Leave the ankle and wrist weights to old men jogging around your local park.
To enhance speed, stick with heavy (or fast) multi-joint ground based lifts and jumps and high intensity sprinting (without ankle weights). If you feel as if you must load the sprints, I'd suggest either doing it environmentally (hills, steps, etc.) or via a more centrally located resistance (vest, parachute, pulley, etc.).
ELITETRACK Founder