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Presentation 1738 − Topic 36. Orthotics and prosthetics
LONG-TERM EFFECTS OF SPECIAL FOOTORTHOSES (FO) FOR PATIENTS WITH LOW BACK PAIN (LBP) Thomas Stief (1), Heiko Wagner (2), Klaus Peikenkamp (1) 1. Biomechanics Research Laboratory, University of Applied Sciences Muenster, Germany 2. Department of Motion Science, WWU Muenster, Germany
Introduction New FO-concepts use Neuromuscular Operating Elements (NME), which were developed by Bourdiol. By influencing the plantar foot sensibility, reflexes should activate so called muscle chain reactions for treating LBP. But NME are still controversially discussed due to the missing scientific background. Classical FO, like Custom Moulded FO (CMFO), focus on orthopaedic problems of the lower limb [Collins et al]. Several scientific studies validated the effects of these FO [Murley et al]. But there is less proof of long-term effects of FO [Mills et al]. So the aims of this study were to analyse both, the long-term effects of CMFO with NME on muscle activation and to check subjective benefits for patients with LBP.
Pain sensation decreases from 3.5 to 1.9 (p=.001). Pearson coefficient (Figure 1) shows a medium, negative correlation (r=-0.611, p=.03) between increased muscle activation of ML and decreased pain sensation.
Methods 12 individuals (6 m, 6 f; 36.7±3.1yr) with LBP participated in this longitudinal trial. The used CMFO were OPCT Tonic01 and the NME PostEva SH 50 (both SIDAS). Activations of 24 muscles at the lower limb and trunk were recorded with SEMG (Biovision; 2 kHz) at the delivery date of the FO and after 8 weeks. Subjects walked on a treadmill at their favored speed. 40 continuing double steps were separated, time-normalized to 100 %gait cycle and compacted to 101 data points. Paired t-Test was used to compare EMG-data at each percentage of the gait cycle. Significant changes (p<.05) are considered as relevant, if they were within the period of activation and last for a continuous timeframe >10 %gait cycle. Pain sensation was detected by visual analog scales and analyzed by paired t-Test (p<.05). Pearson coefficient (p<.05) was used to check correlations between changes in EMG and pain sensation.
Results After 8 weeks of intervention the pelvic muscles of the Extension Chain (EC) are relevantly influenced as follows. The activation of the m. glutaeus max. (GMA) increases in the range of 29-43 %gait cycle by 11 %. Between 6 to 18 %gait cycle m. glutaeus med. (GME) decreases by 41 % and m. multifidii lumb. (ML) increases by 52 % during 54-71 %gait cycle. Journal of Biomechanics 45(S1)
Figure 1: AP view on a CMFO with NME (left), correlation between changes in m. multifidii activation and changes in pain sensation (right)
Discussion Based on the contrary effects at the EC (increases at GMA and ML vs. decrease at GME), our results confirm that the theory of the chain reactions is inadequate to explain the long-term effects of the CMFO with NME. However, there are influences on muscle activation due to the used FO. At the GMA and ML we observe an increase of activation after an 8 week intervention period. That can be interpreted as a mechanism for better stabilization in the lumbar region [McGill et al]. Furthermore pain sensation can be reduced significantly and that correlates with the increased ML activation. So we can deduce that the CMFO with NME have positive long-term effects for patients with LBP.
References 1. Collins et al, Foot Ankle Int, 28: 396-410, 2007. 2. McGill et al, Journal of Electromyography and Kinesiology, 13: 353–359, 2003. 3. Mills et al, Br J Sports Med. 44: 1035-1046, 2010. 4. Murley et al, Clin. Biomech, 25: 728–736, 2010.
ESB2012: 18th Congress of the European Society of Biomechanics