Approximately two out of three people with stroke experience gait problems. Trunk movement control and symmetry is an important prerequisite for functional walking gait. Movement control, measured objectively as kinematics during walking gait, is rarely investigated.
To describe the three-dimensional (3D) kinematics of the trunk during gait in people with stroke, including key spatiotemporal characteristics.
A total of 17 adults with stroke who met the inclusion criteria were selected to participate in this cross-sectional pilot study. An eight-camera T-10 Vicon system with Nexus 1.8 software (Vicon Motion System Limited, Oxford, UK) was used to analyse the 3D kinematics of the trunk during self-selected walking speed. Trunk kinematics throughout the gait cycle and spatiotemporal parameters were extracted using custom-built scripts in MATLAB used at the Stellenbosch University Movement Analysis Laboratory. Stata Version 12.1 software was used to assess differences in trunk kinematics between the affected and unaffected sides during gait using the Sign test (statistical significance level
Participants achieved functional gait speeds although they presented with asymmetrical trunk kinematics. During the full gait cycle, there were statistically significant differences of trunk motion between the affected and unaffected sides in the coronal plane (
This pilot study found significant asymmetry in trunk motion between the affected and unaffected sides that varied across the gait cycle. This suggests the trunk may need to be targeted in clinical gait retraining post-stroke.
Stroke is a major global health concern in terms of mortality and chronic disability (Wissel et al.
The term ‘trunk’ refers to the area between the midpoint of the hip joint centres caudally and the midpoint between the shoulder joint centres cranially (De Leva
In healthy individuals, the trunk is maintained in a relatively neutral orientation, with negligible excursions in the sagittal, coronal and transverse planes during gait (Krebs et al.
Currently there is anecdotal evidence about impaired trunk control or movement during walking gait post-stroke in individuals who had a stroke. To inform rehabilitation strategies, empirical information is needed, which has also been identified by other researchers (Frigo & Crenna
In South Africa, individuals with stroke are referred to the community health centres for rehabilitation on an outpatient basis once they are medically stable. Seventeen participants, nine female and eight male, consented to participate in the study. Five male and five female participants had right hemiparesis and three male and four female participants had left hemiparesis. All the participants were recruited from a community health centre by means of convenience sampling. The inclusion criteria to participate in the study were as follows: men and women of 18 years and older, first ever confirmed stroke, ability to follow simple instructions and the ability to walk 10 m without assistive devices. People with bilateral signs, orthopaedic or other neurological pathologies that influence gait and any known allergies to the adhesive tape used during testing procedures were excluded. The mean age of the participants was 56.3 ± 9.5 (range 30–67 years), with the age at incidence being 51.8 ± 9.8 (range 27–67 years); mean time since stroke was 21 ± 18.0 months (range 2–51 months); and mean body mass index (BMI) for the group was 25.66 ± 4.24 (range 17.10–33.52).
The study was conducted at the 3D Movement Analysis Laboratory of Stellenbosch University, which uses an eight-camera T-10 Vicon system (Vicon Motion System Ltd, Oxford, UK) with Nexus 1.8 software. The associated Vicon Plug-in-Gait (PiG) model was used to capture the 3D motion of the participants during walking at a self-selected comfortable speed.
Twenty-two retroreflective markers (14 mm diameter) were placed on participants’ bony landmarks according to the PiG model (lower limb markers were placed on the anterior and posterior superior iliac spines, lateral knee, lateral malleolus, second metatarsal head, heel, lateral thigh and tibia). The Vicon Motion Analysis system is regarded as the gold standard in 3D movement analysis because of its good reliability and validity (McGinley et al.
The PiG model offers a standardised procedure for the identification and placement of 22 body markers. Anthropometric measurements, including height, weight, leg length and knee and ankle width, were taken by an experienced laboratory technician.
The PiG model defines the trunk in three dimensions using Cardan angles. The Z-axis points downwards (longitudinal axis) and is perpendicular to the transverse plane, calculated from the midpoint between cervical spinous process 7 (C7) and the sternal notch (CLAV) to the midpoint of thoracic spinous process 10 (T10) and xiphoid process of the sternum (STRN). The X-axis points forward (sagittal axis) and is calculated from the midpoint between C7 and T10 to the midpoint between CLAV and STRN; it is perpendicular to the coronal plane. The Y-axis (coronal or transverse axis) points right, perpendicular to the X and Z axes, and runs perpendicular to the sagittal plane (Vicon
Anterior and posterior movement of the trunk (sagittal plane) refers to the trunk rotating latero-laterally, resulting in the anterior and posterior movements (flexion and extension) or tilting (Struyf et al.
