The best replacement for sprints is long distance running.

The best alternatives to sprints are rated as following:
★★★★★  long distance running
★★★★★  long distance
★★★★★  squats
★★★  burpees
★★  jump rope
★★  distance running
★★  distance
★★  hill sprints
★  long runs
  run long distance
  endurance
  running long distance

Your alternative for sprints is not listed? Suggest!
Speaking about sprints, one probably shouldn't forget about tabata.

Other search terms related to sprints and their ratings are:
★★★★★ tabata
You have in mind a companion for sprints and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of sprints in all years. Click on graph for more.
sprints
long distance running
long distance