Altered trunk muscle recruitment patterns
during lifting in individuals in remission from recurrent low back pain
Suehiro T, Ishida H, Kobara
K, Osaka H, Watanabe S. J Electromyogr
2018 ahead of print. 
Take Home Message: People
with remission of recurrent low back pain had delayed onset of the lumbar
multifidus, internal oblique and transverse abdominis muscles during a lifting
task compared with their healthy counterparts.

Low back pain (LBP) is a
debilitating condition and many patients recover but end up caught in a cycle
of symptom resolution followed by symptom recurrence. Adults with LBP have
altered trunk muscle recruitment patterns. However, it is unknown if these
altered patterns persist when people become asymptomatic. If so, they
potentially explain why these people are at risk for the recurrence of LBP. The
authors of this study compared trunk muscle onset time and muscle activation of
trunk muscles during a lifting task between individuals in remission from LBP
and asymptomatic individuals. Twenty-five participants with remission of recurrent
LBP and 20 healthy controls lifted a 5kg box while the authors assessed the
onset and amount of muscle activation in the transverse abdominis, internal and
external oblique, lumbar multifidus, erector spinae and anterior deltoid
muscles. The authors calculated relative onset by subtracting the trunk muscle
onset time from the anterior deltoid onset time (milliseconds). Individuals
with LBP remission had delayed onset of the transverse abdominis, internal
obliques and multifidus compared with the control group. Furthermore, people
with LBP remission had greater abdominal and back muscle activation,
specifically the erector spinae compared with the control group.

The results of this study
show that individuals who are asymptomatic with recurrent LBP have altered
trunk muscle recruitment patterns during a lifting task compared with healthy
controls. While these individuals were in a period of symptom resolution, the
fear of experiencing pain during this task, along with altered proprioception
may explain the changes in recruitment patterns. Similarly, the increase in erector
spinae activation could compensate for the transverse abdominis, internal obliques,
and multifidus failing to activate in a timely manner to stabilize the trunk
during movement. It would be interesting to see if clinical trials support
targeting these altered recruitment patterns among patients at risk for
recurrent LBP. In the meantime, these findings provide support for continuing
lumbopelvic-hip exercises even after symptom resolution in individuals
suffering from LBP.
Questions for Discussion: How
often do you continue your rehabilitation exercises after patients present with
a resolution of symptoms? Do you incorporate lifting tasks, or similar tasks
mimicking activities of daily living into your rehabilitation? Similarly, with
these exercises and tasks, do you encourage your patients to pre-emptively
engage the transverse abdominis and other trunk musculature prior to initiating
Written by: Kyle Morris
Reviewed by: Jeffrey Driban
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