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American Football 101

American Football 101

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Youth Football Resources

These Youth Football Playbooks give you the ability to lead your youth football team to win after win through a series of three eBooks: T Formation, Pistol Offense, and Shotgun Jet/Fly Offense books. Each eBook contains over 70 fully diagrammed, full color plays and a full series based offense. This is not simple a collection of plays; it is a full guide of strategies. Each guide not only contains how to run the play; it gives additional runs and plays that compliment the main strategy. There are simply blocking strategies that you can easily teach your players. As a bonus, the T Formation eBook contains 8 Wildcat Formation Plays you can teach your team. This set of eBooks will help you coach your youth football team on a level they understand.

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Expected Populations and Hazardous Exposures

The event attendance bears some relationship to the expected volume of patients and has implications for the numbers and type of medical personnel needed. However, retrospective research has not yielded any universally acceptable mathematical relationship, and the exposure of the crowd to hazards at an event bears a much greater relationship to the volume of patients than does crowd size. In studying Syracuse University's rock concert, basketball, and football events for 7 years, De Lorenzo found a correlation between crowd size and volume of patients only for the concerts. The duration of the event also correlates with the volume of patients through the duration of exposure to the event and population health risk factors. The 1982 US Rock Music Festival experienced a significant increase in the daily volume of patients on the second day of the 3-day event.

Gender Related Social Groups

Social life outside the family is generally conducted in gender-segregated groups. Men are active in sports groups such as badminton, football, and snooker, and in neighborhood patrols. Women do not generally congregate for leisure, and have less leisure time than men. Both men and women often work cooperatively to make offerings and prepare for ceremonies, but always in gender-segregated groups with specific functions. Women rarely form corporate groups. However, both men and women participate in ephemeral purpose-specific groups known as sekehe these are sometimes gender-specific (e.g., men go squirrel hunting) and sometimes open (e.g., men and women form a harvesting sekehe to raise money for an upcoming religious festival). Intergender social interaction is traditionally rare, to the extent that it is difficult for strangers to work out the families and married couples in a community. Increasingly, schools, work-places, shopping malls, and tourist venues provide sites for new...

Real reliability scores

A rule's range is just a bunch of objects (states, properties, processes, etc.) about which the rule allows us to make a judgment (e.g., all U.S. males, all U.S. children under 10 with reading disorders, NFL football games, etc.). A typical range can be subdivided into many different natural discrimina-ble partitions. A natural partition will divide the objects in the range in terms of properties that could in principle be causally related to the target property. This restriction is meant to rule out partitions that involve

Genetic Engineering and Society

Policies were used to restrict immigration of certain Asian and European populations that were termed genetically inferior. Eugenics had its ultimate expression when it provided the scientific basis for the racial policies of the Nazis before and during World War II. Where the capability exists, so will the temptation. Will parents seek to amplify the gene for human growth hormone in their offspring so that their children could become heftier football linemen or taller basketball players The ability to select the gender of one's offspring by amniocentesis and abortion is already causing problems in some cultures.

Qualitative Analysis Human Movement Diagram

Free Body Diagram Volleyball

The last principle involves the Spin or rotations imparted to projectiles, and particularly sport balls. Spin is desirable on thrown and struck balls because it stabilizes flight and creates a fluid force called lift. This lift force is used to create a curve or to counter gravity, which affects the trajectory and bounce of the ball. A volleyball player performing a jump serve should strike above the center of the ball to impart topspin to the ball. The topspin creates a downward lift force, making the ball dive steeply and making it difficult for the opponent to pass. The spin put on a pass in American football (Figure 2.8) stabilizes the orientation of the ball, which ensures aerodynami-cally efficient flight. The natural application Figure 2.8. The spin imparted to a football during a forward pass serves to stabilize ball flight, to provide aerodynamically efficient flight. Figure 2.8. The spin imparted to a football during a forward pass serves to stabilize ball flight, to provide...

