İnsanlaşmanın ardından gelen 2 milyon yılın izini süren bu kitapta bir çok primat uzmanı, aşktan töre cinayetlerine, insan davranışlarının evrimsel kökenini araştırıyorlar. Australopiteklerden bu y...
magic trickDescription complète
Positive running, a model for high speed running Frans Bosch • positive running posture sums up the right technique for top speed • building blocks in running: Pelvic rotation for- and backward and hamstring function • control of anterior-posterior pelvic rotation is crucial for hamstring function • ground-reaction-force and the whip from the hip
2012
Positive running posture sums up the right technique for top speed
the worlds best sprinters run more positive posture than the “also participating”
Building blocks in running: Pelvic rotation for- and backward and hamstring function Toe off pelvic rotation is controlled by positive running
arm-action
positive running
vertical GRF
positive running
negative running increasing forward rotation pelvis reduced scissors action foot placement in front of the hip
small pendulum big pendulum
quick leg recovery
The most difficult moment in the running-cycle ; reversing the pendulum
right leg abdominals iliopsoas rectus
right leg hamstrings erector gluteus
F
F
L
L
Control of anterior-posterior pelvic rotation is crucial for hamstring function
Energy in the running-cycle
At high speed large quantities of energy are transported from one leg to the other by elastic stretch. (4-5 times per second)
reversing the pendulum
hamstring load
scissors motion
End of stance; low EMG activity
hamstring load
scissors motion
elastic/isometric muscle-work eccentric-concentric muscle-work reactive muscle-work plyometrics tendon compliance Simulation of Biceps Femoris Musculotendon Mechanics during the Swing Phase of Sprinting Thelen et all. 2005
pre-stretch and slack weak relation between ROM and muscle stretch
SLACK
STRECH
INACTIVE ACTIVE
F
L Anterior and posterior tilt of the pelvis plays a important role in making the Hamstring work in its optimum length.
the pelvis as a lever
forward rotation of the pelvis eccentric force on hamstring
Darryl G Thelen 2006
F
L Anterior and posterior tilt of the pelvis plays a important role in making the Hamstring work in its optimum length. Iliopsoas is crucial in Hamstring load >> there is no such thing as an overactive iliospoas.
If at the end of stance the pelvis rotates forward to far, it will have to rotated back during the Hamstring loading phase. Resulting in loss of speed efficiency and increasing Hamstring injury risk
Ground-reaction-force and the whip from the hip
limitation for maximum speed
a) applying force • force direction mainly vertical • horizontal component limited by relative speed of the ground • short ground-contact
b) leg motion • extreme acceleration and deceleration of the legs
horizontal component
relative ground speed limiting for horizontal component
±3 m/s
±10 m/s
0,09 -0,11 sec
direction of the translation
joint rotation
vertical component
At higher speed => less vertical oscillation At higher speed => shorter contact times The problem for running faster is not just applying more force, but more force in shorter time.
The problem for running faster is not just applying more force, but more force in shorter time. We conclude that human runners reach faster top speeds not by repositioning their limbs more rapidly in the air but by applying greater support forces to the ground Weyand et al. 2000
Solution; Just paw back?
leg speed is not limiting
±10 m/s!
!
>>!in 0,1 sec >> ! !
±0m/s
Spring mass model is to simple to represent reality, because horizontal force application is left out
The problem for running faster is not just applying more force, but more force in shorter time and in the right direction. Solution; Just more strength in the weight room?
max strength is not limiting
The problem for running faster is not just applying more force, but more force in shorter time and in the right direction. Solution; preparing the status of the next stance leg before initial contact >> “the whip from the hip”
hamstrings
m. gastrocnemius
The Whip from the Hip
The results of this study emphasize the importance of pre-activity and the activity of the leg extensor muscles during the braking phase of running. Their activity is in many cases well above that recorded during maximal voluntary contractions, suggesting that such contractions cannot be used as an indicator of the full activation potential of human skeletal muscle. Thus, features of central programming and reflex regulation seem to differ between isometric maximal voluntary contractions and stretch – shortening cycle exercises such as running Changes in muscle activity with increasing running speed HEIKKI KYROLAINEN, JANNE AVELA, & PAAVO V. KOMI
slack > time before elastic stretch &
&
#%
&
3%#
regulating stiffness
4
Energy-transport during squat-jump
more hamstring activity
more rectus activity
1 2 Gluteus motor function
Hamstrings directing GRF
3 Rectus and gastrocnemius transporting energy to ground
slack
energytransport
Energy transporting muscles
Kangaroo => optimum build for energy-transport Human => poor build for energy-transport
Angle between Femur and foot optimal for energy transport; a key for talent?
CM direction GRF
Footaction and vertical/horizontal GRF Hamstring repositioning swingleg Energytransport hip to knee
pretension next stanceleg
rotation to translation limitation
many processes have to be synchronized impossible to communicate to athletes like this. we need a simple concept => the whip from the hip
Hamstring directing GRF Energytransport knee to ankle
load and unload timed to ground speed
The timing of all these aspects has to be perfect to get optimum force and direction of force in stance. Getting the status of the to be stance-leg right prior to contact is complicated coordination. Status stance-leg prior to Initial Contact is key to short contact times. “The whip from the hip” technique provides that status.
Spring in the step synchronized with energy-transport
Spring in the step synchronized with energy-transport
Toe up when bringing the foot to the ground and then push the forefoot into the ground hip >> knee >> ankle extension
54
Toe up when bringing the foot to the ground and then push the forefoot into the ground hip >> knee >> ankle extension
57
conclusion; “whip from the hip” technique helps applying force to the ground earlier in stance. “whip from the hip” is a pattern that can be applied in many movement patterns
