Decreased task duration and unchanged trunk muscle activity in low-back pain patients during stair climbing after back extensor muscle fatigue

Introduction Low-back pain (LBP) • Major problem in Western world • Spine control and stability mechanisms are important but complex related to individuals and motor tasks Research gap • Lack of transfer from experimental results to function • Sparse knowledge of interaction between task- related parameters and changes in the neuromusculoskeletal system • Aim • Explore trunk muscle activity and motor task timing in healthy and recurrent LBP patients during stair ascend and descend pre and post lumbar muscle fatiguing • Hypotheses Stair ascend and descend after fatigue results in: • trunk muscle activity in LBP patients and healthy • task duration in LBP patients Methods - procedure • 7 healthy / 5 recurrent mild-to-moderate LBP patients • Questionnaires: Personal and functional status + Oswestry disability index (ODI) • Pain Pressure Threshold (PPT): Lumbar para- vertebral muscles bilateral level L1, L3 and L5 • S-EMG: 3 abdominal / 3 lumbar / 2 gluteal muscles • Video / wireless EMG muscle data recording • 10 concurrent stair ascent / descent steps pre / post lumbar extensor muscle exercises to exhaustion Methods - analysis • Motor task divided in ascend/descend and 6 sub-phases • OWI: comparison by Student’s t-test • Averaged PPT: comparison by ANOVA • Muscle activity: Difference in area under EMG curve (i-EMG) pre / post fatigue in individual muscles in the 6 phases compared between healthy and patients by ANOVA Results • Duration of gait tasks were shorter in LBP patients generally (Fig. 2A), longer during load and shorter during transfer in descend stepping after back extensor fatigue (Fig. 2B) • OWI: higher in LBP patients (P<0.01) • PPT: no difference between healthy and patients Results – continued • Back extensor fatigue resulted in higher back and abdominal muscle activity in healthy than in patients in most phases, but during descend transfer patients activity decreased (P<0.001) Conclusion and discussion What´s new? • First data on complex impact of muscle fatigue on muscular control of the back during stair stepping Conclusion • LBP patients Back extensor fatigue resulted in decrea-sed muscular activity in the trunk muscles during stair stepping compared to healthy. Decreased duration of the motor tasks generally could indicate decreased functional stability and during descend transfer with high stability demands, LBP patients could be at higher risk of load to the lumbar structures. Implications • Affected control of the spine in high stability demands could be important in evaluation of recurrent LBP • More research is needed to explore the mechanisms and the potential role in LBP development • Acknowledgement • The study was supported by UCN Denmark, Aalborg, Department of Physiotherapy. s
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Peer reviewNej
BegivenhedWorld Congress IASP - Rural Conference center, Buenos Aires, Argentina
Varighed: 5 okt. 201412 okt. 2014


KonferenceWorld Congress IASP
ByBuenos Aires


  • Aalborg Universitet
  • Arkadens Fysioterapi v. Michael Harbo
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