Improving flexibility primarily involves which of the following?

Improving flexibility primarily involves stretching and lengthening exercises because these activities are specifically designed to enhance the range of motion in the joints and muscles. Stretching exercises can be classified into several types, including static stretching, dynamic stretching, and proprioceptive neuromuscular facilitation (PNF). Each of these approaches aims to elongate muscle fibers and improve the elasticity of muscles and connective tissues, fostering greater flexibility.

In addition, regular flexibility training can help prevent injury, improve posture, and assist overall movement efficiency. Engaging in dedicated stretching routines, whether static (holding a stretch) or dynamic (moving through a full range of motion), ensures that muscles are sufficiently lengthened and prepared for physical activity.

Other options, while contributing to overall fitness and well-being, do not specifically target flexibility. Endurance training focuses primarily on cardiovascular fitness and muscular stamina, high-intensity interval training (HIIT) is geared towards building strength and power while improving cardiovascular conditioning, and strength training is designed to increase muscle strength and hypertrophy. None of these methods directly aim to enhance flexibility to the same degree as dedicated stretching routines do.