sword cutting science 101
I was reading over the Association for Renaissance Martial Arts site the other day on The Myth of Thrusting versus Cutting swords and What did historical swords weigh? Both are excellent pieces from a european weapons background. The first describes the classic question of swordfighting on which attack style was more effective. European swords diverged early in the medieval period into war weapons and lighter weight day weapons, until the Rennaisance era espoused the benefits of a light thrusting point as the most effective in terms of speed. This light weapon which we today see in the rapier, epee and foil became the weapon of choice for the gentry; nothing as crude and barbaric as a heavy war weapon. In modern terms, it's the equivalent of arguing on if you are Heavy Truck Guy, or if you prefer nimble sports cars.
In terms of effectiveness, the thrust can be quite a damaging attack since it sinks deep, can puncture multiple layers of tissue and organs. It creates a small open wound (rather than the blood-splurting everywhere Quentin Tarantino/John Woo-sytle), but without modern medicine, a strike at the torso could easily become lethal. On the other hand, if you don't hit an important spot, the opponent is still there. This works great for gentlemenly duels but not very practical in actual combat.
The cut or slash takes more strength and physically takes a greater distance of sword travel to be effective, but if it didn't totally amputate something it would eviscerate the muscle and probably break the bones, essentially disabling that body part. You may need more strength with this but that depends upon your weapon's weight and fighting styles.
European heavy weapons were not generally huge and weighty but ranged around 3 pounds and certainly less than 6 pounds for most backswords, broadswords, and such. This is still more than most katanas that are around 2.5 pounds. Also the katana is primarily a two-handed weapon, thereby balancing the weight more evenly, whereas a 3lb backsword is still much heavier to carry on one hand, even 2.5 pounds.
I've never weighed my own primary katana precisely but it's probably about 2.5 lbs, maybe a little more. I do cut single handedly with that but it takes a lot more control with finer muscles. Two hands gives not only more strength but also more importantly better control of the weapon. While the first article talks about the katana being a very effective thrusting weapon, we primarily teach only a single type of thrust or tski.
I was watching National Geographic Channel the other day, a show called Fight Science. This was a really good show but when it came to the bit about the dynamics of swords, I was again disappointed by the poor technique they presented. The thrust for example was shown as an underhanded (rather than overhanded) one, and with the elbow even bent some. This technique simply ignores the skeletal structure, body positioning and only uses muscle to power the thrust. In other words, it takes more strength than necessary to be effective. Thus it would take an extremely fit 200 lb man to deliver the same blow as something a medium fit 100lb middle-schooler could do. (We have had both 300lb 26yr old football players and 80lb 15yr olds in our class, and they both can do almost the same level of attacks). One thing we tell our students is not to waste energy if you don't need to. All you need is one really good hit.
I was really impressed with their Kyudo (archery) demonstration in the show. I'm unranked in Kyudo since I never carried the practice very far, but it looked very serene. Yoga joke: After many hours of yoga practice in a full room, the one person that remains still standing on one leg tree-pose shouts out: "I AM THE SERENEST!" :)
Unfortunately the martial arts world is full of people with heavy egos. The dedicated ones feel slighted if you debate with them, but their intentions are still true: they want to interest and excite more people into their field of study. Even the own style I learn could do a lot more than focus on good cutting techniques. It could do well with more stamina building, more groundwork, more balance work, more disarms and trips, etc. All in good time and there's plenty to learn from. It should be interesting as we go to start an entirely new class/club at the U of Arizona this Fall.