Biomechanical Report for The
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BIOMECHANICAL REPORT FOR THE 100 m Women’s Dr Athanassios Bissas1, Josh Walker1, Dr Catherine Tucker1 and Dr Giorgios Paradisis2 1Carnegie School of Sport, 2NKUA Stéphane Merlino IAAF Project Leader Event Director Project Director Dr Athanassios Bissas Dr Athanassios Bissas Project Coordinator Louise Sutton Senior Technical Support Liam Gallagher Aaron Thomas Liam Thomas Senior Research Officer Report Editor Analysis Support Josh Walker Dr Catherine Tucker Dr Lysander Pollitt Logistics Calibration Data Management Dr Zoe Rutherford Dr Brian Hanley Nils Jongerius Technical Support Ashley Grindrod Ruth O’Faolain Lewis Lawton Joshua Rowe Joe Sails Data Analysts Josh Walker Dr Catherine Tucker Dr Giorgios Paradisis (National and Dr Athanassios Bissas Kapodistrian University of Athens) Pierre-Jean Vazel Project Team Dr Tim Bennett Mark Cooke Dr Alex Dinsdale Helen Gravestock Dr Gareth Nicholson Masalela Gaesenngwe Emily Gregg Mike Hopkinson Parag Parelkar Rachael Bradley Amy Brightmore Helen Davey Jamie French Callum Guest Ruan Jones Philip McMorris Maria van Mierlo Dr Ian Richards William Shaw James Webber Jack Whiteside Dr Emily Williams Jessica Wilson Lara Wilson Dr Stephen Zwolinsky Coaching Commentary Historical Analysis and Coaching Ralph Mouchbahani Commentary Pierre-Jean Vazel Table of Contents INTRODUCTION 1 METHODS 2 RESULTS – FINAL 8 Positional analysis 8 Individual split times 10 Speed analysis 12 Step length analysis 14 Gold medallist profile 15 High velocity running phase 16 Final stage of the race 38 RESULTS – SEMI-FINAL 1 41 Positional analysis 41 Speed analysis 42 Step length analysis 43 RESULTS – SEMI-FINAL 2 44 Positional analysis 44 Speed analysis 45 Step length analysis 46 RESULTS – SEMI-FINAL 3 47 Positional analysis 47 Speed analysis 48 Step length analysis 49 COACH’S COMMENTARY 50 Historical analysis and coaching commentary – Pierre-Jean Vazel 50 Coaching commentary – Ralph Mouchbahani 62 CONTRIBUTORS 64 Figures Figure 1. Camera layout for the women’s 100 m indicated by green in-filled circles. 2 Figure 2. The calibration frame was constructed and filmed before and after the competition. 3 Figure 3. Action from the 100 m women’s final. 4 Figure 4. Race position of the finalists at each 10-metre split. Medallists have been highlighted in respective medallist colours. 9 Figure 5. Mean speed over each 10-metre split. 12 Figure 6. Mean speed over each 10-metre split – medallists only. 13 Figure 7. Mean speed over each 10-metre split – remaining five finalists. 13 Figure 8. Mean absolute step length for each finalist over 100 metres. 14 Figure 9. Mean relative step length for each finalist over 100 metres. 14 Figure 10. Contact, flight and step times during high velocity running for each finalist. Step time is the sum of contact and flight times. Left and right columns indicate left and right legs for each athlete, respectively. 16 Figure 11. Individual centre of mass horizontal velocities for each digitised step. 17 Figure 12. Swing time of one stride for each athlete. For some athletes, the stride was left-left contact, for some it was right-right contact. 18 Figure 13. Relative proportions (%) of braking and propulsive phases during contact. 19 Figure 14.1. CM height and vertical CM velocity during left and right contacts for gold medallist Tori Bowie. 20 Figure 14.2. CM height and vertical CM velocity during left and right contacts for silver medallist Marie-Josée Ta Lou. 21 Figure 14.3. CM height and vertical CM velocity during left and right contacts for bronze medallist Dafne Schippers. 21 Figure 14.4. CM height and vertical CM velocity during left and right contacts for fourth placed Murielle Ahouré. 22 Figure 14.5. CM height and vertical CM velocity during left and right contacts for fifth placed Elain Thompson. 22 Figure 14.6. CM height and vertical CM velocity during left and right contacts for sixth placed Michelle-Lee Ahye. 23 Figure 14.7. CM height and vertical CM velocity during left and right contacts for seventh placed Rosangela Santos. 23 Figure 14.8. CM height and vertical CM velocity during left and right contacts for eighth placed Kelly-Ann Baptiste. 24 Figure 15. The peak vertical velocity of the foot CM during the swing phase. For all athletes, this peak value occurred shortly after toe-off and has been termed ‘foot pick-up velocity’. 27 Figure 16.1. Resultant foot CM velocity during the swing phase for the three medallists, displayed as a percentage of swing time. 28 Figure 16.2. Resultant foot CM velocity during the swing phase for the remaining finalists, displayed as a percentage of swing time. 28 Figure 17. Body schematic denoting angles measured at touchdown. This does not represent any athlete’s posture but is merely for illustration purposes. 