Predictability of maximum voluntary isometric knee extension force from submaximal contractions in older adults
Predictability of maximum voluntary isometric knee extension force from submaximal contractions in older adults
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DOI：
10.1002/mus.10278
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发表时间：
2003-01-01
期刊：
影响因子：
3.4
通讯作者：
Binder-MacLeod, SA
中科院分区：
文献类型：
--
作者：
Stackhouse, SK;Stevens, JE;Binder-MacLeod, SA
本研究的目的是开发和测试一个模型，描述老年人的中枢激活率（CAR；随意肌肉激活的量度）与最大随意收缩百分比（%MVC）力之间的关系，并提供一种更准确地确定随意肌肉激活失败的方法。21 名成年人（64-81 岁）在 25%、50%、75% 和 100% MVC 下对股四头肌进行等长测试。在每次收缩期间，一串 100 Hz、120 ms 的电脉冲被传送到股四头肌，以量化自愿肌肉激活。与年轻健康人群（20-35 岁）类似，老年人的 CAR 和 %MVC 力之间存在曲线关系。使用 CAR-%MVC 力关系的线性模型对受试者的 MVC 进行的预测通常与实际 MVC 的一致性较差。使用先前确定的曲线年轻成人 CAR-%MVC 关系从次最大收缩（25%、50% 和 75%）预测 MVC 效果良好 [ICC (2,1)：分别为 0,81、0.96 和 0.82]。从曲线老年人 CAR-%MVC 关系中也获得了类似的一致性。这些数据表明，年轻人和老年人受试者中的 CAR-%MVC 关系相似，并且这种关系的曲线模型可以更准确地预测老年人的 MVC 力。重新检查 CAR 和 %MVC 力之间的关系可以更准确地确定随意肌激活失败如何导致老年人虚弱。
The purposes of this study were to develop and test a model describing the relationship between the central activation ratio (CAR; a measure of voluntary muscle activation) and percent maximum voluntary contraction (%MVC) force for old adults and to provide a method for more accurate determination of voluntary muscle activation failure, Twenty-one adults (ages 64-81) performed isometric testing of the quadriceps at 25%, 50%, 75%, and 100% MVC. During each contraction, a 100-Hz, 120-ms train of electrical pulses was delivered to the quadriceps muscle to quantify voluntary muscle activation, Similar to a young, healthy population (ages 20-35), a curvilinear relationship existed between the CAR and %MVC force for older adults. Predictions of subjects' MVCs using the linear model of CAR-%MVC force relationship generally demonstrated poor agreement with actual MVCs. Predictions of MVC from submaximal contractions (25%, 50%, and 75%) using a previously identified curvilinear young adult CAR-%MVC relationship were good [ICC (2,1): 0,81, 0.96, and 0.82, respectively]. Similar agreement was obtained from the curvilinear older adult CAR-%MVC relationship. These data suggest that the CAR-%MVC relationship is similar in young and older adult subjects and that curvilinear models of this relationship can predict MVC forces in older adults more accurately. Reexamination of the relationship between the CAR and %MVC force may allow a more accurate determination of how failure of voluntary muscle activation contributes to weakness in old adults.