Would you like to improve your Running Economy and get faster while lessening the chance of Injury?
From the time you were a toddler, natural instincts have been playing a key role in your ability to walk and run. However, are you confident that you are running with the most biomechanically-correct form? Most people provide little to no conscience thought about how they are running, and have no guarantee that they have developed the proper techniques to run as effectively as they can. Although running is something that comes naturally to us, technique usually can and should be improved upon. In doing so, you can improve your running economy which leads to faster running while lessening the chance of injury!
In order to achieve improved running economy we will explain the basic science behind running biomechanics, clarify what running economy is, discuss why a runner would want to improve running economy, provide a fundamental rationalization of how to enhance economy, present detailed steps to improve running efficiency and illustrate how to lessen the chance of injury.
The basic science behind running biomechanics incorporates what is called the stretch-shortening cycle. The stretch-shortening cycle is defined as an active stretch of a muscle followed by an immediate shortening of that same muscle. The active stretch is called the eccentric contraction and the immediate shortening is called the concentric contraction. When running, a great deal of muscle activity occurs. Many neurons continually fire various muscle groups throughout the stride. For example, even in the milliseconds before the foot lands on the ground, several different muscles pre-activate in order to increase stiffness of the leg and joints before landing. The stiffer muscles not only absorb more shock, but also help the muscle-tendon unit store more energy.
The muscle-tendon unit acts like a spring. Upon foot strike, the muscle lengthens (the eccentric contraction). The push off on extension of the running stride causes the immediate shortening of the muscle (the concentric contraction). The concentric contraction is more powerful and more efficient, if it follows the eccentric contraction. In running, this concept can be thought of as the drop and spring idea. The knee drops and the body springs forward with each stride. This concept uses less oxygen and energy, thereby increasing running economy.
Elastic structures in your leg work in series with the contractile components to store energy like a spring after being forcibly stretched. Since the length of the tendon increases due to the active stretch phase, the series elastic component acts as a spring and is therefore storing more potential energy upon foot strike. This energy is released as the tendon is shortened upon push-off of the running stride. Thus, the recoil of the tendon during the shortening phase of the movement results in more efficient movement than one in which no energy had been stored.
One prime example of an effective use of the stretch-shortening cycle is seen when a basketball player slam-dunks a basketball. The athlete bends down (the eccentric contraction) and then bounces back up (the concentric contraction) to obtain a higher vertical jump. The athlete takes advantage of the stretch-shortening cycle using the eccentric contraction followed by the more powerful concentric contraction to attain elevated height. In running, the result of pre-activation and then the eccentric-concentric contraction is that contact time is reduced and performance is improved. Muscles shorten and joints extend enabling forward propulsion when running. Quick cadence and efficient strides stemming from proper biomechanics improves running economy and increases running speed.
The running stride begins when the knee drops and the foot lands for the eccentric contraction. The body springs forward most effectively when the body is leaning forward from the ankles and the stretch-shortening cycle is maximized. The push off on the extension phase of the running stride is generated from the Quadriceps for the concentric contraction. The Hamstrings are then activated upon deceleration of the heel when the knee is coming forward off the stride and preparing the knee for the drop. This is the concept of drop and spring forward, or dab and push or lean and push off versus lift and pull.
In running, the shock absorption that occurs upon foot strike contributes to a greater force production at push off. When the drop and spring technique is applied in running, the stretch-shortening cycle saves energy by temporarily storing potential energy through elastic recoil resulting from an external rapid stretching force. In conclusion, proper running mechanics reduces fatigue, lessens the chance of injury and improves running economy.
So what is Running Economy and why do we want to improve it? Running economy is a measure of how efficiently a person uses oxygen while running at a given pace. Those who are able to consume less oxygen while running at a given velocity are said to have a better running economy. Running economy takes into consideration ones body mass and oxygen consumption at a steady state within his or her aerobic range. Running economy is proven to be a good predictor of race performance. The more economical a runner becomes, the lower the heart rate, oxygen consumption and effort will be at the same VO2 and speed per distance. Improving Running Economy means you will be able to run at a particular pace, longer and with less energy expenditure.
