Electromyographical characteristics and muscle utilization in hemiplegic patients during sit-to-stand activity: an observational study. 
Sit-to-stand is an important process in daily activity, and stroke patients have difficulty completing this task due to many reasons.  To investigate the characteristic of muscle utilization of lower limb muscles between healthy participants and hemiplegic patients during sit-to-stand activity.  This is an observational study.  Inpatients at a rehabilitation hospital.  Thirty-two stroke patients and 36 healthy participants.  The participants were evaluated on sit-to-stand movement.  Muscle strength was assessed by measuring maximal voluntary contraction (MVC) bilaterally in quadriceps, hamstrings, tibialis anterior and gastrocnemius.  Amplitude (average and maximal) and area under the curve (AUC) of quadriceps, hamstring, tibialis anterior, and gastrocnemius of both sides were recorded during this activity.  The average and maximal amplitudes of paretic muscles were significantly less than non-paretic muscles and healthy controls (P<0.05).  AUC of paretic muscles was significantly less than non-paretic muscles (P<0.05) but not statistically different from healthy controls.  The area under the curve of non-paretic muscles was significantly greater than healthy controls (P<0.05), except for tibialis anterior (P=0.07).  The area under the curve/maximal voluntary contraction ratios of quadriceps and hamstrings in both sides of patients were significantly larger than healthy controls (P<0.05), except for paretic quadriceps (P=0.078).  The muscle utilization ratio (MUR) of the patients was significantly higher than that of the healthy participants.  This study demonstrated electromyographical features of sit-to-stand activity in hemiplegic patients.  During sit-to-stand, stroke patients' muscle utilization of both sides increased and MUR of the paretic side is similar to the non-paretic side.  Muscle utilization ratio might help to understand how patients fulfill the sit-to-stand task.  Using this information might improve our training strategy.  Through customized training, paretic patients could fulfill the task with less muscle utilization.