For everyone at #ISB2025 interested in musculoskeletal modeling, I'm giving a talk about MuSkeMo, my model construction and visualization tool, Tuesday 11:30 in Room A1 (Session 6A - Musculoskeletal Model Personalization).

MuSkeMo is my tool for musculoskeletal model construction in Blender.

New paper in @cellpress.bsky.social Current Biology by Karl Bates ea. Karl's physics simulations (validated in a human model) suggest that although Lucy could run - top speed was limited, not leaving much headroom for endurance running.
www.cell.com/current-biol...

I'll be cross-posting my other twitter threads here on Bluesky soon as well, so stay tuned if you're interested in animal and dinosaur biomechanics!

16/18

We didn't prescribe postures: the optimizer was free to select any, but selected these postures in response to anatomical changes.

By sequentially increasing the target speed, we simulated a full walk-to-run transition, and a run-to-walk transition (from top speed down).

6/18

So we did an experiment that's impossible outside the computer: we built a bird, and systematically changed its muscle and tendon anatomy. The muscles were tuned to generate peak forces at columnar, intermediate, and crouched postures, with both rigid and elastic tendons.

5/18

Birds have two related features: long tendons (that store energy like springs), and crouched leg postures (so foot-to-hip distance can change, which can "look" like a spring). In a real bird, you can't isolate these two features, making it hard to explain their running style

4/18

What is running, actually? In humans, running has an aerial phase, a moment without ground contact. But that's neither true for birds, nor many quadrupedal animals - they sometimes run without an aerial phase, maintaining ground contact with at least 1 foot.

2/18

Most birds use a funny running style: grounded running. It's a paradox: GR costs more energy than normal running, but animals usually minimize costs.
Do birds waste energy? We resolve this with a model of the emu (the best bird).
Published in @science.org Advances last Sept
(reposting my x 🧵s)
1/18

Trix the T. rex is feeling festive

Haven't logged on here in a while, but for some reason my follows jumped up. Thanks a lot!

I'm going to be more active here - expect 3D physics simulations of how modern animals and fossils move, and other sciencey things!

For now - here's my emu blooper reel from our recent bird running study