Leadership in Public Arenas

Interestingly, Silvio Berlusconi, the current head of government, displays many of the qualities associated with hegemonic masculinity he is successful, supremely confident, his beautiful wife testifies to a successful virility, and, although not a famous sportsman himself, he is the owner of what many consider to be Italy's most famous football club, AC Milan. There are also some parallel flamboyant displays of feminine success in the political arena. Alessandra Mussolini, Benito Mussolini's granddaughter, is a graduate from medical school as well as an actress whose good looks have been widely publicized in the media. She is currently a councillor in the local government of Naples, representing a right-wing party. Like Berlusconi she exudes self-confidence and has a somewhat brash manner not immediately associated with femininity, while maintaining an aura of glamor and feminine attractiveness.1

Leisure Recreation and the Arts

When asked about their daily work, Mehinako women assured us that they really work hard and that men also work hard. They did not understand the question Which sex worked harder. Perhaps the symmetrical gender structure inhibits comparison of the two separate contributions that are honored equally and are so intimately linked together. In their leisure time, both men and women engage in gender-specific handicrafts or they may lie in their hammocks for a while to rest. Couples converse together and go to take a bath single people play with their friends in gender- and age-related groups or try to make arrangements with their lovers (see below). In the afternoon the young men play football at the central plaza. In the evenings the men gather in front of the men's house. The younger generation men, women, and children like to watch television (see below).

Change in Attitudes Beliefs and Practices Regarding Gender

Telecommunication has not stopped at the gates of Upper Xingu. Three of the nine longhouses have a television set, but only one of them is regularly used provided that permission is obtained from the generator's owner. The generator and the television set belong to different people who have to agree to and be recompensed for their use. When there are no ritual performances, a group of young men and women gather to watch the news, football, and or the telenovela (daily soap). Some men translate the series for their wives, and news from the outside world is sometimes intensely discussed. Watching television seems to compete with the gatherings at the men's house. The influence of the telenovela together with experiences of Mehinako men outside the Xingu region is likely to lead to some changes in interpersonal relations within the younger generation. Some of the young men express their discontent about the strict separation of gender spheres and the common rule not to show affection, as...

Positions for Breast Feeding

Another position for nursing mothers with a cesarean section is the football hold. To use this position, hold the baby's legs and body under your arm, with your hand at the base of its head and neck (imagine holding a football). Place your fingers below your breast. Let the baby latch on while pulling the baby in close, holding the baby's head with its nose and chin touching your breast. Keep your baby's body flexed at the hip with its legs tucked under your arm. The football hold is also a good position to use when

History And Neuropsychological Findings

During this same time period, a unique approach to the study of the effects of mild head injury, preinjury neurocognitive baseline status, and extent and speed of recovery was pioneered at the University of Virginia with the development of the Sports as a Laboratory Assessment Model (SLAM). This methodology involved the study of mild head injury through a highly controlled sports laboratory that examined acceleration-deceleration injuries. In this investigation, more than 2300 football players at 10 universities were assessed before the football season using brief

Osgood Schlatter Disease

This lesion is typically seen in athletic teenagers. Girl and boy athletes are both affected. Football, soccer, basketball, gymnastics, and ballet can cause this injury. The anatomic lesion is the partial separation of the tibial tuberosity at the insertion of the patellar tendon. In about one-fourth of cases, it is a bilateral process. Palpation of the tibial tuberosity reveals tenderness and induration. A lateral x-ray of the proximal tibia with the knee flexed 30 degrees reveals an elevation of the distal portion of the tubercle off of the tibia. Alternatively, ultrasound can be used. Cold compresses, anti-inflammatory drugs, and stopping the offending activity is standard treatment. Follow-up with an orthopedist is advisable for this sometimes chronic condition.

