University Institute for Computing Research, University of Alicante, 03690 Alicante, Spain.
Institute of Telecommunications and Multimedia Applications, Universitat Politècnica de València, 46022 Valencia, Spain.
Sensors (Basel). 2021 Jan 30;21(3):925. doi: 10.3390/s21030925.
Velocity-based training is a contemporary method used by sports coaches to prescribe the optimal loading based on the velocity of movement of a load lifted. The most employed and accurate instruments to monitor velocity are linear position transducers. Alternatively, smartphone apps compute mean velocity after each execution by manual on-screen digitizing, introducing human error. In this paper, a video-based instrument delivering unattended, real-time measures of barbell velocity with a smartphone high-speed camera has been developed. A custom image-processing algorithm allows for the detection of reference points of a multipower machine to autocalibrate and automatically track barbell markers to give real-time kinematic-derived parameters. Validity and reliability were studied by comparing the simultaneous measurement of 160 repetitions of back squat lifts executed by 20 athletes with the proposed instrument and a validated linear position transducer, used as a criterion. The video system produced practically identical range, velocity, force, and power outcomes to the criterion with low and proportional systematic bias and random errors. Our results suggest that the developed video system is a valid, reliable, and trustworthy instrument for measuring velocity and derived variables accurately with practical implications for use by coaches and practitioners.
基于速度的训练是一种现代的训练方法，被运动教练用于根据负载移动的速度来规定最佳负荷。最常用和精确的监测速度的仪器是线性位置传感器。或者，智能手机应用程序通过手动屏幕数字化计算每次执行的平均速度，从而引入人为误差。在本文中，开发了一种基于视频的仪器，该仪器使用智能手机高速摄像机对杠铃速度进行无人值守、实时测量。定制的图像处理算法允许检测多功能力量机器的参考点，以自动校准并自动跟踪杠铃标记，从而提供实时运动学衍生参数。通过比较 20 名运动员完成的 160 次深蹲举重的同步测量，研究了该仪器与经过验证的线性位置传感器（作为标准）的有效性和可靠性。视频系统产生的范围、速度、力和功率结果与标准结果几乎相同，具有低且成比例的系统偏差和随机误差。我们的结果表明，开发的视频系统是一种有效的、可靠的、值得信赖的测量速度和衍生变量的仪器，对教练和从业者的实际应用具有实际意义。
