An often misunderstood concept in the fitness world is that you must lift light weights for high repetitions in order to get that coveted “toned” look. There are many things wrong with this whole statement, so let me take a minute to clarify. Somewhere along the way, words like “toned” became distorted and misused to the point that the general public has little or no concept of what it actually means. Just a word to the wise, always be skeptical of the “one way” approach. If someone claims that there is only one way to do something or achieve specific results, punch them in the face.
A definition straight from my Human Anatomy & Physiology textbook (Marieb, Hoehn):
Muscle Tone: “Skeletal muscles are described as voluntary, but even relaxed muscles are almost always slightly contracted, a phenomenon called muscle tone. Muscle tone is due to spinal reflexes that activate first one group of motor units and then another in response to activation of stretch receptors in the muscles. Muscle tone does not produce active movements, but it keeps the muscles firm, healthy, and ready to respond to stimulation”.
When you see a bodybuilder who has extremely low body fat and visible muscle separation to the point where they resemble an anatomy chart, you are witnessing the hard work of moderate to heavy weightlifting in conjunction with a clean diet and adequate cardiovascular exercise. In order for a muscle to grow, it needs to be put under a gradual amount of stress. This stress is in the form of weight bearing exercise. The body quickly adapts to this stress and will stop responding in terms of growth if there is not a consistent amount of stress applied. This works best when stress is applied in the form of moderate to heavy weight, moderate repetitions (7-12), adequate rest and proper nutrition. We all have the same muscles, more or less built to differing degrees obviously.
SAID Principle (Specific Adaptation to Imposed demands): The type of demand placed on the body will determine the type of adaptation that will occur.
Take Bruce Lee for example, he weighed about 135 LBS. shredded to the bone!
Guess what, he didn’t lift light weight for high reps either. What he did do was a fair amount of cardio in many different forms to compliment his Martial Arts training, he lifted moderate to heavy weight often using compound movements such as barbell squats and bench presses, and he ate a very clean diet that kept his body fat level low. He also paid special attention to his flexibility training for obvious reasons.
Diet is crucial when working to become more defined (I can no longer use the word toned, sorry). In the simplest terms, you need to build muscle by lifting heavy weight consistently, keep your diet in check so you are careful not to take in too many calories and put on body fat, and be sure to include consistent cardiovascular exercise in your routine. This is all going to be different for everyone, so educate yourself, experiment safely and hire a knowledgeable personal trainer for further instruction if need be.