Wundersitz Daniel W, Gastin Paul B, Robertson Samuel J, Netto Kevin J
Centre for Exercise and Sport Science, Deakin University, Melbourne, Australia.
Int J Sports Physiol Perform. 2015 Sep;10(6):681-6. doi: 10.1123/ijspp.2014-0381. Epub 2015 Apr 7.
Accelerometer peak impact accelerations are being used to measure player physical demands in contact sports. However, their accuracy to do so has not been ascertained.
To compare peak-impact-acceleration data from an accelerometer contained in a wearable tracking device with a 3-dimensional motion-analysis (MA) system during tackling and bumping.
Twenty-five semielite rugby athletes wore a tracking device containing a 100-Hz triaxial accelerometer (MinimaxX S4, Catapult Innovations, Australia). A single retroreflective marker was attached to the device, with its position recorded by a 12-camera MA system during 3 physical-collision tasks (tackle bag, bump pad, and tackle drill; N = 625). The accuracy, effect size, agreement, precision, and relative errors for each comparison were obtained as measures of accelerometer validity.
Physical-collision peak impact accelerations recorded by the accelerometer overestimated (mean bias 0.60 g) those recorded by the MA system (P < .01). Filtering the raw data at a 20-Hz cutoff improved the accelerometer's relationship with MA data (mean bias 0.01 g; P > .05). When considering the data in 9 magnitude bands, the strongest relationship with the MA system was found in the 3.0-g or less band, and the precision of the accelerometer tended to reduce as the magnitude of impact acceleration increased. Of the 3 movements performed, the tackle-bag task displayed the greatest validity with MA.
The findings indicate that the MinimaxX S4 accelerometer can accurately measure physical-collision peak impact accelerations when data are filtered at a 20-Hz cutoff frequency. As a result, accelerometers may be useful to measure physical collisions in contact sports.
加速度计的峰值冲击加速度正被用于测量接触性运动中运动员的身体需求。然而，其在这方面的准确性尚未得到确定。
在擒抱和碰撞过程中，将可穿戴追踪设备中加速度计的峰值冲击加速度数据与三维运动分析（MA）系统进行比较。
25名半职业橄榄球运动员佩戴了一个包含100赫兹三轴加速度计（MinimaxX S4，弹射创新公司，澳大利亚）的追踪设备。在设备上附着了一个单一的反光标记，在3项身体碰撞任务（沙袋擒抱、缓冲垫碰撞和擒抱训练；N = 625）期间，由一个12摄像头的MA系统记录其位置。获得每次比较的准确性、效应大小、一致性、精度和相对误差，作为加速度计有效性的指标。
加速度计记录的身体碰撞峰值冲击加速度高于MA系统记录的加速度（平均偏差0.60g）（P <.01）。在20赫兹截止频率下对原始数据进行滤波，改善了加速度计与MA数据的关系（平均偏差0.01g；P >.05）。当在9个量级带中考虑数据时，与MA系统的最强关系出现在3.0g及以下的量级带中，并且随着冲击加速度量级的增加，加速度计的精度趋于降低。在进行的3项运动中，沙袋擒抱任务与MA显示出最大的有效性。
研究结果表明，当数据在20赫兹截止频率下进行滤波时，MinimaxX S4加速度计可以准确测量身体碰撞的峰值冲击加速度。因此，加速度计可能有助于测量接触性运动中的身体碰撞。