Zoos And Animal Welfare

Whatever the role of captive breeding and reintroduction in species preservation may be, an inconsistency arises when it is enlisted as a justification for zoos. Zoos are places where people can see animals. They are places to take children on Sunday afternoons. They are amenities (like football and baseball teams) that can be boasted about by city boosters. Increasingly they are even the sites of rock concerts and fund-raisers. But the best institutions for captive breeding and reintroduction would not play these roles. They would remove animals from excessive contact with people, give them relatively large ranges, and prepare them for reintroduction in ways that zoo visitors might find shocking (e.g., by developing their competence as predators).

Nonoperative Management

Treatment Fractured Humerus

Figure 5 Fracture bracing of humeral shaft fractures. 17-year-old male s p football injury with a humeral shaft fracture treated with fracture bracing. A. AP x-ray taken in emergency room. B. AP x-ray after treatment with a functional brace for 8 weeks. C. AP x-ray of the same fracture after functional bracing for 3 months. (X-rays provided by Heather A. Vallier, MD, Metrohealth Medical Center, Cleveland, Ohio, U.S.A.) Figure 5 Fracture bracing of humeral shaft fractures. 17-year-old male s p football injury with a humeral shaft fracture treated with fracture bracing. A. AP x-ray taken in emergency room. B. AP x-ray after treatment with a functional brace for 8 weeks. C. AP x-ray of the same fracture after functional bracing for 3 months. (X-rays provided by Heather A. Vallier, MD, Metrohealth Medical Center, Cleveland, Ohio, U.S.A.)

The use of disclaimers on food labels

A key question is How likely is it that someone with nut allergy will come across a particle of nut on, say, a spoonful of breakfast cereal that is supposed to be nut-free The answer is that it is probably very unlikely indeed, but it does occasionally happen. A young boy visiting a football match with his grandfather decided at half time to have his usual treat - a milk chocolate bar that he had eaten many times before. He suffered a mild allergic reaction. Looking at the label he saw the warning in small print 'May on rare occasions contain nut traces.' This kind of incident may be rare, but the risks have rung alarm bells in the food industry.

Evidence Collection And Preservation

On the night of 12 June 1994, Nicole Brown Simpson and Ronald Goldman were found brutally murdered at Nicole's home. A few days later Nicole's ex-husband, Orenthal James (O.J.) Simpson, was picked up by Los Angeles police officers and became the chief suspect in the murder investigation. Due to O.J. Simpson's successful football career and popularity, the case immediately drew the public's attention. Over 100 pieces of biological evidence were gathered from the crime scene consisting primarily of blood droplets and stains. DNA samples were sent to three laboratories for testing. Over the summer months of 1994, the Los Angeles Police Department (LAPD) DNA Laboratory, the California Department of Justice (CA DOJ) DNA Laboratory in Berkeley, and a private contract laboratory from Maryland named Cellmark Diagnostics performed the DNA testing using both RFLP and PCR techniques. A number of RFLP and PCR markers were examined in this high-profile case. However, no STRs were typed. The...

Clinical Features Of Rapid Eye Movement Sleep Behavior Disorder

I was a halfback playing football, and after the quarterback received the ball from the center he lateraled it sideways to me and I'm supposed to go around end and cut back over tackle and this is very vivid as I cut back over tackle there is this big 280-pound tackle waiting, so I, according to football rules, was to give him my shoulder and bounce him out of the way, and when I came to I was standing in front of our dresser and I had knocked lamps, mirrors, and everything off the dresser, hit my head against the wall and my knee against the dresser.

Myocardial infarction outside hospital

Seventy five per cent of out-of-hospital deaths in our study occurred in the home and about 60 were witnessed. Advanced life support given by ambulance personnel was attempted in a little over half the cases. Of the 25 of deaths which occurred away from home, 16 happened in a public place, usually the street, 3 in an ambulance, 3 in nursing homes, 1 in doctors' surgeries, and only 2 at the place of work. Sudden death at mass gatherings such as football stadia or railway stations was unusual.

