About me

About me

My name is Ida Kyrilis (prior Clark) and I was born and raised in Stockholm, Sweden. My love for exercise began when I started to play ice hockey at the age of 6. When I was 17, I moved to Canada to attend an elite ice hockey academy.  After a year in Canada, I moved back to Sweden to finish school and play ice hockey, during which time I played in Mälarhöjden bredäng, winning 2 Swedish championships. 

At the age of 20, I moved to the United States to play Division 1 ice hockey at Minnesota State University in Mankato, Minnesota and to complete my undergraduate in Exercise Science. After completing my undergraduate degree, I was offered the opportunity to stay and complete my Masters at Minnesota Sate University under the guidance of Dr. Robert Pettitt. After completing my Masters, I remained in Minnesota for 2 years, lecturing as an associate professor in exercise science. During this time in the US, I started to study the Critical Power concept and how we can apply it to athletes. 

In 2014 I moved to Exeter, England to attend the University of Exeter where I completed my PhD under the mentorship of Associate Professor Anni Vanhatalo and Professor Andy Jones. My PhD was partly sponsored by Nike, investigating how Critical Power and W' are affected by prior endurance exercise. During my time at Exeter, I  was also afforded the opportunity to be one of the researchers on Nike's team for Breaking 2. Our team was responsible for testing 17 elite athletes, taking out the top 3 athletes to attempt to run a marathon under 2h in Monza, Italy. Kipchoge ran at 2:00:25, so close. 

My goal has always been to be able to help athletes with their training to be the best they can be, which is one of the reasons I have moved around the world in my pursuit to learn from the best. I am now living back in Sweden where I work part time as a head coach at Crossfit Täby and run my own business where I help athletes with training and programing and I also use the 3-min all-out exercise test to predict performance and assist in training athletes.  

Areas of Intrest


Critical power; skeletal muscle metabolism; physical training; adaptations to training; muscle tissue analysis; applied physiology; training interventions

Current Work


Swedish Ice Hockey Association

  • Testing Practitioner - Responsible for all testing conducted on the youth men and women as well as the senior women’s national team. 
  • Womens national ice hockey team - Strength and coditioning coach. 
  • Competence network - Member of a panel aimed at evolving Swedish ice hockey. As an exercise physiologist my goal is to implement new testing batteries and improve the education for all ice
    hockey trainers in Sweden.

Riksidrottsförbundet, Bosön, Sweden.

  • Coach - where I coach one-on-one in diffrent areas suchs as crossfit, weightlifting etc, as well as conducts testing such as sprinting, max lifts, jumping etc.

Crossfit Täby, Sweden

  • Crossfit Coach - Coach Crossfit athletes through various exercise programs. Coach groups of athletes with different abilities through complex exercise movements.



PhD Sport and Health Science/Exercise Physiology, University of Exeter, Exeter, United Kingdom

Thesis: Influence of fatigue on the determinants of endurance exercise performance

M.S. Exercise Science/Exercise Physiology, Minnesota State University, Mankato

Manuscript: Alternative procedures for the 3-min all-out exercise test


B.S. Physical Education, Minnesota State University, Mankato


B.A. Scandinavian Studies, Minnesota State University, Mankato



Jones AM, Kirby BS, Clark IE, Rice HM, Fulkerson E, Wylie LJ, Wilkerson DP, Vanhatalo A, Wilkins BW. (2021). Physiological demands of running at 2-hour marathon race pace. J Appl Physiol. 130(2): 369-379.

Clark IE, Vanhatalo A, Thompson C, Joseph C, Backwell JR, Wylie LJ, Ten R, Bailey SJ, Wilkins BW, Kirby BS, Jones AM. (2019). Dynamics of the power-duration relationship during prolonged endurance exercise and influence of carbohydrate ingestion. J Appl Physiol. 127(3): 726-736.

Clark IE, Vanhatalo A, Thompson C, Wylie LJ, Bailey SJ, Kirby BS, Wilkins BW, Jones AM. (2019). Changes in the power-duration relationship following prolonged exercise: estimation using conventional and all-out protocols and relationship to muscle glycogen. Am J Physiol. 317(1): R59-R67.

Clark, I. E., Goulding, RP., DiMenna, FJ., Bailey, S. J., Jones, MI., Fulford, J., McDonagh, STJ., Jones, A. M., Vanhatalo, A. (2019). Time-trial performance is not impaired in either competitive athletes or untrained individuals following a prolonged cognitive task. European Journal of Applied Physiology, 5119(1): 149-161.

Clark, I. E., Vanhatalo, A., Bailey, S. J., Wylie, L. J., Kirby, B. S., Wilkins, B. W., Jones, A. M. (2018). Effects of two hours of heavy-intensity exercise on the power-duration relationship. Medicine & Science in Sport and Exercise, 50(8): 1658-1668.

Kramer, M., Clark, I. E., Jamnick, N., Pettitt, R.W. (2018). Normative data for critical speed and D' for high-level male rugby players. Journal of Strength and Conditioning Research, 32 (3): 783-789. 

Courtright, S. P., Williams, J. L., Pettitt, P. W., Clark, I. E., Dicks, N. (2016). Monitoring interval-training responses for swimming using the 3-min all-out exercise test. International Journal of Exercise Science, 9 (5): 545-553.

Clark, I. E., Gartner, H. E., Williams, J. L., Pettitt. R. W. (2016). Validity of the 3-min all-out Exercise Test on the CompuTrainer. Journal of Strength and Conditioning Research, 30(3): 825-829.

Pettitt, R.W., Placek, A.M., Clark, I.E., Jamnick, N.A., Murray, S.M. (2015). Sensitivity of Prescribing High-Intensity, Interval Training Using the Critical Power Concept. International Journal of Exercise Science, 8 (3): 202-212. 

Clark, I.E., West, B., Reynolds, S., Murray, S.M., Pettitt, R.W. (2013). Applying the critical velocity model for an off-season interval training program. Journal of Strength and Conditioning Research, 27(12): 3335-3341.

Sedgeman, D.T., Dalleck, L.C., Clark. I.E., Jamnick, N.A., Pettitt, R.W. (2013). Analysis of square-wave bouts to verifying VO2max. International Journal of Sports Medicine, 34: 1058-1062.

Pettitt, R. W., Clark, I. E. (2013). High-Intensity Exercise Tolerance: An Update on Bioenergetics and Assessment. Strength and Conditioning Journal, 35: 11-16.

Clark, I.E., Murray, S. M & Pettitt, R.W. (2013). Alternative procedures for the 3-min all-out exercise test. Journal of Strength and Conditioning Research, 27(8):2104-2112.

Pettitt, R.W., Clark, I.E., Ebner, S.M., Sedgeman, D.T., Murray, S.M. (2012). Gas exchange threshold and VO2max testing for athletes: an update. Journal of Strength and Conditioning Research, 27(2): 549-555.

Pettitt, R.W., Jamnick, N.A., Clark, I.E. (2012). 3-min all-out exercise test for running. International Journal of Sports Medicine, 33(6): 426-31.

Andrews, T.R., Mackey, T., Inkrott, T., Murray, S.R., Clark, I.E., Pettitt, R.W. (2011). Effect of hang cleans or squats paired with countermovement vertical jumps on vertical displacement. Journal of Strength & Conditioning Research, 25: 2448-2452.