MRes - Are self-paced variable-intensity intervals the way forward? Engineering the optimal HIIT workout to maximise the adaptive stimulus (Project ID SAS0229)

About the Project

Maximal oxygen uptake (V̇O2max), the highest rate at which the body can take up and use oxygen during exercise, is a key determinant of endurance performance (Joyner & Coyle, 2008). It has been suggested that exercising at high intensities is beneficial to improve V̇O2max (Bacon et al., 2013), and accumulating exercise time at or close to V̇O2max during high-intensity interval training (HIIT) sessions has been shown to facilitate training adaptations (Odden et al., 2024; Turnes et al., 2016).

It has been demonstrated that power output distribution within work intervals affects physiological responses during HIIT (Lisbôa et al., 2015; Zadow et al., 2015). In particular, Bossi et al. (2020) showed that well-trained cyclists spent significantly more time exercising with oxygen uptake above 90% of V̇O2max during HIIT with variable-intensity work intervals (in which power output fluctuates above and below the target during each bout) compared with constant-intensity work intervals, despite identical mean power output. Importantly, this increased cardiorespiratory demand was not accompanied by higher heart rates, blood lactate concentrations, or perceived exertion, suggesting that variable-intensity work intervals may produce a greater training stimulus per dose of exercise. The original study (Bossi et al., 2020) has garnered over 18,000 reads on ResearchGate, has been featured in media outlets including PezCyclingNews and Canadian Running Magazine, and has inspired the adoption of variable-intensity work intervals by professional cyclists worldwide.

However, the original study prescribed exercise intensity as a percentage of maximal aerobic power, an approach shown to produce unequal physiological responses across individuals (Bossi et al., 2023; Iannetta et al., 2020). More recent work by Bossi, Naumann, et al. (2024) demonstrated that prescribing interval training intensity relative to a self-paced maximal sustainable work rate effectively normalises training programme completion rates and reduces variability in acute exercise responses. Integrating variable-intensity work intervals with self-paced prescription may therefore offer a more individualised and ecologically valid approach to HIIT. To date, no study has investigated this combination. Furthermore, the original findings were based on a single session per condition, which does not account for the well-documented intra-individual variability in acute physiological responses to HIIT (Bossi, Timmerman, et al., 2024; Midgley et al., 2007).

This MRes project will compare physiological and perceptual responses between self-paced HIIT sessions with constant-intensity and variable-intensity work intervals. Specifically, the study will test the hypothesis that self-paced HIIT with variable-intensity work intervals elicits a greater time above 90% of V̇O2max compared with constant-intensity work intervals. A minimum of 16 trained cyclists will be recruited. Participants will attend the laboratory on five occasions: an incremental test to exhaustion followed by familiarisation, then four HIIT sessions (two per condition) presented in a randomised, crossover design. Throughout each session, breath-by-breath gas exchange, power output, cadence, heart rate, blood lactate, and ratings of perceived exertion will be recorded. Results from repeated sessions will be ensemble averaged (Benson et al., 2017) to improve the precision of estimates.

An MRes is an ideal route to gain experience in scientific research. These programmes are shorter than a full PhD but still offer valuable experience in project management and direction. You will have the chance to apply the skills you already have while also learning and using new practical and analytical techniques. An MRes is particularly suitable if you are looking to explore or transition into a new subject area, or if you are considering different career paths or academic research options. These programmes also help prepare you for roles that require research experience, including working within professional teams or in large organisations such as the NHS.

If you undertake this research project, you will work full-time for 12 months. You will be part of the School of Applied Sciences, where you will receive comprehensive support throughout your studies, including training and events hosted both locally within the school and by our Research, Innovation, and Enterprise events team. Bespoke training will be provided to help you develop both your research and transferable skills.

Within the School of Applied Sciences, you will have access to a range of leading facilities and expertise, including the Mountain Bike Centre of Scotland. You will join a vibrant and growing community of postgraduate research students at the university, with access to workspace and social space in our researcher community suite.

Academic qualifications

A first degree (at least a 2.1) ideally in sport and exercise science or related subject, with a good fundamental knowledge of exercise physiology and statistics.

English language requirement

IELTS score must be at least 6.5 (with not less than 6.0 in each of the four components). Other, equivalent qualifications will be accepted. Full details of the University’s policy are available online.

Essential attributes:

• Experience of fundamental research methodologies in exercise physiology, including experimental design, data collection and analysis.
• Competency in the use of physiological measurement equipment such as cycle ergometers, metabolic carts, power meters, and heart rate monitors.
• Knowledge of current theories and practices in exercise physiology, particularly related to interval training, exercise intensity prescription, and cardiorespiratory assessment.
• Good written and oral communication skills.
• Strong motivation, with evidence of independent research skills relevant to the project.
• Good time management.

Desirable attributes:

• Prior involvement in laboratory-based data collection with trained or well-trained athletes.
• Experience using statistical software for data processing, analysis, and visualisation.
• Practical experience in endurance disciplines.
• Involvement in published scientific work.

TO APPLY PLEASE CLICK ON FOLLOWING LINK https://evision.napier.ac.uk/si/sits.urd/run/siw_sso.go?Li7JJriJehDCOCkvaJp2SRVPPqzmF5e3HaFVqV3N8cVKWOIm2b

When applying, please quote the application reference SAS0229 on your form.

APPLICATION CHECKLIST

• Completed application form
• CV
• 2 academic references, using the Postgraduate Educational Reference Form (Found on the application process page)
• A personal research statement (This should include (a) a brief description of your relevant experience and skills, (b) an indication of what you would uniquely bring to the project and (c) a statement of how this project fits with your future direction)
• Evidence of proficiency in English (if appropriate)

Funding Notes

This project offers a full Home/UK tuition fee waiver for 1 year of full-time study. Non-UK residents will be considered if able to demonstrate external funding to cover the difference between Home/UK and International tuition fees.