I specialize in strength and conditioning for soccer players. I can’t tell you how many lower body injuries I have seen that could have been prevented. I have also seen a ton of kids who come to me because they are extremely slow and need to be faster. Both of these problems have a fix that is ignored far too long by many kids and parents. The solution is this: get them stronger!!!
Most non-contact injuries occur during deceleration (stopping). The reason for this is very simple physics F=MV (force= mass x velocity). If I have 140lb athlete and they can run 18 mph and they have to stop rapidly to change direction, there is a ton of force necessary to slow them down. Under a weak musculoskeletal system, things will tear/fracture/dislocate etc.
Speed is an expression of how quickly an athlete can apply force into the ground. So the stronger the athlete, and the quicker they can generate that strength, the faster they will go. This is particularly true for acceleration which is the most important component of speed training for soccer (1-15yds). Top end speed is slightly different where some weaker athletes can rely on the elasticity in their hamstrings to help them achieve very fast absolute speed velocities (this is a different topic that I will expound upon in later posts).
The following videos outline some baseline progressions that can be performed with NO EQUIPMENT right there on the pitch as the fitness portion of your practice. Some kids are stronger than others and will need more advanced progressions. All of these can be overloaded with external resistance if need be and if you have access to dumbbells, barbells, Med ball etc.