A comparative study of the effects of trunk exercise program in aquatic and land-based therapy on gait in hemiplegic stroke patients

Abstract

[Purpose] The purpose of this study was to compare the effects of aquatic and land-based trunk exercise program on gait in stroke patients. [Subjects and Methods] The subjects were 28 hemiplegic stroke patients (20 males, 8 females). The subjects performed a trunk exercise program for a total of four weeks. [Results] Walking speed and cycle, stance phase and stride length of the affected side, and the symmetry index of the stance phase significantly improved after the aquatic and land-based trunk exercise program. [Conclusion] These results suggest that the aquatic and land-based trunk exercise program may help improve gait performance ability after stroke.

INTRODUCTION

The restoration of an optimal gait is a major goal in the rehabilitation of stroke patients^1,2,3). Several changes in gait are seen after stroke, such as decreased velocity, asymmetrical stance phase and stride length, and so forth^4,5,6). An abnormal gait after a stroke is caused by many physical conditions such as muscle weakness, abnormal muscle tone, and disorders in balance and posture control, which are all detrimental to gait ability⁷⁾. Recently, many results from studies on the relationship between trunk muscle activity and the gait function of stroke patients have been being reported. The loss of selective trunk control is a major functional deficit in post-stroke patients that leads to abnormal gait parameters^8,9,10,11). Trunk exercises have a beneficial effect on trunk functions including the improvement in standing balance and mobility in stroke patients; they are particularly effective in improving balance, gait, and functional ability¹²⁾. In a previous study, it was suggested that trunk performance was significantly related to gait and functional ability in stroke patients¹³⁾. Aquatic therapy has also been suggested as an effective approach to improve trunk activity¹⁴⁾. There are many studies on the effect of trunk exercise on gait ability in stroke patients that did not consider the exercise environment. However, comparative studies between aquatic trunk exercise and land-based trunk exercise have rarely been conducted. Therefore, the purpose of the present study was to compare aquatic trunk exercise and land-based trunk exercise on the effectiveness of trunk exercise program on gait ability in hemiplegic stroke patients.

