ELIZABETH PINYAN AND VERONIQUE HAUSCHILD
Directorate of Clinical Public Health and Epidemiology
U.S. Army Public Health Center
Aberdeen Proving Ground, Maryland

Strength training, also known as resistance training, is an important part of a balanced exercise program. Strength training requires a source of resistance to induce muscular contractions that will stress the body’s muscles, tendons and ligaments as well as the bones. Exercises are repeated with minimal rest periods. The stress causes tissues to break down and then rebuild, resulting in stronger and better-functioning muscles and joints.

You have many options when it comes to strength exercises. The resistance can come from just the body itself, machines, bands or free weights. Exercises using heavy free weights are especially popular for quickly building muscle size (called muscle hypertrophy) and strength. However, data indicate the risk of injury is greater than compared to exercises where the resistance can be more controlled, such as with lighter weights or using machines or bands.

Most weight training injuries have been attributed to factors such as improper form and excess weights, frequency or duration. Injuries can involve pain, costly treatments, extended physical restrictions and lost duty time, and possible permanent loss of strength. The following describes one example of a particularly common free-weight exercise — the bench press — with suggestions on how to train smart so you can minimize your injury risk.

The bench press
While it is not required by the Army for fitness testing, bench press equipment is universally available at Army fitness centers. The bench press is one of the three events in powerlifting competitions (along with the squat and deadlift) and is an extremely popular upper body weight-training exercise among recreational athletes and Soldiers. The purpose of this multi-joint exercise is to build and strengthen the upper body muscles across the chest (the pectoralis muscles, commonly called “pecs”) along with the anterior deltoids of the shoulder and triceps of the upper back arm.

To perform the bench press, you lay on your back using either a flat or adjustable bench (for incline and decline variations), lift the weighted barbell and slowly lower it toward your chest (see image below). This rather simple-sounding exercise places a lot of force on the shoulder joint. Since the shoulder joint is not well adapted for greater than body weight loads, the musculoskeletal tissues can be especially stressed. Injuries associated with the bench press have been cited more frequently than any other free-weight lift. While you can reduce the injury risk by following good training principles and technique, you are encouraged to discuss alternatives to the bench press with a master fitness trainer or certified fitness instructor.

Bench press injuries
Most bench press injuries occur to the shoulder; but injuries to the elbow, triceps, chest, collarbone and lower back (from arching during the lift) have also been reported (see Figure 1 below).

“Bench pressing puts the shoulder in an at-risk ‘high-five’ position with weights adding pressure on the joint,” said Tyson Grier, a kinesiologist with the U.S. Army Public Health Center. “Even a small imbalance or tilt of weights to one side can create too much force for tissues to react properly. Risk may be greatest while lowering the weight.”

Pectoralis major muscle and tendon ruptures, which typically require surgery and extended rehabilitation time, and dislocations are especially severe shoulder injuries attributed to the bench press. Soldiers almost instantly recognize these and other acute injuries resulting from a single high-force movement. Even more common are the overuse injuries that occur gradually from accumulated micro-tears to the musculoskeletal tissues. These small tears occur during workouts as a necessary part of the body’s process for rebuilding larger and stronger tissues. Injuries occur when the damage becomes too great or there is not enough time between workouts for the body to repair and rebuild. Overuse injuries that occur during the bench press include rotator cuff damage, tendinopathies in the shoulder, and stress fractures or degeneration of the collar bone.

Injury prevention
“Due to several individual factors, there is no single best technique for this lift,” Grier said. “For example, to avoid injury, a recommended safe starting position for your hand placement is approximately 1.5 hand widths from your shoulder. As a quick way to estimate this distance when standing, place your arms at your side with the thumbs touching your thighs with open hands. Depending on your arm length, flexibility and previous or current problems with an injury, the width of your hands may need to be adjusted wider or narrower.”

