The objective of the current study is to investigate how passive exoskeletons affect low-back passive tissues creep during prolonged stooping.
Background
Using exoskeletons could be a new strategy to prevent stress-relaxation deformation (creep) in low-back passive tissues induced by prolonged or repetitive stooping, but previous studies only focused on low-back active tissues.
Method
Twelve healthy males completed 12 min of stooping (with and without a passive exoskeleton), while body kinematics and muscle activities were captured before and after stooping.
Results
Results indicate intact characteristics (i.e., no changes) in both active and passive tissues after enduring a 12-min stooping protocol while using the exoskeleton. However, without the exoskeleton, clear stress-relaxation deformation in low-back tissues, and changes in the load transfer mechanism between active and passive tissues after prolonged stooping, are observed, revealing a 3.19° delayed flexion-relaxation angle, a 5% maximum voluntary contraction increase in lumbar muscle activity, and a 2.8° increase in the maximum lumbar flexion angle.
Conclusion
The supporting force provided by passive exoskeletons effectively limits stress-relaxation deformation in low-back passive tissues, such as ligaments, by preventing excessive elongation during prolonged stooping in a fully flexed posture, thereby reducing the possible risk of spinal instability and low back pain development.
Application
The study reveals the greater value of passive exoskeletons, which protect passive tissues in the low back. The research findings can serve as a valuable reference for practitioners in implementing effective countermeasures in the perspective of assistance devices to enhance occupational safety.
AbboudJ.NougarouF.DescarreauxM. (2016). Muscle activity adaptations to spinal tissue creep in the presence of muscle fatigue. PLoS One, 11(2), Article e0149076. https://doi.org/10.1371/journal.pone.0149076
2.
AlemiM. M.GeissingerJ.SimonA. A.ChangS. E.AsbeckA. T. (2019). A passive exoskeleton reduces peak and mean EMG during symmetric and asymmetric lifting. Journal of Electromyography and Kinesiology, 47(1), 25–34. https://doi.org/10.1016/j.jelekin.2019.05.003
3.
AlstonW.CarlsonK. E.FeldmanD. J.GrimmZ.GerontinosE. (1966). A quantitative study of muscle factors in the chronic low back syndrome. Journal of the American Geriatrics Society, 14(10), 1041–1047. https://doi.org/10.1111/j.1532-5415.1966.tb02885.x
4.
BarashH. L.GalanteJ. O.LambertC. N.RayR. D. (1970). Spondylolisthesis and tight hamstrings. The Journal of Bone and Joint Surgery, 52(7), 1319–1328.
5.
BohannonR.GajdosikR.LeVeauB. F. (1985). Contribution of pelvic and lower limb motion to increases in the angle of passive straight leg raising. Physical Therapy, 65(4), 474–476. https://doi.org/10.1093/ptj/65.4.474
6.
BoschT.van EckJ.KnitelK.de LoozeM. (2016). The effects of a passive exoskeleton on muscle activity, discomfort and endurance time in forward bending work. Applied Ergonomics, 54(1), 212–217. https://doi.org/10.1016/j.apergo.2015.12.003
7.
ChenY. L.LinW. C.LiaoY. H.LinC. J. (2018). Effect of individual flexibility and knee posture on the lumbar curvature and back muscle flexion-relaxation phenomenon. International Journal of Industrial Ergonomics, 68(1), 82–88. https://doi.org/10.1016/j.ergon.2018.06.009
8.
CohenJ. (1988). Statistical power analysis for the behavioral sciences. Routledge.
9.
ContrerasB.VigotskyA. D.SchoenfeldB. J.BeardsleyC.CroninJ. (2015). A comparison of two gluteus maximus EMG maximum voluntary isometric contraction positions. PeerJ, 3(1), Article e1261. https://doi.org/10.7717/peerj.1261
10.
