The effect of backpack weight on the standing posture and balance of schoolgirls with adolescent idiopathic scoliosis and normal controls

Chow, Dhk; Kwok, Monica L.Y.; Cheng, Jack C. Y.; Lao, Miko L.M.; Holmes, Andrew; Au-Yang, A.C.K.; Yao, Fiona Y.D.; Wong, Man Sang

doi:10.1016/j.gaitpost.2005.08.007

Cited by 98 publications

(59 citation statements)

References 19 publications

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“…Larger computed AI variability may be a cue of such a progressive behaviour. These results observed in two orthogonal planes are confirmed by previous studies of gait and standing postures [12,17]. Ontogenic development of spinal deformity associated with the morphotype of SG and with the consequences of biomechanical aspect [1] may explain the variability of dynamic motor strategies.…”

Section: Discussionsupporting

confidence: 87%

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Dynamical asymmetries in idiopathic scoliosis during forward and lateral initiation step

et al. 2009

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Adolescent idiopathic scoliosis (AIS) is characterized by morphological trunk modifications acting on body mass distribution. Some specific biomechanical strategies during postural regulation have been reported. Given that spinal deformity is three-dimensional, some strategy analysis resulting from different stepping directions should lead to a better understanding of the dynamic adaptation of behaviour. The aim of this study is to identify dynamic strategies of AIS patients stepping in lateral and forward directions. Ten AIS patients with a right thoracic curve and 15 controlled volunteers have been tested. Ground reaction forces (GRF) have been recorded for rightlimb stepping and for left-limb stepping associated to forward and lateral directions. Force amplitudes, corresponding occurrences, impulses of stepping phases and an asymmetry index have been computed. Asymmetry and variability increased in the AIS group, compared to the control group, whatever the stepping direction is. Asymmetry for AIS patients systematically provides an increased left initiation GRF compared to a right initiation. Nevertheless, for both groups, lateral initiation shows the largest asymmetry index reported for a forward initiation. More precisely, adaptive dynamic strategies for the AIS group have been characterized by an asymmetry between right and left limbs for lateral and forward initiation. These results can be explained by the influence of scoliosis pathology on dynamic movements due to spinal deformity. A right thoracic curve leads to an extra weight on the limb, which needs to be moved; consequently, stepping initiation with the right limb was more challenging for patients than stepping with the left limb. For the AIS group, the observed variability can also depend on the ontogenesis of adaptive strategies. Lateral step initiation has to be considered as the most relevant paradigm to study scoliosis and may also serve as a clinical basis for treatment to analyse the dynamic postural control and asymmetry strategies of the scoliosis patient.

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Section: Discussionsupporting

confidence: 87%

“…Each subject randomly performed five trials per variable (the order of trials was randomized). The sampling frequency of both force-plates was 100 Hz, which is consistent with the literature [2,12]. The dependent variables were Fx, Fy and Fz.…”

Section: Methodssupporting

confidence: 70%

Dynamical asymmetries in idiopathic scoliosis during forward and lateral initiation step

et al. 2009

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“…Chow et al [12][13][14] in a series of studies, progressively evaluated backpack loads of 0, 7.5, 10.0, 12.5 and 15.0 % of BW in a healthy and scoliotic population Table 1 Means and SDs for the four force curve parameters examined (peak ground reaction force F1 at the first maximum force peak, time T1 needed to reach this force peak, loading rate LRF1 and total contact time T2), for all walking conditions, of both the scoliotic and healthy children Eur Spine J (2012) 21:1936-1941 1939 with mild AIS. They demonstrated a reduction of walking speed and cadence, an increased anterior flexion of the trunk on the pelvis and antero-posterior balance difficulty both in healthy and scoliotic patients.…”

