Biomechanical models, often in the form of static models, are used to quant
ify stresses on the body. It has been shown that static models underestimat
e the stresses of a dynamic activity since static models fail to account fo
r inertial effects. The primary objective of this study was to determine th
e effect of lifting speed on the reactive moments at the joints using sever
al cumulative measures of whole-body stress. Five male subjects lifted a bo
x loaded with weight based on their individual maximum acceptable weights o
f lift at five speeds covering the range from very slow to very fast. When
averaged across the lift, the inertial component accounted for 2.5%, 5.5%,
10%, 12% and 14% of the average dynamic moment at each of the five speeds,
from slowest to fastest, respectively.