SUBJECTS AND METHODS

The participants of this study were 28 hemiplegic stroke patients (20 males and 8 females) who received a diagnosis of stroke and were either admitted to or were receiving treatment at the outpatient center. Patients were randomly allocated to either the aquatic exercise group (13 patients) or the land-based exercise group (15 patients) by drawing lots. The inclusion criteria were (1) a history of only one cerebrovascular accident, (2) a Mini–Mental State Examination (MMSE) score>24 points, (3) the ability to walk independently, (4) no significant musculoskeletal conditions (fracture, back pain, and so forth), and (5) no contraindications to participation in the exercise program^{5, 6)}. The aquatic exercise group participated in concentrated aquatic therapy for four weeks (30 min sessions for 3 days/week) in a therapeutic pool with a water depth equal to the xiphoid process and a water temperature of 30 °C¹⁵⁾. The aquatic therapy program was based on Halliwick, Watsu, and trunk exercise programs. The main objective of the program was to improve trunk muscle activation in stroke patients. The program included warm-ups, trunk-specific exercises, and cool-down periods^{16, 17)}. The warm-up period (5 min) consisted of trunk control with a Hallwick 10-point program including exercises for sagittal rotation control, transversal rotation control, longitudinal rotation control, and combined rotation control¹²⁾. The trunk exercise period (20 min) consisted of abdominal hollowing, abdominal bracing, anteroposterior pelvic tilts, and mediolateral pelvic tilts¹⁸⁾. Finally, the cool-down period (5 min) consisted of a Hallwick 10-point program (sagittal rotation control, transversal rotation control, longitudinal rotation control, and combined rotation control) and Watsu techniques for muscular relaxation and stretching^{19, 20)}. The aquatic therapy program was conducted by physiotherapists who had participated in a certified Halliwick and Watsu therapy course. The land-based exercise group performed exercise three times a week for one month. The exercise included 3 sets held for 5 seconds, each maintained for about 30 minutes with a 1-minute rest between sets. The trunk exercises consisted of six subparts: bridge exercises, curl-ups with arms crossed, curl-ups with straight reaching, curl-ups with diagonal reaching, abdominal hollowing, and quadruped exercises^{21,22,23,24,25)}. Bridge exercises were performed in the supine position. Both knees were flexed at 90° and the feet were hip-width apart while resting on the floor. Arms were crossed over the chest to minimize arm support, and the therapist placed his hands vertically along the lateral aspect of the bilateral knee joint to maintain a hip abduction of 30°. The subject was instructed to lift his or her pelvis comfortably at a self-selected speed while the trunk, pelvis, and thigh were aligned in a straight line. This position was then held for 5 seconds^{21, 22)}. The curl-up exercise consisted of three parts: shoulder curl-ups with the arms crossed, curl-ups with straight reaching, curl-ups with diagonal reaching, and shoulder curl-ups with the arms crossed. The knees were flexed at 90°. For the curl-up exercise, the subject elevated the trunk until the scapular lifted from the mat²²⁾. For abdominal hollowing, the participant was instructed to draw the lower part of the abdominal up and in toward the spine without moving the trunk or pelvis. A pressure biofeedback unit (TN37343, Chattanooga Group, Inc., USA) was used to ensure that the subjects were performing the exercise correctly. A pressure cuff unit was placed under the lumbar spine and was inflated to 40 mmHg before the exercise was performed. When the subject performed the hollowing correctly, the pressure either stayed at 40 mmHg or decreased, and the subjects tilted until the abdomen was hollow. This position was then held for 5 seconds^{23, 24)}. For the quadruped exercise, the participant was initially positioned in a 4-point stance with the knees and hands on the floor with hips flexed to 90° and hands beneath the shoulder joint. In a 2-point stance, the subjects performed a contralateral arm and leg raise. The subject flexed the arm until the lower body segment was parallel to the trunk. This position was then held for 5 seconds²⁵⁾. Gait ability was measured using a motor-driven treadmill (Gait trainer 2 analysis system Inc, America, Biodex Medical Systems), which was adjusted to each subject’s comfortable walking speed^{5, 6)}. This equipment can analyze walking factors such as walking speed, walking cycle, affected side stance phase, affected side stride length, symmetry index of stance phase, and symmetry index of stride length through a sensor installed on the treadmill floor^{5, 6)}. Statistical analyses were conducted using PASW software (version 18.0; SPSS, Quarry Bay, Hong Kong) to calculate averages and standard deviations. The data are expressed as the mean ± standard error (SE) of the measurements. A paired t-test was conducted to compare the participants before and after the trunk exercise. The statistical significance level was set at α=0.05. The protocol for this study was approved by the Committee of Ethics in Research of the University of Yongin, in accordance with the terms of Resolution 5-1-20. Furthermore, all volunteers or their next of kin provided informed consent for participation in the study.

RESULTS

Table 1 shows the general and clinical characteristics of the 28 stroke patients. Walking speed and cycle, stance phase and stride length of the affected side, and the symmetry index of the stance phase significantly improved after the aquatic and land-based trunk exercise program (Table 2).

Table 1. General characteristics of the participants.

Variable		Exercise environment
		Aquatic trunk exercise	Land-based trunk exercise
Age (yrs)		50.5 ± 2.9	37.9 ± 4.4
Gender
	Male (%a/%b)	10 (76.9/35.7)	10 (66.7/35.7)
	Female (%a/%b)	3 (23.1/10.7)	5 (33.3/17.9)
Height (cm)		166.4 ± 1.9	168.9 ± 2.2
Weight (kg)		66.6 ± 2.9	68.6 ± 3.3
BMI (kg/m²)		24.0 ± 0.8	23.9 ± 0.8
Caused of stroke
	Infarction (%a/%b)	10 (76.9/35.7)	9 (60.0/32.1)
Hemorrhage (%a/%b)		3 (23.1/10.7)	6 (40.0/21.4)
	Paretic side
	Right (%a/%b)	10 (76.9/35.7)	7 (46.7/25.0)
	Left (%a/%b)	3 (23.1/10.7)	8 (53.3/28.6)
Onset (mo)		24.1 ± 3.8	17.2 ± 2.2
K-MMSE (score)		24.9 ± 0.4	25.3 ± 0.2

All data are presented as the mean± SE. ^aPercentage in exercise program. ^bPercentage of all participants. BMI: body mass index, K-MMSE: Korean version of the Mini-Mental State Examination

Table 2. Changes after four weeks of trunk exercise program in hemiplegic stroke patients.