Forcetime Principle

Bobby Orr Famous Goal

There are a few movements that do allow movers to maximize the time of force application to safely slow down an object. In landing from a jump, the legs are extended at contact with the ground, so there is near maximal joint range of motion to flex the joints and absorb impact forces. A softball infielder is taught to lean forward and extend her glove hand to field a ground ball so that she can absorb the force of the ball over a longer time interval. Figure 6.15 illustrates two people catching balls which athlete is using a technique that is correctly applying the Force-Time Principle Young children often catch by trapping the object against the body and even turn their heads in fear. Even professional football players (6.15, below) occasionally rely on their Figure 6.15. Catching the ball close to the body (the American football example) is a poor application of the Force-Time Principle because there is minimal time or range of motion to slow down the ball. The softball catcher has...

Qualitative Analysis Of Catching

Biomechanical Picture Catching Ball

As a volunteer youth football coach you are working with your receivers on catching passes. Many young players pick up bad habits from playing neighborhood pick-up football games or watching the pros get by with talent rather than optimal technique. The technique points and cues you typically use are listed in Table 10.5. Notice how the critical features are more advanced and specialized than the catching technique points in chapter 9 (e.g., Table 9.4). Which biomechanical principles are strengths and weaknesses in the catching illustrated in Figure 10.5 How would you diagnosis this situation and intervene Table 10.5 Technique Points and Cues for Catching a Football Pass Figure 10.5. A football player making a catch in practice. Figure 10.5. A football player making a catch in practice. A good intervention strategy would be to praise the player's effort and visual focus on the ball. Reinforcement of important technique points and motivation are good intervention goals while the coach...

Multiple Intelligences

Gardner proposed that there is no single, unified intelligence but rather a set of relatively distinct, independent, and modular multiple intelligences. His theory of multiple intelligences (MI theory) originally proposed seven multiple intelligences linguistic, as used in reading a book or writing a poem logical-mathematical, as used in deriving a logical proof or solving a mathematical problem spatial, as used in fitting suitcases into the trunk of a car musical, as used in singing a song or composing a symphony bodily-kinesthetic, as used in dancing or playing football interpersonal, as used in understanding and interacting with other people and intrapersonal, as used in understanding oneself.

Disorders Involving Medical Intervention 1 Neoplasms

A very frequent occurrence among children of all ages involves traumatic brain injury. Such injuries can occur at various levels, classified as severe (e.g., extended coma, multiple potential residua), moderate (briefer coma, typically fewer physical developmental residua), or mild (brief or no loss of consciousness). Most common causes involve automotive injuries, falls, and sports injuries. The large majority of traumatic brain injuries in the pediatric age population are typically mild concussive incidents with little or only brief loss of consciousness. Diagnosis of such injuries by standard imaging (CAT or MRI scan) or electroencephalographic (EEG) procedures are often not productive, because such procedures are not particularly sensitive to such injuries. That such injuries are important to diagnose and can have serious consequences is, unfortunately, not widely recognized. Neuropsychological examination is con-sensually recognized as the most definitive approach for determining...

Socialization of Boys and Girls

Boys and girls usually play in gender-segregated groups. In coastal towns, soccer (football) is the preferred team sport for boys and almost any round object that can be kicked will be used as a ball. Girls may practice dance steps and chase each other in games of tag. Occasionally, a mixed-sex group of children will enact some adult activity, such as a development rally or witchcraft investigation. If family resources are limited, only the boys, or one boy, may be chosen to attend formal school. Parents fear that girls who are sent to school may become pregnant and leave before they acquire enough education for the wage sector. This common scenario is responsible for the very disparate numbers of boys and girls in the educational system. In general, boys are expected to be more active, aggressive, and mobile than girls. Although all young people are expected to behave with great respect towards their elders, girls are instructed to cast their eyes down and sit with their legs pressed...

