Dalleau Georges, Allard Manon S, Beaulieu Marlène, Rivard Charles-Hilaire, Allard Paul
Centre Universitaire de Recherches en Activités Physiques et Sportives, UFR Sciences de l'Homme et de l'Environnement, Université de la Réunion, 117, rue du Général Ailleret, 97430, Le Tampon, France.
Eur Spine J. 2007 Oct;16(10):1593-9. doi: 10.1007/s00586-007-0404-0. Epub 2007 Jun 14.
Adolescent idiopathic scoliosis girls are known to display standing imbalance. In addition to a motor deficit problem, the axial torsion of the spine and trunk torsion could reflect an imbalance around the vertical axis. Unlike the excursion of the center of pressure (COP), the forces and moments were rarely addressed to characterize the quiet standing balance. Nonetheless, one dynamical parameter, called free moment (T(V)), representing the vertical torque on the feet can reflect the oscillation around the vertical axis associated to the standing imbalance. The objectives of this study were to test if the free moment variability can be utilized to characterize standing balance in a group of able-bodied and non-treated scoliotic girls and to determine if it was associated with that of the COP among each group of subjects tested. Forty-six adolescent girls with half of them presenting an adolescent idiopathic scoliosis were tested during quiet standing balance. Standing balance was assessed with the subjects standing upright and bare feet on a force plate. RMS and range of COP excursions and free moment were calculated. The scoliotic group displayed higher variability in COP excursion by about 24% than the able-bodied girls. Similarly, the T(V) RMS (P = 0.00136) and range (P = 0.00197) were statistically higher by about 42% in the scoliotic group. The variability of T(V) was associated with that of the COP in both groups. In the medio-lateral direction, the significant correlations between the RMS and range of the free moment and those of the COP were about 0.7 for the able-bodied group and 0.5 for the medio-lateral COP range for the scoliotic group girls. Along the antero-posterior axis, the only statistically significant correlations were observed for the scoliotic group. The free moment variability about the COP measured during quiet standing can be suggestive of an asymmetry control of the trunk around the vertical axis during standing balance. Its variability was more pronounced in scoliotic girls and was associated with the antero-posterior COP variability reflecting both biomechanical and motor control deficits. Free moment calculation could be a supplement insight into the standing balance of scoliotic subjects.
众所周知，青少年特发性脊柱侧弯的女孩存在站立失衡问题。除了运动功能缺陷问题外，脊柱的轴向扭转和躯干扭转可能反映了围绕垂直轴的失衡。与压力中心（COP）的偏移不同，很少有人研究力和力矩来表征安静站立平衡。尽管如此，一个称为自由力矩（T(V)）的动力学参数，代表作用在脚上的垂直扭矩，可以反映与站立失衡相关的围绕垂直轴的摆动。本研究的目的是测试自由力矩变异性是否可用于表征一组身体健全和未经治疗的脊柱侧弯女孩的站立平衡，并确定其在每组测试对象中是否与COP的变异性相关。对46名青少年女孩进行了安静站立平衡测试，其中一半患有青少年特发性脊柱侧弯。让受试者赤脚直立站在测力平台上，评估站立平衡。计算COP偏移的均方根（RMS）和范围以及自由力矩。脊柱侧弯组的COP偏移变异性比身体健全的女孩高约24%。同样，脊柱侧弯组的T(V) RMS（P = 0.00136）和范围（P = 0.00197）在统计学上也高出约42%。两组中T(V)的变异性都与COP的变异性相关。在中-侧方向上，身体健全组自由力矩的RMS和范围与COP的RMS和范围之间的显著相关性约为0.7，脊柱侧弯组女孩中-侧COP范围的相关性约为0.5。在前后轴上，仅在脊柱侧弯组观察到统计学上的显著相关性。安静站立时测量的关于COP的自由力矩变异性可能表明站立平衡期间躯干围绕垂直轴的不对称控制。其变异性在脊柱侧弯女孩中更为明显，并且与反映生物力学和运动控制缺陷的前后COP变异性相关。自由力矩计算可能是深入了解脊柱侧弯受试者站立平衡的一个补充指标。
