Speed is straight line running velocity. Agility is your ability to decelerate, change direction and accelerate again, usually in response to something happening around you. Change of direction ability is the physical half of agility; the other half is reading the play and deciding early. Training them separately matters, because a fast sprinter can still be slow to turn, and a sharp turner can still be out-run.

Both. Muscle fibre make-up and limb proportions set part of your ceiling, and those are inherited. The rest, including force production, sprint technique, braking control and how well you accelerate from a stop, responds to training. Most athletes who have never sprint trained have plenty of room to improve, particularly over the first 10 to 20 metres, where technique and strength matter most.

Early improvements often come from technique and coordination, and some athletes feel sharper within a few weeks. Gains that come from added strength and power usually take longer, because the muscle and tendon adaptations build over months. Your coach retests the same sprint and change of direction measures at set points, so progress is tracked with numbers rather than feel. Rates of change vary.

No. Most sessions run on turf, court or a flat grass strip in running shoes, because that is where your sport is played. Spikes suit track athletes and are introduced only when the training calls for them. If you play on court, your usual court shoes are appropriate, since the braking and cutting surfaces differ from grass and your footwear should match.

Often yes, once you can run pain free and your rehabilitation has progressed to higher speeds. Sprinting at high velocity is part of a complete return to sport, not something to delay until the last week. Your coach works with your physiotherapist so the volume and intensity climb in steps, and sessions stop short of the point where your running mechanics change.

Yes. Maximum speed and power decline earlier than endurance, and both respond to training at any age. Sprinting also loads tendons and bone in a way that jogging does not. The difference is in the build-up: your coach starts with lower volumes, more recovery between efforts, and a longer lead-in of strength work before full intensity sprints are added.