So, suppose I want to describe my foot, the ancle joint and my achilles tendon as a lever. I look at my foot as if it was standing on a step of a stair with my heel protruding out into the air, or if i was standing on solid ground, lifting my heels just a millimeter from the ground. Like this: ______L___I X Where X is the supporting point, L is my ancle joint and I is the Achilles tendon. I say that the distance from X to L is 2, and the Distance from L to I is 1 (units will not be relevant here). I suppose that my weight is evenly distributed on both feet. As I am completely stationary, there is no net-torque on my foot. Now, as I see it, I can describe the above as a first class lever, like a see-saw. L is the fulcrum, and the force on the point X is Fa= ½*bodymass*g. The lever is 2 long. So, the torque on the lever will be τa = bodymass*g on the left side. On the right side, I have the same torque τa=τb. However, I have a lever only 1 long, so I get the force on the achilles tendon to be Fb = bodymass*g = 2*Fa. However. I see many pages on the internet looking at the case like this: The fulcrum is the supporting point, X, the joint, L, is the load point, and the effort is on the point I, the achilles tendon. In this way the system is like a 2nd class lever. I go on to calculate. The Load on the L is Fa=½*bodymass*g. The lever is 2, so the torque from the load of the body on the joint is τa=bodymass*g. The torque must be zero, so I say, looking only at magnitudes of forces and torques: τa=τb⇔ 2*Fa=3*Fb => Fa=3/2Fb But HEY! Fa is the same in the two cases. In the first case I got Fb=2Fa In the second: Fb=2/3Fa How can this be? What way should I look at this?