“The hips crave intensity, the shoulders crave complexity.”
Where I heard this is lost on me now, but I love how simple a concept it illustrates. A vast majority of our training revolves around the hips and shoulders. And these two joints look and perform very similarly. We even go as far as to speak of one joint as an analogy to the other. But the stimulus each needs is different in both intensity and complexity, and this is dictated to a large degree by how the joints are shaped and put together.
Let us begin with the hip. I like the hip. It is where all of my power is derived from. I am just a legs guy walking around in an arms guy world. The hip is also the seat of power for all of us. This is where power is generated for running, jumping, throwing, et al. It can be made to bear incredible loads, hence its craving for intensity (intensity in the exercise science community is a measurable variable derived from a percentage of your one rep maximum for a certain movement).
The hip is also a pretty simple ball and socket joint. The socket that the femur (leg bone) rests in is called the acetabulum (hip capsule). The acetabulum is a fairly deep socket as far as sockets of the human body go. Because of this, the femur is restricted in its range of motion. You can bring your thigh to your chest (hip flexion), you can take your thigh slightly down behind your pelvis (hip extension), and then you can bring it across your body or out to the side (hip adduction and abduction, respectively). There is not a whole lot of range in those motions though.
The hip is also surrounded by some of the largest and strongest muscles of the body: hamstrings, quadriceps, and glutes. It is an oversimplification, but the glutes and hamstrings extend the hip while the quads and hip flexors flex the hip. Extension is what happens at the top of your pull on a clean or snatch. Flexion is what happens while you are doing toes to bar.
All this is to say that your hip craves intensity of movement. It desires heavy, compound movements in the way of squats and pulls. It wants to be loaded up with either weight on your back or in your hands and then it wants to flex and extend. This is why we spend so much time under tension with heavy loads squatting and pulling. If you want strong and healthy hips, squat and pull heavy weight.
But the shoulder is a different animal. We call it the mini-hip, but it is actually a lot more complex than the hip. The humerus (arm bone) sits in to the glenoid fossa (shoulder capsule or socket). The shoulder capsule is a lot shallower and more open. The shoulder also possesses a neat trick in that it has another joint called the sternoclavicular articulation. This second joint plus the shallow, open capsule gives the shoulder a greater degree of range of motion. The shoulder can throw a fastball, play a cello, perform open-heart surgery, cast a lure, hold a child, and many, many more actions. We can thank the complexity of the joint for this.
But with that complexity comes a couple of woes. Woe is to the athlete who does not train her shoulder equally in all ranges of motion. You must balance your horizontal pulling with horizontal pushing. The same goes for vertical ranges of motion. It is folly to bench press three days a week and never do any sort of row work. A sign of a good program is one that possesses myriad shoulder work in all planes. Some heavier, high intensity work coupled with some lighter endurance work should be found in the program. A programmer can also mix up the implements utilizing just the body, kettlebells, dumbbells, barbells, ropes, rings, and many other objects.
So make sure that you are getting adequate work in for both ball and socket joints. And make sure that you are getting in the right kind of work, too. This will keep you a balanced athlete, and a balanced athlete is always going to be stronger and healthier for a longer time.
Remember! The shoulders crave complex movement to become strong and robust. The hips crave intensity of movement like sprinting, jumping, and lifting heavy.
P.S. – Mark that the quote uses the word “crave” and the not the word “require.” It would be a gross oversimplification to think one needs only intensity OR complexity for a specific joint.