Mobility is most important!
Strength + Flexibility = Mobility
Mobility is the single most defining and important factor in your fitness. It is not strength or flexibility that matters most— it is mobility. What is mobility? By a basic definition, it is the ability to move freely; in the fitness world, we would define this as the area where your strength and flexibility meet.
A visual example would be if I hold your leg up as high as your body allowed—that would be your flexibility. Your strength alone would be how much weight that leg can lift or push in a strength-based motion like a squat or lunge. But your mobility is the ability and height of that leg when you hold it up, using both flexibility and strength together (with no aid from anyone else).
This is important because in fitness, mobility is true health! Remember that your body can’t just be strong or just be flexible; the two are not complete without each other. Working toward mobility is working toward pain-free movement and the freedom to use your body at its best capacity.
How do you work your mobility? The Kettlebell Kickboxing workout found here are full of drills that develop mobility. Just about every kick and swing you do will help develop that for you. Another way to help develop mobility is in your warm-ups and cool-downs.