A failure to recognize the difference between correlation and causation is perhaps the number one culprit precipitating virtually all fitness myths and misconceptions. We observe that a training “intervention” (a mode, variable, or style of exercise) is correlated with some physiological outcome or phenomenon and our brains almost unconsciously assume a cause and effect relationship. We watch marathon runners on TV during the Olympics and we assume that running makes a person thinner. We see the muscular guy at the gym lifting incredibly heavy free-weights and we assume that heavy weights cause muscles to grow larger. We observe a ballet dancer perform and we assume those hours of dancing, year after year, contribute to the toned, lean, petite physique that we witness.
In reality, the above examples are simply correlations. More specifically, they are assumed cause and effect relationships that are actually inverted. Being thin and possessing an “ectomorphic” physique is a physiological advantage for long distance running. Someone with this physique gravitates towards distance running because they possess inherit traits that allow them to excel at running. Lifting heavy weights doesn’t make our muscles grow larger; instead, people who have large muscles are capable of lifting heavy weights and so that’s what they do (where do you think really muscular guys hang out? The gym!). Ballet dancing does not cause our bodies to become lean, toned, and petite, instead, having a lean, toned, and petite physique is distinct advantage and without it, we couldn’t excel as a dancer. Being 6’8” is a distinct advantage in playing the game of basketball. However, playing more basketball won’t help an average height athlete grow taller. This intuitively makes sense to us. However, when it comes to other examples of extreme physiological characteristics (muscle size, body composition, etc.) we assume that the training or exercise employed is the “cause” of the physiological wonder that we witness. This is simply not the case.
Take Home Message: Don’t look at someone’s body, fitness, or performance and assume that what they are doing in terms of exercise, fitness, or training is in anyway the cause of what you witness. This way of thinking is almost hardwired into our brains and thus it takes a conscious awareness to avoid this faulty thinking.