29 Figure 18. Body schematic denoting joint angles measured at toe-off. This does not represent any athlete’s posture but is merely for illustration purposes. 31 Figure 19.1. Hip, knee and ankle angular velocity over one stride for gold medallist Tori Bowie. 34 Figure 19.2. Hip, knee and ankle angular velocity over one stride for silver medallist Marie- Josée Ta Lou. 34 Figure 19.3. Hip, knee and ankle angular velocities over one stride for bronze medallist Dafne Schippers. 35 Figure 19.4. Hip, knee and ankle angular velocities over one stride for fourth placed Murielle Ahouré. 35 Figure 19.5. Hip, knee and ankle angular velocities over one stride for fifth placed Elaine Thompson. 36 Figure 19.6. Hip, knee and ankle angular velocities over one stride for sixth placed Michelle- Lee Ahye. 36 Figure 19.7. Hip, knee and ankle angular velocities over one stride for seventh placed Rosangela Santos. 37 Figure 19.8. Hip, knee and ankle angular velocities over one stride for eighth placed Kelly-Ann Baptiste. 37 Figure 20. Comparison of step time of the penultimate step and the side-matched analysed step from the middle section of the race. Data shown for each of the medallists. 38 Figure 21. Trunk angle relative to the horizontal (angle α) at penultimate step touchdown (PS- TD) and toe-off (PS-TO), final completed step touchdown (FS-TD) and toe-off (FS- TO), and initial ground contact when crossing the line (L-TD). Data displayed for each of the medallists. 40 Figure 22. Race position of the athletes from semi-final 1 at each 10-metre split. 41 Figure 23. Mean speed over each 10-metre split. 42 Figure 24. Mean absolute step length for each athlete over 100 metres. 43 Figure 25. Mean relative step length for each athlete over 100 metres. 43 Figure 26. Race position of the athletes from semi-final 2 at each 10-metre split. 44 Figure 27. Mean speed over each 10-metre split. 45 Figure 28. Mean absolute step length for each athlete over 100 metres. 46 Figure 29. Mean relative step length for each athlete over 100 metres. 46 Figure 30. Race position of the athletes from semi-final 3 at each 10-metre split. 47 Figure 31. Mean speed over each 10-metre split. 48 Figure 32. Mean absolute step length for each athlete over 100 metres. 49 Figure 33. Mean relative step length for each athlete over 100 metres. 49 Tables Table 1. Variables selected to describe the performance of the athletes. 5 Table 2.1. Split times every 10 metres for each athlete. 10 Table 2.2. Cumulative split times every 10 metres for each athlete. 11 Table 3. Mean step length, relative step length, step rate and step width across two steps for each finalist. 16 Table 4. Mean running velocity across two steps for each finalist. 17 Table 5. Horizontal distance from the point of ground contact to the body’s CM at both touchdown (DCM TD) and toe-off (DCM TO). 18 Table 6. Horizontal distance that the CM travelled during ground contact. 19 Table 7. Horizontal velocity of the foot centre of mass at the instant before touchdown and the instant of touchdown. Data presented for left and right feet individually as well as a left-right means at each instant. 25 Table 8. Vertical velocity of the foot centre of mass at the instant before touchdown and the instant of touchdown. Data presented for left and right feet individually as well as a left-right means at each instant. 26 Table 9. Peak resultant velocity of the foot CM during the swing phase and time of transition for one stride. 27 Table 10. Joint angles at touchdown for the three medallists. 29 Table 11. Joint angles at touchdown for the remaining five finalists. 30 Table 12. Joint angles at toe-off for the three medallists. 31 Table 13. Joint angles at toe-off for the remaining five finalists. 32 Table 14. Minimum knee joint angles and change in knee angle from touchdown to minimum knee angle during left and right contacts for each finalist. 33 Table 15. Minimum ankle joint angles and change in ankle angle from touchdown to minimum ankle angle during left and right contacts for each finalist. 33 Table 16. Step length, step rate and step velocity for the penultimate step for each of the medallists. 38 Table 17. Contact times and flight times for the penultimate step (PS) and final completed step (FS) for each of the medallists. Percentage increase or decrease in times from PS to FS are also displayed. 38 Table 18. Joint angles measured at touchdown of the penultimate step (PS) and final completed step (FS) for each of the medallists. 39 Table 19. Joint angles measured at toe-off of the penultimate step (PS) and final completed step (FS) for each of the medallists. 39 1 INTRODUCTION The women’s 100 m final and semi-finals took place on Sunday 6th August in good weather conditions.