Article

Impact testing is undertaken to quantify the shock absorption characteristics of
footwear. The current widely reported mechanical testing method mimics the heel
impact in running and therefore applies excessive energy to walking footwear. The
purpose of this study was to modify the ASTM protocol F1614 (Procedure A) to
better represent walking gait. This was achieved by collecting kinematic and
kinetic data while participants walked in four different styles of walking
footwear (trainer, oxford shoe, flip-flop and triple-density sandal). The
quantified heel-velocity and effective mass at ground-impact were then replicated
in a mechanical protocol. The kinematic data identified different impact
characteristics in the footwear styles. Significantly faster heel velocity
towards the floor was recorded walking in the toe-post sandals (flip-flop and
triple-density sandal) compared with other conditions (e.g. flip-flop:
0.36+/-0.05 ms(-1) versus trainer: 0.18+/-0.06 ms(-1)). The mechanical protocol
was adapted by altering the mass and drop height specific to the data captured
for each shoe (e.g. flip-flop: drop height 7 mm, mass 16.2 kg). As expected, the
adapted mechanical protocol produced significantly lower peak force and
accelerometer values than the ASTM protocol (p<.001). The mean difference between
the human and adapted protocol was 12.7+/-17.5% (p<.001) for peak acceleration
and 25.2+/-17.7% (p=.786) for peak force. This paper demonstrates that altered
mechanical test protocols can more closely replicate loading on the lower limb in
walking. This therefore suggests that testing of material properties of footbeds
not only needs to be gait style specific (e.g. running versus walking), but also
footwear style specific.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.
- Chaussures

Langue : ANGLAIS