Setup. A line of four flat markers a metre apart for each keeper. A ball held up, or the crossbar, as something to reach for.
How it runs. Four exercises, 20 seconds on and 40 off, twice through. One: squat jumps, reaching as high as you can. Two: single-leg hops along the markers, then back on the other leg. Three: two-footed jumps over the markers with the shortest ground contact you can manage. Four: two steps, a one-legged take-off with the knee up, touch the ball or the bar.
Make it harder. Catch a ball at the top of every jump. Then land and immediately make a save to one side.
With 4 keepers. Four lines side by side.