For ectomorphs, building muscle mass proves challenging. That's why ectomorphs are known in the weight lifting community as a "hard gainers." Weight gain doesn't come easily, so to build muscle mass on a body with a lean disposition requires discipline, determination, and some creativity.
Do Your Favorite, and Not-So-Favorite, Exercises
The exercises you enjoy doing easily find a place in your schedule. However, building muscle mass necessitates working out the entire body in a variety of ways. In order to get the results you want, you must add some exercises that are far from your favorites' list.
Those unfavorable exercises provide the potential for the greatest gains. By incorporating exercises that you dislike into your regimen, you give yourself the opportunity to engage muscles that were previously neglected. Early on, these muscles will respond quickly, giving you new areas of muscle growth.
Variety and Variations of Exercises
Along with your favorite exercises, search for other exercises that target the same muscles groups differently. For example, bicep curls are great for making the biceps big and strong. Lat pull-downs, upright rows, and pull-ups also work the biceps along with various other muscles. The biceps will reap the benefits of doing these exercises along with curls.
Variations of exercises are great too. You can do a standard bicep curl, either with dumbbells or a barbell. Change your grip to an overhand grip and you can train the biceps and the forearms. Widen your grip on a barbell to target the short head of the bicep more. You can even have a seat on an incline bench to hit the long head of the bicep more. Variety in training will pay great dividends towards your goal of building muscle mass.
Eat for Muscle Growth
With all the training you're doing to build muscle mass, your body needs to receive the proper fuel to provide you with the energy to train and the nutrients to rebuild after training. It takes 3,500 calories to gain a pound. That's in addition to your daily recommended caloric intake. It's hard to add another 3,500 calories to what you already consume in a day. The most common recommendation is to add 500 calories to each day and you'll gain a pound per week.
Maintaining a regular schedule for both your workouts and diet will keep you on task. You must let your desire to build muscle mass show in the effort you put into planning out your regimen and sticking to it. Putting in the work, eating right, and getting plenty of rest, will encourage growth in your muscle mass by leaps and bounds.