Sidaway Ben, Ahn Soyeon, Boldeau Pansy, Griffin Scott, Noyes Bethany, Pelletier Kristin
Physical Therapy Department, Husson College, Bangor, Maine, USA.
J Neurol Phys Ther. 2008 Mar;32(1):32-8. doi: 10.1097/NPT.0b013e318165948d.
Patients with certain neurological or orthopedic conditions often present with asymmetrical weight-bearing in stance. In the treatment of such patients, physical therapists often use manual guidance to promote symmetrical weight-bearing. Research investigating the efficacy of manual guidance to effect a change in weight-bearing status however, is lacking. As a first step in assessing the utility of such guidance, the present study compared the effect of providing two frequencies of manual guidance and of knowledge of results (KR) in the learning of a weight-bearing skill in healthy subjects.
Forty healthy subjects (20 males and 20 females) with a mean age of 21.8 years (SD = 4.9 years) were randomly assigned to one of four groups differentiated on the basis of the type and frequency of information provided for learning. Subjects were required to learn to distribute their weight on their feet at a 70:30 ratio. Following a pretest, one group of subjects was positioned by experimenter-provided manual guidance at the hips until 70% of their weight was on one foot, as determined by a bathroom scale. This guidance was provided on every trial for 10 blocks of 12 trials (GD100%). A second group was provided with guidance on every third trial (GD33%), with the other two trials being performed without any assistance. A third group was verbally provided with KR regarding the percentage of body weight on the test foot after every trial (KR100%) while the final group was given KR after every third trial (KR33%). Following acquisition, retention tests were performed 10 minutes, one day, and one week later during which no feedback or guidance was given.
No difference between groups was found at the pretest, but an analysis of variance performed on the accuracy of achieving the 70% goal in retention revealed main effects for technique and frequency. These effects were overshadowed by a significant interaction of these variables with retention test. Analysis of this interaction revealed that the most accurate performance was exhibited by the KR33% group while the GD100% group consistently exhibited the poorest learning. The GD33% and KR100% groups showed a decrease in performance accuracy with time following practice.
These results indicate that infrequent KR was the most effective technique in learning to modify weight-bearing status and that frequent manual guidance during practice is ineffective for learning this task. The next step is to determine whether these findings hold in subjects with various orthopedic and neurological conditions.
患有某些神经或骨科疾病的患者在站立时往往表现出不对称负重。在治疗这类患者时，物理治疗师经常使用手动引导来促进对称负重。然而，缺乏关于手动引导对改变负重状态效果的研究。作为评估这种引导效用的第一步，本研究比较了在健康受试者学习负重技能时提供两种频率的手动引导和结果反馈（KR）的效果。
40名健康受试者（20名男性和20名女性），平均年龄21.8岁（标准差 = 4.9岁），被随机分配到根据学习所提供信息的类型和频率区分的四组中的一组。受试者需要学会以70:30的比例在双脚上分配体重。在进行预测试后，一组受试者由实验者在髋部提供手动引导，直到根据体重秤确定其70%的体重落在一只脚上。在每个试验中都提供这种引导，共进行10个组块，每组块12次试验（GD100%）。第二组在每第三次试验时提供引导（GD33%），另外两次试验在没有任何帮助的情况下进行。第三组在每次试验后通过口头方式获得关于测试脚上体重百分比的结果反馈（KR100%），而最后一组在每第三次试验后获得结果反馈（KR33%）。在习得阶段之后，在10分钟、1天和1周后进行保持测试，在此期间不给予任何反馈或引导。
在预测试时各组之间没有差异，但对保持测试中达到70%目标的准确性进行方差分析发现，技术和频率有主效应。这些效应被这些变量与保持测试的显著交互作用所掩盖。对这种交互作用的分析表明，KR33%组表现出最准确的表现，而GD100%组始终表现出最差的学习效果。GD33%组和KR100%组在练习后的表现准确性随时间下降。
这些结果表明，不频繁的结果反馈是学习改变负重状态最有效的技术，而练习期间频繁的手动引导对学习这项任务无效。下一步是确定这些发现是否适用于患有各种骨科和神经疾病的受试者。
