question: Why is tearing a bicep relatively easy, while tearing other muscle groups like chest and back is, to my knowledge, alot less common.
comment: This is almost entirely due to the geometry of these body parts - specifically that which relates to tension and leverage. Like pressure, tensile strength depends on the cross-sectional area of the material (i.e. a thicker cable can hold a heavier weight). The sum of all the muscles and bones in your chest and back have a much bigger cross-sectional area than your biceps. The other issue is leverage. Most muscles in your body are class three levers (fulcrum - > effort- > load), which reduce the strength you can exert but increases the speed at which you can move the part. The closer the effort is to the load (i.e. the closer your muscle attaches to the moving end of the bone), the easier it is to move. Your chest, back, and abdominal muscles that move your spine are long and attach near the ends, meaning that most of their strength makes it to the load. Your biceps, on the other hand, are connected very near the fulcrum (your elbow) compared to the load (your hand), which massively reduces how much strength they can exert. For a finite amount of load mass per unit of muscle mass, your biceps would struggle far more than other muscle groups due to pure leverage.
passages: The bicycle targets the rectus abdominals and the obliques. Also, the rectus abdominals can be worked out with the basic crunch, the vertical crunch, the reverse crunch, and the full vertical crunch, and when at a low enough body fat percentage (10-12% for males, 15-18% for females) the individual parts of the muscle become visible; many refer to this visible separation as a six pack. By exercising the internal and external obliques the stomach can be flattened while the waist line can be reduced. The long arm crunch, in which arms are straightened behind you, adds a longer lever to the move and emphasizes the upper part of the abs. The plank exercise not only strengthens the abs but also the back and stabilizes the muscles.
   The shoulder joint is a "ball-and-socket" joint. However, the 'socket' (the glenoid fossa of the scapula) is small, covering at most only a third of the 'ball' (the head of the humerus). It is deepened by a circumferential rim of fibrocartilage, the glenoidal labrum. Previously there was debate as to whether the labrum was fibrocartilaginous as opposed to hyaline cartilage found in the remainder of the glenoid fossa. Previously, it was considered a redundant, evolutionary remnant, but is now considered integral to shoulder stability. Most agree that the proximal tendon of the long head of the biceps brachii muscle becomes fibrocartilaginous prior to attaching to the superior aspect of the glenoid. The long head of the triceps brachii inserts inferiorly, similarly. Together, all of those cartilaginous extensions are termed the 'glenoid labrum'.
   Triceps is maximally efficient with the elbow flexed 20–30°. As the angle of flexion increases, the position of the olecranon approaches the main axis of the humerus which decreases muscle efficiency. In full flexion, however, the triceps tendon is "rolled up" on the olecranon as on a pulley which compensates for the loss of efficiency. Because triceps' long head is biarticular (acts on two joints), its efficiency is also dependent on the position of the shoulder.
   Bipedalism requires strong leg muscles, particularly in the thighs. Contrast in domesticated poultry the well muscled legs, against the small and bony wings. Likewise in humans, the quadriceps and hamstring muscles of the thigh are both so crucial to bipedal activities that each alone is much larger than the well-developed biceps of the arms.
  
  Section::::Physiology.:Respiration.
   Section::::Functions of abdominal muscles.
  
  Abdominal muscles have many important functions, including in breathing, coughing, and sneezing, and maintaining posture and speech in a number of species. The anterior abdominal wall is made up of four muscles—the rectus abdominis muscle, the internal and external obliques, and the transversus abdominis."The two internal muscles, the internal oblique and the transverse abdominis, respond more to increases in chemical or volume-related drive than the two external muscles, the rectus abdominis and external oblique; the basis for this differential sensitivity is unknown".
  
