A lot of people mistake speed and quickness, but these are two completely different matters. You may have one without the other, but if at all possible you want to have both.

Quickness is about reacting rapidly, changing directions, and moving over a short distance.

Speed, conversely, revolves more around strength and power, and is concerned only with covering a lot of ground rapidly in a straight line.

Both speed and quickness involve acceleration. And to accelerate quickly involves powerful musculature. Both are about explosion, blasting out from your starting position to reach your goal.

On the other hand, the similarities end there. When you consider speed, think of a 100 meter sprinter. The one aim is to get from point A to point B in the least amount of time possible, and it's well known the shortest distance between point A and point B is a straight line. So speed is about moving rapidly in a straight line. It's linear, basically. Two things matter most for speed: 1) the ability to explode and drive yourself forward, which stems from strong muscles, and 2) appropriate form and technique, which makes sure your motions are efficient and that you are not wasting energy.

Quickness, on the other hand, is not about moving rapidly in a straight line. It comes down to having the capability to move swiftly in any direction. In other words, it's multi-directional rather than linear. Quickness also demands agility and reaction time. You need your body to respond swiftly to what you observe on the field or the court.

When thinking of quickness, imagine an NFL defensive back. The wide receiver knows exactly where he would like to go, but the DB doesn't. He has to purely react to what the wide receiver does. So reaction time and agility are key to quickness.

To become faster with respect to speed, you can keep the focus on the two things mentioned previously: 1) muscle strength and 2) proper form. Visiting the weight room regularly and applying proper form in practice can help you increase speed.

To get faster in terms of quickness, going to the weight room often will not always help. As opposed to focusing on your large muscles, quickness involves strength in the smaller muscles and tendons. Quickness drills and whole-body workouts are the ideal approaches to improve quickness, as they improve your reaction time and condition your body to respond in a particular way.

In conclusion, speed and quickness are two completely different things, and different methods are required to improve in each area. The good news is that it is possible to improve both your speed and your quickness. You need to simply approach each in a different way and make certain you're addressing the areas that can allow you to be most successful.