Background: Low back pain (LBP) affect a majority of the population. Lumbar instability has been identified as a factor in a significant portion of individuals with LBP but movement characteristics of this population has seen limited research regarding functional tasks. Objective: This study examined biodynamic parameters during a step task. Design: Quasi-experimental with 2 factors, group and side (L/R), and 1 repeated measure (stepping). Statistics: Two-way Mixed-Design Repeated Measures ANOVA with Alpha = .05. Movement task: Subjects with LBP and lumbar spine clinical instability classification (N=11) and control subjects (N=11) performed a step down task from a 9.5 inch height on left and right side. Main outcomes: sEMG activation (%MVC), sEMG onset time at first weight acceptance, Ground Reaction Force; rise time GRF(z) and 3D trunk range of motion (ROM) related to three phases of the step: (1) First single leg support, (2) double support and (3) second single leg support. Main results: ROM was reduced in the LBP group in the full step phase in the sagittal plane (p=.003, power= .99), in the final phase in the frontal plane (p=.021, power=.99) and in the transverse plane (p=.018, power=.99) on left steps. GRF(z) was slower in the LBP group at first weight acceptance when leading with the left leg (p=.016, power= .99). EMG onsets: The LBP group had delayed muscle onsets of the right hip abductors (p=.043, power=.99), left abdominals with left stepping (p=.008, power=.91) and right lumbar extensors with right stepping (p=.025, power=.93). The LBP group had delayed onset of right lumbar extensors with right stepping but earlier onset with left stepping (p=.025, power.93). EMG activation levels was higher in the LBP group in both left and right steps of right lumbar extensors (p=.047, power=.93), right hip abductors (p=.017, power= .68) and left hip abductors (p= .035, power= .96). Conclusion: Subjects with LBP demonstrated a high-load movement strategy during this low-load step task with reduced ROM, increased muscle activation, delayed muscle onsets and slow GRF(z) rise time. Left stepping presented more challenge for this group of predominantly right-footed subjects with LBP classified with lumbar instability.
","abstract_html":"<p><strong>Background:</strong> Low back pain (LBP) affect a majority of the population. Lumbar instability has been identified as a factor in a significant portion of individuals with LBP but movement characteristics of this population has seen limited research regarding functional tasks. <strong>Objective</strong>: This study examined biodynamic parameters during a step task. <strong>Design:</strong> Quasi-experimental with 2 factors, group and side (L/R), and 1 repeated measure (stepping). <strong>Statistics:</strong> Two-way Mixed-Design Repeated Measures ANOVA with Alpha = .05. <strong>Movement task:</strong> Subjects with LBP and lumbar spine clinical instability classification (N=11) and control subjects (N=11) performed a step down task from a 9.5 inch height on left and right side. <strong>Main outcomes:</strong> sEMG activation (%MVC), sEMG onset time at first weight acceptance, Ground Reaction Force; rise time GRF(z) and 3D trunk range of motion (ROM) related to three phases of the step: (1) First single leg support, (2) double support and (3) second single leg support. <strong>Main results: ROM</strong> was reduced in the LBP group in the full step phase in the sagittal plane (p=.003, power= .99), in the final phase in the frontal plane (p=.021, power=.99) and in the transverse plane (p=.018, power=.99) on left steps. <strong>GRF(z)</strong> was slower in the LBP group at first weight acceptance when leading with the left leg (p=.016, power= .99). <strong>EMG onsets:</strong> The LBP group had delayed muscle onsets of the right hip abductors (p=.043, power=.99), left abdominals with left stepping (p=.008, power=.91) and right lumbar extensors with right stepping (p=.025, power=.93). The LBP group had delayed onset of right lumbar extensors with right stepping but earlier onset with left stepping (p=.025, power.93). <strong>EMG activation levels </strong>was<strong> </strong>higher in the LBP group in both left and right steps of right lumbar extensors (p=.047, power=.93), right hip abductors (p=.017, power= .68) and left hip abductors (p= .035, power= .96). <strong>Conclusion: </strong>Subjects with LBP demonstrated a high-load movement strategy during this low-load step task with reduced ROM, increased muscle activation, delayed muscle onsets and slow GRF(z) rise time. Left stepping presented more challenge for this group of predominantly right-footed subjects with LBP classified with lumbar instability.</p>","abstract_has_math":false,"creators":["Poulsen, Kim M."],"institution":null,"degree_name":"PhD Health Sciences","degree_level":"Dissertation","degree_discipline":"Health and Medical Sciences","degree_department":null,"school":null,"contributors":["Lee Cabell, Ed.D","Fortunato Battaglia, Ph.D","Raju Parasher, Ed.D"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-05-18T07:00:00Z","date_published":"2015-05-18T07:00:00Z","updated_at":"2026-07-24T04:32:59Z","subjects":["Low","back","pain","instability","classification","step","Medicine and Health Sciences"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarship.shu.edu/dissertations/2056","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Lee Cabell, Ed.D","Fortunato Battaglia, Ph.D","Raju Parasher, Ed.D"]},{"key":"dc:creator","label":"Author","values":["Poulsen, Kim M."