Estimating maximum performance: effects of intraindividual variation
Estimating maximum performance: effects of intraindividual variation
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DOI：
10.1242/jeb.011296
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发表时间：
2008-04-15
影响因子：
2.8
通讯作者：
Pickering, Trevor
中科院分区：
文献类型：
--
作者：
Adolph, Stephen C.;Pickering, Trevor
研究人员经常使用每个个体的少量试验来估计动物的表现能力。这个过程不可避免地低估了最大性能，但很少有研究已经检查了这种影响的大小。在这项研究中，我们探讨了个体内变异和个体样本大小对运动性能参数估计的影响。我们在两个温度（20摄氏度和35摄氏度）下测量了蜥蜴Sceloporus occurentalis的冲刺速度，每个个体获得20个测量值。速度没有随时间变化，表明没有训练或疲劳的影响。在每个温度下，约50%的速度总体变化是由于个体内变化。虽然速度是可重复的，但重复性随着试验之间的间隔增加而略有下降。在20摄氏度和35摄氏度的速度呈正相关，表明在不同温度下的重复性。我们进行了统计抽样实验，其中我们随机抽取了每个人的20次试验的子集。正如预期的那样，样本的最大速度随着每个个体的试验次数而增加;例如，五次试验产生的估计值平均为真实最大值的89%。试验次数也会影响20 ℃和35 ℃下平均速度之间的样本相关性;例如，5次试验产生的相关系数平均为真实相关性的90%。因此，个体内的变化导致低估的最大速度和速度之间的相关性，在温度。这些偏差随着每个人的试验次数的增加而下降，并取决于个体内变异的大小，如使用修改后的数据集进行的抽样实验所示。
Researchers often estimate the performance capabilities of animals using a small number of trials per individual. This procedure inevitably underestimates maximum performance, but few studies have examined the magnitude of this effect. In this study we explored the effects of intraindividual variation and individual sample size on the estimation of locomotor performance parameters. We measured sprint speed of the lizard Sceloporus occidentalis at two temperatures ( 20 degrees C and 35 degrees C), obtaining 20 measurements per individual. Speed did not vary temporally, indicating no training or fatigue effects. About 50% of the overall variation in speed at each temperature was due to intraindividual variation. While speed was repeatable, repeatability decreased slightly with increasing separation between trials. Speeds at 20 degrees C and 35 degrees C were positively correlated, indicating repeatability across temperatures as well. We performed statistical sampling experiments in which we randomly drew a subset of each individual's full set of 20 trials. As expected, the sample's maximum speed increased with the number of trials per individual; for example, five trials yielded an estimate averaging 89% of the true maximum. The number of trials also influenced the sample correlation between mean speeds at 20 degrees C and 35 degrees C; for example, five trials yielded a correlation coefficient averaging 90% of the true correlation. Therefore, intraindividual variation caused underestimation of maximal speed and the correlation between speeds across temperatures. These biases declined as the number of trials per individual increased, and depended on the magnitude of intraindividual variation, as illustrated by running sampling experiments that used modified data sets.