### Two determinants that determine running speed are stride cadence and also stride length. Due to the fact that athletes propel themselves forward only as soon as their foot is in contact with the ground, the stance step of the running stride have to be the emphasis of speed enhancement programs.You are watching: Which two factors determine speed of motion

The following is an exclusive excerpt from the bookDeveloping Speed, published by person Kinetics. All text and also images provided by person Kinetics.

Two factors that identify running speed room stride cadence and also stride length.

Stride cadence refers to the number of strides taken per second, and also stride size refers to the distance traveled by each stride. The product the these components gives a mathematically accurate summary of running speed. Timeless thinking has argued that if among these deserve to be enhanced with the various other remaining constant, running rate will increase. Therefore, the focus of rate training has been on enhancing stride cadence, boosting stride length, or boosting both. However, current research suggests that while improving these factors plays a role in determining running speed, castle may administer the coach restricted tools when occurring speed cultivate programs.

In particular, the ide of stride length, traditionally measured as the distance between each successive foot contact, deserve to be problematic. Too much emphasis on artificially lengthening an athlete’s stride can result in put the foot ahead of the athlete’s facility of mass. This position compromises the athlete’s ability to generate force and ultimately slows to run speed. Instead, an reliable stride length should be the focus. This is the distance traveled by the athlete’s center of heaviness per stride. An effective stride size is created by using a force into the soil (pushing turn off the ground) and also propelling the athlete forward rather than reaching forward through the legs in an attempt to traction the athlete forward. The force developing capacities of the athlete are fundamental to achieving optimal stride and also length and maximal speed.

Stride cadence is a role of call time (the time spent on the ground v each stride) and also flight time (the time spent in the waiting on each stride). Research has shown small variation in trip time between runners of various speeds, and also the best variations in cadence are a an outcome of distinctions in ground contact time (Weyand et al. 2000). Therefore, initiatives to enhance stride cadence should focus on shortening ground-contact times quite than concentrating on to ride bicycle the legs faster.

Stride length is largely a function of the impulse and also velocity generated at toe-off. The velocity the the athlete’s facility of gravity, i m sorry is a vital factor in dictating stride length, does not alter in between successive steps. Prefer impulse, the is generated throughout the time the athlete’s foot is in contact with the ground (the view phase). Therefore, efforts to enhance stride size by technical means during the trip phase, the moment the human body is not in contact with the ground, are restricted and must instead focus on generating impulse and also velocity during the time the athlete is in call with the ground.

The conversation of stride length and also stride cadence needs an evaluation of the phases that a running stride. Each to run stride have the right to be separated into 2 components: a view phase and a trip phase. This phases are outlined in figure 1.1. The stance step occurs when the athlete’s foot is ~ above the ground and also consists the the time between the initial call with the ground and the subsequent toe-off.

The view phase can be further separated into very early stance, a midstance, and a so late stance. During the at an early stage stance, when the foot makes call with the ground, the athlete’s human body absorbs the landing forces, which deserve to vary indigenous two and also a half to five times the bodyweight, relying on the speed and also distance the a sprint. The leg muscle absorb the landing pressures through eccentric contraction, i beg your pardon lengthens the muscles. This has the potential come cause far-ranging braking pressures unless the athlete has actually the strength capacities and also required muscle stiffness to effectively repel this force.

During this phase, the athlete can develop elastic energy, which is beneficial in later stages. During the midstance, the athlete switches from soaking up force to exerting a concentric force, which shortens the muscles and also generates maximal upright force. The elastic power generated in the beforehand stance can contribute to the force created through the mid and late stance. In so late stance, the body speeds up forward together a an outcome of the concentric forces generated.

The flight phase is the duration between toe-off and also the following foot call (see figure 1.2). During this step the athlete makes no call with the ground, so in significance is in flight. Velocity throughout the flight phase can not be increased, and also the athlete should cycle the leg in preparation for the next footfall. An i can not qualify to bike the leg efficiently results in suboptimal ground contact on the following stance phase, and also therefore limits speed expression. Since athletes have the right to propel themselves front only once their foot is in contact with the ground, the view phase must be the main focus of speed enhancement programs.

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