Trunk muscle activation during movement with a new exercise device for lumbo-pelvic reconditioning.

Tobias Weber,Paul W Hodges,Sauro E Salomoni,Nick Caplan,Volker Damann,Enrico De Martino,Jonathan Scott,Edith L Elgueta Cancino,Dorothée Debuse

doi:10.14814/phy2.13188

Abstract

Gravitational unloading leads to adaptations of the human body, including the spine and its adjacent structures, making it more vulnerable to injury and pain. The Functional Re‐adaptive Exercise Device (FRED) has been developed to activate the deep spinal muscles, lumbar multifidus (LM) and transversus abdominis (TrA), that provide inter‐segmental control and spinal protection. The FRED provides an unstable base of support and combines weight bearing in up‐right posture with side alternating, elliptical leg movements, without any resistance to movement. The present study investigated the activation of LM, TrA, obliquus externus (OE), obliquus internus (OI), abdominis, and erector spinae (ES) during FRED exercise using intramuscular fine‐wire and surface EMG. Nine healthy male volunteers (27 ± 5 years) have been recruited for the study. FRED exercise was compared with treadmill walking. It was confirmed that LM and TrA were continually active during FRED exercise. Compared with walking, FRED exercise resulted in similar mean activation of LM and TrA, less activation of OE, OI, ES, and greater variability of lumbo‐pelvic muscle activation patterns between individual FRED/gait cycles. These data suggest that FRED continuously engages LM and TrA, and therefore, has the potential as a stationary exercise device to train these muscles.

Highlights

Absence of effects of gravity in Low Earth Orbit, reduces the magnitude and frequency of mechanical forces acting on the human body, resulting in profound bone loss in the lower limb and atrophy of some muscles (Fitts et al 2001; Chang et al 2016)
The present study investigated the activation of lumbar multifidus (LM), transversus abdominis (TrA), obliquus externus (OE), obliquus internus (OI), abdominis, and erector spinae (ES) during Functional Re-adaptive Exercise Device (FRED) exercise using intramuscular fine-wire and surface EMG
No difference observed in the mean activation between FRED exercise and treadmill walking, consistent with the phasic-to-tonic shift in LM reported by Caplan et al (2015), the pattern of intramuscular LM EMG during FRED exercise was characterized by less fluctuating continuous activation

Summary

Introduction

Absence of effects of gravity in Low Earth Orbit, reduces the magnitude and frequency of mechanical forces acting on the human body, resulting in profound bone loss in the lower limb and atrophy of some (in particular the socalled “anti-gravity”) muscles (Fitts et al 2001; Chang et al 2016). Long-term bed-rest (LTBR) is used as a ground-based analog of microgravity, and has been found to induce similar changes, including: atrophy of deep spinal muscles, IVD swelling, and a reduced lordotic lumbar spine a 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society. Spinal extensor muscle activation becomes more phasic in nature and this persists for at least 6 months following re-ambulation (Belavy et al 2007)

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