Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
Phys Ther. 2010 Aug;90(8):1165-75. doi: 10.2522/ptj.20090394. Epub 2010 May 20.
Ankle strength (force-generating capacity) and power (work produced per unit of time or product of strength and speed) capabilities influence physical function (eg, walking, balance) in older adults. Although strength and power parameters frequently are measured with dynamometers, few studies have examined the reliability of measurements of different types of contractions.
The purpose of this study was to examine relative and absolute intrarater reliability of isometric, isotonic, and isokinetic ankle measures in older women.
This was a prospective, descriptive methodological study.
The following dorsiflexion (DF) and plantar-flexion (PF) measures were assessed twice (7 days apart) by the same examiner in 30 older women (mean age=73.3 years, SD=4.7): isometric peak torque and rate of torque development (RTD), isotonic peak velocity, average acceleration and peak power, and isokinetic peak torque and peak power (30 degrees/s and 90 degrees/s). Several statistical methods were used to examine relative and absolute reliability.
Intraclass correlation coefficients (ICCs) for the DF tests (ICC=.76-.97) were generally higher than ICCs for matched PF tests (ICC=.58-.93). Measures of absolute reliability (eg, coefficient of variation of the typical error [CV(TE)]) also demonstrated more reliable values for DF tests (5%-18%) compared with PF tests (7%-37%). Isotonic peak velocity tests at minimal loads were associated with the lowest CV(TE) and ratio limits of agreement values for both DF (5% and 14%, respectively) and PF (7% and 18%, respectively). Isometric RTD variables were the least reliable (CV(TE)=16%-37%).
This study was limited to a relatively homogeneous sample of older women.
Test-retest reliability was adequate for determining changes at the group level for all strength and power variables except isometric RTD. Minimal detectable change scores were determined to assist clinicians in assessing meaningful change over time in ankle strength and power measurements within individuals.
踝关节力量（产生力量的能力）和功率（单位时间内产生的功或力量和速度的产物）能力会影响老年人的身体功能（例如，行走、平衡）。尽管力量和功率参数经常使用测力计进行测量，但很少有研究检查过不同类型收缩的测量的可靠性。
本研究旨在检查老年女性等速、等张和等长踝关节测量的相对和绝对内部测试者可靠性。
这是一项前瞻性、描述性方法学研究。
同一位检查者在 30 名老年女性（平均年龄=73.3 岁，SD=4.7）中两次（相隔 7 天）评估以下背屈（DF）和跖屈（PF）测量值：等长峰值扭矩和扭矩发展率（RTD）、等速峰值速度、平均加速度和峰值功率以及等速峰值扭矩和峰值功率（30 度/秒和 90 度/秒）。使用多种统计方法来检查相对和绝对可靠性。
DF 测试的组内相关系数（ICC=.76-.97）普遍高于匹配 PF 测试的 ICC（ICC=.58-.93）。绝对可靠性指标（例如，典型误差的变异系数[CV（TE）]）也表明，DF 测试（5%-18%）的可靠性值高于 PF 测试（7%-37%）。在最小负荷下进行的等速峰值速度测试与 DF（分别为 5%和 14%）和 PF（分别为 7%和 18%）的 CV（TE）和比例一致性值的最低限制相关。等长 RTD 变量的可靠性最低（CV（TE）=16%-37%）。
本研究仅限于相对同质的老年女性样本。
除等长 RTD 外，所有力量和功率变量的测试-再测试可靠性均足以确定组水平的变化。最小可检测变化分数的确定有助于临床医生评估个体内踝关节力量和功率测量在一段时间内的有意义变化。
