Arnar Larusson, Tymewear

Arnar Larusson, co-founder of Tymewear, makes the case that minute ventilation is the best field measure of internal work, and that a chest strap can capture it without a face mask. We look at what the VitalPro measures versus infers, and where threshold detection stands. Ventilation vs power: what each tells you about internal workload How a chest strap estimates tidal volume Validation: what’s published and what’s still pending VT1/VT2 detection: measurement and threshold identification are separate problems VE/power divergence in long sessionsTymewear: tymewear.com / @tymewear

**CORRECTION** John asked us to note that he gave incorrect figures for the wattage standard deviations during the episode. The best outdoor tests currently achieve standard deviations of approximately 0.8 W, while indoor testing has achieved a standard deviation of 0.3 W.John Buckley of Streamlines returns to discuss the outdoor tire rolling resistance testing he conducted with cyclist and Escape Collective contributor Ronan Mc Laughlin — covering the methodology behind measuring CRR with an aero testing rig, the temperature sensitivity finding that nearly sank the dataset before it began, and what the data actually shows about tire pressure, width, and the widely-cited breakpoint theory.Key Points Streamlines' method establishes CDA on baseline runs, then holds it fixed and solves for CRR as the energy remainder. Repeating baselines are the integrity gate for any outdoor tire test  Tire CRR sensitivity to temperature is approximately four times larger than published literature suggests, and the relationship is nonlinear at low temperatures.  Once vertical stiffness is equalized across widths, rolling resistance on smooth tarmac is nearly identical regardless of tire width.  John has never observed the pressure breakpoint in any of his field data. His critique is both theoretical — the mechanism requires a sudden onset of vibrational losses not supported by the data — and empirical: pressure sweeps consistently show gradual, small differences rather than a hockey-stick curve.Links & Resources Streamlines: https://streamlines.aero Streamlines in the field — aero testing with Mattie Dodd: https://streamlines.aero/blogs/news-insights/position-data-and-a-blustery-november-aero-testing-with-mattie-dodd Contact / inquiries: [email protected] Ronan Mc Laughlin's Escape Collective tire testing article: https://escapecollective.com/introducing-escape-tyre-testing-get-ready-to-rethink-accepted-wisdom/ BicycleRollingResistance.com — GP5000 multi-width comparison: https://www.bicyclerollingresistance.com/specials/grand-prix-5000-comparison John Buckley on Endurance Innovation (August 2022): https://zencastr.com/z/h0CqHZy5

Sports aerodynamicist Ingmar Jungnickel joins the show to discuss AiRO, a new CFD-based aero analysis tool built for bike fitters and coaches. He outlines why traditional wind-tunnel and field-testing approaches struggle with cost, complexity, and repeatability, and explains how recent advances in computing and AI now make high-fidelity CFD practical at the fit-studio level. The discussion highlights AiRO’s emphasis on breadth of exploration—rapidly testing wide parameter ranges—rather than pursuing ever-higher fidelity in isolated conditions.Key Points Ingmar’s background spans wind-tunnel work, velodrome testing, CFD development, and elite projects with Specialized, the German Cycling Federation, and U.S. Speed Skating. Conventional aero tools—wind tunnels, track testing, field testing, PIV, and ultrasonic tomography—are limited by scalability, environmental control, rider repeatability, and cost. AiRO’s core components include:a parametric human model fitted from simple photographs and basic anthropometrics,a digital-twin rider posture controlled through ~18 intuitive sliders,fast, cloud-based CFD simulations. AiRO’s strategic focus is breadth over depth: enabling broad parameter sweeps, positional permutations, and large-scale exploration that would be infeasible in a tunnel or on a track. Digital repeatability eliminates rider-movement noise, one of the main sources of error in physical aero testing. Current limitations include the absence of textured-surface modelling (aero socks, advanced skinsuits) and single-yaw simulations, though both are technically feasible as compute economics improve.Links & Resources AiRO: https://airo.app Contact Ingmar Jungnickel: [email protected] AiRO Instagram: https://www.instagram.com/airo_app/

