Although easily accomplished, rest can be an often overlooked variable for muscle growth. In fact, inadequate rest between workouts can increase your chances for injury, while excessive rest can curtail possible fitness outcomes. Therefore, understanding program design for muscle growth enables efficient rest periods for successful hypertrophy, or increased muscle mass.
Physiology of Rest and Muscle Growth
Muscle movement occurs when minuscule muscle fibers slide past each other and contract. Weight-bearing activity increases the friction between sliding fibers and breaks down the outside layer of utilized fibers. Unlike other musculoskeletal injuries, minor fiber breakdown during weight lifting is a natural and desired outcome -- as long as adequate rest permits mending. While training promotes breakdown, or muscle catabolism, resting enables building, or muscle anabolism – your main goal for muscle hypertrophy.
Novice Weight Lifters
Generally, weight-trained muscle requires 24 to 48 hours of rest between workouts. However, rest days vary with your training status, workout schedule and fitness goals. For example, novice weight lifters should begin a program with two to three strength-training sessions per week, as stated by the American College of Sports Medicine. Additionally, sessions should be completed on nonconsecutive days -- providing one to two days of exercise-free days between sessions. Previously sedentary individuals might require additional rest days and should begin with two sessions per week on nonconsecutive days.
Intermediate to Advanced Weight Lifters
Continued muscle growth demands an increased exercise frequency and intensity over time. Transitioning toward a split routine augments training variables without compromising required rest. Split routines target one to three muscle groups per session using specific-muscle-group exercises, known as isolation exercises. Examples of isolation exercises include bicep curls, knee extensions and shoulder presses. Although intermediate and advanced weight lifters exercise four to six days per week, their muscles receive adequate rest, of 24 to 48 hours, as other muscles are worked on various days.
Regarding Muscle Soreness
Heavier lifting loads usually produce greater post-exercise muscle soreness and can require longer rest periods between sessions. Weight lifting with sore muscles limits your ability to exert force and accomplish an effective workout for muscle growth. Therefore, you should listen to your body and provide additional rest days between workouts, when needed. You can avoid lengthy rest periods by increasing your lifting load or session duration at a slow pace instead of attempting too much, too soon. Consult a doctor before beginning an exercise program.