Variable, because the actual location of the center of mass is

Variable, because the actual location of the center of mass is impossible to assess on video. One strategy is to identify a location on the runner’s pelvis and then to use this as a surrogate for the center of mass. Vertical displacement during running has key implications for injury mechanics as well as energetics. Increased excursion of the center of mass vertically has been found to be predictive of the peak knee extensor moment, the peak vertical ground reaction force, as well as braking impulse during running, all very important variables in running mechanics.21 This variable can become a problem in “bounders,” runners who increase float time, often in response to other deficits (eg, reduced hip extension). The end result is increased work required by the runner to perform this type of running. It has been found that increasing cadence by 10 during running can reduce significantly the vertical displacement of the center of mass.28 Additional Variables Auditory–A lot of information can be gathered from the sounds made during running. Certainly, auditory information differs between treadmills and runners of varying sizes. However, the clinician can quickly calibrate the normal or typical AZD4547 custom synthesis impact sounds of their treadmill, and this can be very useful in gathering information about impact during running. Greater noise with striking the treadmill may be associated with higher impact forces. In addition, asymmetries can quickly be identified by listening to the foot strike patterns of the runner. All of this information can be very valuable for a biomechanics running analysis.Author Manuscript Author Manuscript Author Manuscript Author ManuscriptPhys Med Rehabil Clin N Am. Author manuscript; available in PMC 2016 February 01.SouzaPageShaking of the treadmill–In AZD4547 site addition to auditory information, the reaction of the treadmill at the time of impact can also provide important information. Some large, sturdy treadmills may not provide this information, but many models provide differing amounts to shaking or giving way in response to impact, and this can be very informative to the observant evaluator. Cadence–The step rate, or cadence, should be evaluated in all runners. This variable is easily measured in a variety of ways. One strategy is to count the number of right heel strikes over a 1-minute period. This number is equivalent to the “stride rate.” Multiplying this number by 2 equates to the “step rate.” Several recent studies have evaluated the biomechanical consequences of manipulating cadence.28?2 These data suggest that an increase in cadence can result in several biomechanical changes in running form, many of which may be desirable in specific runners. For example, it has been demonstrated that increasing cadence by 10 can reduce center of mass vertical excursion, braking impulse, and mechanical energy absorbed at the knee, as well as decrease peak hip adduction angle and peak hip adduction and internal rotation moments during running.28 The optimal cadence has been an area of debate, with some suggesting that approximately 180 steps per minute being ideal. However, the majority of support for this comes from running economy studies, not studies on injury mechanics.33,34 Although it may be too early to suggest that all runners should run at a specific cadence, it is becoming clear that cadence is an important biomechanical running variable, and one that can be easily manipulated in runners when appropriate.Author Manuscript Autho.Variable, because the actual location of the center of mass is impossible to assess on video. One strategy is to identify a location on the runner’s pelvis and then to use this as a surrogate for the center of mass. Vertical displacement during running has key implications for injury mechanics as well as energetics. Increased excursion of the center of mass vertically has been found to be predictive of the peak knee extensor moment, the peak vertical ground reaction force, as well as braking impulse during running, all very important variables in running mechanics.21 This variable can become a problem in “bounders,” runners who increase float time, often in response to other deficits (eg, reduced hip extension). The end result is increased work required by the runner to perform this type of running. It has been found that increasing cadence by 10 during running can reduce significantly the vertical displacement of the center of mass.28 Additional Variables Auditory–A lot of information can be gathered from the sounds made during running. Certainly, auditory information differs between treadmills and runners of varying sizes. However, the clinician can quickly calibrate the normal or typical impact sounds of their treadmill, and this can be very useful in gathering information about impact during running. Greater noise with striking the treadmill may be associated with higher impact forces. In addition, asymmetries can quickly be identified by listening to the foot strike patterns of the runner. All of this information can be very valuable for a biomechanics running analysis.Author Manuscript Author Manuscript Author Manuscript Author ManuscriptPhys Med Rehabil Clin N Am. Author manuscript; available in PMC 2016 February 01.SouzaPageShaking of the treadmill–In addition to auditory information, the reaction of the treadmill at the time of impact can also provide important information. Some large, sturdy treadmills may not provide this information, but many models provide differing amounts to shaking or giving way in response to impact, and this can be very informative to the observant evaluator. Cadence–The step rate, or cadence, should be evaluated in all runners. This variable is easily measured in a variety of ways. One strategy is to count the number of right heel strikes over a 1-minute period. This number is equivalent to the “stride rate.” Multiplying this number by 2 equates to the “step rate.” Several recent studies have evaluated the biomechanical consequences of manipulating cadence.28?2 These data suggest that an increase in cadence can result in several biomechanical changes in running form, many of which may be desirable in specific runners. For example, it has been demonstrated that increasing cadence by 10 can reduce center of mass vertical excursion, braking impulse, and mechanical energy absorbed at the knee, as well as decrease peak hip adduction angle and peak hip adduction and internal rotation moments during running.28 The optimal cadence has been an area of debate, with some suggesting that approximately 180 steps per minute being ideal. However, the majority of support for this comes from running economy studies, not studies on injury mechanics.33,34 Although it may be too early to suggest that all runners should run at a specific cadence, it is becoming clear that cadence is an important biomechanical running variable, and one that can be easily manipulated in runners when appropriate.Author Manuscript Autho.