Get Bigger Biceps by Just Tensing Your Muscles

If you tense your muscles 100%, then you will gain strength and muscle like you would if you used a barbell.

Steps

Relax and breathe.
Let your arm hang loose.
Tense your biceps as hard as possible and Imagine you're holding the heaviest barbell in the world.
Slowly lift for about 10 seconds.
Then slowly let your arms back down (while tensing still).
Concentrate on the exercise.
Do 20 repetitions.
Hold the forearm or wrist of one arm and oppose with the other arm. This is a method which was used by Charles Atlas to grow big biceps. The advantage to this method is that no weights are involved and the stronger you become from this, the more strength you gain through continuous practice. It involves holding one arm by the wrist or forearm and opposing the movement of the other arm while curling the arm in use like you're lifting an imaginary dumbbell. Do this for a count of 10 reps. As you grow stronger and can endure more punishment, you can create sets comprising of up to 40 reps per set.
- After a month you should notice an increase in size and strength.

Isometrics and Dynamic tension exercises are not advised to be done by people with high blood pressure.
Harry Wong `s book "Dynamic Strength" also provides a lot of information on dynamic tension.
If your interested then Look into Charles Atlas`s books.