{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/31247"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/31247","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Prolonged Lumbar Flexion Disturbs Paraspinal Reflex Behavior","abstract":"The neuromuscular response to prolonged lumbar flexion has recently been extensively studied in felines but has not been examined in humans. Animal studies suggest that prolonged lumbar flexion disturbs neuromuscular control of paraspinal muscles. This disturbance was linked to creep deformation of passive spinal tissues. Past research indicates that disturbance of paraspinal reflexes may limit spinal stability. The current study aimed to examine this behavior in humans. We hypothesized that prolonged lumbar flexion will disturb paraspinal reflex behavior in human subjects. Reflex behavior was quantified following a fifteen minute period of static flexion. There was a trend suggesting an increase in reflex magnitude after flexion (p = 0.055). This trend was only significant in female subjects (p < 0.003). Increased reflex following flexion was associated with a transient period of EMG hyperexcitability similar to felines. A second study was performed to quantify reflex behavior and creep deformation during flexion and recovery. Results indicated that creep occurred during prolonged flexion (p < 0.001). Reflexes were inhibited following flexion (p < 0.03). Both creep deformation and paraspinal reflex (p > 0.05) failed to exhibit significant recovery during the length of the test. Inhibited paraspinal reflexes may contribute to spinal instability and risk of low back pain for workers using flexed postures, due to the inability of the neuromuscular system to coordinate an appropriate muscle response following an unexpected loading event. Future studies must examine appropriate work/rest intervals for workers using flexed postures to limit reflex disturbance from prolonged ligament strain.","abstract_html":"The neuromuscular response to prolonged lumbar flexion has recently been extensively studied in felines but has not been examined in humans. Animal studies suggest that prolonged lumbar flexion disturbs neuromuscular control of paraspinal muscles. This disturbance was linked to creep deformation of passive spinal tissues. Past research indicates that disturbance of paraspinal reflexes may limit spinal stability. The current study aimed to examine this behavior in humans. We hypothesized that prolonged lumbar flexion will disturb paraspinal reflex behavior in human subjects. Reflex behavior was quantified following a fifteen minute period of static flexion. There was a trend suggesting an increase in reflex magnitude after flexion (p = 0.055). This trend was only significant in female subjects (p &lt; 0.003). Increased reflex following flexion was associated with a transient period of EMG hyperexcitability similar to felines. A second study was performed to quantify reflex behavior and creep deformation during flexion and recovery. Results indicated that creep occurred during prolonged flexion (p &lt; 0.001). Reflexes were inhibited following flexion (p &lt; 0.03). Both creep deformation and paraspinal reflex (p &gt; 0.05) failed to exhibit significant recovery during the length of the test. Inhibited paraspinal reflexes may contribute to spinal instability and risk of low back pain for workers using flexed postures, due to the inability of the neuromuscular system to coordinate an appropriate muscle response following an unexpected loading event. Future studies must examine appropriate work/rest intervals for workers using flexed postures to limit reflex disturbance from prolonged ligament strain.","abstract_has_math":false,"creators":["Rogers, Ellen Louise"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Mechanical Engineering","degree_department":"Mechanical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Granata, Kevin P."],"committee_members":["Madigan, Michael L.","Nussbaum, Maury A."],"year":2005,"date_issued":"2005-02-16","date_published":"2005-02-16","updated_at":"2026-07-22T22:20:32Z","subjects":["Reflex","Flexion","Spine","Stability","Low back pain"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-02162005-131821"],"render_values":[{"text":"etd-02162005-131821","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/31247","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Granata, Kevin P."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Madigan, Michael L.","Nussbaum, Maury A."]},{"key":"dc:contributor.department","label":"Department","values":["Mechanical Engineering"]},{"key":"dc:creator","label":"Author","values":["Rogers, Ellen Louise"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:31:49Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:31:49Z","2006-02-21"]},{"key":"dc:date.issued","label":"Date","values":["2005-02-16"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Reflex","Flexion","Spine","Stability","Low back pain"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-02162005-131821"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/31247"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The neuromuscular response to prolonged lumbar flexion has recently been extensively studied in felines but has not been examined in humans. Animal studies suggest that prolonged lumbar flexion disturbs neuromuscular control of paraspinal muscles. This disturbance was linked to creep deformation of passive spinal tissues. Past research indicates that disturbance of paraspinal reflexes may limit spinal stability. The current study aimed to examine this behavior in humans. We hypothesized that prolonged lumbar flexion will disturb paraspinal reflex behavior in human subjects. Reflex behavior was quantified following a fifteen minute period of static flexion. There was a trend suggesting an increase in reflex magnitude after flexion (p = 0.055). This trend was only significant in female subjects (p < 0.003). Increased reflex following flexion was associated with a transient period of EMG hyperexcitability similar to felines. A second study was performed to quantify reflex behavior and creep deformation during flexion and recovery. Results indicated that creep occurred during prolonged flexion (p < 0.001). Reflexes were inhibited following flexion (p < 0.03). Both creep deformation and paraspinal reflex (p > 0.05) failed to exhibit significant recovery during the length of the test. Inhibited paraspinal reflexes may contribute to spinal instability and risk of low back pain for workers using flexed postures, due to the inability of the neuromuscular system to coordinate an appropriate muscle response following an unexpected loading event. Future studies must examine appropriate work/rest intervals for workers using flexed postures to limit reflex disturbance from prolonged ligament strain."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Prolonged Lumbar Flexion Disturbs Paraspinal Reflex Behavior"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Granata, Kevin P."],"dc:contributor.committeemember":["Madigan, Michael L.","Nussbaum, Maury A."],"dc:contributor.department":["Mechanical Engineering"],"dc:creator":["Rogers, Ellen Louise"],"dc:date.accessioned":["2014-03-14T20:31:49Z"],"dc:date.available":["2014-03-14T20:31:49Z","2006-02-21"],"dc:date.issued":["2005-02-16"],"dc:description.abstract":["The neuromuscular response to prolonged lumbar flexion has recently been extensively studied in felines but has not been examined in humans. Animal studies suggest that prolonged lumbar flexion disturbs neuromuscular control of paraspinal muscles. This disturbance was linked to creep deformation of passive spinal tissues. Past research indicates that disturbance of paraspinal reflexes may limit spinal stability. The current study aimed to examine this behavior in humans. We hypothesized that prolonged lumbar flexion will disturb paraspinal reflex behavior in human subjects. Reflex behavior was quantified following a fifteen minute period of static flexion. There was a trend suggesting an increase in reflex magnitude after flexion (p = 0.055). This trend was only significant in female subjects (p < 0.003). Increased reflex following flexion was associated with a transient period of EMG hyperexcitability similar to felines. A second study was performed to quantify reflex behavior and creep deformation during flexion and recovery. Results indicated that creep occurred during prolonged flexion (p < 0.001). Reflexes were inhibited following flexion (p < 0.03). Both creep deformation and paraspinal reflex (p > 0.05) failed to exhibit significant recovery during the length of the test. Inhibited paraspinal reflexes may contribute to spinal instability and risk of low back pain for workers using flexed postures, due to the inability of the neuromuscular system to coordinate an appropriate muscle response following an unexpected loading event. Future studies must examine appropriate work/rest intervals for workers using flexed postures to limit reflex disturbance from prolonged ligament strain."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-02162005-131821"],"dc:identifier.uri":["http://hdl.handle.net/10919/31247"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Reflex","Flexion","Spine","Stability","Low back pain"],"dc:title":["Prolonged Lumbar Flexion Disturbs Paraspinal Reflex Behavior"],"dc:type":["Thesis"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:32Z"}