1. The increased blood flow delivers more nutrients to muscle cells thus helping them to grow during adaptation and recovery phase.

2. Its ability to reduce inflammation helps muscles that have been subjected to extreme stresses.

Given its close relationship with arginine care should be taken in applying small doses and increasing them gradually until an optimum level is reached. Bear in mind that many protein powders and other supplements are fortified with amino acids so check labels carefully. The manufacturer's instructions should be followed in all instances.

3. Biceps brachii - biceps covers front part of upper arm and consists of a long head and a short head. The long head crosses shoulder joint and works with front deltoid to raise arm to front.

4. Triceps brachii - triceps covers the back of upper arm and consists of three sections - long, lateral and medial heads. The role of triceps is to straighten arm at elbow.

5. Brachialis - this muscle lies between upper arm bone and biceps. It helps biceps to bend elbow when palm is facing sideways.

6. Forearm muscles - forearms consist of many little muscles called flexors and extensors. The largest forearm muscle is brachioradialis that lies close to elbow.