Which type of stretching is known to oppose the desired effect by tightening the muscle?

The correct choice is related to ballistic stretching, which involves quick, bouncing movements that attempt to push a muscle beyond its normal range of motion. This method can provoke a stretch reflex in the muscles, causing them to contract rather than relax. When muscles are subjected to this rapid stretching, the body's natural response is often to tighten up to protect the muscle from potential injury, thus opposing the desired effect of lengthening or relaxing the muscle.

In contrast, static stretching involves holding a stretch in a fixed position for a period of time, allowing muscle fibers to relax and elongate effectively. Dynamic stretching consists of controlled movements that gently take muscles through their range of motion, which helps prepare the body for exercise without invoking a reflex response that tightens the muscle. PNF (Proprioceptive Neuromuscular Facilitation) stretching incorporates both stretching and contracting of the targeted muscle group, which effectively enhances flexibility and does not promote muscle tightening.

Thus, ballistic stretching stands out as the type that can induce an unwanted tightening of the muscle, making it the correct answer.