Do core stability exercises improve upper limb function in chronic stroke patients?

The present study was held in the outpatient clinic, Faculty of Physical Therapy, Cairo University between May 2017 and March 2018. It is a randomized controlled trial; it was approved by the ethical committee of the faculty of physical therapy, Cairo University, Egypt (Approval Number: P.T.REC/012/001594).

Thirty patients had experienced their first stroke, whether ischemic or hemorrhagic. The stroke diagnosis was based on the World Health Organization guidelines [24] and was confirmed by clinical examination and magnetic resonance imaging. All patients were subjected to a full clinical neurological assessment. Study participants were randomly allocated to either control group (group A) or study group (group B) by means of a random computer-generated list specific to each center. The randomization was managed by an external person uninvolved in the treatment. The method of allocation was concealed in sequentially numbered, sealed envelopes.

All patients followed the conventional therapy program for stroke patients provided for a period, consisting of 30 min of treatment per session, three times per week for 6 weeks (18sessions).

Inclusion criteria: Included in this study are patients with spasticity on the Modified Ashworth Scale (MAS) between grade (+ 1 and 2) [25], the duration of illness was more than 6 months, and age ranged between 45 and 60 years old. The affected upper limb had a moderate motor impairment. The scores of upper limb motor performance ranged from (19–40) according to Fugl-Meyer scale for the section of upper limb and hand [26].

Exclusion criteria included patients with balance disturbance due to neurological disorders other than stroke (example: Parkinson’s disease, inner ear, vestibular, or cerebellar dysfunctions), with musculoskeletal disorders such frozen shoulder or degenerative diseases affecting the posture and motor performance as ankylosing spondylitis, with communication problems, and those with a history of previous stroke or other neurologic diseases or disorders. Patients with pain, limited motion, or weakness in the non-paretic lower extremity that affect performance of daily activities, those with uncontrolled hypertension or symptomatic cardiac failure or unstable angina, and patients with respiratory disorders or conditions that may influence the posture of the skeletal system of the back (example: asthma).

The patients with pain in non-paretic lower limb were excluded from our study because some exercises like bridging and quadruped involve weight bearing on both lower limbs which hampers the performance of the exercises.

The functional ability of the upper limb was assessed by wolf motor function test (WMFT) which is valid and commonly used assessment tool of upper extremity functional ability [27].

For the stroke population, it uses two strength measurements and a series of 15 functional tasks that progress from simple movements in proximal joint areas to complex movements in distal joint areas. Each of the 15 tasks is timed to completion, up to a maximum of 120 s. Functional ability sub-scores represent the quality of the movement during the performance of these functional tasks.

Trunk function was evaluated with the trunk impairment scale (TIS). This consists of a total of 17 items: three regarding static sitting balance, ten regarding dynamic sitting balance, and four about coordination. Patients receive a total between 0 and 23 points [28].

Range of motion of shoulder flexion and abduction was recorded in degrees with the utilization of a standard goniometer. The reliability of a goniometer is shown with an intra-class correlation coefficient (ICC) of 0.95 by Khamwong and colleagues [29].

The patients in group A received stretching exercises for shoulder girdle muscles such as pectoralis major muscle; the patient put both hands behind the head and the therapist was behind him attaching the elbow with pulling the arms backward, maintaining the action for 30 s [30]; strengthening exercises for shoulder muscles including active resisted shoulder abduction—the patient was asked to do active resisted shoulder abduction within the available range of motion and within the limit of pain; active resisted shoulder external rotation—the patient was asked to do active resisted shoulder external rotation within the available range and against resistance keeping the trunk aligned; upper trapezius muscle strengthening—the patient performed the shoulder shrugging within the available range against suitable resistance while keeping the trunk well aligned. Serratus anterior muscle strengthening—the patient was asked to push forward by his upper limb against the applied resistance and was asked to keep proper trunk alignment [31] and trunk control exercises including (active trunk flexion), the patient was sitting, and then was asked to do active trunk lateral flexion while the therapist guides the motion. Active trunk rotation—the patient was asked to do active trunk rotation while keeping the trunk in the extended position [32]. Each exercise was repeated for ten times in two sets, giving rest in between for 10 s after each set. The duration of the session was 30-min duration with rest in between.

