2/ Before diving in, it's essential that all training, including interval training, first addresses the critical performance determinants of the sport & event; underpinned by first principles understanding of the unique requirements 🧑‍🔬👇 https://x.com/RodSiegel/status...

3/ Next, individualisation: as we discussed previously, understanding an athletes’ physiological profile is critical. Tailoring training to the event & athlete MUST be the 1st dominos to fall to optimise the stimulus, adaptation & performance potential 🔑👇https://x.com/RodSiegel/status...

4/ Now the nitty gritty. How do we structure interval sessions to augment the stimulus & ⬆️ gains? @ingvillodden showed sessions with ⬆️ average %VO2max produce greater TT improvements. Time >90% VO2max (T>90%) is a strong predictor of adaptation, guiding further optimisations 📊

5/ We also discussed how the %VO2max @ LT2 predicts T>90%: Higher % favours longer intervals for superior accumulation, while lower % require shorter efforts, yielding larger VO2max gains (8.7% vs. 2.6%). Profiling informs this selection 🔬👇 https://x.com/RodSiegel/status...

6/ First up, work-to-rest ratios. 2:1 ratios (e.g. 30s on/15s off) accrue more T>90% than 1:1 (e.g. 30s on/30s off) by sustaining elevated VO2. This may suit “endurance” profiles, whereas longer recovery might be needed for “speed” profiles to limit fatigue & maintain quality 💥

7/ Recovery Intervals (RI): rather than set RI's, we can evolve them as the session progresses—shorter early to maintain elevated VO2 when fresh, longer later to curb fatigue & maintain output; especially important in speed profiles ⏱️

8/ Active vs Passive RI’s: active (light pedalling/jogging @ 40-60% VO2max) keeps VO2 elevated vs. passive, ⬆️ T>90%. This can suit endurance profiles, whereas passive recovery assists when wanting to maintain quality & hit high speeds/powers; useful for speed profiles 🌀

9/ Intensity variations: @ahbossi showed varying intensity within intervals (e.g. high-low-high) sustains higher mean %VO2max longer than steady-state intervals by modulating effort to prevent early fatigue, extending T>90% without added volume 📈

10/ Fast-start intervals: by initiating with a 20-30s supramaximal surge (e.g., 120-140% CP) before settling into pacing, VO2 ramps faster to higher levels, elevating peak & mean VO2, prolonging T>90%⚡

11/ Session-wide intensity progressions: starting with lower intensities delays fatigue, enabling greater cumulative T>90% in some profiles by sustaining quality across reps. Starting harder primes VO2 kinetics early, then reducing lowers strain to maintain high VO2 longer 🚀

12/ Within-session interval duration: Starting with longer reps & progressively shortening ⬆️ VO2 early, yielding more T>90% than constant-duration protocols. Conversely, building from short to long, or pyramids (short-long-short) may delay fatigue in some profiles 📉

13/ Cadence: for cyclists, incorporating higher cadences (100-120 rpm) at a fixed power ⬆️ VO2 cost. It also recruits more fast-twitch fibres, augmenting the stimulus for oxidative adaptations & enhancing Type II fatigue resistance qualities 🔄👇 https://x.com/RodSiegel/status...

14/ Terrain inclines: Uphill intervals (e.g. 5-10% grade) recruit more muscle & raise VO2. This can boost T>90% vs. flat intervals at similar intensities, ideal for runners & cyclists to further enhance gains 🏔️

15/ There are many tools in the toolbox to augment the training stimulus. The trick is knowing which tools to use—how & when—for each athlete given their physiological profile, to truly maximise n=1 performance potential 🔎🧬 #Running #Cycling #Swimming #Rowing #Triathlon