A muscle being stretched is a muscle being recruited. The old-school donkey calf raise does this very well, stretching and recruiting both major calf muscles.
- Strap on a loaded dipping belt and stand on a block or whatever you have handy, toes on the edge.
- Bend at the waist and do calf raises.
- Hold the bottom stretched position for two seconds and hold the top position for at least one second, contracting hard.
- You can perform them bilaterally (both legs) or unilaterally (one leg at a time).