Muay Thai Kickboxing is probably the most brutal sport I've seen around next to all these mixed martial arts competition. They practically train themselves into the ground and their intensity and dedication is just unbelievable. Then again, to become a National Muay Thai Champion in Thailand is like becoming a God.
The professional lifespan of a Muay Thai kickboxer (if you train like they do in Thailand) is 2 - 3 years max before they begin to feel the effects of their training techniques catch up to them. You're looking at long term damage to ligaments and tendons (osteoarthritis and joint pain especially when older). This is where chi kung comes in handy. By systematically developing the "iron leg", you protect yourself from these long term effects with the same end result. But then, most Muay Thai Kickboxers don't have an hour a day for 3 years to spend on chi kung.
Of course anybody training in Muay Thai Kickboxing doesn't have to punish themselves to that level to learn to defend themselves. Maybe halfway could do?
Schloaty is absolutely right on the kicking Travis...
In all martial arts, there are a myriad of kicks which can be categorized by low, mid and high. 75% of the time, the most effective kicks are low (below the waistline). 20% are mid level (between waist and solar plexus). Only 5% are effective above the solar plexus. It takes too much energy to lift your leg that high and also it's too far of a distance to move, allowing your opponent to "read" you. Of course, if you can bring your opponent down first, it would make things a lot easier to kick to their head. I'm strictly talking about self defence application here. At a competitive level, I don't know of one organization that allows you to kick below the waistline.
So why do we train high kicks? For flexibility and in case we are able to sneak one in, but you have to be really sneaky about it and the risk factor is often very great.
I apologize for taking so much space in this forum... martial arts is my #1 passion... CP's #2. I literally, eat, breath and crap martial arts, it's not funny... but it's very satisfying.