  Section::::Core training.
   Biarticular muscles cross two joints in series, usually in a limb, but the details of the origin (proximal attachment) and insertion (distal attachment) can play a large role in determining muscle function. For instance, the human gastrocnemius technically spans both the knee and ankle joints. However, the origin point of the muscle is so close to the axis of rotation of the knee joint that the muscle's effective lever arm would be very small, especially compared to its large lever arm at the ankle (needs citation!). As a result, even though it spans two joints, the strong bias in lever arms allows it to function primarily as an ankle flexor. Other muscles, such as the hamstrings, do not display such biases, so their function is not immediately evident from anatomy alone.
   It is important to work the triceps muscle through its full range of contraction. Given that this is a two joint muscle (with attachments that cross both the elbow and shoulder) the most comprehensive training approach will have you train the triceps with exercises that fully straighten the elbow with the arm behind the body (to fully shorten the triceps long head).
  
  Ruptures of the triceps muscle are rare, and typically only occur in anabolic steroid users.
  
  Section::::Clinical significance.
   BULLET::::- Interneuronal injury—when dysfunction occurs at one joint or segment, the related agonist muscles are also affected. If uncorrected, the antagonistic muscles eventually become involved as well, leading to dysfunction of both muscle groups. This presents as decreased range of motion with pain and/or tenderness in the area.
  
  Section::::Mechanism of action for muscle energy techniques.
   Surgery may be arthroscopic or open. A 2011 study analyzing current surgical methods for management of symptomatic femoral acetabular impingement, suggested that the arthroscopic method had surgical outcomes equal to or better than other methods with a lower rate of major complications when performed by experienced surgeons; consequently, the surgery is now rarely done open.
  
  Outcomes of arthroscopic surgery are currently being studied, but have generally been positive. When performed on elite athletes, most are able to return their previous level of competition.
  
  Long term, randomized controlled trials evaluating the efficacy of conservative and operative treatments are underway.
  
  Section::::History.
   BULLET::::- 36% had few or no muscular fibers, but a "soft fibrous link" between the scapula and the latissimus dorsi
  
  BULLET::::- 21% had little or no connecting tissue between the two structures.
  
  Section::::Structure.:Triangles.
  
  BULLET::::- The lateral margin of the latissimus dorsi is separated below from the obliquus externus abdominis by a small triangular interval, the "lumbar triangle of Petit", the base of which is formed by the iliac crest, and its floor by the obliquus internus abdominis.
   The "latissimus dorsi" muscle lies atop the "serratus ventralis" muscle, and is separated from it by a layer of fat. This muscle is generally found in the chuck area and the upper portion (toward the spine) of the plate. It adds thickness to chuck and rib short ribs, but is less prized by chefs than the "serratus ventralis" muscle.
   Bifid rib
  
  A bifid rib is a congenital abnormality of the rib cage and associated muscles and nerves which occurs in about 1.2% of humans. Bifid ribs occur in up to 8.4% of Samoans. The sternal end of the rib is cleaved into two. It is usually unilateral.
   Extension is limited by the olecranon reaching the olecranon fossa, tension in the anterior ligament, and resistance in flexor muscles. Forced extension results in a rupture in one of the limiting structures: olecranon fracture, torn capsule and ligaments, and, though the muscles are normally left unaffected, a bruised brachial artery.
  
  Section::::Structure.:Blood supply.
   The upper portion, attached principally to the cartilage of the fifth rib, usually has some fibers of insertion into the anterior extremity of the rib itself.
  
  Section::::Structure.:Size.
  
  It is typically around 10 mm thick (compared to 20 mm thick superficial fat), or 20 mm thick in young athletes such as handball players.
  
  Typical volume is around 300 cm³ in non-active individuals, or almost 500 cm³ in athletes (tennis players).
  
  Section::::Structure.:Blood supply.
   It has been suggested to strengthen the interosseus membrane proximally, provide restraint for the rotatory movements of the forearm, or that the ligament may stop bone bending and preventing buckling failure. However, due the orientation of its fibers, the oblique cord is unlikely to transfer force due to limb loading from the radius to the ulna.
  
