Biodynamic Parameters During a Step Down Task in Subjects with Chronic or Recurrent Low Back Pain Classified with Lumbar Instability

<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>

Name thesis:degree_name

PhD Health Sciences

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Health and Medical Sciences

Year dc:date.available

2015

Author dc:creator

• Poulsen, Kim M.

Contributors dc:contributor

• Lee Cabell, Ed.D
• Fortunato Battaglia, Ph.D
• Raju Parasher, Ed.D

• Low
• back
• pain
• instability
• classification
• step
• Medicine and Health Sciences

Repository record dc:identifier

https://scholarship.shu.edu/dissertations/2056

OAI identifier oai:identifier

oai:scholarship.shu.edu:dissertations-3094