The adverb to ask someone to kick a ball with less power

Question

Suppose a kid is playing football inside the house and you want to ask him to kick the ball with less power. Which adverb can be used here?

e.g. John, kick the ball .... !

• more calmly
• more weakly
• more slowly
• etc.

Answer 1

The degree to which one kicks a ball is referred to by native speakers as power, usually (supported by the fact that this is what it's called in pretty much every football game ever).

Therefore, the adverbs you'd use need to relate to how powerfully you do something. The most common way you'd get that across is with gently/softly.

John, kick the ball more [gently | softly]!

However, that's still not quite how you'd say it natively. You'd be more likely to say

John, don't kick the ball so hard!

Preventive imperatives tend to be more useful and clearly-understood when we explain what the recipient should not do, rather than telling them to do the opposite of the thing we want them to stop doing.

Answer 2

I think the situation is quite similar to Cricket batting where the batsman is asked to play not aggressively/powerfully.

We use the term steadily. I mean this could be one of the options.

So,

John, kick the ball steadily

steadily here means in a controlled way, steady way.

Another term could be gently. But it might be too soft to use here.

However, I'm not acquainted with a football jargon, if any.

[I don't think that any dictionary would support this. It's a coined term for Cricket i.e. a special use of that English word].