Applications in sport/Limits of performance S2W8 Flashcards
What limits human performance?
- strength/effort
- timing
- coordination
Definition of skill
- “The ability to bring about some end result with maximum certainty and minimum outlay of energy” (Schmidt)
- Someone who can do a strategy at high speed with as little energy as possible will be seen as more skilful than someone who does the same strategy with more effort/energy
simulation model of triple jumping (Allen, 2010)
- 13 rigid segments
- 5 wobbling segments
- 20 torque generators: representing muscular forces around the joints
- VE foot-ground interface - springs at 3 points along foot
- vary activation profiles - how long/when the muscles switch on and off
- looking at recorded jump vs simulated jump, the model does a good job of replicating real world activity
simulation model of triple jumping (Allen, 2010) - How can technique be optimised? What would happen if we were stronger or ran faster?
- asymmetrical arms in recorded jump
- when technique was optimised its moved to a double arm shift - both arms working symmetrically
- increase approach velocity = increased distance jumped until it tails off (optimum approach velocity)
- tails off because if you’re not strong enough you see collapsing during take off and don’t jump as far
conclusion:
- sometimes strength can be a limiting factor and in sport minimising effort is not always the underlying strategy
elite gymnastics - traditional vs scooped bar dismount
- scooped technique creates a bigger release window (larger margin for error)
gymnastics bar dismount - determining the margin for error in timing the release
t0 = the first time at which they could let go of the bar and perform correct movement when they have sufficient angular momentum and appropriate flight conditions
t1 = the last time they can let go and perform the correct movement then they will no longer have sufficient angular momentum and appropriate flight conditions
release window = t1 - t0
release window - margin for error formula
release window = t1 - t0
margin for error = (t1 - t0) / 2
data collection on traditional vs scooped bar dismount
- Sydney Olympic qualifying comp
- 8 scooped giant circles
- 3 traditional giant circles
- need to use simulation model because once gymnast lets go of bar, we don’t know what would have happened if they hadn’t let go at that time, use simulation model to see what happens if you let go slightly later
- from the matched performances using simulation model we can calculate release window
- four segment simulation model
- input: joint angle history
- output: linear and angular momentum
data collection on traditional vs scooped bar dismount - margin of error in timing the release
- ± 10% angular momentum
- 1.0 m < landing away from the bar < 3.5 m
- time of flight > 1.2 s
- on average gymnasts using scoop technique have larger release window
why do gymnasts using the scooped technique have a larger release window?
because . . .
- for traditional release, path of the mass centre is very circular
- whereas for scoop technique, the path of the mass centre becomes a straight line leading to release
- meaning no matter where on this straight line you release, as long as you have enough angular momentum, you will have a very similar flight conditions
conclusion:
- the scooped technique flattens the path of the mass centre giving a greater margin for error when releasing the bar
What defines success?
athletes must operate . . .
- within strength limits
- within anatomical/flexibility limits
- within a noisy environment (want to be robust to the noise within the motor system)
and athlete must satisfy the biomechanics requirements . . .
- angular momentum (somersaults)
- linear momentum (flying over the bar properly)
- flight time
- need to satisfy all the constraints on the system (Newell’s 1986 model)
