deadlift where the bar is less than 9 inches off the floor. This is due to the mechanical advantage
of the muscle driven linkage of the body at a more extended leg position.
The same may be true with tire flipping. By placing the feet back, the hip and knee joints can be
more extended at the start of the lift, thus providing a potential advantage to the lifter. A prob
-
lem with this theory could be the relative angle of the force vectors at this starting position. As it
turns out, the difference in the moment arms is less than 1% using the simulated TS-03 with feet
placed at 4.0 inches behind the chest pads as compared to 17.5 inches behind the chest pads.
The orientation of the lifters is shown in Figure 21.
Figure 22 (the side view of the same lifters in Figure 21) shows the relative moment arms of the
force vector of the body (
F
B
in Figure 15). As noted, these are generalized force application vec
-
tors to rotate the FLIPPER and are considered representative of the force applied to the handle,
as presented in the free body diagram in Figure 15.
18
Using the Flipper - Foot Placement
90°
22°
50.0
Ø
0.26*H
Fig 20
Fig 21