De LoozeM. P.BoschT.KrauseF.StadlerK. S.O’sullivanL. W. (2016). Exoskeletons for industrial application and their potential effects on physical work load. Ergonomics, 59(5), 671–681. https://doi.org/10.1080/00140139.2015.1081988
11.
De LucaC. J.GilmoreL. D.KuznetsovM.RoyS. H. (2010). Filtering the surface EMG signal: Movement artifact and baseline noise contamination. Journal of Biomechanics, 43(8), 1573–1579. https://doi.org/10.1016/j.jbiomech.2010.01.027
12.
FickR. A. (1911). Handbuch Der Anatomie Und Mechanik Der Gelenke: T. Spezielle Gelenk-Und Muskelmechanik (Vol. 2). G. Fischer.
FloydW. F.SilverP. H. S. (1955). The function of the erectores spinae muscles in certain movements and postures in man. The Journal of physiology, 129(1), 184–203. https://doi.org/10.1113/jphysiol.1955.sp005347
15.
GajdosikR. L.AlbertC. R.MitmanJ. J. (1994). Influence of hamstring length on the standing position and flexion range of motion of the pelvic angle, lumbar angle, and thoracic angle. Journal of Orthopaedic & Sports Physical Therapy,20(4), 213–219. https://doi.org/10.2519/jospt.1994.20.4.213
16.
GajdosikR. L.HatcherC. K.WhitsellS. (1992). Influence of short hamstring muscles on the pelvis and lumbar spine in standing and during the toe-touch test. Clinical Biomechanics, 7(1), 38–42. https://doi.org/10.1016/0268-0033(92)90006-P
17.
GombattoS. P.NortonB. J.SahrmannS. A.StrubeM. J.Van DillenL. R. (2013). Factors contributing to lumbar region passive tissue characteristics in people with and people without low back pain. Clinical Biomechanics, 28(3), 255–261. https://doi.org/10.1016/j.clinbiomech.2013.01.005
18.
GracovetskyS. (1988). The spinal engine. Springer-Verlag.
19.
GrahamR. B.AgnewM. J.StevensonJ. M. (2009). Effectiveness of an on-body lifting aid at reducing low back physical demands during an automotive assembly task: Assessment of EMG response and user acceptability. Applied Ergonomics, 40(5), 936–942. https://doi.org/10.1016/j.apergo.2009.01.006
IlahiS.MasiA. T.WhiteA.DevosA.HendersonJ.NairK. (2020). Quantified biomechanical properties of lower lumbar myofascia in younger adults with chronic idiopathic low back pain and matched healthy controls. Clinical Biomechanics, 73(1), 78–85. https://doi.org/10.1016/j.clinbiomech.2019.12.026
22.
JinS. (2018). Biomechanical characteristics in the recovery phase after low back fatigue in passive and active tissues. International Journal of Industrial Ergonomics, 64(1), 163–169. https://doi.org/10.1016/j.ergon.2018.01.014
23.
JinS.MirkaG. A. (2015). A systems-level perspective of the biomechanics of the trunk flexion-extension movement: Part I–Normal low back condition. International Journal of Industrial Ergonomics, 46(1), 7–11. https://doi.org/10.1016/j.ergon.2015.01.008
24.
JinS.NingX.MirkaG. A. (2012). An algorithm for defining the onset and cessation of the flexion-relaxation phenomenon in the low back musculature. Journal of Electromyography and Kinesiology, 22(3), 376–382. https://doi.org/10.1016/j.jelekin.2012.01.003
25.
KoopmanA. S.KingmaI.FaberG. S.de LoozeM. P.van DieënJ. H. (2019). Effects of a passive exoskeleton on the mechanical loading of the low back in static holding tasks. Journal of Biomechanics, 83(1), 97–103. https://doi.org/10.1016/j.jbiomech.2018.11.033
26.
LotzC. A.AgnewM. J.GodwinA. A.StevensonJ. M. (2009). The effect of an on-body personal lift assist device (PLAD) on fatigue during a repetitive lifting task. Journal of Electromyography and Kinesiology, 19(2), 331–340. https://doi.org/10.1016/j.jelekin.2007.08.006
27.
