Application of Ergonomics of the Foot - Fundamentals and Assessment Tools for Occupational Ergonomics - page 595

30
Application of
Ergonomics of the
Foot

30.1 Foot Leg ................................ 30-1

Anatomy † Physiology † Dimensions
30.2 Activities of the Foot . ...................... 30-4
Standing † Walking † Running † Stepping
30.3 Accidents . . . ............................. 30-5
Problem of Falls † Causes

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Solutions of Falls

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30.4 Fatigue / Comfort .......................... 30-7

Running † Standing
30.5 Foot Controls ............................. 30-10
Pedals † Switches
30.6 Defining Terms ............................ 30-10

Walking

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Stephan Konz
Kansas State University

30.1 Foot Leg

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30.1.1 Anatomy
Figure 30.1 shows the bones of the foot and ankle. The toes (foot fingers) are divided into metatarsals and
three phalanges (except for the big toe, which only has two phalanges). In supporting the body, the calcaneus
(heel) supports 50%of theweight, the first and secondmetatarsals 25%, and the third, fourth, and fifthmeta-
tarsals 25%. In between are two arches: (1) themedial arch (calcaneus, the talus, the navicular, the cuneiform
bones, and the first, second, and third metatarsals) and (2) the lateral arch (calcaneus, talus, cuboid, and the
fourth and fifth metatarsals). The plantar facia is a fibrous tissue that forms the arch underneath your foot
from the heel to the toes. If it weakens, the facia can cause pain to either the heel end or the toe end.
Under the heel (calcaneus) is a very important shock absorber, the heel pad (about 1.8 cm thick). The
bottom of the calcaneus is not spherical but has two small “mountains”; the pad reduces the pressure on
these mountains, and thus on the ankle, knee, and back.
The foot is connected to the ankle with a mortise and tenon joint. The vertical leg of the mortise is short
on the outside (lateral side); in addition, the ligaments holding the bottom of the fibula (lateral malleo-
lus) to the talus and calcaneus are relatively weak. In contrast, the vertical leg of the inside (medial)
mortise is longer, and the ligaments holding the bottom of the tibia (medial malleolus) to the talus
are relatively strong.

This chapter is a concise version of material in Konz and Johnson (2004).

30-1