The right angle: the geometry behind building muscle

Men's Fitness, April, 1999 by Christopher M. Lockwood

The next time you exercise your biceps, try performing some seated incline dumbbell curls. The positioning of your humerus (upper arm) just slightly behind your torso will increase the initial stretch on your biceps, forcing them to work through a different range of motion to complete the exercise.

The same reasoning applies to your triceps. Performing extensions with your arms extended overhead, compared to doing a traditional pressdown, increases the stretch on the long head of your triceps because its point of origin is above your shoulder.

To effectively build your biceps and triceps, you have to tax those muscles over both joints.

1. Sternocleidomastoid

2. Sternocleidomastoid

3. Trapezius

4. Pectoralis major

5. Rectus abdominis

6. Deltold

7. Biceps brachii

8. Brachialis

1. Triceps brachii

2. Latissimus dorsi

3. Teres major

4. Deltoid

5. Infraspinatus

6. Rhomboid

7. Trapezius