The patients in group B received treatment as in group A in addition to core stability exercises aiming for increasing trunk stability and increasing activation of abdominal and back muscle. The duration of the session was 30 min with 10-min rest in between fora period of 6 weeks [33]. The core stabilization exercises consisted of two subparts: First, the bed exercises that consist of bridge exercise—patient lies supine with hips and knees bent 90° with feet flat on floor and palms are down at sides, draw in the abdominal muscles and then slowly raising buttocks off the table by using gluteus and hamstrings [34]; bridge exercise with legs crossed—patient lies supine with one hip and knee bent to 90° with feet flat on floor and another leg rested on the opposite knee and palm-down at sides then draw in abdominal muscles then slowly raising his buttocks off the table by using his gluteus and hamstrings [34]; bridge exercise with one leg—patient lies supine with his knees bent and his feet flat on the floor. The patient lifts pelvis forming a bridge. Then lifting right leg off the floor and extends it [34]. Curl-ups with straight reaching—patient lies supine with his knees bent and his feet flat on the floor. “Crunch” or curl his stomach to lift the shoulders just off the floor [34]. Curl-ups with diagonal reaching—patient lies supine with his knees bent and his feet flat on the floor. The patient crunches or curls the stomach to lift the shoulders off the floor and twist, reaching his right elbow towards his left leg. Then returning to the floor and repeat twisting in the opposite direction lifting his shoulders just off the floor [35]. Quadruped exercise—patient balances on the floor on his hands and knees. The patient’s back should be flat and hips parallel to the floor. Then the patient is asked to do cat and camel motion (spine flexion and extension) [34]. Bird dog exercise—patient balances on the floor on his hands and knees. The patient’s back should be flat and hips parallel to the floor. The patient raises his right arm out in front of him and raises his left leg out behind him, keeping it straight [35]. At each exercise, there is hold for 3–5 s and repetition from 10 to 20 times.

The second subpart is the ball exercises that consisted of bridge exercise—the patient lies supine on the floor with knees straight, feet resting on physio-ball, arms at sides; draw in abdominal muscles; slowly lift the buttocks off floor and segmental rotation—the patient lies supine on the floor with hips and knees bent to 90° over a physio-ball; draw in abdominal muscles; slowly and with control, rotate knees to one side keeping hips in contact with the floor; engage abdominal obliques to pull knees back to center and repeat on the opposite side [34]. At each exercise, there is hold for 3–5 s and repetition from 10 to 20 times.

All measurement outcomes were assessed pre- and post-testing phases of the study; after applying the treatment program for the patients for successive 6 weeks. The posttreatment assessment was done at the end of the last treatment session.

The collected data were coded, tabulated, and statistically analyzed using IBM SPSS Statistics (Statistical Package for Social Sciences) software version 22.0, IBM Corp., Chicago, USA, 2013. Descriptive statistical analysis was performed for all pre- and posttreatment variables and all data are expressed as mean and standard deviation. The box and whiskers plots of the tested variable were done to detect outliers. Normality test of data using Shapiro-Wilk test was used, that reflect the data was normally distributed for all dependent variables. Accordingly, 2 × 2 mixed design MANOVA was used to compare the tested variables of interest at different tested groups and measuring periods. With the initial alpha level set at 0.05. Prior to final analysis, data were screened for normality assumption, homogeneity of variance, and presence of extreme scores. This exploration was done as a pre-requisite for parametric calculations of the analysis of difference. Descriptive analysis using histograms with the normal distribution curve showed that ROM of shoulder abduction and flexion, WFMT (function ability score and time, grip strength), and Trunk impairment (static and dynamic sitting balance score and coordination) score were normally distributed and not violate the parametric assumption for the measured dependent variable.