Affiliations: Department of Construction Management and Industrial
Engineering, Louisiana State University, Baton Rouge, LA, USA | Industrial and Management Systems Engineering, West
Virginia University, Morgantown, WV,USA
Note: [] Address for correspondence: Fereydoun Aghazadeh, 3128 Patrick F.
Taylor Hall, Louisiana State University, Baton Rouge, LA 70803-6409, USA. Tel.:
+1 225 578 5367; Fax: +1 225 578 5109; E-mail: aghazadeh@lsu.edu
Abstract: Objective: In this study, the effect of prolonged forward flexion on
the recovery process of the reflexive muscle activity of the lumbar musculature
to its original state is studied using human participants. Methods: The behavior of the lower back erector spinae muscle during
20 minutes of forward bending and three hours of recovery was evaluated
experimentally using electromyography (EMG) and mathematical modeling. Participants: Ten healthy males participated in this study. The EMG
of erector-spinae muscle from two different lumbar levels was recorded and
expressed as normalized integrated EMG (NIEMG). Results: In general, the average NIEMG values of the erector spinae
muscles demonstrated an exponential decrease during the 20-minute loading
period. The biexoponential structure, derived from the animal model, did not
completely explain the muscle behavior during recovery period. Inclusion of the
"intrinsic loading factor" to the biexoponential structure improved the fit of
the recovery model to 100%. Conclusions: Most of the recovery (almost 50%) of the reflexive
activity of erector spinae muscle was observed in the initial 30 minutes; yet
by the end of three hours, complete recovery was not observed.
