Civil Engineering Reference
In-Depth Information
100
90
80
70
D
= 93 ± 3 cm
H
= -9 cm
60
50
80
40
50
60
70
30
90 deg.
δ
: Pedal angle
FIGURE 10.13 Effects of ankle (pedal) angle d — see Figure 10.11— on foot force generated by ankle rotation.
(With permission by the publisher from Kroemer, et al., Ergonomics: How to Design for Ease and Efficiency,
Prentice Hall, Upper Saddle River, NJ, 2001. All rights reserved.)
10.8 Summary
Muscle contraction is brought about by active shortening of muscle substructures. Elongation of the
muscle is due to external forces. Maximal muscle tension depends on the individual's muscle size and
exertion skill.
Prolonged strong contraction leads to muscular fatigue, which hinders the continuation of the effort
and finally cuts it off. Hence, maximal voluntary contraction can be maintained only for a few seconds.
100
0.95 reach
90
80
0.85 reach
70
-40
-30
+20
-20
-10
0
+10
+30 cm
H
: Pedal height below/above seat (SRP)
FIGURE 10.14 Effects of pedal height H and leg extension — see Figure 10.11 — on pedal push force. (With
permission by the publisher from Kroemer et al., Ergonomics: How to Design for Ease and Efficiency, Prentice Hall,
Upper Saddle River, NJ, 2001. All rights reserved.)
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