Exercise and Physical Activity

The term 'physical activity' refers to bodily movement produced by skeletal muscle that results in energy expenditure it thus includes activities of daily living, as well as leisure activity from sport and exercise. The term 'exercise' refers to planned or structured bodily movements, usually undertaken in leisure time in order to improve fitness (e.g., aerobics), while 'sport' is physical activity usually in structured competitive situations (e.g., football). Physical activity at recommended levels (moderate intensity for 30 min for 5 days each week) is associated with many health benefits these include lower all-cause mortality rates, fewer cardiovascular events such as myocardial infarction and stroke, and a lower incidence of metabolic disorders including non-insulin-dependent diabetes mellitus and osteoporosis. Levels of activity have been falling in Westernized societies largely because of a decrease in physical activity at work (from increasing mechanization) and increasingly...

Gender over the Life Cycle

In large families much of the daily childcare duties are overseen by older siblings who tend to be less sensitive to the needs of younger siblings. Boys commonly play with toy guns, watch football on television (especially in Centennial Park), and engage in rough-house games of tag. Girls prefer to play with dolls, coloring books, and household items. Both genders enjoy watching cartoon videos and jumping on large trampolines.

S Mass Gatherings

Each year over 200,000,000 people show their support for their favorite sports team by attending an event affiliated with the National Basketball Association, the National Football League, major league baseball, the National Hockey League, National Collegiate Athletic Association division I college football and basketball, or National Association for Stock Car Auto Racing (NASCAR) (TabJe.6-1). Not included in these figures are the millions who attend high school athletics events, Olympic festivals, local and state fairs, music concerts, and religious, political, or professional gatherings.

History

In 1965, two spectators collapsed and died in the University of Nebraska football stadium. Cardiopulmonary resuscitation (CPR) was not available. Based on the need to address this problem and the expanding philosophy at that time involving CPR, airway management and defibrillation were included in the emergency medical care provided for the stadium. In the 8 years that followed, 18 spectators developed a cardiac or pulmonary emergency. Of these, 9 experienced cardiac arrest. Eight of the 9 were successfully resuscitated and discharged from the hospital. Other specific experiences with medical care provided at mass gatherings have been reported by the Denver Mile High Stadium the University of Arizona, Tucson the 1984 Los Angeles and 1996 Atlanta Summer Olympic Games the 1986 World's Exposition In Vancouver, British Columbia the XV Winter Olympic Games in Calgary, Canada the Indianapolis 500, the Carrier Dome at Syracuse University and the 1982 US Rock Music Festival in Devore,...

Exponential Growth

Most people do not have an intuitive feeling for exponential growth. As a simple mental exercise, picture folding a standard sheet of paper in half, then in half again, and again. Imagine that you could continue folding it in half 50 times. How tall would the folded stack of paper then be a meter 100 m a football field) New York to San Francisco ( 5000 km) After first trying to guess, calculate an approximate answer by assuming that the paper is 0.1 mm thick and doubles each time it is folded (or 0.1 mm x 250). (Note 210 -103.)

Sudden Death

A distinction must be made between sudden unexpected death and sudden cardiac death, as the first includes many causes, such as a seizure, asthma, or toxic ingestion. Sudden cardiac death includes just those causes that directly relate to cardiovascular dysfunction. The rate of sudden unexpected death in children is 2.3 percent of all deaths or 1.3 cases per 100,000 patient years. 6 Sudden cardiac death encompasses approximately one-third of these deaths, or about 600 deaths per year in the United States. Excluding trauma, sudden cardiac death is the most common cause of sports-related death in young athletes.7 The sports most frequently associated with sudden death are basketball, football, and track events.8 The greatest risk for sudden cardiac death is among patients with congenital or acquired structural cardiac disease, including postoperative congenital heart disease. The most frequent causes of sudden cardiac death in children are acute myocarditis, cardiomyopathy, cyanotic and...

Emergency Delivery

Modified Ritgen Maneuver

A point of practical concern is the need to maintain control of the newly born infant. The combination of amniotic fluid, blood, and white, cheesy desquamation called vernix makes the infant very slippery. It is useful to prepare for the delivery by placing the posterior (left) hand underneath the infant's axilla prior to delivering the rest of the body. The anterior hand may then be used to grasp the infant's ankles and ensure a firm grip. In obstetric training, the student is often instructed to hold the infant close to his or her chest like a football.

