For capturing extremely steady handheld footage while rapidly running with the subject, which native iPhone stabilization technology is specifically designed for such dynamic movement?

The native iPhone stabilization technology specifically designed for capturing extremely steady handheld footage while rapidly running with the subject is Action Mode. Action Mode leverages a combination of advanced sensor-shift optical image stabilization and sophisticated software-based electronic image stabilization. Sensor-shift optical image stabilization is a hardware-based method where the camera's entire sensor physically moves in real-time to counteract camera shakes and vibrations, providing a fundamental level of stability. This physical compensation is highly effective against the significant and rapid movements encountered during running. Simultaneously, the iPhone employs electronic image stabilization, a software-based technique that analyzes video frames to detect unwanted motion, then digitally crops and shifts the image within the frame to smooth out the footage. In Action Mode, the system applies a more aggressive digital crop, providing a larger buffer zone around the captured image. This increased buffer allows the advanced electronic image stabilization algorithms to compensate for even very aggressive, dynamic movements, such as those from rapid running, far more effectively than standard video stabilization. This integrated hardware and software approach is specifically optimized to deliver incredibly stable, gimbal-like footage in high-intensity, dynamic scenarios without requiring external equipment.