Section: Discussionmentioning

confidence: 99%

Loading rate patterns in scoliotic children during gait: the impact of the schoolbag carriage and the importance of its position

et al. 2012

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Purpose Concerns have been raised regarding the effects of schoolbag carriage on adolescent schoolchildren and particularly those with a pre-existing spinal deformity. The purpose of this study was to determine the effect of school backpack loads in scoliotic and healthy school-age children during walking, in terms of peak vertical ground reaction forces and loading rates. We hypothesized that walking with a loaded backpack would have a greater effect on gait kinetics of scoliotic compared to healthy. Methods Eight children with idiopathic scoliosis and eight healthy children were assessed. Kinetic data were collected using two AMTI OR6-7 force-plates, while the subjects walked freely along a 6-m walkway under three walking conditions: (1) without a schoolbag, (2) carrying a schoolbag bilaterally (over both shoulders-symmetrical load) and (3) carrying a schoolbag unilaterally (over each shoulder-asymmetrical load). Kinetic data were collected and four parameters were calculated; peak ground reaction force at the first maximum force peak (F1), time needed to reach F1 (T1), loading rate of F1 (LRF1) and total contact time (T2). ResultsWe found no significant differences between the scoliotic and healthy children for any of the kinetic variables examined. In addition, the position of the bag did not seem to have any effect on loading rate. Conclusions The results of this study indicate that in terms of kinetic parameters during normal gait, the schoolbag load (symmetrical or asymmetrical) does not have a different effect on children with mild adolescent idiopathic scoliosis compared to normal controls.

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“…The conditions involved unload condition with eyes open (EO), the asymmetrical loading of the shoulder (left shoulder-LS vs. right shoulder-RS) and the pelvis (right pelvis-RP vs. left pelvis-LP). The load added, which corresponded to 15% of the weight of the body segment in question [12], was that found to increase the inertia of the trunk segment in walking for AIS subjects. Vernazza et al [35] have suggested that this increase in the segmental inertia may be due to a combination between age and parameters such as the body weight, the segment masses and the segment length.…”

Section: Methodsmentioning

confidence: 99%

Idiopathic scoliosis: relations between the Cobb angle and the dynamical strategies when sitting on a seesaw

Bruyneel¹,

Chavet²,

Ebermeyer³

et al. 2010

Eur Spine J

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The aim of this study was to determine the influence of the severity of the spinal curve on the postural regulation when self-imposed disturbances occur in a seated position in anteroposterior (AP) and mediolateral (ML) orientations. Twelve female adolescents with a right thoracic scoliosis (Cobb = 30.4°± 9.7) were included in this study. The ground reaction forces (GRF) were studied while the subjects were maintaining their sitting on a seesaw (ML or AP destabilisation). Five conditions were tested: eyes open; with additional loads placed onto the subject's right or left shoulder; or onto the subject's right or left pelvis. We tested the correlation between the Cobb angle and the postural parameters (index of performance and GRF variability) for each condition. When the destabilisation was AP, the Cobb angle was significantly correlated with GRF variability and anterior and concavity index of performance. Two conditions showed higher correlations: stabilisation with the concavity pelvis load (GRF variability) and the open eyes (index of performance). In contrast, whatever the condition tested was, no link was found when the destabilisations were applied in ML direction. The destabilisation in a seated position highlights the influence of the curve severity on the postural organisation. In seated position, the postural control strategies specific to the scoliotic patients were always correlated by severity of curve, especially when the destabilisation is applied in AP directions. This study showed that the unstable seating position can be considered as a pertinent paradigm to help finding a postural clinical index for adolescent idiopathic scoliosis.

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The effect of backpack weight on the standing posture and balance of schoolgirls with adolescent idiopathic scoliosis and normal controls

Cited by 98 publications

References 19 publications

Dynamical asymmetries in idiopathic scoliosis during forward and lateral initiation step

Dynamical asymmetries in idiopathic scoliosis during forward and lateral initiation step

Loading rate patterns in scoliotic children during gait: the impact of the schoolbag carriage and the importance of its position

Idiopathic scoliosis: relations between the Cobb angle and the dynamical strategies when sitting on a seesaw

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