@article {26, title = {Body-foot geometries as revealed by perturbed obstacle position with different time constraints.}, journal = {Exp Brain Res}, volume = {236}, year = {2018}, month = {2018 Mar}, pages = {711-720}, abstract = {

This study examined the geometrical relationships between the feet, pelvis and an environmental obstruction when crossing an obstacle with unexpected changes to its position. Nine healthy young adults stepped over an obstacle 19\ cm high with their right leg leading. The obstacle could be static or advanced at either lead (early detection) or trail (late detection) foot contact prior to clearance to force an adaptive reorganization of body-foot geometry and foot proximity to the obstacle. Stride length, minimum foot clearance over the obstacle, and foot-obstacle horizontal proximity before and after clearance were measured along with the relative position of the pelvis to each foot at eight points (four for each foot) during approach and clearance: heel contacts before and after crossing the obstacle, maximum foot heights and foot clearances. With early obstacle movement, trail limb stride length before crossing was lengthened, but foot proximity was still far from the final obstacle position. Clearance was less affected for the trail foot as compared to the lead foot. Proximity of the lead limb following clearance was the same for both early and late perturbations and closer than for the static obstacle condition. For relative body-foot positioning, significant differences were found only in the anterior-posterior direction. Following obstacle displacement, body-foot geometry was initially adapted, but then re-established to static obstacle values with an apparent focus on a balance geometry with the forward placed foot establishing new contact. These findings support an overall balance geometry that can be temporarily adjusted and coordinated with foot proximity to the obstruction to maintain continual gait and safe clearance.

}, issn = {1432-1106}, doi = {10.1007/s00221-017-5161-7}, author = {Dugas, Louis-Philippe and Bouyer, Laurent J and McFadyen, Bradford J} } @article {22, title = {Effect of experimental muscle pain on the acquisition and retention of locomotor adaptation: different motor strategies for a similar performance.}, journal = {J Neurophysiol}, volume = {119}, year = {2018}, month = {2018 May 01}, pages = {1647-1657}, 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.

}, issn = {1522-1598}, doi = {10.1152/jn.00411.2017}, author = {Bouffard, Jason and Salomoni, Sauro E and Mercier, Catherine and Tucker, Kylie and Roy, Jean-S{\'e}bastien and van den Hoorn, Wolbert and Hodges, Paul W and Bouyer, Laurent J} } @article {24, title = {Hip kinematics during functional tasks in females with patellofemoral pain: Modification following rehabilitation and correlation with clinical improvement.}, journal = {Phys Ther Sport}, volume = {32}, year = {2018}, month = {2018 Mar 23}, pages = {7-14}, abstract = {

OBJECTIVES: To compare hip kinematics during two functional tasks in females with and without patellofemoral pain (PFP), and to determine if hip kinematics and, symptoms and functional limitations were improved after a rehabilitation program.

DESIGN: Cross sectional and longitudinal.

PARTICIPANTS: Sixteen females with and 15 without PFP.

SETTING: Laboratory and physical therapy clinic.

MAIN OUTCOME MEASURES: Hip adduction (HADD) and medial rotation (HMR) peak angles, time integrals and inter-movement variability during step-down and vertical drop jump, symptoms and functional limitations evaluated using the Activities of Daily Living Scale of the Knee Outcome Survey (KOS-ADLS).

RESULTS: At baseline, no significant differences were found in step-down and vertical drop jump between PFP and controls. Following rehabilitation, significant improvements were reported in KOS-ADLS (p < 0.001). There was a significant decrease in HADD and HMR variability (p < 0.05), a trend for decreased peak HMR (p = 0.06) during step-down, and a significant decrease in HADD variability (p < 0.05) during vertical drop jump. These kinematic changes did not correlate with changes in KOS-ADLS (all p > 0.05).

CONCLUSION: Females with and without PFP demonstrated no hip kinematic differences during functional tasks. A rehabilitation program improved symptoms and functional status, and modified hip kinematics in females with PFP; however these changes were not correlated.

}, issn = {1873-1600}, doi = {10.1016/j.ptsp.2018.03.001}, author = {Pairot de Fontenay, Benoit and Esculier, Jean-Fran{\c c}ois and Bouyer, Laurent and Roy, Jean-S{\'e}bastien} } @article {23, title = {Lower extremity outcome measures: considerations for clinical trials in spinal cord injury.}, journal = {Spinal Cord}, year = {2018}, month = {2018 Apr 27}, abstract = {

STUDY DESIGN: This is a focused review article.

