Discussion
chronic post-stroke, post-stroke, chronic stroke, stroke, Delayed trunk muscle reaction, impaird muscle activity, Post-stroke, trunk muscle weakness, sub-acute stroke
STROKE
This study aimed to determine whether the hip joint mobilization with movement technique affected the EMG muscle activity, postural control, and functional and dynamic balance among chronic post-stroke patients. The between-group analyses revealed some significant improvements in most of the variables in the experimental group compared to the control group.Hip joint mobilization with movement technique plays important roles in repositioning the joint and normalizing tracking [This study indicated a significant improvement in both timed up and go test and berg balance scale in both groups, which is consistent with previous studies on the effect of mobilization with movement technique on balance [The results of the current study indicated the postural stability variables significantly reduced after treatment in the experimental group, which is in agreement with a previous study in which talocrural mobilization with movement technique combined with conventional physiotherapy modified ankle kinetics and balance in post-stroke patients [Among the multiple hypotheses related to the effectiveness of the mobilization with movement technique, both peripheral (positional fault) and central (neurophysiology) mechanisms have been discussed [In the experimental group, the amplitude of extensor muscles (rectus femoris, tibialis anterior, and erector spine) increased and the onset time decreased on the affected side during static balance test, accompanied by decreased amplitude and onset time of the extensors on the other side. Meanwhile, during the dynamic test, the EMG activity increased and the onset time decreased on both sides. Post-stroke patients rely mostly on the less affected side to compensate both the delayed and weak muscle responses on the affected side [The results indicated equal reliance on both sides during the static balance test due to reduced activation of knee, ankle, and hip muscles. The increased activity on both sides during dynamic balance test may indicate bilateral muscle coordination against larger disturbances. Moreover, hip joint mobilization with movement technique can cause cross-activation on the contralateral untrained side. Also, the greater activity of rectus femoris and tibialis anterior muscles were recorded after hip joint mobilization with movement technique through proximal lower limb selective motor control and the kinematic chain from proximal to distal joints.The impaird muscle activity preparation on the affected side along with the inability to produce the maximum sustained effort are some possible reasons for greater variability in the sequence of muscle activity and postural instability [Delayed trunk muscle reaction, trunk muscle weakness, and impairment of trunk position sense and performance are common in post-stroke patients [This study had some limitations. Firstly, the results may not be generalized to acute or sub-acute stroke patients. In this study, patients had chronic stroke and cannot represent all post-stroke patients. Secondly, the participants in the experimental group might have a better result regardless of the extra time in each treatment session. The comparison between the experimental group and the placebo-control or the sham-control group is needed to elucidate these effects. Finally, this study included a small sample size, and therefore small sample size may make it difficult to generalize the statistical results. Further studies are required to evaluate the efficacy of hip joint mobilization with movement technique combined with conventional physiotherapy at all stages of stroke and compare the proximal and distal joints.