Muscle growth (hypertrophy) is not a quick process. It requires time, commitment, and consistency and is about more than lifting weights. It also involves a thoughtful training plan, eating adequately, and getting enough rest and recovery.

The amount of muscle you gain and how quickly you can add it will differ for everyone. Your body type, fitness level, and genetics all play a role.

Everyone builds muscle at different rates, especially because genetics plays a big role. Other factors that can influence your muscle growth include:

• Age
• Training load and duration
• Training frequency and recovery from training
• Protein and carbohydrate intake
• Hydration
• Hormonal influences

Research suggests that you could see changes in your muscle growth as early as seven sessions after starting a training regimen, while other studies say it could take up to 18 sessions.

For instance, one study found that muscle growth can be seen after about 10 workout sessions. However, significant muscle growth is seen after about 18 sessions.

Differences in Muscle Building Between Males and Females

Sex also plays a role in muscle building. For example, testosterone is a major factor. Men have as much as 15 times more testosterone than women, so they tend to build muscle faster, and their muscle mass is typically greater. Men also tend to be taller with longer bones, which gives them more leverage when lifting weights, resulting in quicker muscle growth.

Other research has found that women may experience greater strength improvements while men can be more prone to strength training injuries. The size and distribution of muscle fibers may also explain sex differences in muscle endurance. For instance, when testing isometric muscle endurance (how long you can hold a muscle contraction), women experience less fatigue than men.

You create muscle tension when you contract your muscles against some sort of resistance—like lifting weights or doing bodyweight exercises. Researchers believe that this tension slightly damages the muscle tissue, resulting in a growth response.

Keeping your muscles exposed to this tension also causes a build-up of various metabolites like lactate and creatine. This process causes metabolic stress in your muscle tissue, which also triggers growth.

Your genetics, your age, and your body type largely influence how much muscle you gain and how fast. For example, a male in their 20s with a large percentage of fast-twitch muscle fibers (those that respond to growth the easiest) could gain lean muscle mass at a rate of two pounds per month. That rate declines as he ages and his body adapts.

By contrast, someone the same age with a different genetic profile and body type may only be able to build muscle at a rate of one-half pound per month. The speed and growth of muscle will vary from person to person, but anyone with an effective training program and supportive nutrition can build muscle.

Most people think that you should focus on strength training to gain muscle, but there is some evidence that cardio is also important.

Here are some training tips to ensure you are making the most of your workouts to reach your goal of muscle growth.

Strength Training

Strength training is the heart of muscle building. In order to grow your muscles, they must experience a load or weight they are unaccustomed to for a certain period of time. When this happens, they respond by increasing in thickness.

The American College of Sports Medicine (ACSM) provides the following guidelines when lifting weights:

• Start by targeting your main muscle groups with 8-10 exercises at least twice weekly
• Perform 8-10 repetitions of each exercise and do 2-3 sets of those exercises with no more than 60 seconds of rest between sets
• Use a weight that challenges for you or requires an effort level of 8-10 (on a scale of 1-10)

You can base the amount you lift on your “one repetition maximum” (one rep max)—or the heaviest weight you can lift once. Select weights 70-80% of your one rep max weight.

Cardio

It had been rumored that cardio (or aerobic exercise) worked against muscle growth. However, some research indicates this may not be the case, especially because cardio strengthens your cardiovascular system. This can help with your overall exercise capacity and boost muscle growth and function, especially if you are an older adult.

Researchers indicate that the key lies in your cardio’s frequency, intensity, and duration. They recommend exercising at an intensity of 70-80% of your heart rate reserve (HRR). Your HRR is determined by subtracting your resting heart rate (RHR) from your maximum heart rate.

You also need to keep your cardio sessions to about 30-45 minutes long and do them 4-5 days per week.

Rest and recovery play important roles in muscle building. When lifting weights, you need to consider how long to rest between sets and the frequency of your rest days to allow your body to recover after working out.

If you rest too long or not long enough, you risk undermining your muscle-building goals, so it is important to plan accordingly.

Resting Between Sets

It is generally recommended to wait about 60 seconds between sets when lifting weights to promote muscle growth. Resting longer than one minute compromises the metabolic stress of training.

Resting for less than 60 seconds does not allow your body enough time to recover, and your muscles may not perform well in the remaining sets.

Recovery Days

To keep your muscle growth on track and help prevent overuse injuries, your muscles need time to rest and regenerate between workouts. One way to accomplish this goal is to choose a muscle group to work once or twice a week. This allows your body to adapt to the changes and build muscle.

For instance, concentrate on your chest, shoulders, and triceps on Monday, followed by your legs on Wednesday, and your back and biceps on Friday.

Research shows that waiting 72 hours before training the same muscle group again allows enough time for your muscles to repair themselves. This will help you reach your muscle-building goals.

Eating enough protein also supports your muscle growth goals.

Before Working Out

Experts often recommend eating 20-40 grams of protein every 3-4 hours or 0.25-0.40 grams of protein per kilogram (kg) of body weight. Your body can only use about 20-40 grams of protein at each meal, so eating more is not necessarily better.

The greatest muscle protein synthesis occurs immediately after a workout up to two hours after, so try to consume protein within 30 minutes after your workout if possible to boost muscle recovery and gains. You can also opt for 10-12 grams of essential amino acids to stimulate muscle protein synthesis if pressed for time.

After Working Out

You also need to fuel your body before workouts. Consider eating at least 30-60 grams of carbs plus 5-10 grams of protein about 30-60 minutes before you plan to workout. Doing so can help you get the most out of your workout.

Eating this combination before a workout can improve your recovery and increase lean mass.

Supplements

Finally, ensure you are eating plenty of fruits and vegetables, and if you have a potential nutrient deficiency, take a supplement to fill that need.

Ask your healthcare provider to test for deficiencies like vitamin D, which is essential for muscle building.

Supplementing with creatine may also be beneficial, but talk to your doctor for guidance.

Hypertrophy (muscle growth) requires time, commitment, and consistency and includes a training plan that features both weight lifting and cardio, as well as rest and adequate nutrition.

Everyone can build muscle, but not everyone will experience the same gains or speed of muscle growth. Genetics, age, hormones, nutrition, and other factors play a role.