Freek Van de Casteele

PhD, Ghent University (@TeamDerave) • Football analytics 📊
Skeletal muscle fiber type composition research 🔬

[Freek Van de Casteele @CasteeleFreek]

Does one biopsy cut it? Short answer: no. Find out the longer answer below 🧵👇

This thread is based on our new @japplphysiol paper, where we investigated human muscle fiber type composition variability by analyzing repeated biopsies. Lots of them.

https://t.co/6yAHbrurqc

[Thibaux Van der Stede @ThibauxV]

Proud to have our paper featured on the cover of the April issue of @Cell_Metabolism. It shows an exercise-induced degranulating mast cell releasing histamine. Thanks a lot for the design Emma @DrawImpacts.

Read the full story here: https://t.co/ptk17Iy72p

@TeamDerave

[Freek Van de Casteele @CasteeleFreek]

@Roger_MorenoJ @NatureComms @atul_deshmukh1 @Metabolcenter @ThibauxV @TeamDerave Congrats, @Roger_MorenoJ & @ThibauxV!

[Journal of Applied Physiology @japplphysiol]

From @ugent @karolinskainst @uni_copenhagen @CasteeleFreek et al.: Does one biopsy cut it? Revisiting human muscle fiber type composition variability using repeated biopsies in the vastus lateralis and gastrocnemius medialis 💪

🔗https://t.co/L2z0zDGCLj

[Wannes Swinnen @WannesSwinnen]

Inter‐Individual Variability in Muscle Fiber–Type Distribution Affects Running Economy but Not Running Gait at Submaximal Running Speeds | https://t.co/zFn2Iio2hI

[Martino V. Franchi @MVFranchi]

-Does one biopsy cut it? Revisiting human muscle fiber type composition variability using repeated biopsies in the vastus lateralis and gastrocnemius medialis-

New in @japplphysiol by @TeamDerave - nice work!

https://t.co/1KBESAWuJU

[Freek Van de Casteele @CasteeleFreek]

@DebevecTadej @japplphysiol Most interventional applied studies (e.g. training study) are short-term and likely have no or a small effect on MFTC. To investigate the intervention effect properly we need to reduce the variability of the MFTC measurement, or increase sample size, and ideally both. (2/2)

[Freek Van de Casteele @CasteeleFreek]

Does one biopsy cut it? Short answer: no. Find out the longer answer below 🧵👇

This thread is based on our new @japplphysiol paper, where we investigated human muscle fiber type composition variability by analyzing repeated biopsies. Lots of them.

https://t.co/6yAHbrurqc

[Freek Van de Casteele @CasteeleFreek]

@DebevecTadej @japplphysiol Thanks, Tadej! I would propose collecting 4 samples from 2 biopsy needles inserted in opposite directions through 1 incision. I get that this is still a burden on the participant and researchers, and maybe not feasible for everyone, but necessary. (1/2)

[Freek Van de Casteele @CasteeleFreek]

@GarrettHester2 @TeamDerave @eline_lievens @ThibauxV @MobergPhD @WiApro @HorwathOscar @RuudVanThienen Thanks, Garrett! Microbiopsies cause less discomfort, but they also extract a smaller number of fibers. If you're using them, I would collect multiple biopsies and aim for at least 200 fibers per biopsy. The needles could be inserted at the same spot but oriented differently

[Andy Galpin, PhD @DrAndyGalpin]

Glad this stuff keeps coming out.

The variability in 'fiber type' from each biopsy is quite large, so results should be interpreted with caution - probably explains much of the 'mixed results' that plagued the field for decades.

https://t.co/QdZ2DusSns

👏@WiApro et al.

[Freek Van de Casteele @CasteeleFreek]

It was a pleasure working on this with @TeamDerave, @eline_lievens, @ThibauxV, our Swedish 🇸🇪 collaborators @MobergPhD, @WiApro, @HorwathOscar, and biopsy master @RuudVanThienen. Many thanks to all of you🙏

[Freek Van de Casteele @CasteeleFreek]

Sidenote: although type I % is not considered a direct determinant of V02peak, a significant positive relationship is expected as type I fibers generally have a higher capillary density and greater oxidative capacity than type II fibers