Fundamentals of Acceleration + Sprinting
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When broken down simply a sprinting athlete is either pushing on the ground to propel forward in space, or is preparing in the air for the next contact. As Jonas Dodoo discusses in his most recent masterclass there are 3 fundamental components of high speed running. Identifying and addressing how these relate to an individual athlete can have a significant effect on their performance.
Projection
Projection refers to the horizontal orientation of movement ie moving further with each step by producing large forces on the ground through large ranges of movement. This is primarily a combination of horizontal hip displacement and step length. We want to ‘Spend enough time in the air to travel far without wasting time’
Key Components of Projection:
Extension - creating large forces on the ground by pushing strongly with the trail leg
Flexion - preparing effectively for the next step, pretensioning the swing leg to attack the ground.
Projection can look slightly different during acceleration and upright running.
- In upright running airtime is your friend - faster athletes travel further in the air
In acceleration airtime is you foe - horizontal force can only be applied on the ground, higher air time can reduce step frequency and prolong acceleration. There should be a larger focus on hip displacement over step length for these athletes
Switching
Switching refers to the ability to create and reverse large ranges of movement in a short period of time. It can also be referred to as Thigh Angular Velocity (thigh range/ time)
Ideally reciprocal hip flexion and extension occur at the same time across a stable pelvis. A stable pelvis allows the thighs to cover a large range to push and prepare effectively and forceful reverse of ranges to allow the athlete to be quick with each step
Switching can be difficult for athletes as it requires large forces into the ground with some adequate hip extension combined with short ground contacts and front-side mechanics, which can decelerate the limb early during the ground contact.
Effective switching however creates pretension in the swing leg which allows a ‘whip from the hip’ mechanism enabling the athletes to spike their ground reaction force This then enables the stance leg to decelerate and start its next cycle as a swing leg.
Switching can be broken into 2 phases:
- Early phase: TAV in the air (toe off - touchdown)
The athlete needs to attack the ground to land their foot under the body, spike ground reaction forces early.
- Late phase: TAV on the ground (touchdown - toe off)
Create large propulsive forces on the ground to travel far with each step.
Reactivity
Reactivity refers to whole system stiffness during ground contact. The athlete needs to have the ability to reduce large vertical compressive forces while applying force quickly into the ground. Foot placement is often a key component in reactivity. Landing with the foot under the body minimises the braking impulse and reduces ground contact time, resulting in increased reactivity.
It is important to note that athletes with good RSI + RFD testing are not always able to translate these fast reaction times in the gym to running. Reactivity in running should be individually evaluated during the task.
Key Components of Reactivity:
- Landing with foot close to centre of mass
- Limited hip and knee collapse at footstrike
- Quick ground contact time
All elements of Projection, Switching and Reactivity work in synergy, if an athlete has high levels of stiffness and reactivity their projection can happen early and be aggressive.
Drills addressing these fundamentals are often the best way to allow the athlete to understand and master the required skills prior to implementing them into running.
Drilling can be incorporated into warm up or team training to maximise training efficiency but should be introduced when sufficient attention can be given to technique and execution.
Find out more about PSR and how this is implemented clinically in Jonas Dodoo’s masterclass - Running Re-Education