Bio

Personal site

I design and drive studies using wearables that combine modelling, data analysis and software development to ultimately address problems that limit human performance, with a particular emphasis on female health, and translate findings into practical solutions.

I have a broad academic background which encompasses computational modelling of immune function in lymph nodes, miRNA extraction from lymphatic vessels and musculoskeletal modelling. I am from the UK where I completed a PhD in Bioengineering at Imperial College London. Following my PhD I worked as a researcher in a gait analysis start-up company targeting pre and post orthopedic surgery patients, encompassing a broad range of roles from software adaptation and musculoskeletal modelling to website design. Outside of academia I am an avid runner, having represented my university at a national level.

Research Interests

My current research interests focus around using smartwatch data to address the lack of research regarding hormonally triggered symptoms and physiological effects of contraception :

1. Improve prediction of bone injuries based on based on biomechanically informed models. Existing overtraining and recovery models focus primarily on heart rate and mileage. We aim to additional information related to pace and cadence to assess whether we can improve personal prediction of stress fractures.
2. Quantify the impact of the menstrual cycle in endurance athletes. Demand for increased research and advice for female athletes has recently dramatically increased. To develop and test intervention efficacy it is necessary to quantify baseline changes. We are looking at a range of variables including heart rate for a given effort, hormonal contraceptive use and injury risk.

Degrees

Ph.D. in Bioengineering, Imperial College London, 2019
M.Res. in Bioengineering, Imperial College London, 2014
B.S. in Biological Sciences (Cell Physiology and Pharmacology), University of Leicester, 2013

Honors and Awards

The Alan Turing Institute Sep 2021 Data Study Group: Drive Approach Award.2021
Lymphatic Education Research Network (LE&RN) Best Scientific Early Stage Researcher Poster Award. Lymphatics Forum. 2017
LE&RN Travel Award: NIH conference ‘Lymphatics as Regulators in health and disease’. 2015
Athletics Sports Scholar on the Developing Excellence Scheme at Imperial College London 2016
British Universities Championships 10000m Silver Medallist.2015
1st Year Academic Scholarship at the University of Leicester. 2012
British U20 5000m England Athletics Gold Medallist. 2011

Representative Publications

Sarah C Johnson *, Johanna O’Day *, Emily Kraus, Scott Delp, Jennifer Hicks. Decoding menstrual health across the lifespan: a scoping review on the use of digital health tools to improve women’s health and performance. npj Women’s Health. May 2026. https://www.nature.com/articles/s44294-026-00146-7.

Alexander Gonzalez, Johanna J. O’Day, Sarah C. Johnson, Jeongeun Kim, Summer Jasinski, Kristen Holmes, Scott L. Delp, Jennifer L. Hicks. The menstrual cycle through the lens of a wearable device: insights into physiology, sleep, and cycle variability. 2025. Accepted npj Digital Health May 2026.doi.org/10.1101/2025.09.11.675620

Skyler R. St. Pierre, Sarah C. Johnson, Julie Muccini, Brianna Bourne, Benjamin H. Laniakea, Scott Delp, Jennifer Hicks. One year of testosterone therapy in a transmasculine amateur triathlete affects hormone cycles, exercise capacity, and muscular physiology. 2025.Preprint: doi.org/10.1101/2025.09.11.25335594

Shou Y¹, Johnson SC¹, Quek YJ, Li X, Tay A. Integrative lymph node-mimicking models created with
biomaterials and computational tools to study the immune system. Mater Today Bio. 2022 Apr 21;14:100269.
doi: 10.1016/j.mtbio.2022.100269. PMID: 35514433; PMCID: PMC9062348

Johnson S, Frattolin J, Edgar LT, Jafarnejad M , Moore JE Jr. Lymph node swelling combined with
temporary effector T cell retention aids T cell response in a model of adaptive immunity.2021 Royal
Society Interface. doi/10.1098/rsif.2021.0464

Johnson S , Chakraborty S, Drosou A, Cunnea P, Tzovara D, Nixon K, Zawieja D C, Muthuchamy M,
Fotopoulou C and Moore JE Jr. Inflammatory state of lymphatic vessels and miRNA2 profiles associated
with relapse in ovarian cancer patients. 2020. PLOS ONE. doi.org/10.1371/journal.pone.0230092