System calibration was performed as per the standard Vicon guidelines (Vicon
Participants were instructed to walk at a self-selected, comfortable speed along a 10 m distance of an even 30 m surface in the laboratory setting for a total of six trials, wearing the shoes they wore on the day of data capturing. The participants were allowed two practice trials. An average of all the shod trials was analysed and described in this paper. A stool was placed at either end of the walkway length for participants to rest if needed.
Preliminary marker reconstruction and labelling were performed using standard Vicon Nexus operations. Gap filling was performed using the standard Woltring filter supplied by Vicon. Specific points during the gait cycle were calculated, in degrees, using marker trajectories that correlated with gait phases. Trunk kinematics in the three different planes and spatiotemporal parameters were analysed in MATLAB (Mathworks, Natick, MA) using custom-built scripts.
Descriptive statistics were calculated for spatiotemporal gait parameters and for trunk kinematics with mean and standard deviations in the three different planes. The mean and standard deviations of the kinematics were produced. Stata software was used to calculate the differences between the two sides (affected and unaffected) using the Sign test (statistical significance level
Mean and standard deviation group spatiotemporal parameters.
Spatiotemporal parameters | Mean | SD | Max | Min | Range |
---|---|---|---|---|---|
Walking speed (m/s) | 0.91 | 0.24 | 1.47 | 0.40 | 1.07 |
Cadence (steps/min) | 101.63 | 16.21 | 130.00 | 67.00 | 63.00 |
Step length (m) | 0.55 | 0.09 | 0.73 | 0.33 | 0.14 |
Stride length (m) | 1.07 | 0.19 | 1.38 | 0.65 | 0.73 |
Step time (s) | 0.61 | 0.10 | 0.90 | 0.46 | 0.44 |
Stride time (s) | 1.21 | 0.17 | 1.70 | 0.94 | 0.76 |
SD, standard deviation; Max, maximum; Min, minimum; m/s, metres per second; m, metre; s, second.
There was minimal trunk motion noted in the sagittal plane during the full gait cycle. The trunk largely remained anterior to neutral on both the affected (mean 4.28°, SD 0.87°) and unaffected sides (mean 4.33°, SD 0.90°).
Trunk kinematics in the sagittal plane affected versus unaffected.
At initial contact, the trunk on the unaffected side was more anteriorly positioned (5.33°) than the affected side (3.56°), but this difference was not statistically significant. At foot off, there was a second difference noted with the affected side slightly more forward (1.77°). This finding reached statistical significance (
Mean (standard deviation) peak trunk angle during the full gait cycle, in the sagittal, coronal and transverse planes as well as at initial contact and foot off.
Thorax kinematics | Affected (degrees) | Less affected (degrees) | Mean difference (degrees) | Significance ( |
---|---|---|---|---|
Sagittal | 4.28 ± 0.87 | 4.33 ± 0.90 | −0.05 | 0.500 |
Coronal | −2.17 ± 1.88 | 2.25 ± 1.93 | −4.42 | < 0.001 |
Transverse | −3.54 ± 2.49 | 3.60 ± 2.61 | −7.15 | < 0.001 |
Sagittal | 3.56 ± 5.98 | 5.33 ± 6.77 | −1.77 | 0.988 |
Coronal | −2.01 ± 2.41 | 2.45 ± 3.19 | −4.46 | < 0.001 |
Transverse | −6.63 ± 6.78 | 0.66 ± 6.16 | −7.29 | < 0.001 |
Sagittal | 4.35 ± 1.29 | 2.58 ± 1.41 | 1.77 | < 0.001 |
Coronal | 0.26 ± 1.42 | 4.82 ± 1.35 | −4.56 | 0.049 |
Transverse | −2.45 ± 2.00 | 4.86 ± 1.57 | 7.31 | 0.013 |
, statistical significance (
Trunk kinematics in the coronal plane affected versus unaffected.
At initial contact on the affected side, the trunk moved in a downward direction (mean −2.01°, SD 2.41°). In contrast, at initial contact on the unaffected side, the trunk tended to move upwards (mean 2.45°, SD 3.19°). At foot off on the affected side, the trunk was almost stationary, whereas on the unaffected side it moved upwards (mean 4.82°, SD 1.35°).
