Inter-individual variability in a repetitive lifting task

Abstract

Trunk kinematics directly impact the biomechanical loading of the tissues of the low back. Quantifying the variability in trunk kinematics may provide deeper insights into biomechanical loading and low back injury risk. Inter-lifter variability in trunk kinematics was assessed as twenty participants performed a repetitive lifting task at three levels of the NIOSH Lifting Index. Trunk kinematics were captured and Levene’s test of homogeneity of variance was used to test the hypothesis that variance in kinematic parameters increased as a function of level of lifting index. Results showed considerable levels of variability in all kinematics parameters, and for sagittal range of motion, mean sagittal velocity, transverse range of motion, and mean transverse velocity the variance was significantly affected (p<0.05) by level of lifting index. The results of this study demonstrate that variability (both inter- and intra-lifter) should be considered as one considers the relative risk of a lifting task.

The Effectiveness of Active Shooter Responses for Civilians and Law Enforcement

“…As it has been shown time and time again, without training and evaluations tailored to specific populations, they can be ineffective, inaccurate, and even dangerous (Fales et al, 2021;R. Stone et al, 2019;Tabary et al, 2021;Tetteh et al, 2021;Wang et al, 2022) while the personalized training methods can also improve performances (Middelcoop et al, 2021). Although many will not have to worry about whether their actions will guarantee someone else's death, the moral dilemma is still present for many professionals, such as teachers.…”