The pectoralis major muscle is a large muscle in the upper chest1, fanning across the chest from the shoulder to the breastbone. The two pectoralis major muscles, commonly referred to as the “pecs,” are the muscles that create the bulk of the chest.
A developed pectoralis major is most evident in males, as the breasts of a female typically hide the pectoral muscles.
A second pectoral muscle, the pectoralis minor, lies beneath the pectoralis major.
The pectorals are predominantly used to control the movement of the arm, with the contractions of the pectoralis major pulling on the humerus to create lateral, vertical, or rotational motion.
The pectorals also play a part in deep inhalation, pulling the ribcage to create room for the lungs to expand.
Six separate sets of muscle fiber have been identified within the pectoralis major muscle, allowing portions of the muscle to be moved independently by the nervous system.
Injuries
Injuries to the pectoralis major can occur during weightlifting, as well as other bodybuilding exercises that place excessive strain on the shoulders and chest.
Symptoms of a pec major sprain will include a sudden sharp pain at the front of the upper arm near the shoulder where the pec major tendon attaches. There is likely to be rapid swelling of the front of the shoulder and upper arm. Tests which will reproduce pain and help confirm the diagnosis include getting the patient to pull their arm across the front of the chest or rotate it inwards against resistance. A visible gap or lump in the muscle may appear.
Metabolism is the process by which your body converts what you eat and drink into energy. During this complex biochemical process, calories in food and beverages are combined with oxygen to release the energy your body needs to function.
Even when you’re at rest, your body needs energy for all its “hidden” functions, such as breathing, circulating blood, adjusting hormone levels, and growing and repairing cells.
The number of calories your body uses to carry out these basic functions is known as your basal metabolic rate — what you might call metabolism. Several factors determine your individual basal metabolic rate, including:
Your body size and composition. The bodies of people who are larger or have more muscle burn more calories, even at rest.
Your sex. Men usually have less body fat and more muscle than do women of the same age and weight, burning more calories.
Your age. As you get older, the amount of muscle tends to decrease and fat accounts for more of your weight, slowing down calorie burning.
Energy needs for your body’s basic functions stay fairly consistent and aren’t easily changed. Your basal metabolic rate accounts for about 70 percent of the calories you burn every day.
The average adult heart beats 72 times a minute; 100,000 times a day; 3,600,000 times a year; and 2.5 billion times during a lifetime.[5]
Though weighing only 11 ounces on average, a healthy heart pumps 2,000 gallons of blood through 60,000 miles of blood vessels each day.[3]
A kitchen faucet would need to be turned on all the way for at least 45 years to equal the amount of blood pumped by the heart in an average lifetime.[1]
The volume of blood pumped by the heart can vary over a wide range, from five to 30 litres per minute.[6]
Every day, the heart creates enough energy to drive a truck 20 miles. In a lifetime, that is equivalent to driving to the moon and back.[1]
Because the heart has its own electrical impulse, it can continue to beat even when separated from the body, as long as it has an adequate supply of oxygen.[3]
French physician Rene Laennec (1781-1826) invented the stethoscope when he felt it was inappropriate to place his ear on his large-bosomed female patients’ chests.[5]
The foetal heart rate is approximately twice as fast as an adult’s, at about 150 beats per minute. By the time a foetus is 12 weeks old, its heart pumps an amazing 60 pints of blood a day.[7]
The heart pumps blood to almost all of the body’s 75 trillion cells. Only the corneas receive no blood supply.[3]
During an average lifetime, the heart will pump nearly 1.5 million barrels of blood—enough to fill 200 train tank cars.[1]
Five percent of blood supplies the heart, 15-20% goes to the brain and central nervous system, and 22% goes to the kidneys.[1]
The “thump-thump” of a heartbeat is the sound made by the four valves of the heart closing.[1]
The heart does the most physical work of any muscle during a lifetime. The power output of the heart ranges from 1-5 watts. While the quadriceps can produce 100 watts for a few minutes, an output of one watt for 80 years is equal to 2.5 gigajoules.[1]
The heart begins beating at four weeks after conception and does not stop until death.[7]
“Atrium” is Latin for “entrance hall,” and “ventricle” is Latin for “little belly.”[1]
A newborn baby has about one cup of blood in circulation. An adult human has about four to five quarts which the heart pumps to all the tissues and to and from the lungs in about one minute while beating 75 times.[7]
The heart pumps oxygenated blood through the aorta (the largest artery) at about 1 mile (1.6 km) per hour. By the time blood reaches the capillaries, it is moving at around 43 inches (109 cm) per hour.[7]
Early Egyptians believed that the heart and other major organs had wills of their own and would move around inside the body.[4]
An anonymous contributor to the Hippocratic Collection (or Canon) believed vessel valves kept impurities out of the heart, since the intelligence of man was believed to lie in the left cavity.[5]
Plato theorised that reasoning originated with the brain, but that passions originated in the “fiery” heart.[5]
