送交者: HunHunSheng 于 2005-11-22, 10:28:11:
Free Weight vs Machine: You Decide!
The age-old debate continues between free-weight exercises and machines. Despite what you may have heard, one is not necessarily better than the other in all cases. In fact both are beneficial given the right circumstances.
My definition of a free-weight exercise is; any exercise or piece of equipment that does not balance the load for you. For instance, when you are performing the pull-up your body is the weight and only your arms balance it. That makes the pull-up a free-weight exercise. Conversely, if you use the Gravitron machine to do your pull-ups your feet will be resting on the pegs which balances your body. To help you differentiate between free-weight exercises and machines here are a few examples of each.
Free-Weight Exercise vs Machine
Squat vs Leg Press
Bench Press vs Lat Pulldown machine
Dumbbell Curls vs Leg Extension
Pull-up vs Gravitron machine
Let’s get right to the advantages and disadvantages of each type of exercise so you will have a better handle on what fits into your specific situation.
FREE WEIGHTS:
Advantages
Forces you to recruit more muscles than machines. These "extra" muscles are recruited to help you stabilize the weight. In essence, they are balancing the bar and are called stabilizer muscles.
Does not force you to work in the same plane of movement every time. This is an important advantage for safety reasons because using machines only can lead to serious injury. They do this by inadvertently over developing the muscles and causing undo stress to the connective tissue in the area worked by the machine. When using free-weights your body naturally adjusts to the exercise and you will adjust your posture for the most comfortable position. Each time this position will be slightly different so you reduce the chance of over use syndrome.
More calories expended due to the higher amount of muscles involved. This is pretty self-explanatory the more muscles you use the more calories you burn. Another side to this advantage is the fact that free-weight exercises encourage work from the larger muscles in the body. Which means, you guessed it, more calories burned.
Better adaptability than machines for targeting specific muscles, and for simulating sport-specific movements. Sport-specific exercises are those that emulate a movement in a particular sport. The wrist curl is sport-specific to the follow through in the golf swing. I know of cases where golfers have added 20 yards to their drive from doing wrist curls! Here are a few more examples of sport-specific exercises along with the sport with which they are associated.
Exercise - Sport Specific Movement
Pullover Pitch - Baseball
Wrist curls - Golf swing
Dumbbell flyes - Tennis forehand
Allows you to increase strength bilaterally. When you work with dumbbells you can increase the strength of your weak arm or leg separate from your strong limb. This can be very advantageous to beginners if form is good.
Disadvantages
Increased risk of injury because you are more likely to have bad form with free-weight exercises.
With free-weight exercises you need the assistance of another person as a spotter.
Free-weight exercises generally require more set up time than machines.
MACHINE WEIGHTS
Advantages
Reduced risk of injury due to load stabilization throughout the exercise.
You can efficiently target a weak or underdeveloped muscle group without recruiting other muscles.
You can complete a circuit of only machines, which will work your entire body, in less than 30 minutes.
No need for assistance from a spotter.
Disadvantages
You can’t recruit as many muscles simultaneously as you can with free-weight exercises.
Fewer calories burned in comparison to free-weight exercises.
During exercise you are stuck in one plane of movement. What does this mean you ask? This means that in time you will over-develop certain muscles causing an imbalance, which could lead to future injury. The specific path that the machine follows each time you use it causes this. This path locks your joint and connective tissue into the same spots every time, thus subjecting them to injury.
Not as adaptable for sport-specific exercises.
The best personal trainers realize that all situations are different, and that all individuals require unique training programs to reach their fitness goals. In general I recommend machines for the first month of training to reduce the risk of injury. The second month I like to go right to the dumbbells to equalize strength bilaterally. From this point on, I recommend that clients vary usage between machines and free-weights so the body doesn’t have a chance to adapt. Remember that the body is highly adaptable and your results will begin to suffer if you use the same program for too long. Try to vary your program every 6 weeks for maximum results.