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[1/thread] Now that our new article comparing sprint starts in world-class male sprinters and hurdlers from @IAAForg @WICBham2018 is finally ready to share via @FrontSportsAL, I wanted to share some of the thinking behind how it came together… frontiersin.org/articles/10.33…
[2] Whilst the body of research on sprint start and initial acceleration mechanics is considerable & growing (link.springer.com/article/10.100…) there is very little in the biomechanics literature examining this phase of the race specifically in high hurdlers
[3] So what? Well, I have never claimed to be an athlete of any great standing, but surely even for the very best hurdlers, putting a 1.07 m barrier in the way only seven steps after being down on all fours must be a significant obstacle to overcome?
[4] As we know, initially from the work of @jb_morin, in the early phase of a flat sprint horizontal projection is key to optimal performance ncbi.nlm.nih.gov/pubmed/21364480
[5] So given these seemingly competing requirements (want to go forwards, have to go upwards), is there anything we can learn by comparing elite sprinters and hurdlers in otherwise similar conditions? That’s what we set out to look at…
[6, an aside] A lot of academic work relies on taking ideas from other peoples’ work and adapting them to your own, or to put it another way, all academics are thieves. We wanted to give those people whose ideas we “borrowed” some credit here
[7] @R_Nagahara previously presented these cool stick figures showing how sprint technique changes with each step of the acceleration phase. We used that idea to look for differences between sprinters and hurdlers (next tweet) bio.biologists.org/content/3/8/689 
[8] So what does our figure show (SWDOFS)? a) different block set-up, b) similar block exit body orientations & c) at touchdown and take-off events sprinters shank and trunk segments were more forward orientated
[9] @wildy_jj created these nice figures showing differences in kinematics of initial acceleration between pro rugby players and trained sprinters. We used that idea to present differences in centre of mass translation in our study (next tweet) tandfonline.com/doi/abs/10.108…
[10] SWDOFS? The biggest differences in CM translation occurred during the block phase, particularly during the single leg push phase, and then in the actual sprint during each flight phase. During ground contact phases CM translations were similar
[11] Lees, @ScienceJos & de Clercq created these brilliant (IMHO) visualisations of differences in time series data for comparisons of vertical jumping. We added confidence intervals in our study (next tweet) sciencedirect.com/science/articl…
[12] SWDOFS? Only small differences in segment orientations during block phase, but hurdlers had more vertically orientated trunk and shank late in swing phases, before re-aligning with sprinters early in subsequent contact phases
[13] I also really wanted to include our own version of this figure created by @jb_morin, showing joint centre paths during a gait cycle, but we had to stop somewhere #already6000wordsforabiomechanicspaper #thisisnotpsychology frontiersin.org/articles/10.33…
[14] Then, inspired by the various works of Ryan Chang and @DrRobNeedham, @AdamBrazil91 created some really nice visualisations of the coupling angles and their differences between sprinters and hurdlers through the initial acceleration phase (next tweet)
[15] SWDOFS? Well, actually it shows that generally the coordination patterns adopted by the two groups of athletes were very similar. Although still relatively small, the largest differences in each couple occurred either in the blocks or during ground contact
[16] So, overall there were some differences in the blocks. Those differences that then tended to occur during flight and around touchdown had generally disappeared by take-off. We think this might create the false impression that hurdlers are “popping up”
[17] Actually then, this suggests that hurdlers are almost as effective at horizontal projection as are their sprint counterparts (with the caveat that this analysis is based on kinematics, not kinetics, due to the constraints of the competition data collection)
[18] So what might this mean for athletes and coaches? We think there might be different implications depending on whether the current focus is on sprints or hurdles…
[19] For sprinters, we think there’s little here that suggests that you should struggle with performing an effective approach to the first hurdle. The opportunity for talent transfer is considerable, and you might find a new talent you didn’t know you had
[20] For hurdlers, much can be learned about effective acceleration from sprinters. Consider training for acceleration with and without hurdles, and focus on the similarities between the two events and tasks
[21] This paper truly was a team effort, so I’d like to acknowledge the efforts of all my co-authors, @AdamBrazil91 @Hans_von_Lieres @CoachWood1 @gparadi Brian Hanley @CatTuc @Lysander2012 @StephaneMerlino @pjvazel @joshwalker456 & @NassosBissas
[22] Thanks also to @R_Nagahara and @SlawinskiJean for their constructive comments during the review process that undoubtedly lead to a stronger finished product
[23] Finally, I’d particularly like to thank @NassosBissas for inviting me to contribute to this project and putting his trust in me with such a remarkable data set
[24/24] TLDR – Yes there were some differences in kinematics between sprinters and hurdlers, but overall they were pretty similar, so perhaps it makes sense to consider coaching them as such.
