Introduction
Acceleration is an essential component in many different field sports including games such as rugby, soccer, American football and tennis (Spencer, Bishop, Dawson and Goodman, 2005). It is widely considered the most important attribute in team sports (Wilson, Lyttle, Ostrowski and Murphy, 1995), therefore the ability to enhance it would be valuable to many sporting events (Cronin and Hansen, 2006). An athlete’s ability to accelerate is dependent upon numerous factors, including technique/body position (kinematics) and the force production capability (kinetics) of the body (Cronin, Hansen, Kawamori and McNair, 2008). Important kinematic factors that affect acceleration performance include step frequency and step length (Hunter, Marshall, and McNair, 2004; Murphy, Lockie and Coutts, 2003), duration of the stance phase (Murphy Lockie and Coutts, 2003), position of foot strike through the athlete’s centre of mass (Chu and Korchemny, 1993), knee flexion angle before and after foot strike (Murphy, Lockie and Coutts, 2003), the magnitude of hip extension at toe-off (Vonstein, 1996), the angle of take-off of the athlete’s centre of mass at toe-off (Hay, 1985) and trunk lean progressively decreasing from 45⁰ to 5⁰ (Baechle, and Earle, 2008).
Kinematic factors, in particular trunk flexion may change slightly when an athlete fatigues, as fatigue of the trunk musculature has been shown to cause an increase in trunk flexion during running (Hart, Kerrigan, Fritz and Ingersoll, 2009). Koblbauer, Schooten, Verhagen and Van Dieen (2013) found that an increase of just 4⁰ trunk flexion whilst running in novice athletes can increase risk of injury of the lower limbs and back musculature by exposing the knee to increased load (Z...
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...ervention. Furthermore future research needs to identify if the small change in trunk flexion found in this study could lead to any long term effects on sprint kinematics. This will allow coaches to understand how weighted vests may impact on sprint kinetics and how it can be manipulated to increase acceleration power and decrease risk of injury.
In conclusion there was no significant difference in trunk flexion at 5%, 7.5% and 10% (p=0.83) resistance in resisted vest sprint training compared to unloaded sprinting. The study highlights that low percentages of resisted sprint resistance will not cause injury through change in trunk kinematics. Although trunk flexion did increase slightly to the response of an external stimulus, recent research (Koblbauer, Schooten, Verhagen and Van Dieen, 2013) suggests this increase is not enough to cause concern for injury.
6. REUTER G, DAHL A, SENCHINA D. Ankle Spatting Compared to Bracing or Taping during Maximal- Effort Sprint Drills. International Journal Of Exercise Science [serial online]. January 2011;4(1):305-320. Available from: SPORTDiscus with Full Text, Ipswich, MA. Accessed January 26, 2014.
What is Biomechanics? It is the study of forces and their effects on the living system (McGinnis, 2013). In this essay, I will be looking at the biomechanics of running. Running, as well as any other sport requires skills for which advancement is due to consistent deliberate practice and effective development. However, runners should establish a training system that actively builds their original running pattern instead of basing it on what works well for others. Understanding the biomechanics of running gives a better knowledge of their running techniques and points out areas of concerns that require improvement. Despite the fact that running is dependent on the interaction of the whole body, breaking down the running pace into single components allows us to further understand how minor changes can increase improve performance and decrease injury risk.
As we have learned through our reading, most all bodies skeletal muscles are made up of primarily three types of skeletal muscle fibers, but their proportion differs depending on what action the muscles is doing. For example, type I fibers such as muscles of the neck, back, and leg have a higher proportion. According to Quinn (2014), type I muscles are slower and more effective, they tend fire a lot slower than fast twitch fibers and they fatigue at a much slower rate. Hence, slower twitch fibers are pronounced at helping athletes run marathons and bicycle for hours. Shoulder and arm muscles are not always active but are intermittent in their use; these muscles tend to have a larger amount of tension for uses in throwing and lifting. These muscles have a combination of both type I and type II B fibers. These fast twitch fibers use anaerobic metabolism to create energy and are the "classic" fast twitch muscle fibers that excel at producing quick, powerful bursts of speed. These muscles are used in events such as 100m sprint, basketball, soccer and football. Since this muscle fiber fires at such a high rate of contraction it will fatigue much faster and will not last long before needing to rest.
I described and applied physiological and biomechanical concepts related to physical activity and skill in EXS 397 lab. A student in the lab was tested on their VO2 max using The Bruce Treadmill protocol. With the data I recorded from the test, I was able to apply physiological and biomechanical concepts to explain the subject’s energy sources during the run.
