This paper investigated the effects of three different external foci of attention instructions. Drop jumps were performed with contact cue (1), height cue (2) and a quiet cue (3). The results showed that all cues provided a specific response, e.g. contact cue reduced the ground contact time whereas quiet cues reduced outcomes associated with injury risk. 

Practitioners should consider the type of cue used when young soccer players perform the drop jump because different cues have been shown to elicit different responses.

Oliver, J. ., Barillas, S. R., Lloyd, R. S., Moore, I., & Pedley, J. (2019). External cueing influences drop jump performance in trained young soccer players. J Strength Cond Res, 35(6), 1700–1706.