Boxing Jab at Short Distance

Question

Just curious how people deal with punching a heavy bag. My trainer recommended I not only work on long distance jabs, but ones at short or medium distance. Typically at long distance I have fist horizontal or even thumbs down (as learned from earlier question)

When punching at short distance, how do boxers usually punch? One option is bend the wrist, which is Not recommended. Second is punch at a slight angle or vertical.

Last is lift the elbow. However lifting elbow shows intention to opponents, and not recommended? After trying all methods, I believe third one is probably best, however doesn't it break a cardinal rule?

Resources:

https://www.youtube.com/watch?v=Y42MEns6B4s

https://www.quora.com/Should-the-elbows-not-flare-out-when-throwing-a-punch-in-boxing-Why

For short-medium distance punches:

1. Bend the wrist when punching from a short distance

2. Punch at a slight angle, or vertical

3. Punch normally, however, lift the elbow

Answer 1

Keep things simple. When working on short and medium range jabs, you needn't need make any changes to your technique other than to tense your muscles earlier (because you will make contact with the bag earlier). Maintain your use of the foot-leg-hips-shoulders-arm kinetic chain.

Your fist rotation can remain unchanged. By this I mean, rotate your fist as normal. As you are making contact with the bag earlier, your fist will not have rotated as much as if you had you thrown a longer punch. Circumstances may dictate lesser or greater fist rotation; an issue dealt with in reasonable depth here.

Do not bend your wrist. This will weaken your wrist and your punch. Keep the top of your hand aligned with the top of your forearm, as per photograph 3. When properly taped and cinched into a glove, you will not be able to bend your wrist much anyway.

An orthodox jab does not require conscious lifting of the elbow. The elbow inevitably raises laterally during an orthodox jab, as a consequence of fist rotation.

Conscious lifting of the elbow is useful when employing what I call a corkscrew jab (note: some Youtubers use this term to describe very different punches). This punch is similar to an overhand right, in that the raising of the elbow allow a fighter to 'screw' down and over an opponent's outstretched arm, and as such is particularly useful against southpaws. Fist rotation for a corkscrew jab can be as great as 60 degrees beyond horizontal.

The video link you provide describes a straight right, not a jab.