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2015-05-14T07:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Health and Medical Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["PhD Health Sciences"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Low","back","pain","instability","classification","step","Medicine and Health Sciences"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarship.shu.edu/dissertations/2056"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Background: Low back pain (LBP) affect a majority of the population. Lumbar instability has been identified as a factor in a significant portion of individuals with LBP but movement characteristics of this population has seen limited research regarding functional tasks. Objective: This study examined biodynamic parameters during a step task. Design: Quasi-experimental with 2 factors, group and side (L/R), and 1 repeated measure (stepping). Statistics: Two-way Mixed-Design Repeated Measures ANOVA with Alpha = .05. Movement task: Subjects with LBP and lumbar spine clinical instability classification (N=11) and control subjects (N=11) performed a step down task from a 9.5 inch height on left and right side. Main outcomes: sEMG activation (%MVC), sEMG onset time at first weight acceptance, Ground Reaction Force; rise time GRF(z) and 3D trunk range of motion (ROM) related to three phases of the step: (1) First single leg support, (2) double support and (3) second single leg support. Main results: ROM was reduced in the LBP group in the full step phase in the sagittal plane (p=.003, power= .99), in the final phase in the frontal plane (p=.021, power=.99) and in the transverse plane (p=.018, power=.99) on left steps. GRF(z) was slower in the LBP group at first weight acceptance when leading with the left leg (p=.016, power= .99). EMG onsets: The LBP group had delayed muscle onsets of the right hip abductors (p=.043, power=.99), left abdominals with left stepping (p=.008, power=.91) and right lumbar extensors with right stepping (p=.025, power=.93). The LBP group had delayed onset of right lumbar extensors with right stepping but earlier onset with left stepping (p=.025, power.93). EMG activation levels was higher in the LBP group in both left and right steps of right lumbar extensors (p=.047, power=.93), right hip abductors (p=.017, power= .68) and left hip abductors (p= .035, power= .96). Conclusion: Subjects with LBP demonstrated a high-load movement strategy during this low-load step task with reduced ROM, increased muscle activation, delayed muscle onsets and slow GRF(z) rise time. Left stepping presented more challenge for this group of predominantly right-footed subjects with LBP classified with lumbar instability.
"]},{"key":"dc:title","label":"Title","values":["Biodynamic Parameters During a Step Down Task in Subjects with Chronic or Recurrent Low Back Pain Classified with Lumbar Instability"]}]}],"canonical_facts":{"dc:contributor":["Lee Cabell, Ed.D","Fortunato Battaglia, Ph.D","Raju Parasher, Ed.D"],"dc:creator":["Poulsen, Kim M."],"dc:date.available":["2015-05-14T07:00:00Z"],"dc:description.abstract":["Background: Low back pain (LBP) affect a majority of the population. Lumbar instability has been identified as a factor in a significant portion of individuals with LBP but movement characteristics of this population has seen limited research regarding functional tasks. Objective: This study examined biodynamic parameters during a step task. Design: Quasi-experimental with 2 factors, group and side (L/R), and 1 repeated measure (stepping). Statistics: Two-way Mixed-Design Repeated Measures ANOVA with Alpha = .05. Movement task: Subjects with LBP and lumbar spine clinical instability classification (N=11) and control subjects (N=11) performed a step down task from a 9.5 inch height on left and right side. Main outcomes: sEMG activation (%MVC), sEMG onset time at first weight acceptance, Ground Reaction Force; rise time GRF(z) and 3D trunk range of motion (ROM) related to three phases of the step: (1) First single leg support, (2) double support and (3) second single leg support. Main results: ROM was reduced in the LBP group in the full step phase in the sagittal plane (p=.003, power= .99), in the final phase in the frontal plane (p=.021, power=.99) and in the transverse plane (p=.018, power=.99) on left steps. GRF(z) was slower in the LBP group at first weight acceptance when leading with the left leg (p=.016, power= .99). EMG onsets: The LBP group had delayed muscle onsets of the right hip abductors (p=.043, power=.99), left abdominals with left stepping (p=.008, power=.91) and right lumbar extensors with right stepping (p=.025, power=.93). The LBP group had delayed onset of right lumbar extensors with right stepping but earlier onset with left stepping (p=.025, power.93). EMG activation levels was higher in the LBP group in both left and right steps of right lumbar extensors (p=.047, power=.93), right hip abductors (p=.017, power= .68) and left hip abductors (p= .035, power= .96). Conclusion: Subjects with LBP demonstrated a high-load movement strategy during this low-load step task with reduced ROM, increased muscle activation, delayed muscle onsets and slow GRF(z) rise time. Left stepping presented more challenge for this group of predominantly right-footed subjects with LBP classified with lumbar instability.
"],"dc:identifier":["https://scholarship.shu.edu/dissertations/2056"],"dc:subject":["Low","back","pain","instability","classification","step","Medicine and Health Sciences"],"dc:title":["Biodynamic Parameters During a Step Down Task in Subjects with Chronic or Recurrent Low Back Pain Classified with Lumbar Instability"],"thesis:degree_discipline":["Health and Medical Sciences"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["PhD Health Sciences"]},"updated_at":"2026-07-24T04:32:59Z"}