness. We therefore recommend that the AFO stiffness should be individually optimized to best improve gait.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Trial registration number<\/jats:title>\n                    <jats:p>\n                      Nederlands Trial Register 5170. Registration date: May 7th 2015.\n                      <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"http:\/\/www.trialregister.nl\/trialreg\/admin\/rctview.asp?TC=5170\">http:\/\/www.trialregister.nl\/trialreg\/admin\/rctview.asp?TC=5170<\/jats:ext-link>\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s12984-019-0600-2","type":"journal-article","created":{"date-parts":[[2019,10,17]],"date-time":"2019-10-17T09:10:08Z","timestamp":1571303408000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":54,"title":["Modifying ankle foot orthosis stiffness in patients with calf muscle weakness: gait responses on group and individual level"],"prefix":"10.1186","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4025-7137","authenticated-orcid":false,"given":"Niels F. 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The study protocol of the PROOF-FO trial was approved by the medical ethics committee of the Academic Medical Center (AMC) in Amsterdam, The Netherlands (register: METC_2014_397).","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Not applicable","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}}],"article-number":"120"}}