Final answer:
The end feel associated with thumb IP flexion is typically firm, due to the tension in surrounding joints and ligaments.
Step-by-step explanation:
The type of end feel associated with thumb interphalangeal (IP) flexion is typically a firm end feel. This firm end feel occurs due to the tension in the joints and ligaments surrounding the joint, such as the flexor retinaculum and the trapezium, among others.
When the thumb IP joint is flexed, it involves articulation between the distal end of the first metacarpal bone of the hand and the proximal phalanx of the thumb. The motion allows for flexion and extension within the plane of the palm, and the end feel reflects the physiological limitation of the joint's range of motion.