Because of individual variables, the best way to prevent injury is to consult an Army master fitness trainer or certified personal trainer for one-on-one guidance. Be sure to explain prior injuries and positioning that seems awkward or painful, and establish good form before increasing weights. While certified personal instruction should be your first step, being familiar with best practices for preventing injuries may help you reduce some injury risks. Additional recommendations include:

• Set up with safety in mind.
  - Choose a spotter that knows what to do (how to stand, hand grips alternating) and is cable to help with the amount of weight you will be lifting. Let them know your plan.
  - Use safety clips appropriately to avoid the potential “tilt” that can lead to injury.

• Choose the amount of weight and repetitions based on your goals.
  - If your primary goal is to build muscle size, use higher weights but a lower number (six to eight) of repeated lifts, or reps. If your goal is to increase lean muscle endurance, use less weight but with more reps (12 to 15).
  - In general, do two to three sets of your reps with a short rest break in between each set. When using heavier weights, rest breaks should be two to three minutes for muscle recovery. Breaks should be between 30 seconds to one minute for higher-rep workouts with lower weights.
  - With your planned reps and sets in mind, choose an amount of weight that is challenging but won’t result in the loss of good form.
  - Once you can conduct entire sets without difficulty, you can increase the amount of weight — but only in small increments. Remember to constantly check your form. Keep in mind everyone has off days, so you may have to lower the weight occasionally.

• If you lose good form, stop.
  - While some advanced weight trainers aim for muscle fatigue or complete muscle failure, these factors may increase the injury risk, especially since this can lead to improper form. Avoid exercises that stress arm and shoulder muscles prior to bench press workouts.
  - If you have difficulty completing your first set while maintaining good form, reduce the amount of weight. The last few repetitions of the final set should be the most difficult; but if your muscles and form are failing, it’s time to stop. Signs of poor form include an arching back, bent wrists, lowering the bar too low with the elbows below the bench, or holding your breath.

• Improve shoulder stability with other exercises.
  - The bench press and upper body lifts such as the overhead press, push-ups, chest dips only build the larger muscles of the chest, shoulders, and upper arms. Overtraining with these lifts often means undertraining the smaller muscles of the rotator cuff, which are critical for supporting the shoulder joint.
  - To strengthen your rotator cuff, add exercises with internal and external shoulder rotations, such as crossovers, the reverse fly and the upright row. Army doctrine (FM 7-22) provides additional guidance to improve stability.

• Use alternative equipment and/or exercises.
  - Push-ups and resistance bands can strengthen the same muscles as the bench press by using movements that push the arms out or across, such as crossover flies. If heavier weight is desired, use a pin to select stacked weights on a bench press machine. This can offer more control and balance. Bench pressing can also be performed with equal-weight dumbbells in each hand. Dumbbells tend to be lighter than a barbell and put control in each arm, reducing the potential for imbalance or tilting.
  - Since bench press alternatives work the same muscle groups, there is always some risk of injury. Some exercises, such as cable crossovers, can also cause other injuries if arms hyperextend behind the shoulder or back. Avoid doing exercises that work the same muscle groups on the same or repeated days (48 hours).

• Be aware of the dangers of anabolic steroids and supplements.
  - Though the military and professional sports have deemed anabolic steroids illegal, some may be tempted to use them to build muscle quickly. Evidence shows, however, anabolic steroids are associated with numerous health problems, including susceptibility to injuries. The benefits of certain supplements can also come with risks. For more details, see the Department of Defense high-risk supplement list at https://www.opss.org/opss-high-risk-supplement-list.

Authors’ note: This article reflects views of U.S. Army Public Health Center experts in consideration of American College of Sports Medicine (ASCM) positions. For additional information, email the APHC at usarmy.apg.medcom-phc.mbx.injuryprevention@mail.mil or see APHC factsheets at https://phc.amedd.army.mil/topics/discond/ptsaip/Pages/Army-Injury-Prevention-Factsheets-and-Training-Products.aspx.