Safety Considerations for Exercise

When properly performed exercise can stimulate the body to produce dramatic improvements in muscular strength and endurance, bone strength, cardiovascular and metabolic conditioning, flexibility, and body composition. However, when improperly performed, exercise can produce serious injury. There are several general safety considerations which must be observed to reduce this risk.

1. Slow, controlled speed of movement
2. Proper breathing
3. Head and neck stabilization
4. Relaxation of grip, neck and facial muscles
5. Understanding how to avoid exercise induced headache (EIH)
6. Understanding the distinction between exertional discomfort and pain

Slow, Controlled Speed of Movement

Injury results when a tissue is exposed to a force which exceeds its structural strength. Moving slowly and minimizing acceleration during dynamic exercise exposes the body to less force for a given level of resistance, decreasing the risk of injury.

“It is a misconception that excessive weight causes injury during exercise. Many well-meaning physicians recommend reduced weight for patients without realizing the real danger; force. Many injuries sustained through activities pursued as exercise were caused when little or no additional weight was involved – the acceleration of the subjects own limbs often causes the injury (for example: the impact on a jogger’s knees, tennis elbow, a baseball pitcher’s shoulder, a lower back injury sustained while picking up a golf ball, even weight-training injuries sustained with “light weight, low reps” often cause injury). The key to minimizing injury is minimizing force. Force equals mass times acceleration. In physics, this is known as the acceleration law:

F=ma

While it is natural to beware the amount of weight (mass); acceleration, the greater danger, is almost universally ignored. If you limit the speed of movement (don’t heave, explode or use any other ballistic movement) you significantly reduce the probability of injury. This also enables people rehabilitating injuries to work them directly by significantly reducing the possibility of exacerbating them. Strengthening the damaged structure directly will speed rehabilitation.”

– SuperSlow® founder Ken Hutchins

To keep the force the body is exposed to during an exercise within a safe level you should move and reverse direction slowly and smoothly, avoiding fast, jerky movements.

Move at least slowly enough that it takes you four seconds to complete the lifting (positive) phase of the repetition and another four seconds to complete the lowering (negative) phase of the repetition. A metronome set to 60 bpm can be used for accurate cadence counting.

When beginning an exercise apply force against the resistance gradually. Slowly increase the force you are applying until movement begins. Then, apply only enough force to keep moving slowly. Concentrate on contracting the target muscles continuously throughout the exercise.

As you approach the end of the positive or negative movement, gradually decrease speed so can perform the turnaround in a slow and controlled manner, with no jerking, bouncing, or sudden acceleration.

On compound pushing movements (squat, leg press, chest press, overhead press, dips, etc.) turnaround prior to full extension of the elbows or knees to avoid unloading.

On compound pulling movements (compound row, pull down, chin ups, etc.) and simple movements (rotary movements such as arm and leg curls and extensions) pause for a few seconds in the most contracted position. Do not pause at the lower turnaround (end of the negative) or allow the arms and shoulders to rest.

If you can bottom-out the weight stack of a machine or set the weights down at the start of an exercise, only allow the weights to just barely touch. Then immediately but slowly begin the next repetition.

When it seems almost impossible to produce any further movement against the resistance, concentrate on contracting the target muscles as hard as you can, attempting to keep the resistance moving even if it seems to barely move at all. When positive movement appears to cease continue to contract the target muscles intensely for about ten more seconds just to be sure (advanced trainees should reduce this to about five seconds). If despite contracting as intensely as possible no more positive movement occurs, you have achieved momentary muscle failure.

When you have achieved momentary muscular failure, do not accelerate or in any way sacrifice proper form for the sake of finishing the repetition. The purpose of performing an exercise is to inroad the strength levels of the target muscles to stimulate growth, not to simply lift the weight for the sake of lifting the weight.

Do not just drop the weight at this point. Lower it slowly and gradually ease off after setting it down.

Proper Breathing

During exercise you should breathe as relaxed and naturally as possible, through an open mouth. Do not purse your lips and blow or clench your teeth and hiss. Let your jaw hang with your mouth open wide and face relaxed.

Do not attempt to match your breathing to your movement, inhaling during the negative and exhaling during the positive as is often recommended.  If you move adequately slowly you will need to take several breaths for each repetition. Just breathe.

Do not hold or force your breath. Forcefully holding your breath, contracting the muscles in your abdomen and chest as though you are trying to forcefully expel air while keeping your throat (glottis) closed increases pressure in the thorax and abdomen causing blood pressure (BP) to rise dangerously high, very quickly. This can cause dizziness, fainting, painful exercise induced headaches (EIH), and in those susceptible to it, even stroke. This is called Val Salva’s maneuver.

