نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه بیومکانیک ورزشی، دانشکده علوم ورزشی، دانشگاه بوعلی سینا، همدان، ایران
2 گروه بیومکانیک ورزشی، دانشکده علوم ورزشی، دانشگاه بوعلی سینا، همدان، ایران.
3 گروه ارتوپدیک، دانشکده پزشکی، دانشگاه علوم پزشکی، همدان ، ایران
4 Department of Human Kinetics, University of Quebec in Trois-Rivieres, QC, Canada;
5 Kinesiology Department, Montreal University, QC, Canada
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Aims: Adolescent Idiopathic Scoliosis (AIS) is a complex three-dimensional spinal deformity (Cobb angle >10°) (1, 2) affecting 2-4% of adolescents (3-6), with higher prevalence in girls during puberty (10-11 years) (7). While the exact etiology remains unknown, AIS is associated with neuromuscular and biomechanical abnormalities, including altered muscle activation patterns, impaired proprioception, and reduced postural stability (8-11). These deficits lead to structural changes in the spine, rib cage, and pelvis, resulting in asymmetric posture and altered weight distribution during both static and dynamic activities (12-15).
The biomechanical consequences of AIS are evident during gait. Asymmetric loading patterns may contribute to curve progression by affecting the growing musculoskeletal system (16), making gait analysis essential for understanding AIS. Key measures include the Center of Pressure (COP), representing ground reaction force application (17-19), and the Free Moment (FM), reflecting rotational moments during stance (20, 21). COP changes reveal neuromuscular control strategies (17-19, 22), while FM variations indicate compensatory balance efforts (20, 21, 23).
Studies reveal altered COP behaviour in AIS, linking curve severity to COP displacement (24), and FM differences in rotational control (25). However, inconsistencies may stem from combining lumbar/thoracic curves and left/right convexities, obscuring subgroup differences, problematic since distinct curves likely drive unique gait adaptations.
This study addresses these gaps by focusing solely on lumbar AIS and analyzing right and left convex curves separately. We assess two COP components: anteroposterior displacement (COPAP), which reflects stance-phase progression, and mediolateral sway (COPML), which indicates balance control. Combined with FM analysis, these measures evaluate gait dynamics in AIS. We hypothesize:
a) Lumbar AIS significantly alters COP and FM compared to controls, and
b) Right and left convex curves exhibit distinct COP trajectories and FM patterns.
The findings of this study could potentially inform whether each scoliosis subgroup needs distinct rehabilitation strategies. Including unique curve types, our findings may help resolve inconsistencies in the literature and improve understanding of AIS biomechanics during functional activities.
Materials and Methods:
About 7,000 high school students were screened for scoliosis signs. Out of 45 individuals with curves >10° confirmed by X-ray, 14 with isolated lumbar scoliosis (apex at L2-L3) participated. They were divided into right (Cobb=19.7°±3.2) and left-curve (Cobb=19.4°±2.9) subgroups. A control group included 16 healthy adolescents. Participants with neurological issues, recent injuries, or surgeries were excluded. All were right-foot dominant. Ethics approval (No (ID: IR.BASU.REC.1399.003–May 02, 2020) and informed consent was obtained.
Two Kistler force plates (2000 Hz) recorded GRF components during walking. After warm-up and static capture, participants completed five walking trials at self-selected speed.
COP and FM were calculated during the stance phase (GRF >10N), and FM data were normalized to body weight, respectively. Metrics included mean, range, and RMS of COP-mediolateral (COPML), COP anteroposterior (COPAP), FM, and the impulse of FM. MANOVA with Tukey post-hoc tests (Bonferroni-corrected) for discrete values and Statistical Parametric Mapping (SPM) for time-series data were applied.
Results: The scoliosis and control groups had similar age, weight, and shoulder/pelvis dimensions. However, scoliosis participants were significantly taller (+5 cm, p = 0.021) and had longer trunks (+6.6 cm³, p = 0.052). No significant differences in mediolateral COP parameters were found between the scoliosis and control groups. The left foot of the left lumbar scoliosis subgroup had a significantly greater COPanterior range compared to controls (p = 0.027).
In the right foot, FM values (mean, range, RMS, impulse) showed no significant differences between the groups. However, the left foot of the left lumbar scoliosis subgroup had significantly higher FM and FM impulses than the right lumbar scoliosis subgroup (p = 0.019) (Table 4).
SPM comparisons revealed no significant differences in COP trajectories in either direction across groups. However, a brief but significant difference in left foot FM was found between the control group and the right lumbar scoliosis group during 4.71–5.13% of the stance phase (p = 0.005).
DISCUSSION: This study uniquely focused on gait differences between the left and right lumbar scoliosis and the controls, with a special reference to COP and FM components. The increased height and trunk length in scoliosis patients mirror past findings and may signal a shared growth pattern across scoliosis types. It may also suggest that taller trunk length is a risk factor during growth spurts.
No differences were found in COPML between the groups. This is in contrast with studies that noted changes in side-to-side sway (16, 17). These discrepancies could stem from differences in curvature types or broader patient variability in prior studies.
For COPAP, only the left lumbar group showed increased displacement in the left foot. This aligns with prior research linking greater anteroposterior COP motion to impaired dynamic balance (18).
The left lumbar subgroup had higher FM and impulse values, indicating more muscular effort to maintain posture, particularly in the left foot. SPM analysis confirmed this with a small but statistically significant FM difference between the control and right lumbar groups.
These findings suggest that both curvature type and direction affect gait mechanics. The left lumbar subgroup appeared most affected, highlighting the need to consider the polarity of scoliosis curvature in rehabilitation design. Though the sample size was small, especially in subgroups, the data support scoliosis-specific interventions focusing on postural control and gait correction.
Conclusion: Scoliosis is associated with taller body and trunk heights. In right lumbar scoliosis, no changes in COP and FM parameters, in any direction, were observed. However, in the left lumbar scoliosis, COPML remained unchanged, but changes in COPAP and FM impulse were observed in the left foot (on the convex side). This research indicates that the extent and nature of changes are linked with the polarity of scoliosis, with left lumbar scoliosis patients showing changes in COP kinematics. In contrast, right lumbar scoliosis did not show alterations. A tailored rehabilitation program should be designed separately for each group. Additionally, gait pattern correction should be prioritized in the rehabilitation process.
کلیدواژه‌ها [English]
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