You never want to train with sore or tight muscles. Triceps are especially important since push ups and punches require them to work. Stretching correctly will increase your flexibility and reduce the risk of injuries caused by lesions of the connective tissues (such as the periosteum) and other nasties.
Overhead Lat Stretch
Put one arm overhead. Grasp elbow or wrist overhead with other hand. Pull elbow toward head and back or pull arm down toward opposite shoulder. Lean torso to side, away from direction of arm behind head. Hold stretch. Repeat with opposite arm.
This stretches the Latissimus dorsi and Teres Major. Avoid over stressing the neck in the front.. See Overhead Triceps Stretch for a similar exercise which can be performed with this stretch.
Rhomboid Arm Across Chest Stretch
The rhomboid muscles of the upper back are responsible for pulling your shoulders backward, as you might do if you were standing at attention. Excessive contraction of these muscles can lead to tension in the upper back. Actions that pull the shoulders forward while broadening the upper back, such as giving yourself a hug, stretch the rhomboids.
Begin this exercise standing tall with your back and neck straight. Gently take your arm across your body using your other arm to take it a little further (figure 2). Hold at a mild to moderate stretch pain free for 15 seconds and repeat 4 times on each arm.
Upper Trapezius Stretch
The trapezius muscle covers a large area of the back, neck and shoulders. Its main function is to move the scapula, or shoulder blade, and help support your arms. If you spend a lot of time sitting at a desk or behind the wheel of a car, the trapezius muscle can shorten and tighten, which affects mobility in your neck.
Grasp wrist or hand from behind and pull arm to opposite side. Tilt head away from lowered shoulder by positioning ear toward front of opposite shoulder. Hold stretch. Repeat to other side. You can also pull your head to one side with the same arm but be gentle and don’t tug…just stretch slowly.