In his book, written in 1940, Edwin L Haislet teaches using the shoulders to defend against the right hand. He had been the boxing instructor at U of Minnesota for 13 years at that point, and was considered on of the top amateur trainers of the day.
To me the big change seems to have come in the 30's-40's, with the guard going from waist level, to chest level or below the chin in general. After that the changes seems to me to have been pretty minor for the next four decades or so, but for the last 20-30 years I'd say that the guars have become higher below MW/SMW. The biggest guys on the other hand have rather gone in the other direction. But I can't come to think of many 130-140 lbs fighters of recent years with both hands low. Their guards are in the most cases up to the cheekbone/temple from what I've seen. Yes, you can find moments where Loma taunts opponents with his hands very low, but this is when he feels secure enough in his superiority to showboat, not when he respects the danger the opponent poses.
In the sport the standard modern guard developed in the 30s as a mainstream stance, but a preference of a high or low guard has in all possibility existed for as long as humans realised they could punch one another.
Nobody fights with both hands low. Except bums like Jack Johnson, whom senile nostalgists claim would have a chance against modern fighters who understand combos, jabs, and high guards.
Find me a moment in Langford vs Flynn, between the incessant clinching, where Flynn doesn’t use a high guard when Langford attacks. The Fireman invented the high guard confirmed.
This is a great question and thread. I think the reality is that throughout history, fighters have adapted their styles to utilize varying degrees of high guard - depending on the individual. Some used it a lot, some not at all, some a blend, depending on the moment, and talent level. Most elite fighters realized that a high guard in a long fight was fatiguing to the shoulders/arms, and sometimes limited fast reactions. Hence, they preferred to utilize timing of punches, timing of hand lifts to block, combined with head movement, clinching, and footwork. A fighter with his hands down often knows how to raise them up at the right moment, or how to utilize guard in conjunction with other techniques. A major factor, I do believe, is the size of the gloves. A high guard with 2- or 5-ounce gloves is not going to be as effective, because the gloves are so small, blows can penetrate the guard more easily nevertheless. Sometimes guard is not enough. When gloves got bigger, they could be utilized more effectively for blocking. James J. Corbett said he was taught to use his guard to block, but early on he found that despite his attempts to block, often the blows got through nevertheless. So he adapted and utilized head movement, footwork, and clinching more than simply attempting to parry and block blows. So I think ultimately it depends on individual talents - the faster the reflexes and speed - the less blocking is necessary, as well as glove size, and length of the fight, and just what winds up working for that particular individual.
