ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology during our centenary year, but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Stacey Shield and Naoya Muramatsu are authors on ‘ Chasing the cheetah: how field biomechanics has evolved to keep up with the fastest land animal’, published in JEB. Stacey is a Lecturer, and Naoya a PhD student, in the lab of Amir Patel at University of Cape Town, Rondebosch, South Africa, investigating the mechanics and control of high-speed legged manoeuvrability.

Stacey Shield and Naoya Muramatsu

Describe your scientific journey and your current research focus

Stacey: My journey into bio-inspired robotics started in 2014, with the final research project ending off my undergraduate degree in Mechatronics. I designed a robot emulating the dragline mechanism jumping spiders use to regulate body pitch while they are in the air. My advisor, Dr Amir Patel, invited me to join his new African Robotics Unit for my Master's the following year, and to spend what would turn out to be the last 3-month summer holiday of my life so far writing my project up into a conference paper. Luckily, sacrificing the holiday turned out to be worthwhile, and I travelled to Hamburg to present the paper at the International Conference on Intelligent Robots and Systems (IROS). As soon as I returned, we started the process of upgrading my Master's to a PhD. My thesis, which focused on the use of trajectory optimization to simulate high-speed legged manoeuvres, was completed last year and I have officially been able to call myself Dr Shield since December. I'm currently working on a project assessing the contribution of the cheetah's tail to stabilizing body position.

Naoya: Since childhood, I've always found cheetahs' running to be the most beautiful motion in the world. As a third-year undergraduate student, I became fascinated with the idea of applying bio-/neuro-mechanics to engineering. At the University of Tsukuba in Japan, I started my first research project, which sparked my interest in neural networks and robotics – the focus of my Bachelor's and Master's theses. As I progressed to my PhD programme, I was fortunate to find Dr Amir Patel, who is now my supervisor and shares my passion for this field. Currently, my research is focused on obtaining and analysing 3D motion data of wild animals.

How would you explain the main message of your Review/Commentary to a member of the public, and how would you explain the broader impact of research in this area?

Obtaining the detailed information about the motion of wild cheetahs is necessary to explain and robotically imitate their unrivalled speed and is a challenging problem that pushes field biomechanics technology to its limits. This makes it a flashpoint for the development and application of new technologies, which advances our ability to study other species – including humans.

Is there anything that you learned while writing this Review that surprised you?

Stacey: The process of writing this paper reinforced something that has surprised me for as long as I've been involved in the research community, which is how isolated different research fields are – often to the detriment of our scientific efforts. Cheetah locomotion research relied primarily on the film and direct observation for decades, before progressing in leaps and bounds once interest from the legged robotics community caused engineers and biologists to start talking to each other.

Naoya: Although many researchers in robotics are interested in animal motion, we have found few studies that incorporate actual biological data in engineering applications. Most robots inspired by cheetahs only use basic concepts, such as bending the spine. This underscores a significant disparity between biology and engineering.

What do you see as the main value of Review-type articles?

As transfers from robotics, we have personal experience with how valuable reviews and commentaries can be in helping newcomers to a field quickly familiarize themselves with key developments and outstanding questions. For us specifically, it's especially valuable to be able to pinpoint questions where technology is the primary barrier to entry. Even for established researchers in a field, reading a review is an excellent way to regain perspective and re-establish the broader context you often lose while ‘zoomed in’ on your highly specific focus area.

Naoya Muramatsu, Stacey Shield and collaborator Ardian Jusufi measuring cheetah tails at Cheetah Outreach in Cape Town.

Naoya Muramatsu, Stacey Shield and collaborator Ardian Jusufi measuring cheetah tails at Cheetah Outreach in Cape Town.

Are there any important historical papers from your field that have been published in JEB?

The 1999 paper ‘Templates and anchors: neuromechanical hypotheses of legged locomotion on land’ by Full and Koditschek (doi:10.1242/jeb.202.23.3325) is a foundational paper that has perhaps had an even more profound impact on legged robotics than on its home field. Template models – particularly the spring loaded inverted pendulum (SLIP) – are used as heuristics for the control of complicated locomotion throughout legged robotics. It is telling how often roboticists describe their template-based control schemes without even citing this paper: the concepts it defines feels so fundamental, and are now so widespread, that doing so seems almost like citing Newton's Laws.

Are there any modern-day JEB papers that you think will be the classic papers of 2123?

Several essential papers describing the locomotion and anatomy of fast quadrupeds have been published in JEB within the last 10 years. One that has become required reading in our lab is ‘High speed galloping in the cheetah (Acinonyx jubatus) and the racing greyhound (Canis familiaris): spatio-temporal and kinetic characteristics’ by Hudson et al. (2012) (doi:10.1242/jeb.066720). This provides essential quantitative information that supports research such as ours that requires detailed models of the animals.

Another paper we frequently return to is ‘Don't break a leg: running birds from quail to ostrich prioritise leg safety and economy on uneven terrain’ by Birn-Jeffrey et al. (2014) (doi:10.1242/jeb.102640). This paper introduced me to the idea of inverse optimal control, and the contribution of a fellow legged roboticist, Christian Hubicki, provided an inspiring example of how my similar skillset could be applied to understanding the locomotion of humans or animals.

What changes do you think could improve the lives of early-career researchers, and what would make you want to continue in a research career?

As South African researchers, funding is the biggest barrier to participation for us. Of course, this affects researchers at all career stages, but early career researchers are especially impacted as we have fewer sources available to us, and many of us subsist on small stipends that make self-funding prohibitively expensive. While the proliferation of online and hybrid conference offerings following the pandemic has helped, setting aside funds specifically towards promoting publication and conference attendance among geographically isolated early career researchers would do much more to ensure we are not left out.

It is also essential that international researchers who wish to study African animals do so in partnership with African institutions. In addition to addressing the topical problem of ‘helicopter research’, collaborations are a highly effective way to grow skills and infrastructure in developing nations, and to help early-career researchers in these nations find a foothold in the international scientific community.

What's next for you?

Stacey: I've recently taken up an academic position at the University of Cape Town, with a large component of my job being teaching introductory feedback control to the undergrads. Open access to education is an issue I'm especially passionate about, so one of my first goals is to produce a series of online lectures to help scientists from different backgrounds learn the fundamentals of control theory over a weekend. On the research front, I am currently extending our work on motion tracking and analysis to other wildlife projects, and I will also be taking my interest in high-speed manoeuvrability in a more practical direction using our newly developed bipedal robot, Baleka.

Naoya: To address the question of how a quadrupedal robot can achieve the same manoeuvrability as a cheetah, we must gather and analyse animal motion data and construct robots. I have already collected motion data from wild animals in a national park in South Africa, which I will use to generate a large dataset of 3D animal motions in order to identify the key principles of animal movement.

Stacey Shield and Naoya Muramatsu's contact details: Mechatronics Lab, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa.


Da Silva
Chasing the cheetah: how field biomechanics has evolved to keep up with the fastest land animal
J. Exp. Biol.