Michael welcomes UK-based triathlon coach and data analyst Russ Cox to unpack Ironman’s major overhaul of its World Championship slot allocation system. Drawing on his 14 years of statistical modeling and 16 years of coaching experience, Russ explains how Ironman’s shift from participation-based to performance-adjusted qualification is reshaping who gets to Kona — and what that means for athletes, coaches, and the broader triathlon community. The origins of Coach Cox’s Ironman results database and its evolution from manual HTML scraping to modern race analytics Key environmental and geographic factors influencing Ironman course speed (heat, humidity, elevation, wind, road surface) The 2024–25 transition from the legacy slot allocation system to Ironman’s new performance-adjusted ranking model How adjustment factors are derived from the top 20 % of Kona finishers by age group Implications of a single combined men’s/women’s pool and early evidence of gender and age-group skew Why 50–54-year-old men have disproportionately benefited, and how that may (or may not!) self-correct over time Effects on athlete race choice, qualification strategy, and how coaches can advise under the new framework Practical guidance on interpreting adjusted times and using Russ’s online tools to benchmark Kona qualification potential. Coach Cox Website – Ironman Stats & Qualification Tools Coach Russ Cox on Instagram Ironman Rules for Qualifying

This week, Michael welcomes Jamie Pugh, co-founder of EXO Analytics and senior lecturer at Liverpool John Moores University. Jamie’s research focuses on carbohydrate metabolism and the role of gut function during endurance exercise. The conversation explores the novel means that EXO Analytics brings lab-grade carbohydrate oxidation testing to athletes, the physiological insights behind carb intake, and the practical implications for fueling strategies in training and racing.Key Takeaways What EXO Analytics Measures: EXO tests how much of the carbohydrate an athlete consumes during exercise is actually used by the muscles, using stable-isotope tracers and indirect calorimetry. Why It Matters: Understanding exogenous carbohydrate oxidation helps athletes personalize fueling to avoid both under-fueling and gastrointestinal distress. Individual Variation Is Wide: Even among trained athletes, optimal carbohydrate use ranges from about 60 to 120 grams per hour, with little correlation to performance level. Gut Training & Adaptation: While athletes can improve tolerance to carbohydrate intake, current evidence doesn’t confirm that “gut training” increases absorption efficiency—though it likely improves comfort and logistics. Beyond the Lab: EXO’s home-testing kit combines breath sampling and portable metabolic measurement, offering a simplified way for athletes to assess real-world fueling capacity.To learn more, visit exoanalytics.co.uk or follow Jamie on Instagram at @jamiepughperformance.

This week, we welcome Joe Staunton, owner of Ceyrest Performance, a coaching and sport consulting company. Joe, with a background in archaeology and anthropology, offers a unique perspective on endurance sports, decision-making, and the evolving role of coaching. The conversation covers how evolutionary traits influence modern choices, the impact of information overload, and the practical application of data and AI in athletic training. Evolutionary Context of Decision-Making: Human biology has remained largely unchanged for tens of thousands of years, while society has rapidly evolved. Our capacity for shared knowledge and cooperation is a key evolutionary advantage. Mismatch Theory and Modern Challenges: We face issues because we live in environments unfamiliar to our evolutionary adaptations, such as constant information consumption and altered living patterns, impacting well-being and decision-making. Simplicity in Training & Nutrition: A core principle for both training and nutrition is simplicity. Focusing on fundamental elements, such as uncomplicate workouts and correct, periodized fueling is often more impactful than complex strategies. AI's Role in Coaching: AI is transforming coaching by automating data analysis, allowing coaches to prioritize the human element of their work—building relationships, providing guidance, and fostering intrinsic motivation.To learn more, follow Joe on Instagram.

