One of the decisions you must make when you begin a training program is which muscle groups to train together. By choosing the right muscle groups to work out on the same day, you can build your physique and see improvements faster. A general rule of thumb is to try to train smaller muscle groups that are used in exercises for large muscle groups. For example, triceps are typically trained on days when you train your chest, because the triceps are used in the bench press, which is a centerpiece of chest training. Once you are familiar with muscle groups and how they function, you can readily incorporate more exercises into your training program.
Chest & Triceps
Training your chest and triceps muscles on the same day is a common workout strategy. Chest exercises, which work the pectoral muscles, are very popular with weightlifters. The bench press is perhaps the most well-known weight-lifting exercise and is often the first exercise of the day in a weight-lifting routine. When you push the barbell up from your chest during bench pressing, you also work your triceps muscles, which are the muscles located on the back of the upper arm. Triceps muscles are used in any sort of motion or exercise that requires you to straighten your arms. Since you straighten your arms for some of the major exercises in chest routines (bench press, incline bench press) it makes sense to add some triceps exercises to the same day you train your chest. Try adding at least two different triceps exercises to the end of your chest workout. Two great exercises for triceps are rope pushdowns and lying triceps extensions.
Back & Biceps
Train your back and biceps together. Exercises that train the large muscles of the back (latissimus dorsi) need the biceps in order to be performed properly. The biceps are located on the front of the upper arm and are used for any sort of pulling motion where the arm is bent in toward the body. Several well-known back exercises such as lat pulldowns, pull-ups and rows cannot be done without the aid of the biceps. After you finish your back exercises, add two or three biceps exercises such as barbell curls, alternate dumbbell curls or concentration curls.
Hamstrings & Quadriceps
An efficient leg workout should include exercises that train the hamstrings and quadriceps muscles. You always want the back of your leg (hamstrings) to be as strong as the front of your leg (quadriceps, or thigh). If one side of your leg becomes stronger than the other, you risk straining or even tearing the weaker side during exercise. Many leg exercises work both the hamstrings and quadriceps muscles at the same time. Some examples of these exercises are: squats, deadlifts and lunges. Make sure you incorporate some of these exercises. Additionally, if you do an isolation exercise for either side of the leg, make sure to do an exercise for the other side. A common example of this is to do a set of leg extensions for the quadriceps and then do a set of leg curls to work your hamstrings.