The HIDF‑CFT is an experimental human‑powered force‑transmission system based on a dorsal trunk support point, designed to explore how coordinated activation of the arms, legs, and torso may influence mechanical efficiency. The concept reinterprets the classical ornithopter principle by shifting the external fulcrum from the ventral side of the body—as seen in historical designs—to the posterior side, enabling new ways to study human strength as an integrated system.

A first prototype, built with simple materials and tested through personal trials under gym‑like conditions, produced several preliminary observations. During isolated arm or leg work, the effort felt more fatiguing and less effective. In contrast, coordinated full‑body activation gave the subjective impression of producing more power, greater stability, and a more efficient use of effort. These impressions suggest a conceptual analogy with the coordinated action of the flight muscles in birds, where power emerges from the engagement of entire muscular chains rather than from a single region.

The HIDF‑CFT reproduces this principle in a controlled environment, functioning as a biomechanical test bench to study force transmission from a fixed dorsal support. The two images included in this submission illustrate the functional phases observed during testing:

Opening Phase:

The user lies in a supine position with the back firmly supported. The arms open widely from the front toward the sides while the legs flex toward the abdomen. This phase highlights how the dorsal support stabilizes the trunk and enables simultaneous activation of upper and lower body muscles.

Force Phase:

The arms are brought together in front while the legs extend. This coordinated action produces the moment of maximum perceived effort. If applied to a mechanical system, this movement would correspond to the downward stroke of wings in a flight‑inspired mechanism.

The current system includes a stable dorsal support point, a set of pulleys and cables that allow qualitative analysis of force direction, and a structure that maintains body alignment to reduce energy loss. Although future developments may explore more advanced configurations, this proposal focuses strictly on what has already been observed: that coordinated full‑body activation from a dorsal support may improve the subjective perception of efficiency during exertion.

Beyond its aero‑biomechanical interest, the HIDF‑CFT could be explored in the future for potential applications in rehabilitation or sports training, particularly in contexts where global coordination, proprioception, and full‑chain muscular activation are relevant.

In summary, the HIDF‑CFT provides an initial experimental foundation for future research on human force transmission applied to advanced mechanisms. The preliminary observations—supported by personal trials and visual documentation—suggest that the human body, when functioning as an integrated system from a dorsal support, may achieve a more efficient perception of force generation.