Principle Of Spin

There is one more advantage of imparting spin to a projectile that is not related to fluid or contact forces on a surface. This third advantage of projectile spin is related to Newton's laws and conservation of angular momentum. Any object in angular motion without external-acting torques (like a projectile) will conserve angular momentum. This inertia in a rotating object can be used to keep the projectile in a certain orientation. A pass in American football does not create significant lift force, but the spin stabilizes the flight of the ball in a streamlined position. Divers and gymnasts

Sports Injuries

Spinal injuries occur in both contact and noncontact sports. The specific injury is related to the mechanism, the force involved, and the point of application of the force rather than to the specific sport. Injuries can occur to the supporting tissue, the disk, or the bone. The majority of injuries are self-limiting soft tissue injuries. Injuries at the level of the disk result in disk herniation or degeneration. Those that occur at the level of the bone can range from minimal avulsion-type fractures to compressions or fracture dislocations. Most bony injuries are not associated with neurologic sequelae. Rarely, however, sports injuries do result in significant neurologic compromise. When neurologic impairment occurs, it is usually secondary to direct axial forces. Catastrophic injuries have been associated with football, water sports (especially diving), gymnastics, rugby, and ice hockey.13

Blunt Injury

The head, shoulders, and chest offer protection to the neck when it is in the neutral position. Hyperextension, hyperflexion, rotation, and direct blows contribute to blunt injuries. Most commonly, injury results from motor vehicle crashes, when the extended neck strikes the steering wheel or dashboard. 15 Shearing forces from shoulder safety belts are also responsible for injury. Motorcycles, snowmobiles, and all-terrain vehicles have been implicated in clothesline injuries. These occur when the exposed neck strikes a stationary cord. They are associated with severe laryngotracheal and esophageal injuries. Other mechanisms include direct blows sustained during sports (football, karate, hockey), handlebar injuries from bicycles, assaults, and strangulation. 16

Laws Of Kinetics

Inertia Direction Outline Drawing

A considerable body of kinesiology research has focused on the percentage of fat and lean mass in the human body. There are metabolic, mechanical, and psychological effects of the amount and location of fat mass. in sports performance, fat mass can be both an advantage (increased inertia for a football lineman or sumo wrestler) and a disadvantage. increasing lean body mass usually benefits performance, although greater mass means increasing inertia, which could decrease agility and quickness.When coaches are asked by athletes How much should I weigh they should answer carefully, focusing the athlete's attention first on healthy body composition. Then the coach can discuss with the athlete the potential risks and benefits of changes in body composition. How changes in an athlete's inertia affect their sport performance should not be evaluated without regard to broader health issues.

Multiple Births

It is possible to breast-feed twins at the same time by nursing one baby at each breast. You can hold one baby at each side using the football hold (described earlier), or you can cradle them both in front of you with their bodies crossing each other as they would have been in utero. Alternate the breast each baby uses at each feeding, or at least once a day. If this is

Zoo Animals

Zoo has been defined as the short form for zoological garden, or a collection of living animals usually for public display, but that definition is incomplete. The mission of modern zoos includes education of the public, scientific studies, and the conservation and breeding of endangered species. Zoos remain one of the strongest links to living animals for many people. More than 26 million adults visit a zoo at least once a year. The total attendance at the member institutions of the American Zoo and Aquarium Association in 2002 was over 142 million people, which is greater than the attendance at the National Football League, Major League Baseball, National Hockey League, and National Basketball Association games combined.

