Ankle weights are best used as part of a strength training workout. The question of whether to wear ankle weights while running remains controversial, but most trainers don’t recommend it. Some exercisers think that running with hand weights or ankle weights is a good way to make a workout tougher and burn more calories, but some fitness experts argue that this puts unnecessary strain on muscles and joints that could lead to injury.
Instead, make ankle weights one of your components of fitness power during a strength training workout. Use ankle weights when you do standing leg lifts or lunges to add intensity on your cross training days.
If you want more intensity during your fitness running workouts, add some speed work. After a few easy miles, try increasing your speed to 80% of your maximum for one minute then slow down to an easy pace for one minute. Repeat 4-6 times, and finish with a few more miles at an easy pace.