The Major Limitation of a Free Weight: Unilateral Resistance
Arthur Jones, founder of Nautilus Sports Medical Industries and later the MedX Corporation succinctly stated, "Man is a rotary animal." When we contract our muscles, we are causing rotational movement around a joint or a series of joints. Herein lies the primary limitation of a free-weight; while our joints are causing rotary movement, gravity acts on a free-weight in only one direction. The end result is that in most free-weight exercises, the targeted muscle is exposed to direct resistance for only a small portion of the range of motion. An intelligently designed machine includes mechanical elements that make the resistance omnidirectional; thus our muscles must create limb movement that directly opposes the resistance throughout the entire range of motion. This is the foundational advantage of machines when compared to free-weights; an advantage that the vast majority of exercisers and fitness professionals are completely unaware of. Arthur Jones says it best: "Since the "direction of movement" of the involved body-parts is constantly changing, the "direction of resistance" must change in exact accord, automatically, simultaneously, instantly; again, this requirement can only be provided by a rotary form of resistance."
Intensity Defined
The scientific literature clearly delineates that “intensity” is the primary stimulus for our bodies to change and improve as a result of engagement in a resistance exercise program. Intensity is most important controllable factor (uncontrollable factors include percentage of fast twitch or slow twitch muscles fibers, muscle belly length, tendon length, and muscle insertion) in an individual’s response to an exercise program. It appears that the other variables of an exercise program, although important, are simply not as meaningful as the intensity with which we exercise. This leads us to an important (and often ignored) question: What is intensity? Intensity can be defined as a percentage of our momentary ability to perform an exercise. Stated other wise, it has nothing to do with the amount of weight we lift, it has everything to do with our effort. Lifting a relatively heavy weight for 6 reps or a relatively light weight for 20 reps are both deemed “intense” so long as it is utterly impossible to lift a 7th rep or a 21st rep. When looking to produce better results, faster results, or to break through a plateau, the first place to turn your attention to should be your training intensity. Most well intended trainees err in almost the opposite direction. They add more exercises, add more sets, and/or increase the number of weekly workouts. All of these are steps in the wrong direction.
I'm going to sign up for a marathon to help me lose weight
This is the intention of many first time marathoners. The assumption is something like this: Training for a marathon involves a heck of a lot of running; if I sign up for a marathon really get serious about running, I'll lose a heck of a lot of weight in the process. The reality is far different from this. A 2010 research study indicated that of novice marathoners completing a 3-month training program (a time period in which they ran literally hundreds of miles and expended tens of thousands of calories), some people lost weight, some stayed the same, and many gained weight. Here is a breakdown of what happened:
New Research: It's not the amount of weight that matters
The Process for Sustained Results
Business and self-improvement authority, Brian Tracy asserts that long-term thinking and decision-making is the hallmark and commonality among all successful people. Certainly, this mindset lends itself to effective exercise. The commitment to "sustainable" or long-term resistance exercise is the cornerstone of an intelligent fitness prescription. Performed properly, resistance exercise mitigates chronic disease risk factors, reverses aging, and stimulates fitness improvements while minimizing injury risk. If you take a long-term approach to resistance exercise, I think the process should look like this:
Most importantly, the above process only works when it is built upon a foundation of evidence-based exercise. That is, the exercise prescription should be a representation of the preponderance of scientific research. This is the only way to guarantee safe and result-producing exercise. If you aren't using an evidence-based approach, you are just making it up as you go. |
Our Favorite Area of Research
One of the most important discoveries in the field of exercise over the last 10-15 years is that resistance training is far more beneficial for our health and the prevention of chronic disease than we ever would have imagined. Traditionally, we assumed resistance training outcomes centered around increases in muscle strength, muscle size, improved athletic ability, and increased bone mineral density. We relegated health improvements to aerobic exercise. A considerable body of research has shifted our understanding and all but deconstructed this false dichotomy that resistance training is for strength and aerobic exercise is for "health." But why is strength training so beneficial for our health? Emerging science tells us that the answer is, in short, "myokines." Myokines are proteins that are created when our muscles contract. These myokines influence the "crosstalk" between different organs in an autocrine, endocrine, or paracrine fashion. Through these channels, it appears that myokines may have a profound positive effect on metabolic disorders, type 2 diabetes, obesity, and a number of cardiovascular disease risk factors. 20 years ago we knew that resistance training made you stronger. 10 years ago we realized that it makes you healthier. We now are starting to understand that myokines are the probable physiological mechanism for the myriad of health benefits we see from resistance training (benefits that most exercisers, researchers, and health care professionals are still unaware of). The next time someone asks you why you strength-train, your answer should be, "To produce myokines, Bro."
The Ever Controversial "How Many Sets?"
In the strength training and the fitness world, you are viewed as a bit of an outcast if you recommend the performance of only one set per strength training exercise. Over the past 14 years, I have had clients, coaches, physical therapists, physicians, bodybuilders, athletes, and a myriad of fitness professionals tell me that in order to reap the maximum benefit from strength training, you need to perform multiple sets of an exercise. Indeed, the default recommendation seems to be: Perform 3 sets of 10 repetitions. Interestingly, the research does not support this long held axiom. Two scientific journal articles published over the last two years address this very topic. The authors of both articles, Dr. Ralph Carpinell from Adelphi University and James Fisher from the United Kingdom, performed a critical examination of a recent meta-analysis (a meta-analysis is a statistical tool that allows a researcher to pool multiple studies together to look for a collective conclusion) published in a popular strength and conditioning journal. In their separate publications, Carpinelli and Fisher examined each study that was included in this particular meta-analysis. Both researchers concluded that the studies included in the meta-analysis did NOT support the assumption that multiple sets are superior to single sets.
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