Effect of experimental muscle pain on the acquisition and retention of locomotor adaptation: different motor strategies for a similar performance

Abstract

As individuals with musculoskeletal disorders often experience motor impairments, contemporary rehabilitation relies heavily on the use of motor learning principles. However, motor impairments are often associated with pain. Although there is substantial evidence that muscle pain interferes with motor control, much less is known on its impact on motor learning. The objective of the present study was to assess the effects of muscle pain on locomotor learning. Two groups (Pain and Control) of healthy participants performed a locomotor adaptation task (robotized ankle-foot orthosis perturbing ankle movements during swing) on two consecutive days. On day 1 (acquisition), hypertonic saline was injected in the tibialis anterior (TA) muscle of the Pain group participants, while Control group participants were pain free. All participants were pain free on day 2 (retention). Changes in movement errors caused by the perturbation were assessed as an indicator of motor performance. Detailed analysis of kinematic and electromyographic data provided information about motor strategies. No between-group differences were observed on motor performance measured during the acquisition and retention phases. However, Pain group participants had a residual movement error later in the swing phase and smaller early TA activation than Control group participants, thereby suggesting a reduction in the use of anticipatory motor strategies to overcome the perturbation. Muscle pain did not interfere with global motor performance during locomotor adaptation. The different motor strategies used in the presence of muscle pain may reflect a diminished ability to anticipate the consequences of a perturbation. NEW & NOTEWORTHY This study shows that experimental muscle pain does not influence global motor performance during the acquisition or next-day retention phases of locomotor learning. This contrasts with previous results obtained with cutaneous pain, emphasizing the risk of directly extrapolating from one pain modality to another. Muscle pain affected motor strategies used when performing the task, however: it reduced the ability to use increased feedforward control to overcome the force field.

Motor Strategies Learned during Pain Are Sustained upon Pain-free Reexposure to Task

“…Furthermore, these studies induced topical skin pain, and it is unclear whether similar effects would be observed during musculoskeletal pain, as nociceptive inputs that originate from cutaneous and muscle tissue trigger distinct sensory and motor responses (15). In a previous study, we found that saline-induced muscle pain did not affect locomotor performance during low-intensity ankle perturbations, but caused delayed muscle activation within the step cycle compared to the pain-free Control group (16). Although these activation delays were reduced upon pain-free training of the same task, suggesting a shift towards the strategy used by Controls, it is impossible to rule out the influence of automatic spinal circuits involved in gait.…”

Motor Learning in Response to Different Experimental Pain Models among Healthy Individuals: A Systematic Review

“…No sig effect of cutaneous pain on total motor performance during both acquisition and retention phases Bouffard et al (2018) Healthy (N=47) (pain group N=17, f=7, age: 25 ± 1 yrs); (control group N=30, f=14, age: 25 ± 1 yrs) Hypertonic saline to the tibialis anterior muscle prior to baseline 1 in the first day; the intensity of pain was 5.3 ± 1.2 out of 10-measuring by NPRS Walking task in the presence of a force field adaptation paradigm in two days (acquisition (baseline 1, baseline2, adaptation, and washout) and retention (baseline, adaptation, and wash-out))…”

“…The methodological quality of the included studies was assessed based on the modified version of Downs and Black checklist, which is provided in Table 2. Out of 17 studies, eleven studies (Bilodeau et al, 2016;Boudreau et al, 2010;Bouffard et al, 2014Bouffard et al, , 2016Dancey et al, 2016a;Dancey et al, 2014;Dancey et al, 2016b;Dancey et al, 2018Dancey et al, , 2019Ingham et al, 2011;Salomoni et al, 2019) were evaluated as fair quality and 6 articles as poor quality (Arieh et al, 2021;Boudreau et al, 2007;Bouffard et al, 2018;Gallina et al, 2018;Lamothe et al, 2014;Mavromatis et al, 2017). Inter-rater reliability was 0.72 between the assessors who evaluated the methodological quality of the included articles.…”

“…The titles and abstracts of 3075 studies were screened after removing 425 duplicates. The full text of 26 studies were assessed in agreement with the inclusion and exclusion criteria in which only 16 studies (Arieh et al, 2021;Bilodeau et al, 2016;Boudreau et al, 2010;Boudreau et al, 2007;Bouffard et al, 2014Bouffard et al, , 2016Bouffard et al, 2018;Dancey et al, 2016a;Dancey et al, 2014;Dancey et al, 2016b; All rights reserved. No reuse allowed without permission.…”

“…A total of 484 healthy participants were included across all studies with the ages ranging between 18 and 47 years. Out of the seventeen studies, Arieh and colleagues (Arieh et al, 2021) included only male participants, but both male and female participants were included in the other sixteen studies (Bilodeau et al, 2016;Boudreau et al, 2010;Boudreau et al, 2007;Bouffard et al, , 2016Bouffard et al, 2018;Dancey et al, 2016a;Dancey et al, 2014;Dancey et al, 2016b;Dancey et al, 2018Dancey et al, , 2019Gallina et al, 2018;Ingham et al, 2011;Lamothe et al, 2014;Mavromatis et al, 2017;Salomoni et al, 2019). Extensive information concerning each study is represented in Table 1.…”