Sam Barley, a bike fitter, aero tester for Body Rocket and triathlon coach is on the show to discuss aerodynamic testing and how it shapes bike fit. He shares how he moved from traditional bike fitting to aero-guided fit. Sam reveals surprising findings from testing top athletes, showing that what looks fast isn't always best and that real-world aero gains can differ from expectations. The conversation also covers how athletes balance getting more aero with staying comfortable and powerful for races on varied terrain.Key Takeaways Aero Testing is Key: Sam uses tools like Body Rocket for precise aerodynamic measurement. Surprising Results: Testing shows that sometimes higher positions are faster, and typical aero gear might offer smaller gains than expected. Comfort vs. Speed: It's vital to find an aero position that a rider can maintain comfortably and powerfully throughout a race. Race-Specific Setup: Elite athletes adjust their aero positions based on specific race courses and demands, not just one "fastest" setup. Practical Advice: For better aerodynamics, focus on your bike's adjustability and integrate hydration/nutrition into your aero setup during training.Give Sam a follow on Instagram: fittedbysamThe study on the aero impact of shuffling by Callum Barnes.

For this episode we welcome Ronan McLaughlin, Senior Tech Editor for Escape Collective and host of the Performance Process and Geek Warning podcasts. Michael and Ronan delve into the world of performance optimization in cycling, covering everything from aerodynamic testing nuances to higher-level strategies for improvement. Key insights include: Ronan's meticulous aero and rolling resistance testing and the 'why' behind his painstaking approach. The complexity of aerodynamic testing, and the myriad of factors that can influence results and conclusions. Ronan's philosophy around iterative improvements over silver-bullet, "fastest" setups Outside the box thinking for for performance gains

Michael and Andrew welcome professional triathlete and coach Miranda Tomenson to the podcast. Miranda shares her experience prepping for and racing the IM NA Championship in the Woodlands TX, Texas, a notoriously challenging race for athletes just shaking off winter. Following that chat, Michael and Andrew discuss their observations from the race expo and course, focusing on bike technology trends and an interesting calculation related to performance in the heat. Miranda's heat prep in training, including the construction of a makeshift heat chamber using a portable greenhouse around her indoor trainer. On race day, she encountered gastrointestinal issues during the run, which impacted her calorie absorption and ability to maintain pace. Miranda utilized the "Cool Bottle" during the bike segment, reporting that it helped provide cooling through contact points and the wet sleeve, in addition to its large fluid capacity. Michael and Andrew observed trends in bike technology at the event, including the prevalence of integrated and custom front-end cockpits on high-end bikes and the design of the new Ventum Tempus bike. Discussion on helmet design trends notes wider frontal profiles intended to integrate with the rider's shoulders and improve aerodynamics. Andrew presents a calculation showing that the difference in air density between 20°C and 30°C can equate to a power difference of approximately 8 watts at 40 km/h, potentially saving around three and a half minutes over an Ironman bike course. The episode concludes with a brief interview segment featuring professional triathlete Lauren Brandon, a veteran of Ironman Texas.

Cycling coach Marinus Petersen returns to revisit bicarbonate supplementation tips and to discuss training around the first lactate threshold (LT1).  Petersen shares his views on intensity domains, the importance of LT1, and how he incorporates this concept into his coaching. Bicarb Neutralization: A discussion on whether mixing bicarbonate with acidic substances like jelly or jam neutralizes its effectiveness. Petersen argues that the acidity of the stomach far outweighs any pre-ingestion neutralization. Practicality of Bicarb Use: The challenges of using bicarb in conjunction with a regular work schedule, and tips for timing bicarb intake around workouts. Importance of LT1: Petersen considers LT1 the most critical metric for an athlete due to the significant difference in fatigue levels when training above or below it. Measuring LT1: Lactate testing to accurately determine LT1, using 10-minute stages with 10-watt increments to pinpoint the threshold. Coaching Considerations: A discussion on the challenges of balancing structured training with the enjoyment of riding, allowing flexibility in training as long as the intensity of endurance rides stays below LT1. Sub-LT1 Work: Considerations for aerobic training at very long durations at well below LT1 vs. relatively shorter bouts just below LT1.