What causes muscles to get bigger when you exercise?

Answer 1

Muscle grows larger from exercise because more muscle filaments are created within each cell. There are thick myosin filatments and thin actin filaments which form cross bridges with each other. The heads of the thick filaments undergo a power stroke in which they bind to the thin filaments and the head bends down, pulling the thick filament across the thin filament, shortening the muscle and creating tension.

Think of a pulling a car with a rope. you are the thick filament, the rope is the thin filament. You grab the rope and pull, and then move your hands down the rope and do it again, this is like the power stroke. Now, add more people and more ropes, you can pull a much heavier load. That is how the muscle gets stronger.

Answer 2

Muscle size increases due to hypertrophic adaptation and an increase in the cross section area of individual muscle fibers. This will reduce the muscle's energy supply which will then cause damage to the muscle tissue. During recovery, the supplies of glycogen and phosphocreatine will replenish from carbohydrates and creatine ingested as food. Amino acids supplied in the diet will trigger the protein synthesis that repairs the damaged muscle and which leads to the creation of bigger muscle fibers.

Answer 3

Now that you know what a negative contraction is, let's discuss why resistance training makes you bigger and stronger if you already don't know. The point of resistance training is to cause skeletal muscle damage. Or what I like to call "positive damage". When you work out you cause microscopic tears in the muscle fibers and with adequate rest and nutrition, the fibers repair and regenerate and are able to handle future bouts of similar work while experiencing significantly less damage. What does this mean to you? It means you cause positive muscle tissue damage, your muscles repair, adapt to the demands you place on them and you become bigger and stronger. By progressively forcing your muscles to do more and more work over time, this repairing process will repeat and your muscles will continue to grow and get stronger.

Bringing It All Together

Now to my main point - using negative training to build stronger and bigger muscles. Without beating around the bush any longer, eccentric contractions cause greater muscle damage and thus provide the stimulus to make your muscles grow and strengthen. This may be due to eccentric contractions allowing greater force production in addition to less fiber recruitment, which means the fibers are stressed more and more damage occurs. This damage usually is experienced by the soreness you feel the next day or two. If you've ever experienced the soreness in your thighs while performing simple tasks such as walking down stairs or sitting on the toilette days after a tough leg workout, you know what I mean. If it wasn't for eccentric contractions you'd fall on your ass during a squat, slam the weight stack back down on leg extensions and leg curls, and probably cave your chest in with the force from your knees on a leg press machine.

Working Negatives Into Your Routine

You may want to consider slowing down the eccentric portion of your repetitions during your workouts and really concentrate on lowering the weights slowly and completely under control. Something I personally enjoy doing sometimes (especially on an incline or flat dumbbell bench press as my second exercise) is lowering the weight very slowly and deliberately for a count of maybe 4-5 seconds and then when I reach the bottom, I explode up forcefully. You won't be able to perform as many repetitions as you usually do with the same weight so you'll need to use a lighter weight. But if done properly, you'll get a great stretch and pump and chances are you'll feel it the next day. Another way to work negatives into your program if you have a training partner is to do eccentric-only contractions for one exercise. This will allow you to really increase the weight you normally use, because you can create greater force production eccentrically. One of the best examples is with the leg extension machine. Load up the plates or set the pin in the weight stack with much more than you normally use. Have your training partner(s) lift the leg pad up all the way for you and then you fight against the resistance on the way down and slowly lower it, then your partner(s) will lift it up again and then you will perform the negative again. Repeat for 6-10 reps total for no more than 3 sets for one exercise per session. The National Strength and Conditioning Association suggest using a weight of 125% of your 1RM for the exercise. So if your maximum weight for one concentric repetition on the leg extension is 100 lbs., then you would set it to 125 lbs. and perform as many eccentric-only repetitions as you can. You may also want to consider performing "forced negatives" sometimes. You will perform a standard set of repetitions and then when you are fatigued and cannot perform one more concentric repetition a partner will lift it for you and then you will work the negative by yourself. Repeat for 2 to 4 reps or until fatigued. I would only recommend that you perform this kind of training at the end of your last set for each muscle group to completely fatigue the targeted muscle. Keep in mind that this kind of training can be implemented without a workout partner for exercises that you can use dumbbells with one arm at a time for. You would simply spot (perform the concentric portion of the movement) with your free hand. It works well for arm exercises such as the preacher dumbbell curl and any of the variety of dumbbell triceps extensions. In my opinion, one muscle group in particular that I feel responds well to added emphasis on negatives and slow and controlled repetitions are the abdominals - All you need to do is slowly return to the beginning position while keeping constant tension in the abdominals before contracting concentrically again.

Summing It All Up

Don't go overboard with negative or eccentric training, because it will cause more skeletal muscle damage than normal and will require more recuperation and recovery time. Performing negatives too much may then cause you to become overtrained. Also keep in mind that if negatives are not performed properly and safely you risk unfavorable damage to your connective tissues as well as your muscles by stretching them too much. This can be avoided by not performing negatives every training session, or at the very least by changing the kind of negative training you used last. By safely incorporating eccentric training into your current resistance training program you will create greater overload and spark new growth and greater gains.

Answer 4

Because your muscles get protein from the food you eat!!

Answer 5

Your muscles decrease due to deteoration with old age.