Tim van der Zee

Tangentieel trappen de beste fietstechniek? Nee, concludeert bewegingswetenschapper Dinant Kistemaker “De beste plek om te trappen ligt rond de bal van de voet” @DinantKistemak1 @VU_FBW @VU_FGB @VUamsterdam @VvBN_nieuws parool.nl/ts-b00d823b via @parool

@neuromecHAHNics @JosefinaManieu @MVFranchi @PaternosterFlo @Geoff_A_Power @WolfgangSeiberl @kiisanishikawa @BrentRaiteri @NeilJCronin84 @OlivierSeynnes Hi Josefina, I believe @NHaelewijn tried to use TimTrack on panoramic images at some point. Although TimTrack isn't developed for panoramic images, it worked reasonably well. Might need some adaptations though. journals.plos.org/plosone/articl…

@JosefinaManieu @MVFranchi @PaternosterFlo @Geoff_A_Power @WolfgangSeiberl @kiisanishikawa @BrentRaiteri @Tim_vd_Zee @NeilJCronin84 @OlivierSeynnes

Big Q to my ultrasound sports scientist out there: anyone knows of an automated algorithm to track FL, muscle thickness and pennation angle in panoramic view US? 🧐 @MVFranchi @neuromecHAHNics @PaternosterFlo @Geoff_A_Power @WolfgangSeiberl @kiisanishikawa

@wscottselbie @cmotioninc That's cool! I wasn't aware of the tutorial yet. @wscottselbie thanks for sharing :)

I was especially pleased to see that the data were stored in #c3d files and #Visual3D #cmo files. To facilitate the exploration of this dataset, @cmotioninc has created a tutorial using #Visual3D and #Inspect3D for modeling and cleaning the data. c-motion.com/v3dwiki/index.…

Thanks @cmotioninc for creating such a cool tutorial using our #Visual3D dataset 🙏 The tutorial explains how #Inspect3D may be used to clean and visualize the raw data files: c-motion.com/v3dwiki/index.…

Data: springernature.figshare.com/collections/A_… Code: github.com/timvanderzee/h…

Curious how biomechanics of human walking changes with increasing step lengths, widths, frequencies and speeds? Our data descriptor paper was published today in Nature Scientific Data (see: rdcu.be/cZNIy). Apart from data, we also provide code for analysis on GitHub.

@neuromecHAHNics @Owen1Beck @WannesSwinnen @LTrej0314 @JordynSchroede4 @FranzBiomech @gregory_sawicki @japplphysiol Might be interesting to compare (ascending limb) short length conditions to force-matched and F/F0-matched (descending limb) long length conditions in humans. I guess this hasn’t been done yet?

@Owen1Beck @WannesSwinnen @LTrej0314 @JordynSchroede4 @FranzBiomech @gregory_sawicki @japplphysiol This 1st answer was related to the in vivo world. Below, you'll find a paper that investigated th rate of ATP utilisation in isolated muscle. Even at the same F/F0, ATP rate was higher at short sarcomere lengths (Fig. 2B). physoc.onlinelibrary.wiley.com/doi/full/10.11…

Shorter Muscle Fascicle Operating Lengths Increase the Metabolic Cost of Cyclic Force Production | doi.org/10.1152/japplp…

How to walk on this terrain? Optimally ofc! Obviously, look ahead for footholds. Otherwise practically no data—most biomechanical studies only do steady level walking. "Humans plan for the near future to walk economically on uneven terrain" Submitted ms by O. Darici & me 🧵 1/

@AelesJ @neuromecHAHNics @WannesSwinnen @Owen1Beck @LTrej0314 @JordynSchroede4 @FranzBiomech @gregory_sawicki @japplphysiol @AelesJ that’s an interesting take, can you explain why you expect slower velocities at shorter length? I would expect faster velocities because series elastic length change is typically greater…

Some say slow walking = high CoT, but that doesn't make sense. Usually wanna get somewhere, don't care about "per distance." We say slow walking = waste of time, which we DO care about. min COT not so useful. biorxiv.org/content/10.110… (submitted ms) End/

Tooting our own horn, T van der Zee from my lab showed model with Zahalak style cross bridges + Ca activation + recruitment. Hill-type models aren’t mechanistic, hopeless for dynamic transient conditions (ie life). 1/

@edwardswb Haha I’ll make sure to also add “Brent” to the list of approved names, I think @BrentRaiteri will also appreciate that 😜

@Tim_vd_Zee Nice work! But you left out the part that it can only be used by people named Tim! 😝

Published today in PLOS ONE: TimTrack, a new (MATLAB-based) algorithm that estimates muscle fascicle length, pennation angle, and other features from ultrasound images without drift-sensitivity journals.plos.org/plosone/articl… All code and example data are freely available on my GitHub

@TaylorJMDick @NKelp @JBiomech @FrancoisHug @KylieJ_Tucker @cclemente4 @UQMedicine That’s fascinating, considering that an isolated LG will likely increase in width during shortening. Thanks for the reply, and good luck with your research!

@Tim_vd_Zee @NKelp @JBiomech @FrancoisHug @KylieJ_Tucker @cclemente4 @UQMedicine yup thats the thought- MG width increases, LG width remains constant or even decreases depending on the contraction level. Perhaps related to the behaviour of soleus, but also neighbouring muscles (particularly in the lateral compartment), and differences in stiffness b/w muscles

New paper led by @NKelp in @JBiomech explores age-related muscle shape changes and architecture in the gastrocs. A truely wonderful team of collaborators @FrancoisHug @KylieJ_Tucker @cclemente4 @UQMedicine authors.elsevier.com/a/1d-DQ4-6-WU08

@NealeTillin @rosshm16 Thanks you so much! I really appreciate it, will definitely check it out

@NealeTillin @rosshm16 That sounds interesting, but the link doesn't work for me (I'm being redirected to ScienceDirect main page), could you perhaps provide another link? (e.g PubMed). That would be great, thanks!

@rosshm16 @jmthomas19 yes fewer # but also less force per crossbridge. @rosshm16 do you mean “why” in terms of evolution?

Our new paper on the role of soft tissue deformations in human walking is out: journals.biologists.com/jeb/article/22… ..suggesting that soft tissues dissipate substantial amounts of energy in a predictable manner The paper is also featured in the "Inside JEB section": journals.biologists.com/jeb/article/22…