During the acceleration phase of stance (the mid-late stance), the greatest contributors to both forward acceleration and support of the center of the body mass are the the soleus and gastrocnemius. However, during the late stance the ankle plantar flexors are the primary contributors to both acceleration and support of the body mass center. The gastrocnemius was required to produce a plantarflexor moment of the ankle at this time during the stance phase. Also, during this part of the stance cycle the gastrocnemius and the rectus femoris were simultaneously activated. In one study, the peak force elicited the by gastrocnemius increased as speed increased from 3.5 to 7.0 m s–1, but showed no significant speed effects after this threshold. The peak force developed by soleus also increased …show more content…
from 3.5 to 7.0 m s–1, however, decreased as running speed increased from 7.0 to 9.0 m s–1. Additionally, the vastus muscles combined ( medialis, intermedius, and lateralis) showed no significant speed effects during stance.
On the other hand, the rectus femoris exhibited a biphasic force pattern. This means in the first half of swing, rectus femoris force increased with running speed in response to larger moments required in hip flexion and knee extension. Whereas during stance, it produced a knee-extensor moment to complement the action of the combined Vastus medialis, intermedius, and lateralis. Also during acceleration, iliopsoas , gluteus maximus, gluteus medius, hamstrings, and rectus femoris all developed significantly larger peak forces throughout the stride cycle. Specifically, the peak forces of gluteus maximus and hamstring because they doubled during the terminal swing. During deceleration phase of stance, the largest contributor to both braking and support of the body mass center is the quadriceps muscle group. The quadriceps muscle group (i.e., vastus lateralis, vastus intermedius, vastus medialis, and rectus femoris) is considered the largest contributor to deceleration of the body mass center during early stance. The soleus is not the largest
contributor. While in the early stance phase of deceleration the quadriceps are the primary muscles to decrease forward speed of the body mass center and provide body weight support, the gluteus medius and maximus providing additional support. In regards to the muscle function during the stance phase, at all running speeds, the soleus provides 50% of the total vertical support impulse needed to accelerate the body upward. Whereas, the gastrocnemius, and Vastus medialis, intermedius, and lateralis provided roughly 75%. However during acceleration up to 7.0 m s–1,the soleus elicited an increase in the vertical ground reaction forces. The Vastus medialis, intermedius, and lateralis contribution to the vertical ground force did not increase as running speed increased. Unfortunately, as running speed increases the ankle plantarflexors shorten at increasingly higher rates. At the times that soleus and gastrocnemius muscles develop their peak forces during sprinting, the muscle fibers contract at 37 and 23% of their maximum shortening velocities, respectively. Thus, the peak forces that could potentially be developed by soleus and gastrocnemius during sprinting are only 30 and 40% of their peak isometric forces, respectively. In regards to functioning of the muscle during the swing phase, the force performed by the hip muscles increased as running speed increased.
The gluteus maximus originates from both the ilium and the sacrum and inserts on the femur. The gluteus minimus abducts and rotates the thigh outward. The biceps femoris originates from the tuberosity of the ischium and is responsible for abducting the thigh and flexing the hindlimb or in humans the thigh/leg. The gastrognemius originates from the lateral sesamoid bone of the femur and extends the hindfoot in minks and the calves in humans (Scott).
Flexion is the bending of a joint so that the angle between the two bones decreases. The primary muscles that flex the knee are a group collectively known as “hamstrings.” The hamstrings consist of the biceps femoris, semitendinosus, semimembranosus. The muscles that assist in flexion are the sartorius, gracilis,...
Enterococcus faecalis is a genus of gram positive cocci and form short chains or are arranged in pairs. They are nonmotile, facultative anaerobic organisms and can survive in harsh conditions in nature. There are over 15 species of the Enterococcus genus but about 90% of clinical isolates are E. faecalis. E. faecalis is a nosocomial pathogen because it is commonly found in the hospital environment and can cause life-threatening infections in humans. It is a bacterium that normally inhabits the intestinal tract in humans and animals but when found in other body locations it can cause serious infections. The most common sites for E. faecalis infections are the heart, bloodstream, urinary tract, and skin wounds. Due to vancomycin-resistant Enterococci, many antibiotics have been shown ineffective in the treatment. In this paper, I will describe the ecology and pathology of E. faecalis; the antibacterial resistance; treatment; and, what you can do to prevent Enterococcus infection.
Anderson, D. I., & Sidaway, B. (2013) Kicking biomechanics: Importance of balance. Lower Extremity Review Magazine.
Irregular bowel movements or constipation is quite a major and common concern in adults and babies as well. The condition becomes more challenging when it comes to babies. Parents of infants worry when their infant’s bowel movement is not regular and clear as that causes formation of gas and stomach pain.
This skill involves jumping in the sagittal plane about the transverse axis. It consists of hip, knee, ankle, and shoulder joints. In the preparation phase in propulsion, the subject has flexed knees and hips which will need to be straightened by the strength of their corresponding joints such as the hinge joint at the knee joint. The hip joint is a ball and socket joint that bears the body weight and allows for jumping motion. During th...
The digestive system, in organisms like the mink and human, is supposed to break down the food being eaten to transfer into energy. This energy helps other functions of the body that would in turn keep it alive. The digestive system includes organs such as the stomach, intestines, liver, etc. Digestion starts at the mouth, though.