There is often a strong association between performing intense muscular contractions and Val Salva’s maneuver. This association can be difficult to break in some people, but it is essential. If during an exercise you feel the urge to hold or force your breath or notice yourself doing so, try to breathe more. It is preferable to experience some slight dizziness from over-breathing than to suffer a painful exercise induced headache, impair your venous return and cardiac blood flow, or even faint and fall or risk dropping a weight on yourself as a result of holding your breath.

Have Nothing In Your Mouth

Have nothing in your mouth during exercise. It is dangerous to do so while breathing heavily due to the risk of aspiration. If you are eating something, chewing gum, or sucking on a candy or lozenge and aspirate it you may choke and die.

Head and Neck Stabilization

Your head and neck musculature are either directly or indirectly under load during the performance of most exercises. To decrease the risk of neck strain or headache it is necessary to minimize tension in this area when performing exercises for other areas of the body. To do this, it is important to keep your head and neck in a neutral position.

The ideal head and neck position relative to the body differs slightly from exercise to exercise, but it is generally head facing straight forward, with the neck slightly flexed (chin about fist distance from the sternum).

During exercises where the back of your head is resting on a seat, bench, or head support, it is essential that you do not push back against this with your head, as this can greatly increase tension in your neck.

During prone leg curls your head should be positioned so your forehead is resting on the bed of the machine with your neck slightly flexed, and not resting on your chin or the side of your head. To rest your head on your chin forces the neck into an extremely extension and to rest your head on either side forces your neck into extreme rotation, both of which tend to irritate the neck muscles and may even cause a strain.

Relaxation of Grip, Neck and Facial Muscles

Many exercise machines for the lower body have handles for no other purpose than to provide you with a place to put your hands, or play a minor role in maintaining proper positioning or alignment during exercise. When using these it is important to keep your grip relaxed. Tension in your forearm muscles can cause a significant increase in BP. When you grip tightly you also tend to tense up your shoulder and neck muscles, which should be avoided.

Excessive gripping or contraction of muscles not directly involved in the performance of an exercise can interfere with concentration on concentration of the target muscles. If you find it difficult to break the habit of gripping tightly and tensing up your forearms during these exercises, placing your thumbs on the same side of the handles as your fingers decreases the tendency to do so.

In pulling exercises for the upper body which require a strong grip like chin ups, pulldowns, and compound rows tension in your forearm muscles is unavoidable. This is also the case with most barbell and dumbbell exercises, where a secure grip is required to control the weight. The performance of compound pushing exercises on machines do not usually require a strong grip, though. In the case of a chest press or overhead press machine, the application of pressure against the handles with the palms is all that is required and excessive gripping should be avoided.

It is common to see people grimace, clench their teeth, and tense up their facial muscles while grunting or yelling and gripping excessively during the last few hardest reps of an exercise. This behavior is counterproductive and should be avoided.

It is necessary for muscles not targeted by or required to perform the exercise to remain relaxed to prevent larger increases in BP,  minimize neck tension, and you to better concentrate on intensely contracting the target muscles.

The majority of the neurons in the primary motor cortex (the area of the brain responsible for voluntary control of skeletal muscles) control the muscles in body areas requiring the most precise motor control such as your face, tongue and hands. In comparison, the sections of the primary motor cortex controlling the larger muscle groups which do not require such precise motor control, such as the muscles of your hips and thighs, are very small.

It has been suggested by Doug McGuff, MD, that the greater amount of neural activity in the section of the primary motor cortex involved in contraction of the facial muscles, may somehow override or inhibit neural activity in the sections which control the muscles one is working during a particular exercise, reducing the intensity of the contraction in those muscles (the number of motor units one is able to recruit), and decreasing the effectiveness of the exercise.

Understanding How To Avoid Exercise Induced Headache (EIH)

If you ever feel like you are beginning to get a headache during an exercise, stop immediately. Carefully set down the weight. Relax for a few minutes, closing your eyes and breathing deeply. Then, if you can no longer sense any trace of the headache, continue.

If you still feel even a slight head pain, however, do not finish the workout. Take a few days off before attempting to exercise again. If you attempt to work through this head pain, it may develop into an exercise induced headache (EIH).

EIH are often more painful than a migraine and can last anywhere from a few days to two weeks. It was previously believed that EIH was related to tension in the muscles of the neck, similar to tension headaches, and was often addressed by performing a neck extension and/or flexion exercise at the beginning of the workout, to produce fatigue induced relaxation of the neck muscles. This was done to minimize tension in the neck muscles during the more intense exercises involving greater body masses, such as the leg press.

