Running is a natural form of human locomotion. To many, running is an essential aspect of most sports and is also a simple way that requires little to get exercise anywhere. But because many people have adapted to improper forms of running over time, numerous physical injuries are the results. With the help of understanding the physics behind running, people can learn to run in such a way that expends less energy from the body. Keeping physics in mind may also lead to less injuries and effortless running. Remember, physics can be very helpful when running!
External Forces When Running
According to mechanical physics, a force is an effect that may cause a body to accelerate. Also as stated in Isaac Newton’s second law of motion, force is a vector quantity (has magnitude and direction) that is proportional to the product of the mass of a body and its acceleration.
F = ma : where F is force; m is the mass of the body; and a is the acceleration due to that particular force
When running, there are four important external forces that definitely affect the kinetics of running: drag force, gravity, normal force, and friction.
Drag Force
Due to the interaction with air on Earth, runners experience a resistive force against the airflow. This is called the drag force, or air resistance. The equation for this drag force is given as :
Drag Force = 1/2pvvAD
where p is the density of the fluid (in runner’s case: air); v is the velocity of the runner; A is the cross-sectional area perpendicular to the runner’s velocity; and D is the dimensionless quantity called the drag coefficient.
The drag force is always working against the forward motion of a runner, trying to move them in the negative horizon...
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...energy.
-Second, hip rotation also helps the runner to have a more natural and smoother run and again reduces the energy required to move the runner’s center of mass.
-Finally, the pelvic rotation decreases the impact at contact with the running path felt by the runner.
Bibliography
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Inman, Verne T., Henry J. Ralston, and Frank Todd. Human Walking. Williams & Wilkins. Baltimore, MD. 1981
Watkins, James. An Introduction to Mechanics of Human Movement. MTP Press Limited. Lancaster, England. 1983.
Zatsiorsky, Vladimir M. Kinetics of Human Motion. Sheridan Books. Champaign, IL. 2002.
Oatis C. (2009) Kinesiology: The Mechanics & Pathomechanics of Human Movement (Second ed.). Glenside, Pennsylvania: Lippincott Williams & Wilkins.
Newtons second law can be indentified more easily using the equation F=ma. This is an equation that is very familiar to those of us that wish to do well in any physics class! This equation tells us many things. First it tells us the net force that is being exerted on an object, but it also tells us the acceleration of that object as well as its mass. The force on an object is measured in Newtons (I wonder where they got that from). One Newton is equal to one (kg)(m)/s^2. For example, if superman pushes on a 10,000kg truck and it is moving at a rate of 2m/s^2, then the force that superman is exerting on the truck is 20,000N. For those of us that wish to move on in the field of physics, Newtons second law (F=ma) will forever haunt us!
Anderson, D. I., & Sidaway, B. (2013) Kicking biomechanics: Importance of balance. Lower Extremity Review Magazine.
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...
Drag is caused by the disrupted air immediately behind an object moving through fluid/air. It acts perpendicular to and in the opposite direction of travel of the object and impedes the motion of the object. It would make sense that if the drag is minimized, the object will travel farther. Lift or curve in the motion of an object through air is a phenomenon that is noticeable in a ball traveling through fluid/air. This change in direction is due to the effect that spin has on the object in motion.
Retrieved 14 May 2014, from http://www.teachpe.com/a_level_analysis/movement_analysis_webpage.html. Thibodeau, G., & Patton, K. (1993). "The Species of the World. " Chapter ten: Anatomy of the muscular system. In Anatomy and Physiology (1st ed., p. 252).
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.
Let's examine a basic tumbling run. All three of Newton's Laws can be seen in this one tumbling run. We can see Newton's first law before the gymnast takes even one step. Until she takes a step, the gymnast is at rest. When she is ready to tumble the gymnast applies the force. A gymnast takes a running start when approaching a tumbling run, and as she is moving across the floor she is increasing her momentum. This is a demonstration of Newton's second law.
Esther Thelen, explains how infants develop their independent walking. Upright bipedal locomotion is a very complex skill and demanding motor task.5 In her article, Hidden Skills: A Dynamic Systems Analysis of Treadmill Stepping during the First Year. Monographs of the Society for Research in Child Development, Thelen states, “First a walker must generate a synchronized ensemble of muscle contractions to produce the locomotor movement. This usually involves muscles spanning many joints and body segments: the legs alternate in a pattern of swing and stance, the pelvis rotates and tilts, and the arms and shoulders swing forward and back in phase with the opposite leg. But locomotion, like all other motor actions, involves not just muscle contractions but also the interrelation between the motor patterns and the biomechanical and dynamic requirements of moving segments with mass and viscosity through a gravitational environment.”5 This excerpt supports the prior explanation of what the DST and Hierarchical Theories are and how they are interrelated; both are required to explain the principles of how infants learn to
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
The acceleration of a body or object is directly proportional to the net force acting on the body or object and is inversely proportional to its mass. (F=ma)(Newman)
If a force acts on a body, the body accelerates in the direction of the force. In the example of the force of gravity, small things like textbooks are pulled downward toward the center of the large mass of the Earth, not up into space, even if some people think that this might happen. Isaac Newton was the first to conceive of weight as the gravitational attraction. between the body and the Earth. The force that results from the gravitational attraction of the Earth on its surface is what we call weight. Science has chosen to measure the mass of objects in units that are roughly equivalent to the weight of those objects on Earth.
Dapena, Jesus, and Alexander P. Willmott. “Scientific Services Project: (USA Track & Field),HIGH JUMP #23 (Men) Research Report.” “Diss. Indiana University, 2002.” Kirkpatrick, Larry D., and Gerald F. Wheeler. Fourth Edition Physics A World View. Fort Worth: Harcourt College Publishers, 2001.
Sir Isaac Newton is the man well known for his discoveries around the term, Motion. He came up with three basic ideas, called Newton’s three laws of motion.
This attraction has a gravitational field strength, Newton wanted to calculate the gravitational field strength of the earth. Newton discovered that when a force is applied to an object, it will cause the object to accelerate, therefore the object will change its velocity. The acceleration will be proportional to the magnitude of the force and in the same direction as the force. The proportionality constant is the mass, m, of the object. F = ma To prove this, astronauts on the moon dropped a hammer and a feather on the moon's surface.