So how do you improve running economy and lessen the chance of injury? First, you must address Biomechanics and improve running form. Biomechanics is defined as the application of the principles and techniques of mechanics to the structure, functions and capabilities of living organisms. The Biomechanics of running is the technique or form component of running. Good running biomechanics improves speed and helps prevent injury. The landing force exerted on each leg while running can be as high as 3.5 times the weight of the body. With correct biomechanics there is a reduction in vertical oscillation, heel-strike braking forces, wasteful peripheral dynamic forces and overall load. As a result of good biomechanics, stress and impact on the body are decreased to as little as 1.5 times the body weight per each foot strike. Since too much stress and impact during the running stride often leads to injury, improving form will reduce the potential for injury.
To improve biomechanics and reduce stress and impact with each stride, you must understand and improve the peripherals. Peripherals are defined as the surface or outer part of a body or organism. As such, the legs and arms are considered peripherals when running. Running peripherals often contain muscular imbalances and tightness which can be found throughout the body. Each running peripheral must be assessed and any deficiency corrected. If there is damage or weakness in a peripheral, more stress is placed on other parts of the body resulting in a higher heart rate, and causes an increase in the chance of physical breakdown and injury. Specific training must be incorporated to improve the function of the neuromuscular system, specifically the contact time and reflexes while running, thereby enhancing running economy.
Concentrated training must be planned and implemented in order to improve peripherals. Runners naturally develop muscular imbalances. They generally become very strong in the larger muscle groups such as the Quadriceps and Hamstrings. These muscles may become over-developed while the smaller stabilizing muscles such as the low back, core, adductors and abductors often become (relatively) weak. Because running occurs in one plane of motion, other training must be incorporated to balance the overall body. Training in all directions and all planes of motion improves muscular control, lessens fatigue and reduces the chance of injury. Sport specific functional strength and core training that addresses over-developed muscles, underdeveloped muscles and conditioning in all planes of motion is essential for long term success in running. Specific and controlled plyometric training also increases a runners ability to store and use energy thereby producing the same force with less energy demand. Together, specific functional strength, core and plyometric training will enable an athlete to run faster, longer while lessening the chance of injury. Assessing and addressing the peripherals will improve biomechanics and lead to performance enhancements.
Before explaining the specific steps to improve running economy, lets first explain the three essential factors that influence running economy: Running Mechanics, Peripherals and the Central System. Correcting running mechanics will improve how the body is landing, moving and the muscles are firing during each running stride. Evaluating peripherals will identify muscular weaknesses and tight areas throughout the body that must be strengthened or stretched. Finally, the central system must be effectively trained. In order to improve running biomechanics and become more economical at running, one must run! The aerobic system must continually be trained to strengthen the aerobic engine. Training must include various intensities, durations and focuses through a coordinated plan. Running must be consistently maintained with the appropriate frequency, duration, volume and intensity.
With a basic background of these three essential factors, we can now extensively discuss the four major components used to evaluate the actual running mechanics, thus improve running economy. The four components are: Running Stride, Body Alignment (including Forward Lean), Momentum Inhibitors and Symmetry. Efficiency during the running stride is important. Running stride includes stride rate and stride length. Stride rate, also known as cadence, should be quick and effective with the goal of reducing the amount of time the foot is on the ground. The less time the foot is on the ground, the less impact the body acquires with each stride. The foot should land under the body and aid in balance and propulsion with an efficient stride length. Next, one must evaluate the bodys alignment as viewed from the side profile of the running stride. This is the forward lean angle. In order to effectively use the stretch-shortening cycle and achieve propulsion with the Drop and Spring idea, the runner must be leaning forward from the ankle so the knee can drop, the foot can dab and then push off. If the body alignment is too upright (less than 10 degrees forward), the runner must overcome this position by lifting the knee and then pulling the foot through on each stride which causes an increase in braking forces and increased vertical oscillation. This leads to the next component, momentum inhibitors. In evaluating the loading/unloading cycle during the running stride, the key is to reduce and nearly eliminate all braking forces and vertical oscillation by landing mid-foot, under the body while maintaining a strong core, forward lean and effective arm swing. The last component is achieving symmetry. Asymmetric gyrations in running form must be compensated for by other elements in the body. However, running evenly with proper form through body awareness and activation of specific muscular groups, a runner can reduce overall muscular fatigue thereby improve running economy.
The most effective way to enhance biomechanics and thus improve running economy and lessen the chance of injury is by a critical analysis of the four major components listed above. The following six steps should be taken, in this specific order, to evaluate and fix running mechanics.