MadineiS.AlemiM. M.KimS.SrinivasanD.NussbaumM. A. (2020). Biomechanical evaluation of passive back-support exoskeletons in a precision manual assembly task: “expected” effects on trunk muscle activity, perceived exertion, and task performance. Human Factors, 62(3), 441–457. https://doi.org/10.1177/0018720819890966
NingX. (2017). An EMG-Assisted modeling approach to assess passive lumbar tissue loading in vivo during trunk bending. Journal of Electromyography and Kinesiology, 36(1), 1–7. https://doi.org/10.1016/j.jelekin.2017.06.004
30.
NingX.HaddadO.JinS.MirkaG. A. (2011). Influence of asymmetry on the flexion relaxation response of the low back musculature. Clinical Biomechanics, 26(1), 35–39. https://doi.org/10.1016/j.clinbiomech.2010.08.012
31.
NingX.JinS.MirkaG. A. (2012). Describing the active region boundary of EMG-assisted biomechanical models of the low back. Clinical Biomechanics, 27(5), 422–427. https://doi.org/10.1016/j.clinbiomech.2011.11.003
ShinG.MirkaG. A. (2007). An in vivo assessment of the low back response to prolonged flexion: Interplay between active and passive tissues. Clinical Biomechanics, 22(9), 965–971. https://doi.org/10.1016/j.clinbiomech.2007.06.003
37.
ShinG.ShuY.LiZ.JiangZ.MirkaG. (2004). Influence of knee angle and individual flexibility on the flexion–relaxation response of the low back musculature. Journal of Electromyography and Kinesiology, 14(4), 485–494. https://doi.org/10.1016/j.jelekin.2003.12.001
38.
ShojaeiI.Allen-BryantK.BazrgariB. (2016). Viscoelastic response of the human lower back to passive flexion: The effects of age. Annals of Biomedical Engineering, 44(9), 2817–2826. https://doi.org/10.1007/s10439-016-1569-7
39.
SnijdersC. J.VleemingA.StoeckartR. (1993). Transfer of lumbosacral load to iliac bones and legs: Part 1: Biomechanics of self-bracing of the sacroiliac joints and its significance for treatment and exercise. Clinical Biomechanics, 8(6), 285–294. https://doi.org/10.1016/0268-0033(93)90002-Y
40.
SolomonowM. (2004). Ligaments: A source of work-related musculoskeletal disorders. Journal of Electromyography and Kinesiology, 14(1), 49–60. https://doi.org/10.1016/j.jelekin.2003.09.011
41.
SolomonowM. (2009). Ligaments: A source of musculoskeletal disorders. Journal of Bodywork and Movement Therapies, 13(2), 136–154. https://doi.org/10.1016/j.jbmt.2008.02.001
42.
SolomonowM.BarattaR. V.ZhouB. H.BurgerE.ZieskeA.GedaliaA. (2003). Muscular dysfunction elicited by creep of lumbar viscoelastic tissue. Journal of Electromyography and Kinesiology, 13(4), 381–396. https://doi.org/10.1016/S1050-6411(03)00045-2
43.
UlreyB. L.FathallahF. A. (2013). Effect of a personal weight transfer device on muscle activities and joint flexions in the stooped posture. Journal of Electromyography and Kinesiology, 23(1), 195–205. https://doi.org/10.1016/j.jelekin.2012.08.014
44.
VleemingA.Pool-GoudzwaardA. L.StoeckartR.van WingerdenJ. P.SnijdersC. J. (1995). The posterior layer of the thoracolumbar fascia. Spine, 20(7), 753–758.
45.
WilkenJ. M.RodriguezK. M.BrawnerM.DarterB. J. (2012). Reliability and minimal detectible change values for gait kinematics and kinetics in healthy adults. Gait & Posture, 35(2), 301–307. https://doi.org/10.1016/j.gaitpost.2011.09.105
