Final answer:
Improper resistance training or insufficient warm-up can result in microscopic tearing of muscle fibers, known as muscle strains or pulled muscles. Adequate recovery times, proper exercise alignment, and warm-ups are essential to prevent such injuries.
Step-by-step explanation:
The type of stretching that poses a greater risk of causing microscopic tearing of muscle fibers and connective tissue is resistance training when done improperly. Injuries such as muscle strains, which are also known as pulled muscles, can result from stretching when muscles are overextended or when there is a failure to properly warm up before engaging in physical activity. The increased strain could cause microscopic tearing in the muscle fibers, along with damage to tendons and even bones if the load during resistance training is too excessive or the body is not given sufficient time to recover between workouts.
Proper alignment during exercises is critical to avoid such injuries. Additionally, it's important to do a proper warm up before strenuous activity to prevent strain-stiffening of the muscle cytoskeleton and the subsequent strain-softening that occurs after a stretch is released, likely due to the inelastic unbinding of cytoskeletal cross-links and actomyosin crossbridges. In summary, overstretching and improper warm-up are factors that contribute to an increased risk of muscle and connective tissue injuries.