ISB 2015_acceleration hip extensors
This document discusses research on the role of hamstring muscles in horizontal ground reaction force production during sprint acceleration. The research found that horizontal ground reaction force and impulse are paramount for sprint acceleration. Elite athletes produced higher ratios of horizontal to vertical forces at high speeds. Preliminary results from studies using instrumented treadmills, force plates, electromyography, and isokinetic testing found that horizontal ground reaction force during initial acceleration correlated with eccentric hamstring torque and gluteus muscle activity late in the swing phase. This suggests that the ability of hip extensor muscles like the hamstrings and glutes to produce force may be important for generating high horizontal forces required for maximal sprint acceleration.
ISB 2015_acceleration hip extensors
- 1. SPRINT ACCELERATION MECHANICS THE ROLE OF HAMSTRING MUSCLES IN HORIZONTAL GROUND REACTION FORCE PRODUCTION @jb_morin Morin JB University of Nice, France Edouard P University of Saint-Etienne, France Gimenez P University of Franche-Comté, France Arnal P University of Saint-Etienne, France Jimenez-Reyes P Catholic University of San Antonio, Murcia, Spain Samozino P University of Savoy, France Mendiguchia J Zentrum Rehab Center, Baranian, Spain Brughelli M Auckland University of Technology, New-Zealand jean-benoit.morin@unice.fr
- 2. Survival of the fastest? Acceleration is the key…
- 3. 2011 -‐ 2015 Sprint acceleration: importance of Horizontal Force Production Sprint Instrumented treadmill Track-‐Embedded Force Plates Elite Athletes Med Sci Sport Exerc 2011 Eur J Appl Physiol 2012 Scand J Med Sci Sport 2015 J Biomech In Press Horizontal GRF / impulse is paramount Vertical / resultant GRF is not « Ratio of Forces » and Hzt Force at high speed higher in top athletes
- 4. Higher RF at high, not low speeds… How to produce High net HZT Force At High running speed?? The « Hip Extensors » hypothesis
- 5. Synchronized EMG (2 kHz) and 3D GRF (1 kHz) Treadmill Sprint Accelerations 2D Motion Knee and Foot Knee Extensor Hip Extensor Isokinetic Torque The « Hip Extensors » hypothesis
- 6. The « Hip Extensors » hypothesis
- 8. Preliminary results…. Paper in preparation Isokinetic Torque alone NOT correlated to GRF Muscle activity (EMG) alone: NOT correlated to GRF Multiple Regressions: FHZT entire acceleration correlated to : Eccentric Hamstring torque EMG BF during end-of-swing phase FHZT initial acceleration correlated to : Eccentric Hamstring torque EMG BF during end-of-swing phase Concentric Glutei torque EMG Glut during end-of-swing phase Quadriceps…. Contact phase: NS 2D Motion (speed, range of motion) of Knee and Foot: NS
- 9. « Prepare and Repair » Importance of Horizontal GRF (especially at high speed) What balance between hip extensors and other groups in training? Hamstring Eccentric Force and Activation: Performance AND Injury Prevention Associated with: high hip extensors force (Glut in CONC and Ham in ECC) high end-of-swing EMG activity
- 10. MERCI !!