This week I was asked a question that certainly comes up from time to time; which is better, machines or free weights? The answer really depends on what the intention of the exercise is. Both forms of resistance training have a lot to offer and can be a beneficial part of many training plans. Let's take a look at some key features of each.
Features of Exercise Machines
Before we can properly discuss the features of exercise machines it's important to make a few small clarifications about just what we're talking about. A wide variety of exercise machines exist ranging from cardio equipment such as treadmills and ellipticals to resistance machines like the leg press or even to free cable pulley resistance stations. For the purpose of this discussion we'll be focusing on machines that guide the movement such as a seated row, or leg press and so on. Cardio equipment is great, but comparing it to free weights is a discussion for another day. Cable pulley stations are actually a lot more similar to free weights than to other machines so they will also not be included in this analysis.
In part 1 we talked about how to use specificity for developing strength and in part 2 of this series energy systems were discussed in the same context. Part 3 is going to discuss flexibility.
Specificity and flexibility
Flexibility refers to a muscles elasticity or ability to lengthen. Inflexible muscles restrict movement around the joints they cross, while flexible muscles allow for freedom of movement. Training flexibility is important because, just like all other fitness attributes, if you don't use it - you lose it. As far as specificity goes, this simply means that flexibility training should be done for specific muscles that cross joints.
Energy Systems - Basic Primer
Energy systems are the ways that our bodies convert substrates (think food) into energy (a compound called ATP - adenosine triphosphate) to power physical activity. For simplicity we're going to discuss energy systems in three categories.
The ATP/PC system uses the very limited supply of stored energy in the muscles. This makes the energy instantly available in a powerful and short burst, but it runs out quickly as well. Count on this burst lasting up to ten seconds, any longer and the energy will need to come from a different energy system, such as the glycolytic pathway also known as the lactic acid system.
Energy produced by the lactic acid system is drawn from carbohydrates. Sugar in the blood and muscle stores called glycogen are broken down into ATP (energy). This system can produce a fairly substantial supply of energy, but in order to create energy this fast the carbohydrates aren't broken down completely causing a build up of lactic acid. The build up of lactic acid will cause an individual to slow down and rely on the aerobic energy system after about two minutes.
Finally, the aerobic system can use the power-house of completely breaking down carbohydrates and fat for energy, which allows for a nearly endless supply of potential energy. It just takes longer to make this energy available, so the power (work per unit of time) output isn't as great in the short-term, but over the long term this is the primary energy system that fuels activity.
It seems everywhere you look there is some new exercise program promising to be the Holy Grail of a fitnessdom that will finally get you the "results" that you so desperately desire. While some of these programs have very good information, there are no magic bullets in the fitness industry. The fact is that to get results a person needs to put in the time for working out and make healthy eating a priority. However, what you work at can make all the difference in helping you achieve the goals you have.
It's important to understand the law of specificity when planning your work-out routine. The law of specificity dictates that your body will adapt to the demands imposed on it. It's quite simple and logical really, but sometimes gets overlooked. For instance most people would quickly realize that lifting weights that are so heavy only three repetitions can be completed for a few sets isn't going to prepare them to run a marathon this spring (certainly not as a stand alone method anyway). However, sometimes I'll still see this basic rule being disobeyed. For instance I had the privilege of working with a client that was fairly serious about playing hockey which is an extremely fast paced game requiring sudden bursts of speed and changes of direction. However for conditioning he had been advised to spend hours skating laps or running for periods of 30-60 minutes. Understanding specificity it is apparent that this type of training isn't optimal. It might be appropriate as a phase of training, especially early on to build up an aerobic base in a deconditioned athlete. But a closer look will quickly reveal that with short shifts on the ice that short (no more than two minute) higher intensity intervals would more closely match the demands this athlete is up against.