The term “heartfelt” originated from Aristotle’s philosophy that the heart collected sensory input from the peripheral organs through the blood vessels. It was from those perceptions that thought and emotions arose.[5]
Prolonged lack of sleep can cause irregular jumping heartbeats called premature ventricular contractions (PVCs).[2]
Cocaine affects the heart’s electrical activity and causes spasm of the arteries, which can lead to a heart attack or stroke, even in healthy people.[1]
Galen of Pergamum, a prominent surgeon to Roman gladiators, demonstrated that blood, not air, filled arteries, as Hippocrates had concluded. However, he also believed that the heart acted as a low-temperature oven to keep the blood warm and that blood trickled from one side of the heart to the other through tiny holes in the heart.[5]
Galen agreed with Aristotle that the heart was the body’s source of heat, a type of “lamp” fuelled by blood from the liver and fanned into spirituous flame by air from the lungs. The brain merely served to cool the blood.[5]
In 1929, German surgeon Werner Forssmann (1904-1979) examined the inside of his own heart by threading a catheter into his arm vein and pushing it 20 inches and into his heart, inventing cardiac catheterisation, a now common procedure.[5]
On December 3, 1967, Dr. Christiaan Barnard (1922-2001) of South Africa transplanted a human heart into the body of Louis Washansky. Although the recipient lived only 18 days, it is considered the first successful heart transplant.[6]
A woman’s heart typically beats faster than a man’s. The heart of an average man beats approximately 70 times a minute, whereas the average woman has a heart rate of 78 beats per minute.[2]
Blood is actually a tissue. When the body is at rest, it takes only six seconds for the blood to go from the heart to the lungs and back, only eight seconds for it to go the brain and back, and only 16 seconds for it to reach the toes and travel all the way back to the heart.[3]
Physician Erasistratus of Chios (304-250 B.C.) was the first to discover that the heart functioned as a natural pump.[5]
In his text De Humani Corporis Fabrica Libri Septem, the father of modern anatomy, Andreas Vesalius (1514-1564), argued that the blood seeped from one ventricle to another through mysterious pores.[5]
Galen argued that the heart constantly produced blood. However, William Harvey’s (1578-1657) discovery of the circulation system in 1616 revealed that there was a finite amount of blood in the body and that it circulated in one direction.[5]
Some heavy snorers may have a condition called obtrusive sleep apnoea (OSA), which can negatively affect the heart.[2]
The right atrium holds about 3.5 tablespoons of blood. The right ventricle holds slightly more than a quarter cup of blood. The left atrium holds the same amount of blood as the right, but its walls are three times thicker.[7]
Grab a tennis ball and squeeze it tightly: that’s how hard the beating heart works to pump blood.[1]
In 1903, physiologist Willem Einthoven (1860-1927) invented the electrocardiograph, which measures electric current in the heart.[6]
List by Tayja Kuligowski, published November 28, 2016
References
1 Avraham, Regina. The Circulatory System. Philadelphia, PA: Chelsea House Publishers, 2000.
2 Chilnick, Lawrence. Heart Disease: An Essential Guide for the Newly Diagnosed. Philadelphia, PA: Perseus Books Group, 2008.
3 Daniels, Patricia, et. al. Body: The Complete Human. Washington, D.C.: National Geographic Society, 2007.
4 Davis, Goode P., et. al. The Heart: The Living Pump. Washington D.C.: U.S. News Books,1981.
5 Parramon’s Editorial Team. Essential Atlas of Physiology. Hauppauge, NY: Barron’s Educational Series, Inc, 2005.
6 The Heart and Circulatory System. Pleasantville, NY: The Reader’s Digest Association, Inc., 2000.
7 Tsiaras, Alexander. The InVision Guide to a Healthy Heart. New York, NY: HarperCollins Publishers, 2005.
A study said “Water is good for you, but you should just drink it when you feel thirsty and not go overboard.”
(They really said “Given that excessive fluid consumption is a primary etiologic factor in EAH, using the innate thirst mechanism to guide fluid consumption is a strategy that should limit drinking in excess and developing hyponatremia while providing sufficient fluid to prevent excessive dehydration”.)
This post quotes extensively from an article (PDF) by Dr Geoffrey C. Goats (School of Occupational Therapy and Physiotherapy, University of East Anglia, Norwich, UK) in the British Journal of Sports Medicine, Volume 28, Issue 3, 1994, which reviewed previous research into the effects of massage on blood flow and composition, oedema, connective tissue, muscle and the nervous system.
Massage – the scientific basis of an ancient art: part 2. Physiological and therapeutic effect
The physiological and therapeutic effects of massage are frequently questioned. This article reviews previous research into the effects of massage on blood flow and composition, oedema, connective tissue, muscle and the nervous system. Although further investigations are clearly required in certain areas, the discussion demonstrates that the use of massage in sports medicine can be justified according to orthodox scientific criteria.
Arterial blood flow
Massage dilates superficial blood vessels and increases the rate of blood flow. Massage appears to be better for improving blood flow than other techniques routinely used for the purpose. Tracer experiments have shown that effleurage, one of the least penetrating massage techniques, significantly increased blood flow.
