There are two main components that a warm-up should include. Those should be a general warm-up and a specific warm-up.
The general warm-up is a piece that is rarely forgotten. It is typically one of the first items on the practice plan and should last 5-10 minutes. The biggest purpose of this piece to increase our body temperature. The aim in this period is to increase heart rate, blood flow, deep muscle temperature, respiration rate, and perspiration. The "old-school" version of this would be sending players for some laps around the field. However, I would argue this is valuable time that could also be effectively used for skill development. For example, having players dribbling a soccer ball at their feet while performing various activities (outside of foot, practicing turns or moves, while giving high fives, while skipping, etc) can give players an opportunity to improve their skill level and comfort with the ball and hitting each of those objectives necessary in a general warm up.
A specific warm-up involves movement similar to those performed in an athletes sport. This is immediately after or partially tied into the general warm-up and lasts about 8-12 minutes. This almost always includes dynamic stretching, which is movements that put our muscles through the range of motion required for the sport. Throughout the specific warm up, we should be getting more sport-specific with our movements (basketball players should jump, baseball players should throw, soccer players should plant and cut, etc). The intensity should always increase throughout the warm up and finish with the most powerful activities, such as bounding, jumping, and sprinting.
What a warm-up should not include is static stretching. This involves putting our muscles to the maximum stretching point in their range of motion and holding the stretch for an extended period of time. For years this was common practice in warm-ups prior to sport activities. However, research has shown little evidence that static stretching aids in preventing injury or muscle soreness. The research has also shown that static stretching can lead to decreases in force production, power performance, running speed, reaction and movement time, and strength endurance. This means including static stretching in your warm-ups can actually hinder performance in training or a game!
The reason anyone should warm-up prior to activity typically falls under two categories; those are to enhance performance and prevent injury. With a quality warm-up positive effects on performance include faster contraction and relaxation of muscles, improvements in strength and power, improved oxygen delivery, increased blood flow to active muscles, and enhanced metabolic reactions. A quality warm-up can aid in injury prevention as increased core temperature helps make muscles and tendons more resistant to tear.
Being smart about your warm-up has so many benefits. It can allow you to work on specific skills a team may need some extra work in (5 minutes each practice x 3 practices a week is an additional 15 minutes focusing on a skill with a ball!), it can help keep your athletes stay healthy, and most importantly it can help enhance their athletic performance on the field.
I worked with our coaching staff on providing quality warm-up options for our teams when we met this winter. I have created videos for these warm-ups that will be linked below.
All information for this post was taken from NSCA Essentials of Strength and Conditioning, written by Thomas R. Baechle and Roger W. Earle.
Two versions of dynamic warm-ups can be found here: https://vimeo.com/kaizentraining/albums