Electromyographic activity of trunk in subjects with post-stroke hemiparesis in different exercises

Post-stroke subjects often present motor alterations. The most of knowledge about therapeutic approaches are based in lower or upper extremities evaluation, but few studies have investigated the responses of trunk muscles during exercises in patients with hemiparesis. OBJECTIVE: to compare the electric activity of trunk muscle in subjects with hemiparesis with control subjects during different exercises. SETTING: Research Laboratory in Kinesiologic Electromyography, University Hospital. PARTICIPANTS: 12 subjects with hemiparesis after unilateral stroke, with Modified Ashworth Scale between 1 to 4 points and Barthel scoring between 85 to 100 points, mean time after stroke of 11,33 months (standard desviation [sd] = 3,63), mean age of 57,58 years (sd = 8,59) and mean body mass index (BMI) of 24,70 kg/m2 (sd =2,78). Control group was composed by 12 subjects without neurologic or musculoskeletic disfunction paired by gender, age, BMI (mean age of 58,75 [sd = 9,72] and mean BMI of 25,13 kg/m2 [sd = 2,40]). This study was approved by institutional bioethic committee. INTERVENTIONS: Trunk flexion exercises (lower extremities elevation in layed down position, lower trunk rotation in layed down position and pelvic retroversion seated in swiss ball) and extension exercises (upper extremities rising up in seated position, stand up from seated position and pelvic anteversion seated in swiss ball). OUTCOME MENSURES: Electromyographic signal in RMS (Root Mean Square) normalized by maximal voluntary isometric contraction (%MVIC) of rectus abdominis, obliquus externus abdominis and erectus spinae muscles and time of contraction beginning difference (s) between paretic/non paretic side (left/rigt in control). STATISC ANALYSIS: T test was used to compare muscle activation and time of contraction beginning between groups and muscle sides in the same group. To compare different activities, MANOVA was conducted with Tukey post-hoc to identify groups differences. Level of statistical significance was stipulated in 5% (P ≤ 0,05) RESULTS: Rectus abdominis presented higher activation in group with hemiparesis than control group (P = 0,035). During lower extremities elevation paretic obliquus externus showed higher activation than others exercises (P = 0,019). There was none difference in rectus abdominis and erectus spinae muscle activation between exercises. Erectus spinae did not present significance difference between side and group. Comparing the time of contraction beginning comparison there were no difference between groups. CONCLUSION: Subjects with hemiparesis showed muscle electric activity alterations, mainly the rectus abdominis, in comparison with control. Non paretic obliquus externus was used in a compensatory way during lower extremities elevation.