The other day I ordered a DVD containing over 3 hours of information about performing a single exercise - the kettlebell swing. I'm not plugging the DVD - I haven't gotten it yet, it might suck, all the usual reasons, and it's not a review copy (although if anybody has any materials they want to donate so I can review them, send away!) I'm bringing it up for another reason.
I mentioned this to a friend of mine (a non-karateka), who asked me, more or less, why the hell I would pay for or watch 3 hours of material about an exercise I already know how to do.
If you are involved in martial arts you probably don't think there's anything odd about devoting 3 hours (or 3 days, weeks, months, or years) to a single technique in your art - the subtleties of timing and body positioning that make a great punch different from a good punch are complex and, yes, subtle. But you might not often put as much time or thought into your supporting exercises.
Spending hours learning about, then many more hours refining, the fine points of an exercise are important for a couple of reasons.
Safety: If you are moving heavy loads or doing a lot of repetitions of a movement (think of people either doing near maximum lifts or joggers - opposite but similar problems) then the injury potential for the movement becomes large. Small adjustments to your body mechanics can greatly reduce your risk of getting hurt. Squat with 5 lb. dumbells with your knees caving in? Probably okay. Do it 1000 times a day? You'll mess up your knees, hips, and ankles. Do it for fewer reps, but with 250 lbs. on your back? Again, you're going to be sending your chiropractor/orthopedist/physical therapist's kids through college.
Getting your body alignment perfect won't make movement risk free, but it will greatly enhance your safety.
Performance: You might not realize it, but there are a lot of details that go into doing even simple movements (bench press, deadlift) at a high level. As a beginner you're going to make great gains on these movements no matter how you do them. As you get stronger, though, you'll need to focus more and more on perfecting your technique if you want to continue to make progress. Listen to something like Iron Radio and you can hear guys who can talk about the bench or squat for hours - it's not just "put the weight on your back, sit down, then get back up."
Performance is not just a matter of how much you can lift or how often you can safely do a movement before hitting failure - after all, you might not care if your squat is 200 lbs or 400 lbs as long as your legs get stronger. Performance is also a matter of what the training effect will be. If you squat a certain way you might get all the stress on your quadriceps - which is nice, but not great. Improve your technique and you can shift the stress - and therefore the adaptions - to your hips and glutes, which will have a much bigger impact on your overall fitness, athleticism, and martial ability.
Boredom: We all have different tolerances for going into the gym and mindless cranking away at the treadmill, Hammer machines, elliptical, or whatever. Some people can keep that up for years; others can't. I personally am actually pretty good at doing mind numbingly boring stuff in the gym if I think it will help me improve. BUT we all prefer routines that are less boring. Doing the same set of exercises while only half paying attention, listening to music or watching TV is a completely different experience than working to perfect a complex motor skill. That's why people enjoy golf and videogames and bowling in a way they don't enjoy pedaling away on an exercise bike.
Working on the skill of doing exercises - striving to perfect your technique, adjusting to the daily variances in your body's stability and mobility, fully concentrating on the moment you're in - that's not boring. Pushing away at pads on a machine can be.
Brain Health: You, like many people, may be convinced that doing exercise in an engaged way might be less boring, but you'd still rather just watch TV from your treadmill and reap the health benefits of exercise. Sadly, you'll be missing out on a big chunk of those benefits. Your brain, just like any other of your body's systems, gets crapped out with disuse. If you aren't constantly forcing your nervous system to adapt to new demands it will slowly lose the ability to do so. If you stop learning, you eventually lose (or at least decrease) your ability to learn. If you stop acquiring and refining new motor skills you lose the ability to acquire, and to even maintain, motor skills.
Not worried about it? You're okay with growing old and not being able to improve your golf game? That's fine - but if your motor control declines you won't just lose your ability to sink a putt, you'll slowly lose your ability to run, then walk, then get out of a chair. For fun, go into a nursing home and ask the residents how cool it is that they get wheelchairs so they don't have to move around under their own power anymore.
Will kettlebell swings prevent you from ever being incapacitated? I'm not sure. But mainaining your neural efficiency is a big part of maintaining your ability to move yourself around, put boxes on shelves, walk through an airport, have sex - do any of the things that make life worth living. If you're in your twenties that may seem like a pretty distant concern, but the way to be healthy and have a high quality of life (and a well functioning nervous system) in your old age is to start building up your body - muscles, tendons, bones, ligaments, and nerves - now.
Mindlessly pumping away at machines or cardio equipment is just that - mindless - and it doesn't exercise your mind at all. Now doing machine circuits at Curves is certainly better than nothing, but it's nowhere near as good for you as a mentally engaging workout where you are constantly working on form the way a professional dancer is always working on her basic movements.
Summary: The age old machines vs. free weights debate may not have a clear cut answer about which is better for your muscles, but there is no doubt that free weights are better for your nervous system. Be engaged in all your exercises - really focus on form when you do pushups (pack the shoulders, tighten the core, screw your hands into the ground), not just when you do punches, and keep your nerves responsive and healthy! As an added benefit, you'll get stronger and more resilient as well.