Throughout literature countermovement jumps (CMJ) are seen to be higher in contrast to squat jumps (SJ) (Bobbert et al. 1996; Kubo et al. 1999; Bobbert et al. 2005). However present literature regarding the key potential mechanisms behind why greater muscle forces are seen accelerating the body upwards in CMJ in comparison to SJ is somewhat unclear. A CMJ can be defined as a positioning starting upright, beginning the descending motion in advance of the upward motion in contrast to a SJ where the start position is squatted with no preparatory countermovement (Akl 2013). The higher jump heights seen in CMJ in comparison to SJ are apparent even if at the start of propulsion phase the body configuration is identical (Bobbert et al. 1996). In past literature three main mechanisms have looked to provide an explanation for the greater muscle forces seen in CMJ than the SJ. The first plausible theory is that the muscle stretch in CMJ increases the production of force capability of the contractile machinery (Edman et al. 1978; Ettema et al. 1992; Herzog et al. 2003). Secondly the assumption that the muscle fibres are on the descending limb of their force–length relationship at the start of propulsion in the CMJ and SJ, however in CMJ the stretching of a chain of elastic components, they are not as far past optimum length therefore allowing a greater force over the initial phase of their shortening range, with the stretching of sequences of elastic components, this then causes the storage of elastic energy that is then reutilized in the propulsion phase (Ettema et al. 1992). The final explan...
The digestive system is a group of organs that works together to convert food into energy and basic nutrients that will feed the entire body. The digestive system breaks down food so nutrients can be absorbed by the body. The digestive system has three main functions. First, it ingests food then breaks it down so nutrients can be absorbed and it also eliminates what cannot be digested.
Recorded videos were used to analyze the movement patterns of the runners. The participants were an elite (male) and a novice runner (female). The elite runner used a standard track field while the novice used a treadmill in a standard gym. The result showed that the elite runner had a longer stride than the non-expert due to his long legs. The novice runner required less force to move her body than the elite runner. The expert had longer stride resulting in longer step length which made him move faster than the novice. As the feet of both participants touched the ground the expert had a higher ground reaction force than the non-expert. The elite had a higher cadence than the non-elite because his legs moved faster. During stance phase, they both have one foot on the ground and as their foot first hit the ground they both slow down. However, the novice was slower because the elite had a faster speed making him spend less time in the
The purpose of the squat is to train the muscles around the knees and hip joints, as well as to develop strength in the lower back, for execution of basic skills required in many sporting events and activities of daily living. Because a strong and stable knee is extremely important to an athlete or patient’s success, an understanding of knee biomechanics while performing the squat is helpful to therapists, trainers, and athletes alike (11). Because most activities of daily living require the coordinated contraction of several muscle groups at once, and squatting (a multi-joint movement) is one of the few strength training exercises that is able to effectively recruit multiple muscle groups in a single movement, squats are considered one of the most functional and efficient weight-bearing exercises whether an individual’s goals are sport specific or are for an increased quality of life
The pancreas is one of the essential organs in the human body and belongs in the Digestive system. Out of all the internal organs, the pancreas is unique because the pancreas plays a role in both the endocrine gland and the exocrine gland. This means that the pancreas is a dual function gland in which is the reason why the pancreas is such a vital part of the digestive system. This research paper will talk about the anatomy, physiology, and the important functions the pancreas play to maintain homeostasis.
The human foot is an incredibly complex part of the body, it is made up of twenty-six bones which is fully twenty-five percent of the bones in the entire body. The structure of the forefoot includes the five metatarsal bones and the phalanges. The metatarsal bones are for forward movement and provides attachment for several tendons. The phalanges, also known as the toes, movement take place in the joints. The foot movement only has two movements; inversion and eversion. All the joints in the hindfoot and midfoot contributes to these complex movements. The foot has two significant functions: weight bearing and impulsion, which both requires a high degree of stability. The foot must also be flexible so it is able to adapt to uneven surfaces. The various bones and joints of the foot are what allows the foot to be flexible. In order for the foot to be able to support any weight the various of bones must form an arch. The foot has three arches that are maintain by the shape of the bones and by the ligaments. The arches are supported by the muscles and tendons. A foot is a strong, flexible, and durable it allows us to daily activities as we please while carrying all the
To improve your body, biomechanics is unavoidable. Biomechanics is the branch of kinesiology that seeks to understand the behaviour and function of the living human body when it is acted upon by forces. “With the use of biomechanical analysis atletes are able to use to use visual feedback in order to identify both positive and negative aspects of their technique (Shackel 2)”. To advance the body stability is one of the seven principles of biomechanical analysis required. Stability is the lower the center of mass, the larger the base, and greater the mass, the more stability increases. “You need to start from the bottom. If all your stabilizer muscles are strong, you’re creating a strong foundation, which means you’re going to be more efficient
Coaches and elite athletes forever seek to optimise performance and prevent injury through preventative measures. Core stability encompasses the capacity to govern the situation and movement of the trunk over the pelvis for optimal production, transfer and control of force and motion to external regions. Central core for stabilisation and force production is becoming progressively important to the sporting industry. Core stability is portrayed as critical for efficient biomechanical performance, fundamental in maximising force generation and minimising joint loads in all movements. Movement efficiency, effectiveness, endurance and consistency is colloquially associated with core. Documents analysed consider the benefits of core stability for optimising performance and preventing injury in elite athletes. Research addresses the value of these claims and contrasts common appearance within training regimes. Unanimous consensus regarding the concept of core stabilisation is yet to be established, thus such a model has not been confirmed for elite athletic enhancement.