Background: Keirin races are often decided by the "makuri," a final-lap sprint in which a racer from the rear overtakes the leader at approximately 75 km/h. Because direct measurement during races is extremely difficult, its mechanisms remain unclear. This exploratory, hypothesis-generating study used musculoskeletal simulation to examine how pedaling posture may reduce its metabolic cost. Methods: A modified AnyBody BikeModel was checked for plausibility against one professional racer's pedaling force (approximately 150 rpm, 1,000 W). Model-estimated metabolic power–cadence curves were simulated at constant mechanical loads, and only relative differences were interpreted. On these curves, a racer in the group (Point A: seated, 1,200 W, 147 rpm, 73 km/h) changes posture at the same load and cadence (Point A′), then accelerates (Point B: 1,255 W, 151 rpm, 75 km/h). Results: At Point A′, a non-seated posture with the hips anterior to the bottom bracket increased ankle dorsiflexion (possibly promoting stretch-shortening cycle utilization) and reduced metabolic power by 67 W (4%); it also raised the optimal cadence but recruited more fatigue-prone muscles. At Point B, despite a 55 W higher load, metabolic power remained comparable to that at Point A, assuming a slightly smaller drag area; under idealized conditions, the resulting speed difference (0.55 m/s) would close a 5 m gap in approximately 9 s. A seated "makuri" with deliberate ankle dorsiflexion reduced metabolic power by 59 W (4%). Idealized trunk stabilization representing strong core stability (relative pelvic rotation restricted from 5° to 0.5°) reduced it by a further 86–109 W (5–7%). These differences changed little when the scaling factor of the metabolic model was reduced from 1.5 to 1.0. Conclusions: Hip position, deliberate ankle dorsiflexion, and trunk stabilization are experimentally testable candidates for an energy-saving "makuri." Drawing on previous studies, we also discuss hybrid training, in which voluntary agonist contraction is resisted by electrically stimulated antagonists, and the potential of this simulation framework as a "digital trainer" for individualized training and bicycle configuration.