Imagining myself as a high school soccer coach, I would like to optimize my team’s kicking performance. Some players consistently kick the ball successfully with the correct use of power and accuracy. To ensure that all players are able to achieve the same optimal kicking habits, this paper will document (1) the effective and ineffective habits of kicking, (2) describe biomechanical based kicking assessments, (3) describe how these assessments will measure the effective aspects of kicking and expected findings, and (4) provide suggestions on how I may modify programming based on the insights gained from these assessments.
This lab explored the relationship between EMG and force and EMG and fatigue. It has been shown that EMG, fatigue and force levels are dependent upon type of contraction and whether or not the contraction is maximal or sub maximal. Seliger et al. (1980) gained insight into the differing force and EMG profiles of isometric, eccentric and concentric contractions. Fourteen subjects underwent a maximum voluntary contraction in the squat of the concentric, isometric and eccentric variations. He showed that the EMG activity in the rectus femoris showed little statistical difference. However the force reading showed its highest values during an eccentric contraction, it's lowest values during concentric contractions and its second highest values during isometric contractions (Seliger, 1980).
Meylan, C., Nosaka, K., Green, J., & Cronin, J.B. (2011) The effect of three different start thresholds on the kinematics and kinetics of countermovement jumps. The Journal of Strength and Conditioning Research. 25, (4), p1164-1167
Schnall, R. P., & Landau, L. I. (1980). Protective effects of repeated short sprints in
Several articles describe the effects of warm-ups and stretching and whether they have a promoting or a diminishing effect on sprint performances.
The main reason for all of these factors is aging. As a person gets older the body has to work harder to maintain the same capacities that the body could do at a younger age. As individuals get older the factors that affect performance continue to decline in a curvilinear fashion until the athlete reaches 60-70, and at that point the factors begin to decline exponentially. One of the biggest components of aging is that an athlete’s muscles begin to become more fatigued and damaged more when performing in an exercise session. Muscular fatigue is a very strong indicator of how the body can function and maintain hemostasis under the stress of exercise. As a person gets older these seems to be three different components that cause this increase in muscle fatigue and damage. These three are that older individuals are far more susceptible to muscle damage because the age of their muscles, older individuals have a poorer regeneration of the muscle fibers that are torn during exercise, and older individuals have and incomplete functional recovery of skeletal muscles causing them to be sorer for longer periods of time. One of the ways that these factors were tested was having older individuals perform a max voluntary contraction (MVC) before and after a long distance activity (55km trail run), and comparing them to younger athletes. (Brisswalter) This would allow researchers to see if the master athletes are fatiguing faster that the younger ones. After the research was done it was found that both before and after the run that the master athletes could not hold their MVC as long as younger athletes could. This is a prime example of how aging can effect the intensity and performance of master athletes compared to younger athletes in the same competitions. This research can be seen on the
In what ways has the study of biomechanics contributed to a broader understanding of factors important for improving performance in sport and athletic competition?
Fahey, Thomas D., EdD. Specialist in Sports Conditioning Workbook and Study Guide. California: International Sports Sciences Association, 2007. Print
Body size influences the speed, power and endurance of rugby players (Withers et al., 1987). Forwards also require greater body mass than backs; players involved in the scrum need to be strongly built and heavy to withstand and apply forces while scrummaging (Milburn, 1990). Body composition is measured due to the belief that excess body fat is associated with negative performance. This is based on Newton’s second law, which specifies, increases in fat mass without increase in muscle force will reduce acceleration. Furthermore, the displacement of fat mass requires extra energy, causing an increase in the cost of exercise (Duthie, 2006). Therefore, excessive body fat can negatively affect speed, acceleration and economy of movement. The Durnin and Womersley skinfold technique (1974) provides the most valid and reliable method of assessing an individual’s body fat compared to the gold stan...
In order to fully understand the impact and effect of overtraining, defining and establishing the difference of what overtraining is from other conditions, such as overreaching, is necessary. Overtraining is defined as the accumulation of both training and non-training stresses producing a long-term effect on the athlete’s performance capacity, with or without physical and psychological overtraining signs and symptoms in which recovery of the performance capacity will take weeks to months (Halson, 2004 p. 969). Overreaching, however, is defined by the accumulation of training and non-training stresses with a short-term effect on the a...
Gabboth, Tim. "Journal of Strength & Conditioning Research (Lippincott Williams & Wilkins). Feb2012, Vol. 26 Issue 2, P487-491. 5p." N.p., n.d. Web.