Whether training large muscle groups, such as the legs, only once per week is sufficient for growth is a frequent debate among those pursuing fitness. The effectiveness of any training schedule depends entirely on an individual’s current fitness level, genetic makeup, and, most importantly, their specific goal. To determine the right approach, it is necessary to look beyond simple routines and understand the underlying biological response to resistance exercise.
Understanding Muscle Protein Synthesis
Muscle growth, or hypertrophy, is driven by a spike in muscle protein synthesis (MPS) following resistance training. When muscle fibers are stressed, the body elevates the rate at which new muscle proteins are created. This elevated state of MPS must be repeatedly triggered to achieve consistent muscle gain.
For most individuals accustomed to weight training, this spike in MPS is short-lived, typically returning to baseline levels within 24 to 36 hours post-exercise. While untrained beginners may experience elevated MPS for up to 72 hours, the window for optimal anabolism closes quickly for experienced lifters. Allowing the MPS rate to drop for five or six days before the next stimulus is inefficient because it introduces a long period where no muscle-building signal is being sent. This biological timeline suggests that a frequency of once per week is generally suboptimal for maximizing continuous growth.
Sufficiency Based on Fitness Goals
Whether a once-per-week leg day is adequate depends significantly on the individual’s goals. For those focused primarily on maintenance, a single weekly session is sufficient to retain existing muscle size and strength. A lower frequency provides the necessary stimulus to prevent atrophy without demanding significant recovery resources.
However, for individuals whose goal is hypertrophy (muscle growth) or maximizing strength gains, training legs only once every seven days is generally inefficient, particularly for intermediate and advanced lifters. Research shows that training a muscle group at least twice per week yields superior results for muscle growth compared to a single weekly session. A higher frequency allows for a more sustained elevation of the muscle-building signal across the week.
Beginners represent a unique case because the novel stimulus of resistance training is potent enough to produce initial results even with a once-a-week schedule. This rapid early progress, often called “newbie gains,” is largely due to neurological adaptations. However, progression will eventually stall once the body adapts to the low training frequency. To continue progressing, beginners must increase their frequency to challenge the muscle more often and maximize the long-term hypertrophy response.
The Critical Role of Training Volume
While frequency is important, the total weekly training volume remains the primary driver of muscle growth. Volume refers to the total number of challenging sets performed for a muscle group each week. If a person is constrained to training legs only once per week, they must incorporate high volume and intensity into that single session to compensate for the lack of frequency.
Cramming all the necessary weekly work into one lengthy session carries distinct drawbacks. Performing too many hard sets for a single muscle group in one sitting can lead to diminishing returns, often referred to as “junk volume.” Evidence suggests that exceeding 10 to 12 effective sets for a muscle group in a single session may not provide a proportional increase in growth. This concentrated effort can instead increase the risk of injury and systemic fatigue.
A single, high-volume session places a massive strain on the central nervous system, demanding an extended recovery period that can negatively impact other workouts throughout the week. This concentrated effort also increases muscle damage, which prolongs recovery. Distributing this volume across multiple days is generally safer and more productive for hypertrophy.
Effective Training Frequency Alternatives
For those whose goal is to maximize muscle growth, distributing the weekly volume across two or more sessions is a more effective strategy than relying on a single workout. This approach ensures that the muscle-building signal is re-triggered before the effects of the previous session have completely faded. Common, effective training schedules include the Upper/Lower split, where legs are trained twice per week on non-consecutive days. The Push-Pull-Legs (PPL) routine also results in a frequency of roughly twice per week. Full-body workouts stimulate the legs three times per week with a lower number of sets per session. These alternatives allow for a more manageable volume per workout, better recovery, and a sustained anabolic state throughout the week.