1. Unsound Lifting Technique
Possessing correct technique is the first step to avoiding Injury. It's understood that it takes 21 days to develop a habit in the gym. Its up to you weather the habit is good or bad. For all you beginners don't make the mistake of letting your ego take over. Do not jump into the gym and attempt a one-rep max for any exercise until your muscles and lifting technique have adapted and developed. Once the correct form is developed, your strength and gains will shoot through the roof. In under two years of weight training, I more than doubled my max bench press and naturally added almost 50 lbs of muscle mass. Although you may be able to complete a work out using heavy weight without injury, the moment you let your form slip is the moment you will tear a muscle or some of its connective tissue. Attempt to become a perfectionist in the gym.
2. Use Of Extreme Weight
Using heavy weight while performing an exercise is required if you want to build mass. However, using an extreme amount of weight drastically increases the potential for injury. As a rule of thumb, any non-power-lifting exercise should not be performed with a weight which will lead to failure under 5 reps. For example do not perform under 5 reps with side lateral raises or any other exercise that has an awkward stretch. That will surely lead to injury.
3. Un-experienced Spotter
Every bodybuilder will eventually reach a point in their training where they need to have a spotter. A spotter is used when you push yourself to the limit of failure, and are unable to complete another full rep. The most common being the bench press. A good spotter needs to be strong and constantly aware of your point of failure. There's nothing worse then having a spotter that is unable lift the bar off your chest. Having a training partner/spotter who closely matches your strength will cause some friendly competition, and in tern increase workout intensity.
4. Cheating Misuse
Cheating is a technique that will allow you to push your muscles slightly closer to the point of true muscular failure. Cheating is performed by using momentum to raise the weight past the sticking point. When the cheating technique is abused or performed incorrectly it can push the lifter out of his/her alignment and cause an injury. Cheating techniques are proven to work but use a weight where only minimum cheat is required to perform a complete rep. In other words, don't use a weight that will make you cheat every rep of that set. As a rule of thumb, you should only have to cheat the last 2- 3 reps of a set.
First of all you simply will not grow. Overtraining impacts the body's overall level of strength and health. Overtraining destroys your mental and physical energy supplies, slowing overall progress while increasing the potential for injury. The muscle's nervous system is temporarily damaged while training, and its ability to recuperate is lessened. Simply limit yourself to 3?4 training sessions per week and keep each session under an hour.
6. Insufficient Warm Up
Warm up is usually performed using a light weight with high reps. Sometimes two warm-up sets may be required. It is basically used to increase blood flow and to raise the temperature of the muscle before war. 5 quality minutes is plenty for a warm up.
7. Not Stretching
Stretching relaxes and elongates a muscle after a warm up. You should always stretch before, during and after each and every weight training session. As a result of warming up and stretching, the muscle is at its best to handle heavy weights. Stretching between sets helps promote circulation and increases blood flow. Stretching after your workout drastically reduces DORS or next day soreness.
8. Poor Training Program
If you train to the limit in the gym, but don't help the body to replenish its nutrients and re-grow the damaged muscle tissue, an injury is likely to develop. Be sure you eat plenty of quality food, drink lots of water and get lots of sleep.
Train safely, effectively and most importantly, keep it natural.