  One recent comparative study upon primates concluded:
  
  The oblique cord does not limit supination, nor does it seem to have a role in preventing radial buckling failure or
   A cleaver of a triangle is a line segment that bisects the perimeter of the triangle and has one endpoint at the midpoint of one of the three sides. So any cleaver, like any splitter, divides the triangle into two paths each of whose length equals the semiperimeter. The three cleavers concur at the center of the Spieker circle, which is the incircle of the medial triangle; the Spieker center is the center of mass of all the points on the triangle's edges.
   Surgical rehabilitation is vital, progressive and supervised. The first phase focusses on early motion and usually occupies post-surgical weeks one through three. Passive range of motion is restored in the shoulder, elbow, forearm, and wrist joints. However, while manual resistance exercises for scapular protraction, elbow extension, and pronation and supination are encouraged, elbow flexion resistance is avoided because of the biceps contraction that it generates and the need to protect the labral repair for at least six weeks. A sling may be worn, as needed, for comfort.
   formula_1
  
  where
  
  BULLET::::- formula_2 is the force generated along the direction of the muscle action
  
  BULLET::::- formula_3 is the width of the muscle fiber
  
  BULLET::::- formula_4 is the length of the muscle fiber
  
  BULLET::::- formula_5 is the change in length of the assembly
  
  BULLET::::- formula_6 is the thickness of the endomysium
  
  If the change in length (ΔL) is approximated as the longitudinal tensile displacement, the apparent tensile modulus (E) becomes:
  
  formula_7
   Section::::Dieting and cardiovascular exercise.
   While concentrating on collegiate wrestling, Konrad has managed to develop a strong international record as well. In 2005 he won a gold medal at the Pan American Championships in Guatemala City, Guatemala and finished third at the U.S. World Team Trials. In 2006 he won the bronze medal for the 264.5 pounds freestyle weight class at the World University Championships in Ulaanbaatar, Mongolia.
  
  Section::::Mixed martial arts career.
   The elbow joint is a complex of three joints — the humeroradial, humeroulnar, and superior radioulnar joints — the former two allowing flexion and extension whilst the latter, together with its inferior namesake, allows supination and pronation at the wrist. Triceps is the major extensor and brachialis and biceps the major flexors. Biceps is, however, the major supinator and while performing this action it ceases to be an effective flexor at the elbow.
  
  BULLET::::- Muscles: of the arm
  
  Section::::Structure.:Musculoskeletal system.:Forearm.
   Section::::Society and culture.
  
  The biceps are usually attributed as representative of strength within a variety of worldwide cultures.
  
  Section::::Other species.
  
  Section::::Other species.:Neanderthals.
  
  In Neanderthals, the radial bicipital tuberosities were larger than in modern humans, which suggests they were probably able to use their biceps for supination over a wider range of pronation-supination. It is possible that they relied more on their biceps for forceful supination without the assistance of the supinator muscle like in modern humans, and thus that they used a different movement when throwing.
  
  Section::::Other species.:Horses.
   Kevlar strings may also be attached to the lower ribcage to prevent costal flaring. Although this option is often not preferred by surgeons as it can cause extreme amounts of additional pain during recovery and up until the strings are removed. 
   Section::::Safety of abdominal exercises.
  
  Abdominal exercises also put some degree of compressive force on the lumbar spine, putting unwanted stress on the lower back. In addition, exaggerated abdominal exercise can cause respiratory problems. A study of twelve exercises concluded that no single exercise covered all abdominal muscles with high intensity and low compression.
  
  The benefit of focused training on the "deep core" muscles such as the transversus abdominis has been disputed, with some experts advocating a more comprehensive training regimen.
  
  Section::::See also.
  
  BULLET::::- Abdomenizer
  
  BULLET::::- Abdominal fat
  
  BULLET::::- Chin-up bar
  
  BULLET::::- Core (anatomy)
  
  BULLET::::- Crunches
  
  BULLET::::- Pilates
  
  BULLET::::- Roman chair
   BULLET::::2. Internal intercostal muscles aid in forced expiration (quiet expiration is a passive process). They originate on ribs 2-12 and have their insertions on ribs 1-11.Their fibers pass anterior and superior from the upper margin of the rib and costal cartilage to the lower margin of the rib above.(source) The internal intercostals are responsible for the depression of the ribs and bending them inward, thus decreasing the transverse dimensions of the thoracic cavity.
  
  BULLET::::3. Innermost intercostal muscle, the deep layers of the internal intercostal muscles which are separated from them by a neurovascular bundle.
  
  Section::::Structure.:Nerve supply.
  