Athletics Jamie French and Ian Hill Horizontal Jumps

Learning Outcomes Within this lecture and practical series we will:- ◦ Understand the biomechanical principles behind both Horizontal Jumps  Understand the coaching points and biomechanical principles behind horizontal jumps ◦ Understand the link to the physiological considerations behind training for Horizontal Jumps ◦ Discuss the importance of plyometric training for jumps

References Jacoby, E. and Fraley, B. (1995) The complete book of jumps. Human Kinetics: Leeds Grimshaw, P., Lees, A., Fowler, N.and Burden, A. (2006) Sport and Exercise Biomechanics. Taylor Francis: London

Better References Linthorne, N., Guzman, M. and Bridgett, L. (2005) Optimum take-off angle in the Long Jump. Journal of Sports Sciences. 23 (7). 703 – 712 Graham-Smith, P and Lees, A. (2005) A three- dimensional kinematic analysis of the long jump take-off. Journals of Sports Sciences. 23 (9)

Horizontal Jumps – World Records Long Jump ◦ Mike Powell 8.95m  1991 World Athletics Champs in Tokyo ◦ Galina Christyakova 7.52m  1988 Leningrad Russian National Champs Triple Jump ◦ Jonathon Edwards 18.29m  1995 World Champs in Goteborg ◦ Inessa Ktavets 15.50m  1995 World Champs in Goteborg

Records What is consistently the most important factor in these jumps?

Some Important Principles Projectile Motion ◦ R= Range ◦ v = velocity at release ◦ Θ = release angle ◦ g = acceleration due to gravity (-9.81m/sec -2 ) R= v 2 sin 2θ g

Into English Speed at Take Off ◦ Velocity of body upon release Angle of Take off ◦ Angle at which the body takes off at

Speed is Important Horizontal velocity of the CM between 6m and 1 m in front of the takeoff board (in metres per second) Triple Jump Performance (in metres m) (Hutt. Date Unknown)

Phases of the Jump Consistent across all jumps: - Approach - Take off - Flight - Landing (UKA 2004)

Running – Approach Long and Triple Jump Running Gait – split into TWO main phases ◦ Support or Stance – feet on the ground  (No double support phase) ◦ Swing – when foot is off the ground  Also a period of flight  When? ◦ Ratio of these alters faster you travel  40% stance: 60% swing moving to max 20% stance for top sprinters (Grimshaw, Lees, Fowler and Burden. 2006)

Forces Ground Reaction Force ◦ Very Important ◦ First contact with floor is actually breaking ◦ Hips lower by knee and hip flexion  But some good news!!  Energy stored in Achilles as Elastic Potential Energy (Grimshaw, Lees, Fowler and Burden. 2006) Foot Strike (contact point) Ground Reaction Force C of M Direction of Travel Directional forces

Implications for last few strides? What do you think are the implications for how you should coach the last few strides of run up?

Take Off Long and Triple Jump Counter Movement ◦ Prior to take off hip, knee and ankle all under go period of flexion  Knee and ankle same for all jumps, hip will flex more in higher Jumps (Graham-Smith and Lees. 2005) ◦ Knee Flexion between 130 ° °  Lower the better

Why have a Counter Movement? Two Purposes ◦ Stimulate “Stretch-Shorten Cycle”  Up to 10% increase in distance  Faster the better! ◦ What type of Contraction? ◦ Better position for propulsive phase  Greater time for force to be exerted  Long Jump – 0.12 seconds  Triple Jump – 0.18 seconds (Graham-Smith. 2009)  But significant differences in “type” of Jumper

Lets Compare British Champions

Forces at Take-off (LJ & TJ) Foot Strike (contact point) Ground Reaction Force C of M Direction of Travel Directional forces Upper Body Inertia Lower Body Forces

Implications Forward rotation ◦ GRF cause torque and therefore forward somersault movement ◦ Impossible to apply corrective torque in the air  Why?? ◦ But you can SLOW down rotations in the air  Long thin body shape (Moving into flight phase) (UKA 2004)

Long Thin Shape in Air – for both LJ and TJ Relies on definition of angular momentum ◦ AM = moment of inertia X Angular Velocity ◦ As Angular Momentum is constant (in air), rotation (angular velocity) will depend on Moment of inertia ◦ This is controlled by elongating body therefore slowing forward rotation

Long and Triple Flight

Differences in Triple Jump Flight Long Jump Angle of Take Off ◦ ° (Linthorn, Guzman and Bridgett. 2005) ◦ 43 ° (de Mestre, 1990; Hay, 1993), 33 ° (Tan and Zumerchik 2000)  Issues with measurement methodology In what way is this different for Triple Jump?

Think Forces Collapsing from the hop meaning the step is VERY short!! Conservation of momentum through each phase is impossible Overloading upon landing ◦ How to correct?

Alternative Flight Techniques - Hitch Kick – LJ Only ◦ Segments of the body contribute to counteracting the bodies total rotation ◦ Groups of body segments are rotated in a way to generate momentum equal to whole body angular momentum ◦ NO net rotation about centre of mass

Landing Different for LJ and TJ Long Jump ◦ Making an efficient, safe landing  Not backward rotation reducing distance  “All jumps shall be measured from the nearest break in the landing area made by any part of the body to the take-off line....” Rule (IAAF 2006 P144) ◦ Triple Jump  Hop and Step Phases to conserve momentum into next phase