The belief that a successful strength training workout must result in painful muscle soreness the next day is a common notion among many gym-goers. This idea suggests that if you are not sore, your muscles will not grow, making Delayed Onset Muscle Soreness (DOMS) seem like a necessary sign of effectiveness. However, exercise science reveals a more nuanced picture of how muscles respond to training and ultimately increase in size. Clarifying the difference between the sensation of soreness and the biological process of muscle growth is important for a sustainable and effective training approach.
Understanding Delayed Onset Muscle Soreness (DOMS)
Delayed Onset Muscle Soreness (DOMS) is the dull, aching pain and stiffness that affects muscles typically beginning 12 to 24 hours after unaccustomed or strenuous exercise. The discomfort usually peaks between 24 and 72 hours post-activity before gradually subsiding. DOMS is a symptom of exercise-induced muscle damage, not lactic acid buildup.
The contemporary understanding is that DOMS is caused by microscopic tears, or micro-trauma, to the muscle fibers and surrounding connective tissue. This damage is most often triggered by intense eccentric muscle contractions, which occur when a muscle lengthens while under tension, such as the lowering phase of a squat. The pain sensation is a result of the subsequent inflammatory response as the body begins the repair process.
The Biological Drivers of Muscle Hypertrophy
Muscle hypertrophy, the biological term for muscle growth, involves an increase in the size of muscle cells primarily through increased muscle protein synthesis. This growth process is driven by three distinct stimuli generated during resistance training.
The primary and most consistently accepted driver is mechanical tension, which is the sheer force and load placed on the muscle fibers. Lifting challenging weights through a full range of motion creates this tension, activating signaling pathways that promote the creation of new muscle protein.
The second stimulus is muscle damage (micro-trauma), which prompts the body to repair the affected fibers, leading to a stronger structure. Too much damage, however, can hinder growth by diverting cellular resources toward recovery. The third driver is metabolic stress, often called the “pump,” involving the accumulation of metabolic byproducts during high-volume training.
Is Soreness Necessary for Muscle Gain?
The direct answer to whether soreness is necessary for muscle gain is no; it is not a reliable or required indicator of an effective workout. While muscle damage, which causes soreness, is one of the three stimuli for hypertrophy, it is not the dominant factor. The most crucial driver for long-term growth is mechanical tension, which can be achieved without significant soreness.
For trained individuals, the absence of DOMS is often a sign of muscle adaptation, known as the “repeated bout effect.” After initial exposure to a new exercise, muscles rapidly adapt, leading to significantly less damage and soreness in subsequent, similar workouts, even when intensity remains high.
This means a highly effective workout can result in minimal or no soreness because the muscle fibers are structurally more resilient. Consistent progression, such as increasing the weight, reps, or volume over time, is the true measure of a successful muscle-building program, regardless of how a person feels the next day.