Ultrasound

Gerotas Fascia Ultrasound

Gerota's fascia, the renal cortex, the collecting system, the renal sinus, as well as proximal and distal calculi can be visualized. Gerota's fascia is associated with perinephric fat and is visualized as a bright area surrounding the kidney. The renal cortex is homogeneous in appearance and more reflective (brighter) than the renal medulla. The renal pelvis is centrally located and appears echogenic. Dilation of the collecting system by fluid (echo-free) is thus readily apparent. The normal ureter is not visualized, but the dilated ureter can sometimes be seen. In the longitudinal plane, the normal kidney is football-shaped and measures 9 to 12 cm. In the transverse plane, the normal kidney is C-shaped and measures 4 to 5 cm. The kidneys normally measure within 2 cm of each other in the longitudinal axis.

Recent Developments

Sports drinks are a recent innovation that has grown steadily but is still dominated by the pioneer, Gatorade. Sports drinks are designed to replace the water, energy, and electrolytes lost during strenuous exercise. Gatorade was developed in the 1960s by researchers led by Dr. Robert Cade to help the University of Florida football team (Gators) maintain stamina while playing in the hot and humid Florida climate. It was successful with the athletes and soon was used by other teams. Clever marketing got it placed on professional football team benches with large logos on coolers and cups plainly visible on national television. This rapid brand identification made it popular with athletes and sports fans across the country. Soon, Gatorade was sponsoring youth sports events with associated promotion of branded accessories like water bottles, hats, and headbands. Its marketing clout kept other sports drinks from making any inroads until Coke and Pepsi developed products and used their...

Fluid Forces

Bernoulli Principle For Discus

The next time you are at a pool, see if you can detect an increase in buoyant force with increasing depth. Hold a large sport ball (water polo, soccer, football) in one hand and gradually submerge it. Note the downward vertical force you exert to balance the buoyant force of the ball as it descends. Also note the horizontal forces you must exert to keep your hand forces balanced with the buoyant force and gravity Another simple activity is to mark the water line on a floating ping pong ball. Tape dimes to the ball and find the maximum buoyant force of a ping pong ball. Does a forcibly submerged ball have potential energy

Biomechanics Of Bone

Response of bone is dependent on this sandwich construction of cortical and cancellous bone. This design of a strong and stiff material with a weaker and more flexible interior (like fiberglass) results in a composite material that is strong for a given weight (Nordin & Frankel, 2001). This is much like a surf board constructed of fiberglass bonded over a foam core. Cortical bone is stiffer (maximum strain about 2 ), while cancellous bone is less stiff and can withstand greater strain (7 ) before failure. In general, this design results in ultimate strengths of bone of about 200 MPa (29,000 lbs in2) in compression, 125 MPa (18,000 lbs in2) in tension, and 65 MPa (9,500 lbs in2) in shear (Hayes, 1986). This means that an excessive bending load on the femur like in Figure 4.2 would most likely cause a fracture to begin on the lateral aspect that is under tensile loading. Using sports rules to protect athletes from lateral blows (like blocking rules in American football) is wise...

Equipment

Inspection of Figure 11.5 shows that there are several Range-of-Motion differences between the two squat exercises. Squatting with the device results in less knee flexion and ankle dorsiflexion. Note how the lower leg remains nearly vertical, and how the center of mass of the athlete bar is shifted farther backward in this squat. There does not appear to be any obvious differences in trunk lean between the two devices with these performers. What do you think are the training implications for these small differences Which body position at the end of the eccentric phase seems to be more specific to football, skiing, or volleyball this or the front squat

Inertia Principle

In movements where stability is desired over mobility, the Inertia Principle suggests that mass should be increased. Linemen in football and centers in basketball have tasks that benefit more from increasing muscle mass to increase inertia, than from decreasing inertia to benefit quickness. Adding mass to a golf club or tennis racket will make for faster and longer shots if the implement can be swung with the same velocity at impact. If an exercise machine tends to slide around in the weight room, a short-term solution might be to store some extra weights on the base or legs of the machine. If these new weights are not a safety risk (in terms of height or potential for tripping people), the increased inertia of the station would likely make the machine safer.