When it comes to exercise, many of us try to rush though our workouts - it feels productive to get the heart pumping and sometimes we just want to get it done and overwith! That might be OK when you're out for a run or bike ride, but for many types of exercise, slowing down a bit and focusing on your form is going to give you the best results.
When you take movements more slowly and think about your form, you're asking your body to activate the correct muscle groups to help you complete the movement. Instead of simply completing an exercise, think of yourself as "practicing" that exercise and perfecting it over time.
Let's take the squat, for example. The major muscle groups working during the squat are the glutes and the quads. In addition, the hamstrings will be assisting and the transversus abdominis (yes, your abs!) are helping to stabilize. If done correctly you're targeting some major muscle groups! However, the majority of us have muscular imbalances that can lead to incorrect form, causing the wrong muscles to activate and take over the movement - this can lead to future injuries and in the long-run won't help you build muscle where you want it.
By slowing the squat down and focusing on correct form, we can better pinpoint the weak areas and force those muscles to strengthen. Say you have a hard time maintaining an upright torso in your squat and find yourself leaning forward, this could be an indication of overactive hip flexors (common for those with desk-jobs) and weak glutes. Rather than going through the motions with your forward lean, in focusing on your form in the squat, you can ensure your glutes are activating and you can build that strength over time.
Keep practicing your movements and you'll feel (and see) the difference.