Movement amplitude on the Functional Re-adaptive Exercise Device: deep spinal muscle activity and movement control

A Winnard,D Debuse,Nick Caplan,M Wilkinson,T Weber,L Samson

doi:10.1007/s00421-017-3648-3

A Winnard, D Debuse + Show 4 more

Open Access

https://doi.org/10.1007/s00421-017-3648-3

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Abstract

PurposeLumbar multifidus (LM) and transversus abdominis (TrA) show altered motor control, and LM is atrophied, in people with low-back pain (LBP). The Functional Re-adaptive Exercise Device (FRED) involves cyclical lower-limb movement against minimal resistance in an upright posture. It has been shown to recruit LM and TrA automatically, and may have potential as an intervention for non-specific LBP. However, no studies have yet investigated the effects of changes in FRED movement amplitude on the activity of these muscles. This study aimed to assess the effects of different FRED movement amplitudes on LM and TrA muscle thickness and movement variability, to inform an evidence-based exercise prescription.MethodsLumbar multifidus and TrA thickness of eight healthy male volunteers were examined using ultrasound imaging during FRED exercise, normalised to rest at four different movement amplitudes. Movement variability was also measured. Magnitude-based inferences were used to compare each amplitude.ResultsExercise at all amplitudes recruited LM and TrA more than rest, with thickness increases of approximately 5 and 1 mm, respectively. Larger amplitudes also caused increased TrA thickness, LM and TrA muscle thickness variability and movement variability. The data suggests that all amplitudes are useful for recruiting LM and TrA.ConclusionsA progressive training protocol should start in the smallest amplitude, increasing the setting once participants can maintain a consistent movement speed, to continue to challenge the motor control system.

Highlights

Somewhat simplified, the maintenance of spinal robustness to ensure static and dynamic stability (Reeves et al 2007) requires the interaction between two key muscle systems: the short deep muscles that act at a segmental level to modulate spinal stiffness (Hodges 1999, 2004; Hodges et al 2005b; Hodges and Richardson 1996) and optimal alignment (Claus et al 2009), and the superficial lumbo-pelvic muscles that generate movement through torque generation, as well as stiffening the spine through co-contraction (Hodges 2004; Hodges et al 2013b)
A progressive training protocol should start in the smallest amplitude, increasing the setting once participants can maintain a consistent movement speed, to continue to challenge the motor control system
Weber et al (2017) recently found that Functional Re-adaptive Exercise Device (FRED) exercise promotes increased tonic activity of lumbar multifidus (LM) and transversus abdominis (TrA), and reduced activity of the more superficial paraspinal muscles (OI, OE, ES) in asymptomatic participants. Whilst these findings suggest that FRED exercise promotes optimal paraspinal motor control, in line with the specific motor control theory (Hides et al 2011; Hodges et al 2006, 2009; Hodges and Moseley 2003; Macdonald et al 2009; Wallwork et al 2009), further research is needed to determine how FRED exercise influences paraspinal motor control in people with low back pain (LBP)

Summary

Introduction

The maintenance of spinal robustness to ensure static and dynamic stability (Reeves et al 2007) requires the interaction between two key muscle systems: the short deep muscles that act at a segmental level to modulate spinal stiffness (Hodges 1999, 2004; Hodges et al 2005b; Hodges and Richardson 1996) and optimal alignment (Claus et al 2009), and the superficial lumbo-pelvic muscles that generate movement through torque generation, as well as stiffening the spine through co-contraction (Hodges 2004; Hodges et al 2013b). There is evidence that LM provides segmental stiffness (Wilke et al 1995; Panjabi 1992a), and increases robustness of the spine when stability is challenged (Kiefer et al 1998), controls the lumbar lordosis (Claus et al 2009), and makes an important contribution to proprioception (Brumagne et al 2000). Transversus abdominis contributes to segmental spinal robustness by increasing intra-abdominal pressure (Hodges et al 2005a). Dysfunction in TrA is associated with dysfunction in LM (Hides et al 2011), and there is a substantial body of evidence that links LBP with LM and TrA dysfunction (Hides et al 2011; Hodges et al 2006, 2009; Hodges and Moseley 2003; Macdonald et al 2009; Wallwork et al 2009)

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