After 8 wk of high IMT, individuals with LBP showed an increased reliance on back proprioceptive signals during postural control and improved inspiratory muscle strength and severity of LBP, not seen after low IMT. Hence, IMT may facilitate the proprioceptive involvement of the trunk in postural control in individuals with LBP and thus might be a useful rehabilitation tool for these patients.

IntroductionBalance deficits are identified as important risk factors for falling in individuals with chronic obstructive pulmonary disease (COPD). However, the specific use of proprioception, which is of primary importance during balance control, has not been studied in individuals with COPD. The objective was to determine the specific proprioceptive control strategy during postural balance in individuals with COPD and healthy controls, and to assess whether this was related to inspiratory muscle weakness.MethodsCenter of pressure displacement was determined in 20 individuals with COPD and 20 age/gender-matched controls during upright stance on an unstable support surface without vision. Ankle and back muscle vibration were applied to evaluate the relative contribution of different proprioceptive signals used in postural control.ResultsIndividuals with COPD showed an increased anterior-posterior body sway during upright stance (p = 0.037). Compared to controls, individuals with COPD showed an increased posterior body sway during ankle muscle vibration (p = 0.047), decreased anterior body sway during back muscle vibration (p = 0.025), and increased posterior body sway during simultaneous ankle-muscle vibration (p = 0.002). Individuals with COPD with the weakest inspiratory muscles showed the greatest reliance on ankle muscle input when compared to the stronger individuals with COPD (p = 0.037).ConclusionsIndividuals with COPD, especially those with inspiratory muscle weakness, increased their reliance on ankle muscle proprioceptive signals and decreased their reliance on back muscle proprioceptive signals during balance control, resulting in a decreased postural stability compared to healthy controls. These proprioceptive changes may be due to an impaired postural contribution of the inspiratory muscles to trunk stability. Further research is required to determine whether interventions such as proprioceptive training and inspiratory muscle training improve postural balance and reduce the fall risk in individuals with COPD.

Back muscle fatigue decreases the postural stability during quiet standing, but it is not known whether this fatigue-induced postural instability is due to an altered proprioceptive postural control strategy. Therefore, the aim of the study was to evaluate if acute back muscle fatigue may be a mechanism to induce or sustain a suboptimal proprioceptive postural control strategy in people with and without recurrent low back pain (LBP). Postural sway was evaluated on a force platform in 16 healthy subjects and 16 individuals with recurrent LBP during a control (Condition 1) and a back muscle fatigue condition (Condition 2). Back muscle fatigue was induced by performing a modified Biering-Sørensen test. Ankle and back muscle vibration, a potent stimulus for muscle spindles, was used to differentiate proprioceptive postural control strategies during standing on a stable and unstable support surface, where the latter was achieved by placing a foam pad under the feet. Ankle signals were predominantly used for postural control in all subjects although, in each condition, their influence was greater in people with LBP compared to healthy subjects (p \ 0.001). The latter group adapted their postural control strategy when standing on an unstable surface so that input from back muscles increased (p \ 0.001). However, such adaptation was not observed when the back muscles were fatigued. Furthermore, people with LBP continued to rely strongly on ankle proprioception regardless of the testing conditions. In conclusion, these findings suggest that impaired back muscle function, as a result of acute muscle fatigue or pain, may lead to an inability to adapt postural control strategies to the prevailing conditions.

Background: Disturbed body perception may play a role in the aetiology of chronic low back pain (LBP).

Altered proprioceptive postural control has been demonstrated in people with non-specific low back pain (LBP). However, the cause-effect relation remains unclear. Therefore, more prospective studies are necessary. Proprioceptive postural control of 104 subjects was evaluated at baseline using a force plate and with application of vibration stimulation on ankle and back muscles. Spinal postural angles were measured with digital photographs. Psychosocial variables and physical activity were registered using questionnaires. Ninety subjects were followed over two years concerning their LBP status, 14 were lost to follow-up. Four distinct groups were determined after two years based on pain and disability scores: never LBP, no LBP at intake with future mild LBP, mild LBP at intake with no further LBP, LBP at intake with further episodes of mild LBP. Risk factors for developing or sustaining LBP were calculated using logistic regression analysis. A more ankle-steered proprioceptive postural control strategy in upright standing increased the risk for developing or having recurrences of mild LBP within two years (Odds: 3.5; 95% CI: 1.1-10.8; p < 0.05). Increased postural sway, altered spinal postural angles, psychosocial and physical activity outcomes were not identified as risk factors for future mild LBP. These findings could contribute to improving the prevention and rehabilitation of LBP.