title: Co-activation of upper limb muscles during reaching in post-stroke subjects: an analysis of the contralesional and ipsilesional limbs.
abstract: The purpose of this study was to analyze the change in antagonist co-activation ratio of upper-limb muscle pairs, during the reaching movement, of both ipsilesional and contralesional limbs of post-stroke subjects. Nine healthy and nine post-stroke subjects were instructed to reach and grasp a target, placed in the sagittal and scapular planes of movement. Surface EMG was recorded from postural control and movement related muscles. Reaching movement was divided in two sub-phases, according to proximal postural control versus movement control demands, during which antagonist co-activation ratios were calculated for the muscle pairs LD/PM, PD/AD, TRIlat/BB and TRIlat/BR. Post-stroke's ipsilesional limb presented lower co-activation in muscles with an important role in postural control (LD/PM), comparing to the healthy subjects during the first sub-phase, when the movement was performed in the sagittal plane (p<0.05). Conversely, the post-stroke's contralesional limb showed in general an increased co-activation ratio in muscles related to movement control, comparing to the healthy subjects. Our findings demonstrate that, in post-stroke subjects, the reaching movement performed with the ipsilesional upper limb seems to show co-activation impairments in muscle pairs associated to postural control, whereas the contralesional upper limb seems to have signs of impairment of muscle pairs related to movement.
authors.affiliation: Centro de Estudos do Movimento e Actividade Humana (CEMAH), ESTSP-IPP, V. N. Gaia, Portugal. Electronic address: ccs@estsp.ipp.pt.
authors.forename: Cláudia C
authors.initials: CC
authors.lastname: Silva
authors.affiliation: Centro de Estudos do Movimento e Actividade Humana (CEMAH), ESTSP-IPP, V. N. Gaia, Portugal.
authors.forename: Augusta
authors.initials: A
authors.lastname: Silva
authors.affiliation: Centro de Estudos do Movimento e Actividade Humana (CEMAH), ESTSP-IPP, V. N. Gaia, Portugal.
authors.forename: Andreia
authors.initials: A
authors.lastname: Sousa
authors.affiliation: Centro de Estudos do Movimento e Actividade Humana (CEMAH), ESTSP-IPP, V. N. Gaia, Portugal.
authors.forename: Ana Rita
authors.initials: AR
authors.lastname: Pinheiro
authors.affiliation: Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Catarina
authors.initials: C
authors.lastname: Bourlinova
authors.affiliation: INESC-TEC and Faculty of Engineering, University of Porto, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Silva
authors.affiliation: INESC-TEC and Faculty of Engineering, University of Porto, Porto, Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Salazar
authors.affiliation: INESC-TEC and Faculty of Engineering, University of Porto, Porto, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Borges
authors.affiliation: Centro de Estudos do Movimento e Actividade Humana (CEMAH), ESTSP-IPP, V. N. Gaia, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Crasto
authors.affiliation: INESC-TEC and Faculty of Engineering, University of Porto, Porto, Portugal.
authors.forename: Miguel Velhote
authors.initials: MV
authors.lastname: Correia
authors.affiliation: CIFI2D, Faculty of Sport, and Porto Biomechanics Laboratory, University of Porto, Porto, Portugal.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Vilas-Boas
authors.affiliation: Centro de Estudos do Movimento e Actividade Humana (CEMAH), ESTSP-IPP, V. N. Gaia, Portugal.
authors.forename: Rubim
authors.initials: R
authors.lastname: Santos
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D016059:Range of Motion, Articular; D012046:Rehabilitation / Q000379:methods; D012782:Shoulder; D020521:Stroke / Q000503:physiopathology*; D000071939:Stroke Rehabilitation; D060726:Torso; D034941:Upper Extremity / Q000503:physiopathology
keywords: Antagonist co-activation ratio; Ipsilesional limb; Reaching; Stroke