Warm-ups are like workout foreplay – they get your blood flowing and build toward the main event. Yet, too many people take the opposite approach, supplanting the main workout with a never-ending stream of stretches, foam rolling, and "activation" drills before touching a weight.
As well-intentioned as these practices may be, nothing sucks the soul from a workout faster than a protracted warm-up.
Most of these activities focus on either turning "off" tight, overactive muscles to allow for a larger range of motion, or turning "on" weak, underactive muscles to encourage them to do their job.
Unfortunately, the human body isn't a piano that can be tuned by loosening certain strings while tightening others. It would be nice if it were that simple. That's why reverse-engineering compound movements into constituent chunks and then trying to optimize each part in isolation rarely pays big dividends.
Assuming you're not dealing with a specific injury or just want to spend large amounts of time dedicated to doing feel-good stuff, try this:
Jump on a bike, treadmill, or rowing machine for 5-10 minutes. This is enough to increase your heart rate, blood pressure, and core temperature. It'll also start to influence the rate at which your blood cells disassociate oxygen for use by the muscles, which makes energy more readily available.
Next, choose one or two active mobility exercises that are specific to the primary movement patterns for that day, plus one lightweight, ballistic exercise to act as a bridge between the lower intensity warm-up and the main workout. Perform two to three rounds in a circuit format.
Here are two examples:
Finally, there's no more specific of a warm-up than simply doing the actual patterns involved in the lift. That's why I frequently use 2-5 ramp-up sets for main lifts. Think of these as lightweight, low-risk rehearsal sets leading up to the main event.
Not only is this a great way to accumulate submaximal volume, it also turns "on" the exact muscles you want in a way that's specific to how you want to use them.