Resistance training is generally performed to improve strength, power, and hypertrophy. To achieve these goals, one should lift heavy weights in a low-volume resistance training program.
High-repetition resistance work performed in many group fitness classes should be used solely for endurance training. This approach involves overload through training duration and volume (i.e, increasing the amount of “work”), which results in mediocre outcomes for athletes.
Although calisthenics, body-weight exercises, and circuit training with light weights may be challenging for those who are new to resistance training, improvements occur rapidly. Continued development depends on increasing resistance, rather than volume. Recognize that the most significant contributor to improvement is progressive overload. This means you should increase the amount of resistance used for exercises as consistently as possible.
Light Weights and High Reps for Tone?
The suggestion to avoid high-repetition resistance training may seem inconsistent with the frequently used “light weights and high reps” strategy to develop “toned” but not “bulky” muscles. If this training approach is so flawed, why do people train this way and why does it appear to be beneficial?
The explanation for this apparent “toning” phenomenon has to do with the two basic types of muscle fibers: slow twitch, involved in endurance activities, and fast twitch, involved in rapid muscle contractions used for strength and speed. High-repetition training with reduced weight has its greatest impact on slow twitch muscle fibers. Slow twitch fibers are smaller than fast twitch fibers. If the fast twitch fibers are not also stressed with low-repetition, high-intensity training, the muscle cannot develop to its potential.
People who train this way occasionally experience minor benefits, but the strategy is far from ideal.
Will I Get Too Big?
For those who worry about developing excessively large muscles (a common concern among women and aesthetic athletes), recognize that extreme muscle growth is unlikely to occur simply as a result of lifting weights. To develop a physique like a bodybuilder requires hypertrophy-focused training, high testosterone and growth hormone production (or anabolic drugs), and consumption of enough food to gain significant muscle mass. Do not fear heavy lifting if you are trying to avoid large muscles. Your body measurements may actually decrease as you develop more muscle and lose body fat.
If you are one of the unlikely few to find your muscles grow to an undesirably large size after an extended period of heavy training, the solutions are simple: stop increasing the weight, volume, or intensity of your workouts or eat less.
Take home message
For athletes and anyone training to improve body composition, lifting heavy weights in a low-volume resistance training program will contribute to three beneficial outcomes: strength, power, and hypertrophy. Lifting light weights will result in mediocre outcomes in all three domains; this practice should therefore be avoided.