The effectiveness of an exercise depends on various factors. One important aspect is the mind-to-muscle connection. When it comes to abdominal exercises, it's crucial to understand the function of the abs. They contract and roll the body forward at the lumbar spine, not at the hips. So exercises like leg raises or sit-ups may not directly target the abs if the movement primarily involves the hip flexors. To improve the mind-to-muscle connection with your abs, focus on exercises that engage the abs at the lumbar spine, such as rotating the pelvis during leg raises or performing sit-ups with a rolling motion. Additionally, be aware that different angles and variations in exercises can provide a more comprehensive workout for a muscle group. Incorporating novelty in your workouts can help prevent plateaus and stimulate further adaptation. However, it's important to strike a balance and avoid constantly changing exercises just for the sake of novelty.