OBJECTIVES: To identify important concepts in lower extremity (LE) assessment with a focus on locomotor outcomes and provide guidance on how existing outcome measurement tools may be best used to assess experimental therapies in spinal cord injury (SCI). The emphasis lies on LE outcomes in individuals with complete and incomplete SCI in Phase II-III trials.

METHODS: This review includes a summary of topics discussed during a workshop focusing on LE function in SCI, conceptual discussion of corresponding outcome measures and additional focused literature review.

RESULTS: There are a number of sensitive, accurate, and responsive outcome tools measuring both quantitative and qualitative aspects of LE function. However, in trials with individuals with very acute injuries, a baseline assessment of the primary (or secondary) LE outcome measure is often not feasible.

CONCLUSION: There is no single outcome measure to assess all individuals with SCI that can be used to monitor changes in LE function regardless of severity and level of injury. Surrogate markers have to be used to assess LE function in individuals with severe SCI. However, it is generally agreed that a direct measurement of the performance for an appropriate functional activity supersedes any surrogate marker. LE assessments have to be refined so they can be used across all time points after SCI, regardless of the level or severity of spinal injury.

SPONSORS: Craig H. Neilsen Foundation, Spinal Cord Outcomes Partnership Endeavor.

}, issn = {1476-5624}, doi = {10.1038/s41393-018-0097-8}, author = {Bolliger, Marc and Blight, Andrew R and Field-Fote, Edelle C and Musselman, Kristin and Rossignol, Serge and Barth{\'e}lemy, Dorothy and Bouyer, Laurent and Popovic, Milos R and Schwab, Jan M and Boninger, Michael L and Tansey, Keith E and Scivoletto, Giorgio and Kleitman, Naomi and Jones, Linda A T and Gagnon, Dany H and Nadeau, Sylvie and Haupt, Dirk and Awai, Lea and Easthope, Chris S and Z{\"o}rner, Bj{\"o}rn and Rupp, Ruediger and Lammertse, Dan and Curt, Armin and Steeves, John} } @article {25, title = {Predictors of clinical success in runners with patellofemoral pain: Secondary analyses of a randomized clinical trial.}, journal = {J Sci Med Sport}, year = {2018}, month = {2018 Jan 27}, abstract = {

OBJECTIVES: To identify predictors of outcome to a rehabilitation program focused on education and management of training loads in runners with patellofemoral pain (PFP).

DESIGN: Secondary analyses of a randomized clinical trial.

METHODS: Fifty-eight runners with PFP (62\% female, aged 31.2{\textpm}6.6years, running 20.3{\textpm}5.6km/week) were included in analyses. Following baseline collection of demographics, anthropometry, symptomatology, isometric strength, running mechanics and radiological data, runners were randomized to one of the three 8-week intervention program: (1) Education on symptoms management and training modifications; (2) Education+Exercise program; (3) Education+Gait retraining. Clinical success was defined as an increase >=13.6\% on the Knee Outcome Survey - Activities of Daily Living Scale (KOS-ADLS) at 3 months following program completion. Potential predictors were entered into logistic regression analyses.

RESULTS: Forty-five runners (78\%) were categorized as Success. Together, KOS-ADLS score (<70\%), knee extension isometric strength (<70\% bodyweight), presence of patellar tendinopathy (Grade >0) and level of usual pain (>2/10) at baseline predicted treatment outcome with 87.9\% accuracy. The model provided sensitivity of 0.93 (95\% C.I. 0.82-0.98), specificity of 0.69 (95\% C.I. 0.42-0.87), positive likelihood ratio of 3.0 (95\% C.I. 1.3-6.9), and negative likelihood ratio of 0.1 (95\% C.I. 0-0.3). The best individual predictors were KOS-ADLS score and knee extension strength.

CONCLUSIONS: The combination of KOS-ADLS, knee extensors strength, patellar tendon integrity and usual pain best predicted clinical outcome of runners with PFP following an intervention that had a common education component. Further testing is needed before a clinical prediction rule can be recommended to clinicians.

}, issn = {1878-1861}, doi = {10.1016/j.jsams.2018.01.006}, author = {Esculier, Jean-Fran{\c c}ois and Bouyer, Laurent J and Dubois, Blaise and Leblond, Jean and Brisson, M{\'e}lanie and Chau, Luc and Roy, Jean-S{\'e}bastien} }