This debate has been raging on for as long as I can remember. Everybody has their own personal preference, and many claim that the direction the palm faces is completely dependent on where your target is. Personally, I have always thrown hooks with palms facing towards me. It always felt more natural, and as if the wrist was way more secure.
Recently, I saw a video by fightTips, an amazing YouTube channel starring Shane Fazen, in which they collaborated with one of the greatest boxers to have graced the ring, Roy Jones Junior. In this video, Team Roy (comprising of the boxer himself and his coach) go over why they personally train to use the palm in variation of the hook. What I found quite interesting, was that they had some well-versed professionals step in and explain that, not only is the palm in variation of the hook better for generating power, but it also places less strain on the joints and minimises the dangers of rotator-cuff injuries.
Their points on kinetic chains was particularly compelling, claiming that this is a mechanical system by which athletes perform the majority of their movements in a large variety of sports, particularly the movements which required the generation of power – a perfect example of such a motion is the tennis serve motion. In fact, breakage of these kinetic chains, leads to decreased performance in tennis players, or even injuries in their shoulders or wrists, regardless of their age. These disruptions in the kinetic chains are usually caused by:
That last point should be the one that helps you to understand why, according to the professionals, throwing the hook correctly not only leads to increased performance but also minimised risk of injury. An effective kinetic chain, is characterised by two key components:
You know more about kinetic chains than you think. Especially if you have done boxing or MMA before. This is because when any coach explains how to throw a punch, they explain the importance of rotation. This rotation allows you to generate power by kicking off from the ground and placing this power on the inches of your knuckles.
However, there are many points that have been made as to why the hook should be thrown with the palm facing the ground. Some say the activation of the biceps in the hook punch can be detrimental, as it leads to reduced relaxation in the arm, and can stop you from getting that whipping motion that is usually achieved when throwing the hook. Moreover, using the palm in variant of the hook can cause you to hit with all of your knuckles, not just your lead knuckles.
Is this such a bad thing? It really depends on the context. Traditionally, in almost every martial art (and possibly in old-school, bareknuckle boxing) you were taught to hit with the knuckles of your index and middle finger. There is two leading reasons for this:
This means that, in reality, the "correct way" to throw this punch depends completely on what you're throwing the punch for. If you're a proffessional boxer like Roy Jones Jr. then it would make sense to throw the punch with the palm in, as you would be throwing the punch quite often. This is further backed up by the use of boxing gloves and wraps, which hold your wrists securely when you're throwing punches - you wouldn't really have to focus as much on correct forearm technique and alignment.
In contrast, you might just be doing boxing or a martial art for self-defence, in which case, you would probably prefer the palm down variation of the punch. This method of throwing the hook would ensure you only use your front two knuckles if you ever get into a scuffle - throwing a punch without gloves or wraps and landing it with any other knucles would lead to what is called a "boxers fracture". I have experienced this personally: you don't notice the pain at first due to the adrenalin, but in 30 minute or so once you've calmed down, you can barely move the outer half of your hand. The only known method of avoiding this apart from landing your punches correctly is extreme knuckle and hand conditioning, which in the modern day, the average person isn't willing to do.