Adrian Pranata1, Luke Perraton2, Doa El-Ansary3, Ross Clark4, Karine Fortin3, Tim Dettmann5, Robert Brandham6, Adam Bryant3. 1. Centre of Health, Exercise and Sports Medicine, The University of Melbourne, Melbourne, Australia. Electronic address: a.pranata@student.unimelb.edu.au. 2. Monash University, Melbourne, Australia. 3. Centre of Health, Exercise and Sports Medicine, The University of Melbourne, Melbourne, Australia. 4. University of the Sunshine Coast, Queensland, Australia. 5. Kieser, Melbourne, Australia. 6. St Kilda Road Sports and Physiotherapy Centre, Melbourne, Australia.
Abstract
BACKGROUND: The ability to control lumbar extensor force output is necessary for daily activities. However, it is unknown whether this ability is impaired in chronic low back pain patients. Similarly, it is unknown whether lumbar extensor force control is related to the disability levels of chronic low back pain patients. METHODS: Thirty-three chronic low back pain and 20 healthy people performed lumbar extension force-matching task where they increased and decreased their force output to match a variable target force within 20%-50% maximal voluntary isometric contraction. Force control was quantified as the root-mean-square-error between participants' force output and target force across the entire, during the increasing and decreasing portions of the force curve. Within- and between-group differences in force-matching error and the relationship between back pain group's force-matching results and their Oswestry Disability Index scores were assessed using ANCOVA and linear regression respectively. FINDINGS: Back pain group demonstrated more overall force-matching error (mean difference=1.60 [0.78, 2.43], P<0.01) and more force-matching error while increasing force output (mean difference=2.19 [1.01, 3.37], P<0.01) than control group. The back pain group demonstrated more force-matching error while increasing than decreasing force output (mean difference=1.74, P<0.001, 95%CI [0.87, 2.61]). A unit increase in force-matching error while decreasing force output is associated with a 47% increase in Oswestry score in back pain group (R2=0.19, P=0.006). INTERPRETATION: Lumbar extensor muscle force control is compromised in chronic low back pain patients. Force-matching error predicts disability, confirming the validity of our force control protocol for chronic low back pain patients.
BACKGROUND: The ability to control lumbar extensor force output is necessary for daily activities. However, it is unknown whether this ability is impaired in chronic low back painpatients. Similarly, it is unknown whether lumbar extensor force control is related to the disability levels of chronic low back painpatients. METHODS: Thirty-three chronic low back pain and 20 healthy people performed lumbar extension force-matching task where they increased and decreased their force output to match a variable target force within 20%-50% maximal voluntary isometric contraction. Force control was quantified as the root-mean-square-error between participants' force output and target force across the entire, during the increasing and decreasing portions of the force curve. Within- and between-group differences in force-matching error and the relationship between back pain group's force-matching results and their Oswestry Disability Index scores were assessed using ANCOVA and linear regression respectively. FINDINGS:Back pain group demonstrated more overall force-matching error (mean difference=1.60 [0.78, 2.43], P<0.01) and more force-matching error while increasing force output (mean difference=2.19 [1.01, 3.37], P<0.01) than control group. The back pain group demonstrated more force-matching error while increasing than decreasing force output (mean difference=1.74, P<0.001, 95%CI [0.87, 2.61]). A unit increase in force-matching error while decreasing force output is associated with a 47% increase in Oswestry score in back pain group (R2=0.19, P=0.006). INTERPRETATION: Lumbar extensor muscle force control is compromised in chronic low back painpatients. Force-matching error predicts disability, confirming the validity of our force control protocol for chronic low back painpatients.
Authors: Joshua Brodie Farragher; Adrian Pranata; Gavin Williams; Doa El-Ansary; Selina M Parry; Jessica Kasza; Adam Bryant Journal: BMJ Open Date: 2019-08-19 Impact factor: 2.692