Venous blood flow
Deep massage promotes venous return and will increase cardiac stroke volume.
Blood clotting
Thrombosis frequently results from poor venous return and can be prevented by massage.
Oedema
Massage reduces swelling very effectively and is used widely for this purpose in sports therapy.
Connective tissue
Most sports therapists acknowledge that preliminary ‘warming up’ exercises are a necessary preparation for safe athletic activity. One comparative study weighed the efficacy of a standard athletic warm-up programme against massage or stretching exercises (and found that) massage had a significant beneficial effect (while) the ‘warm-up’ exercises were least effective.
Muscle
Muscle spasm is extremely uncomfortable, being both the product and the cause of pain. Massage reduces discomfort, relieves the associated muscle spasm and permits improved function.
Pain
Massage has traditionally been used to relieve pain, although research has only recently provided an acceptable physiological explanation of this observation. Massage produces short-lived analgesia by activating the ‘pain gate’ mechanism. Massage is a potent mechanical stimulus and a particularly effective trigger for the pain gate process.
Relaxation
Manual therapy is a well documented aid to relaxation. Physical relaxation, whether induced for enjoyment or the treatment of pain, can improve blood flow, reduce muscle tone and tension in connective tissue, and thus accelerate physical repair
Summary
Massage is an ancient therapy enjoying renewed interest, particularly in sports medicine. The techniques remain an art but research continues to clarify physiological mechanisms that underpin the various therapeutic effects. Massage is indicated in sports therapy when inflammation fails to resolve or healing is delayed, and when tissue drainage or perfusion appear inadequate. Shortened or adhered connective tissue can be mobilised and elongated. Massage will help to reduce pain, restore normal muscle activity and thus re-establish normal function. The close physical contact that massage requires between therapist and client facilitates accurate assessment of dysfunction. This is responsible, in part, for the therapeutic success of these techniques.
The contraindications to massage are few and primarily designed to prevent a precipitate drop in blood pressure or the spread of some harmful factor in the body fluids.
A safe, low-technology therapy, massage is a valuable treatment option poised to grow once again in importance as the scientific principles upon which it is founded are clarified.
A recent article* reports a study which analyzed the effectiveness of a combined method of massage and electrotherapy with interferential current in individuals with chronic low back pain.
In the study, sixty-two individuals with chronic non-specific low back pain were randomly assigned to an experimental or control group. For 10 weeks the experimental group underwent treatment comprising 20 sessions (twice a week) of massage with interferential current in the lumbar and dorsal-lumbar area, and the control group received superficial lower back massage (effleurage, superficial pressure and skin rolling).
The results revealed that in individuals with chronic non-specific low back pain, interferential current electro-massage achieved a significantly greater improvement in disability, pain and quality of life in comparison to superficial massage after 20 treatment sessions, compared to superficial massage.
During recent years scientific research has demonstrated a growing interest in elastic and anaelastic adhesive taping techniques. However, there are only a few studies investigating the principles behind the effects of taping.
A recent study’s objectives were to investigate the effects of taping application on the tone of the pectoralis major muscle at rest, in absence of any relevant pathologies.
The study involved a prospective, randomised and blinded clinical trial on healthy individuals and a repeated measures study design. Two different taping techniques (facilitatory and inhibitory) were applied over the pectoralis major of 24 healthy volunteers. The outcome measure was passive range of motion of external rotation of the glenohumeral joint.
The study* reported that facilitatory taping significantly enhanced the activity of the underlying muscle. Results showed a negative correlation between facilitatory taping application and the contralateral pectoralis major length, indicating a possible effect on the muscle tone of areas outside the site of direct application. The inhibitory taping application did not produce significant results.
This study was designed and carried out as a final research project at the Bachelor of Science degree in Physiotherapy at the University of Padua, Italy, and was reported in the Journal of Bodywork & Movement Therapies (2014) 18, 405e411
* Kinesiologic taping and muscular activity: A myofascial hypothesis and a randomised, blinded trial on healthy individuals, Alberto Gusella, BSc in Physiotherapy a, Marcello Bettuolo, BSc in Physiotherapy b, Francesco Contiero, BSc in Physiotherapy DipHE c, Giovanni Volpe, BSc in Physiotherapy a a Padua University, Padua, Italy b ASSFER Formazione e Ricerca, Padua, Italy c British School of Osteopathy, London, UK
In a study published in the February 2014 edition of Scientific World Journal, researchers investigated whether chronic low-back pain therapy with massage therapy alone was as effective as combining it with non-steroid anti-inflammatory drugs. The study was conducted on 59 individuals divided into two groups, all of whom suffered from low-back pain and were diagnosed with degenerative changes of the spine, other intervertebral disc diseases or spine pain.
In both patient groups, the pain measured was significantly reduced and the level of disability showed significant improvement compared to the baseline.
Conclusion
Researchers concluded massage had a positive effect on patients with chronic low-back pain and propose that the use of massage causes fast therapeutic results and that, in practice, it could help to reduce the use of anti-inflammatory drugs in the treatment of chronic low-back pain.
