FOR AJAY: You seem to be a tall slim guy - an ideal weight for a guy of your height would be around 170/180 (depending on how much muscle mass you like to gain). To gain muscle, you need to do the following: 1. Change in your daily diet : eat lots more carbohydrate (rice, pasta, potatoes, bread, etc). Since you are slim, you can afford to have extra fat percentage in your food. The fat/carbo/protein ratio for you: 40/30/30 the first month. The second month the ratio (in order above): 30/40/30. Third onwards: 30/30/40. When I mean fat, try to avoid animal fat as much as you can - go for healthier fat source such as walnuts, cashewnuts, peanuts, olive oil, etc. Carbohydrates provide you with energy when you work-out. Protein helps develop the muscle mass. Drink plenty of water - 80 ounce a day. 2. Exercise: the best way to gain lean muscle mass is weight training. Join a local gym, if you can afford hire a trainer for an hour, if not you can ask the guys there on various tips. Begin with dumbell work-out the first couple of weeks - dumbell benchpress, dumbell squat, push-ups, etc. Before weight training, a warm-up & stretch is higly recommend (see my earlier postings). After a month or so, your work-out sequence will be: warmup/stretch - dumbells - barbells - machine - cool-out. For cool-out you can walk for couple of hundred meters. 3. Nutrition Supplements: Right after you are done with work-out dash home and make yourself a protien-shake. Protien shake powders are available at GNC. According to a research, protein shake right after work-out helps repair the torn muscle tissue, and helps develop & grow muscle mass. Since you are slim, you may also wanna try some weight gainer supplements (which will help you gain muscle - but not fat). Some good protien shakes are: MetRx, ProComplex, Myoplex, and any Whey protien powders. Regarding weight gainers: check with GNC. 4. Patience & committment: It will take you atleast 3 months before you see a sizeable difference in your body structure/tone. So have patience. The results depends on your committment. From my experience, work-out is most effective when you have a combination of proper-eating/exercise/nutrition supplements. Gaining muscle won't deprive you of your agility - infact it will add more power to it. A good calf, hamstring, and thigh muscles will make you a powerful sprinter.