Variable	Exercise environment
	Aquatic trunk exercise		Land-based trunk exercise
	Pre-ATEP	Post-ATEP	Pre-LTEP	Post-LTEP
Walking speed (cm/sec)	51.4 ± 5.1	57.9 ± 7.0*	46.5 ± 2.3	52.6 ± 2.3*
Walking cycle (cycle/sec)	0.4 ± 0.0	0.4 ± 0.0*	0.6 ± 0.0#	0.6 ± 0.2*#
Affected side stance phase (sec/%)	36.2 ± 4.2	46.5 ± 3.0*	37.0 ± 2.4	41.6 ± 2.4*
Affected side stride length (cm)	60.2 ± 4.5	67.7 ± 5.4*	49.3 ± 1.7#	52.5 ± 1.5*#
Symmetry index of stance phase (%)	62.6 ± 12.4	84.2 ± 9.0*	62.2 ± 6.6	75.0 ± 7.7*
Symmetry index of stride length (%)	92.9 ± 5.5	97.0 ± 5.7	108.6 ± 6.1	103.0 ± 4.1

All data are presented as the mean ± SE. ATEP: aquatic trunk exercise program; LTEP: land trunk exercise program; *paired t-test between pre- and post-treatment. ^#independent t-test between groups. ^*#p<0.05

DISCUSSION

The loss of trunk control is a major functional deficit that causes gait disturbance in stroke patients. Previous studies have reported that trunk performance remains impaired after a stroke, which is detrimental to balance, gait, and functional ability, highlighting the importance of trunk rehabilitation¹³⁾. Other studies have found that trunk flexor and extensor muscle weakness correlates with Berg Balance Scale scores and locomotion and transfer items of the Functional Independence Measure²⁶⁾. Our study demonstrated the effects of four weeks of trunk exercise in aquatic and land-based environments on gait parameters. According to our data, gait parameters were improved in both groups despite the short period of intervention. A slow pace and asymmetric gait are most common problems in gait in stroke patients¹²⁾. Many previous studies have suggested that the most important parameter to target in stroke patients is walking speed¹²⁾. Perry suggested that gait velocity is a useful indicator that represents clinical trends, gait quality, and the degree to which gait velocity is abnormal in both hemiplegic stroke patients and healthy patients¹²⁾. In addition, velocity is easy to measure and is closely related to the patient’s clinical condition. However, an increase in gait velocity without improvement in symmetry suggests that compensatory strategies are retained and amplified. Therefore, improvements in gait velocity in stroke patients should be accompanied with improvements in symmetry²⁷⁾. According to our data, participants in both groups had improved walking speed and improved stance phase and stride length of the affected side. Some gait parameters differed between the baseline and posttreatment; however, the changes were not significant. As a result, our data demonstrated that trunk exercise improves the gait ability of stroke patients irrespective of the environment. Previous studies on the relationship between gait ability and trunk exercise have demonstrated the effectiveness of trunk exercise using various tools, but these tools were insufficient for the analysis of gait parameters in stroke patients. Our study used Gait Trainer 2, which analyzed gait parameters by a sensor installed on the treadmill’s floor, similar to the GAITRite system. These methods were proven by many studies to be adequately assess gait parameters in hemiplegic stroke patients. Further, our results concur with those of previous studies evaluating the gait trainer system for measuring gait parameters in stroke patients^22,23,24). According to previous studies, water buoyancy can aid posture control in stroke patients. Therefore, we sought to examine aquatic trunk exercises as an effective method to improve gait ability in patients who experienced difficulty controlling the trunk. However, both trunk exercises in water and on land-based were found improve gait parameters in stroke patients. However, further systematic and scientific studies in neurorehabilitation and other fields are needed to confirm the effects of therapy^{28, 29)}.