EIH may be caused by stretching of the dura mater (outermost of the three membranes covering the brain and spinal cord) as a result of increased BP in the cerebral veins caused by retrograde venous flow towards the brain. The onset of EIH is usually experienced during intense exercises for the legs, hips, and trunk, during which there is a large amount of venous congestion in the pelvis and abdomen. In an article entitled The Mystery of Exercise Induced Headache, in Vol. 5, Issue 3 of The Super Slow Exercise Standard, Doug McGuff, MD wrote,

“This congestion is a result of soft tissue compression, Val Salva and massive venous return from the legs stimulated by intense muscular contraction. This massive venous congestion can create a strong enough force to drive venous flow in a cephalad direction (towards the head). Perhaps, in some subjects, the force is great enough to reverse the gradient of cerebral venous drainage so that venous blood is pushed up through the jugular veins into the confluence of sinuses…

…Theoretically, a threshold level of venodilation and pressure transmission would have to occur before the dura could be stimulated. Once this threshold is reached, look out! Dural stimulation produces severe, sudden onset pain that can persist for days.”

In other words, during exercises for the lower body, increased pressure in the abdomen may cause venous blood to be forced back into the cerebral veins, increasing BP in the brain to the point where the dura mater is stretched.

If this is correct, the reason performing exercises for the neck at the beginning of a workout tends to reduce or prevent the onset of EIH would not be due to fatigue induced relaxation of those muscles and the resulting decrease in tension. Instead, it appears that the increased pressure exerted on the jugular veins caused by edema (the “pump”) in the surrounding neck muscles decreases retrograde blood flow. This would reduce BP in the cerebral veins, which would reduce the pressure exerted on the dura mater.

It is best not to develop EIH in the first place, but if you do there are measures which can be taken to minimize the possibility of it recurring.

1. Do not hold or force your breath during an exercise. As previously stated, this causes BP to quickly increase to dangerously high levels.
2. Perform neck extension and flexion exercises at the beginning of the workout. The safest way to perform these is isometrically using timed static contraction protocol.
3. If you are performing a full body workout, perform it in reverse order, with exercises for the trunk and lower body last.

Understanding the Distinction Between Exertional Discomfort And Pain

When properly performed exercise can produce an intense burning, fatiguing sensation in your muscles, labored breathing, elevated heart rate, and sometimes even nausea and dizziness. These are natural responses to intense muscular work and not cause for alarm within the context of a workout. Exercise should not, however, produce any sharp or sudden pain, pain or discomfort in your joints, or any type of pain in areas of your body not involved in the exercise.

If you feel anything you suspect might be an injury, stop moving immediately, slowly lower the weight (or ask your instructor, training partner, or spotter to take it from you if possible), and end the workout. Do not attempt to perform any other exercises, regardless of where the pain is. If you feel something that may be an injury and ignore it or attempt to work through it, you may cause even further damage. If the pain is severe or persists for more than a few days have it checked by a medical doctor.

Summary

Always observe the following safety considerations during exercise, and insist they be practiced by training partners and/or clients:

• Perform every repetition in a slow and controlled manner and minimize acceleration when reversing direction. Take at least four seconds to perform the positive and the negative, and preferably ten seconds.
• Breathe naturally. Do not hold or force your breath during exercise.
• Do not have anything in your mouth during exercise.
• Maintain a neutral position of your head and neck.
• Relax your neck and facial muscles. Relax your hands during exercises where a grip is not required for pulling or controlling a barbell or dumbbell.
• If you think you may feel any sort of pain in the back of the head, stop the exercise immediately to avoid exercise induced headache.
• Understand the distinction between exertional discomfort and pain. Stop moving immediately and slowly set down the weight or transfer it to your instructor if you believe an injury has occurred.

Notes

This is an updated version of an article I posted in January of 2009, which was an update of a handout I wrote over ten years earlier for my personal training clients.

I go over these with all new clients before their first workout, along with several other important considerations such as appropriate workout attire, not socializing during exercise, not carrying a water bottle or anything else with them from exercise to exercise (unless medically necessary), not turning to look at me when I give instructions and giving a verbal answer rather than a nod or head shake if I ask a question to maintain neutral head and neck position, etc.

Consider these are only general considerations, and there are additional considerations specific to the performance of various exercises, the use of different types of equipment, and to specific populations that are beyond the scope of this article. I will be covering these in detail in the book Elements of Form available later this year.

Although I have updated the article I have not edited or removed comments on the previous version. As a result, some comments may refer to specific statements that have been edited or removed.

I welcome questions or comments on these and I am available for consultations for those who wish to discuss them in detail or for personal trainers or physical therapists who would like to learn more about teaching these to clients or patients and instructing them during exercise.