In this plane, the trunk remained in a slightly backward rotated position during the full gait cycle (mean −3.54°, SD 2.49°) on the affected side, and obviously in a slightly forward rotated position (mean 3.60°, SD 2.61°) on the less affected side (
Trunk kinematics in the transverse plane affected versus unaffected.
At initial contact on the affected side, the trunk rotated 6.63° (SD 6.78°) backwards as opposed to a fairly centrally positioned trunk on the unaffected side (mean 0.66°, SD 6.16°), indicating a statistically significant difference (
Ethical approval was granted by the Human Research Ethics Committee (HREC) of Stellenbosch University (reference number: S13/03/056) in July 2013 to conduct this observational descriptive study.
This study aimed to characterise key aspects of trunk motion during the full gait cycle of people with stroke using 3D kinematics for both the affected and unaffected sides. The secondary aims of the study included reporting of the spatiotemporal gait parameters of the sample.
The sample presented with characteristics commonly seen in the gait patterns of people with stroke, namely reduced cadence and walking speed (Shumway-Cook & Woollacott
Overall the trunk did not move through a large range of motion in the sagittal plane (anterior–posterior motion) and would be observed clinically as the trunk being held relatively still in a more anterior or forward tilted posture. Although some extension occurred, this movement never crossed neutrality (0° into extension). Normally there is not a large amplitude of movement, although there are clear flexion peaks at double support (i.e. initial contact) and extension peak at single support (i.e. midstance) (Krebs et al.
Normally the trunk moves side to side in the gait cycle (coronal plane) and aligns over each leg during its stance phase. This might be because of the need for support of the trunk during unilateral stance. It has been reported that the trunk moves towards the weight-bearing leg in normal gait at initial contact and then away from that side at terminal stance (Krebs et al.
During normal gait there is a forward swing of the pelvis on the side of the swinging leg, with either a counter-rotation of the trunk or the contralateral arm swinging forward leading to thoracic rotation (Lamoth et al.
Reducing gait asymmetry has been a goal as well as a measurement of success in gait re-education for people with stroke (Olney & Richards
The sample of this study were recruited from one setting, were a mixture of subacute and chronic, had received differing levels of rehabilitation experience and were all able to walk without the use of assistive devices. Therefore, the results of this study should not be generalised to the wider population of people with stroke and those with different or varying levels of function. This report focuses on the group data only, with an indication of individual variation provided by the standard deviations. It may be that with the expected heterogeneity in a stroke population, further individual analysis would yield more clinically meaningful information. Finally, the laboratory setting may have influenced the participants’ gait pattern as this does not emulate their natural environment.
In this study, trunk motion in people with stroke differed from that expected during normal gait. This took the form of reduced general motion with a tendency to lean forward, to the side and to rotate backwards on the affected side. These characteristics arguably reduce efficiency or increase energy (Patterson et al.
This study was a pilot study and provides preliminary quantified evidence that the trunk has asymmetric motion during gait after stroke in all three planes. Further investigation in a larger sample is required to determine if the trends noted can be replicated. A larger cohort will allow for subgroup analysis, such as determining the impact of the site and severity of lesion, different age groups, time since incident, comorbidities, varying functional levels, gender and BMI. The relationship between spatiotemporal parameters, trunk kinematics (asymmetries) and functional levels should be explored further.
The aim of this study was to describe the kinematics of the trunk during gait of people with stroke. In summary, we found that the trunk remained relatively still during gait, but with significant asymmetries between the affected and unaffected sides. The participants were all functional walkers at a community level, yet still exhibited this asymmetry. It may be that rehabilitation needs to target the trunk as well as the limbs in hemiparetic gait.
This article is based on the thesis of Adnil W. Titus, ‘An Investigation into the Trunk Kinematics of People with Stroke during Gait’, which was presented to the Faculty of Medicine and Health Sciences at Stellenbosch University in fulfilment of the degree of Master of Science in Physiotherapy. The authors would like to thank the Harry Crossly Foundation for financial support, Dr S.J. Cockroft for his assistance with data collection and analysis, and all the participants for their active participation in the study.
The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.
All authors were part of the original project team and drafted this article. All authors contributed to, read and approved the final version of the article.