15 Achilles tendon Tibia 2 se 90 7 cm 25 cm Figure 3 Standin

15 Achilles tendon Tibia 2 se 90 7 cm 25 cm Figure 3. Standing on tiptoe. (a) The muscle and the bone (b) force diagram.

Let Fa and Ft be the forces on Achillle and Tibia.

Fa and Ft are perpendicular to the foot and are anit parallel.

Taking CW and CCW moments of all force about A

Fa*25 = Ft*18

Resolving the forces vertically

W+FaCos15 -FtCos15 =0

replace Ft with Fa*25/18

W= FaCos15(25/18 -1)

Fa = (18/7)*W*Cos15

= 2.48 W

Ft = (18/25) Fa = 1.79 W