1) Incorrect Technique
The most common weight-training injuries are those related to the use of poor exercise technique. Incorrect technique can pull, rip or wrench a muscle or tear delicate connective tissue quicker than you can strike a match. An out-of-control barbell or stray dumbbell can wreak havoc in an instant. Each human body has very specific biomechanical pathways. Arms and legs can only move in certain ways, particularly if you're stress-loading a limb with weight. Strive to become a technical perfectionist and respect the integrity of the exercise —no twisting, turning or contorting while pushing a weight. Either make the rep using perfect technique or miss the weight. Learn how to miss a rep safely; learn how to bail out.
2) Too Much Weight
Using too much weight in an exercise is a high-risk proposition ripe with injury potential. What's too much: If you can't control a weight on its downward, loading trajectory; if you can't contain a movement within its biomechanical boundaries; and if you have to jerk or heave a weight in order to lift it. An out-of-control barbell or dumbbell assumes a mind of its own; the weight obeys the laws of gravity and seeks the floor. Anything in its way (or attached to it) is in danger.
3) Inadequate Warm-Up
Let's define our terms: A warm-up is usually a high-rep, low-intensity, quick-paced exercise mode used to increase blood flow to the muscles. This quick, light movement raises the temperature of the involved muscles, while also decreasing blood viscosity and promoting flexibility and mobility. How? Everyone knows that a warm muscle with blood coursing through it is more elastic and pliable then a cold, stiff muscle. Riding a stationary bike, jogging, swimming, stair climbing and some high-rep weight training are recommended forms of warm-up.
Try a 5-10-minute formalized warm-up before stretching. If you choose high-rep weight training, try 25 ultralight, quick reps in the following nonstop sequence: calf raise, squat, leg curl, crunch, pull-down, bench press and curl. Do one set each with no rest between sets. This can be accomplished in fewer than five minutes and warms every major muscle in the body.
4) Not Stretching
Stretching is different than warming up. Properly performed, a stretch helps relax and elongate a muscle after warm-up and before and after weight training. As a result of warming up and stretching, the muscle is warm, loose and neurologically alert — at its most pliable and injury-resistant. In addition, stretching between sets actually helps build muscle by promoting muscular circulation and increasing the elasticity of the fascia casing surrounding the muscle. Finally, if you perform muscle-specific stretches at the conclusion of your workout, you'll find that this will virtually eliminate next-day soreness.
5) Bad Spotting
If you lift long enough, you'll eventually get to a point where you need to have a spotter(s) for a number of exercises, including the squat and bench press. When you work as hard as you're supposed to, you occasionally miss a rep. Nothing wrong with that — it's a sign that you're working to your limit, which is a good thing if it isn't overdone. Yet when you work this hard, you need competent spotters. A good spotter should conduct himself at all times as though the lifter is on the verge of total failure. Your training partner can also give you a gentle touch that allows you to complete a rep you'd normally miss. A top spotter needs be strong, sensitive and ever alert to the possibility of failure — not looking around or joking with friends.
6) Incorrect Use of Cheating & Forced Reps
Cheating and forced reps are advanced techniques that allow the lifter to train beyond normal. Taken beyond the point of failure, the muscle is literally forced to grow. When incorrectly performed, a cheat or forced rep can push or pull the lifter out of the groove. The weight collapses and a spotter has to rescue the lifter.
Cheating movements work; real-world data prove this statement. Yet cheating, by definition, is dangerous. Any time you use momentum to artificially goose rep speed, thus allowing the lifter to handle more poundage then he could using strict techniques, you risk injury. To play it safe, use the bare-minimum cheat to complete the rep. On forced reps, make sure your training partner is on your wavelength. Don't go crazy.
7) Training Too Often
How does overtraining relate to injury? It negatively impacts the body's overall level of strength and conditioning. Overtraining saps energy that, in turn, retards progress. You can't grow when you're overtrained. It also interferes with both the muscle's and the nervous system's ability to recuperate -- ATP and glycogen stores are severely depleted when an agitated metabolic status is present. In such a depleted, weakened state, is it any wonder that injury is common, particularly if the weakened athlete insists on handling big weights? The solution is to cut back to 3-4 sessions per week and keep session length to no more than an hour.
8) Poor Nutrition
If you undereat and continue to train hard and heavy, you're likely to get hurt. Again, it relates to your overall health: Beware of heavy training when in a weakened state brought on by severe dieting or restricted eating. Best save the big weights, low reps, forced reps and negatives for nondiet growth periods. While dieting requires reduced poundage, this doesn't mean you can't be intense in your workout -- it just means you need to use lighter weight.
Negative (eccentric, or lowering) reps are one of the most difficult and dangerous of all weight-training techniques — and very effective at stimulating muscle growth. What makes negatives so risky? The poundage you can handle in negative exercise is likely to be the highest you'll ever lift.
Normally, we only lift what we're capable of moving concentrically. In negative training, we handle a lot more weight. Most bodybuilders can control approximately 130% of their concentric maximum on the eccentric phase of a lift. Someone using 200 pounds for reps in the bench press, for example, would bench roughly 260 in the negative press. Because of the increased weight with negatives, you need strong, experienced spotters. Exercise extreme caution. If the rep gets away from you, the spotters need to grab the weight immediately.
10) Lack of Concentration
If you're distracted, preoccupied or lackadaisical when you work out, you're inviting injury. Watch a champion bodybuilder train and one thing you'll notice is his or her intense level of concentration. This is developed over time, and the athlete systematically develops a preset mental checklist that allows him or her to focus on the task at hand. More concentration equates to more poundage. More poundage equates to more growth. More poundage can lead to getting hurt if you don't pay attention. Train smart.