With the forces the leg muscles apply when we stand, it is surprising how easy it feels. We had 10 subjects aged 19-55 stand and consider the force applied to the ground. A body brace was then quickly positioned to hold them in the same standing posture so that the muscles were relaxed. They then made a plantarflexion contraction to reproduce the force perceived during standing. This was a 71.8% CI [64.4, 79.2] underestimate of exerted active torque when standing (P<0.001 ANOVA). When the experiment was performed with subjects balancing an inverted pendulum matched to their own bodies, they overestimated 5.3% [-4.4, 15.0] the force exerted (P=0.75). We interpret this as indicating that cortical perceptual centres cannot access the signal of force exerted during standing, whether central or reafferent [1], because the cortical system does not issue the motor command. This implicates a subcortical system in balance drive to the muscles. Reciprocal changes in corticomuscular coherence and galvanic-evoked vestibular reflexes corroborated this. When a muscle is contracted voluntarily through cortical drive, a pressor signal generated centrally is sent to medullary cardiovascular centres to raise blood pressure (BP). We therefore asked whether this response is also generated by the subcortical balance drive. Subjects were supported upright in the posture of standing with the muscles relaxed for 5 minutes. BP remained stable. At that time, the brace was removed so that subjects stood by contracting the leg muscles (18.2% [17.8, 18.6] of measured maximal contraction force). BP did not change. Thus, at this workload, the muscle did not generate a significant metaboreflex response. When repeated by producing a matched contraction voluntarily to balance the inverted pendulum, BP increased by 6.2 mmHg [6.1, 6.3] or 7.2% (P < 0.001 by ANOVA) after 3 minutes. In 8 subjects, we stimulated over the motor point of tibialis anterior with supramaximal tetanic trains (5 @ 40ms) repeated at 1Hz; a workload similar to the calf muscles during standing). When force output was stable, muscle perfusion pressure was changed by raising or lowering the leg. This produced a rapid decline of 4.8% [3.6 6.0] in force output for the 6.2mmHg loss of pressor response, equivalent to that reported for a hand muscle [2]. In the hand muscle, loss of this augmented contractility through the pressor response meant that muscle fatigued twice as fast [3]. Thus, without this pressor response, the leg muscles during standing rely crucially on the hydrostatic head of pressure provided by orthostatic posture. Put another way, you can only stand because you are standing.