Thread by @RodSiegel

Early in my career working with elite Sprint Kayakers in the London 2012 Olympic cycle, I noticed a pattern: some athletes improved rapidly, whilst others on the same training program - similar age, experience, calibre - stagnated. Same training, different results. But why? 🧵👇

Athletic performance at the highest level is complex. Years of training build adaptations to enhance performance. Principles like progressive overload, periodization, and specificity guide our training philosophies and approaches.

But an important aspect of specificity often gets overlooked: training must address the critical performance determinants AND the athlete's unique needs.

Our performance team debated: focus on athletes' weaknesses, or maximise their strengths? The consensus was to target weaknesses while addressing critical performance factors. But for some athletes, this approach led nowhere & I wondered whether it was always the right approach.

I then discovered this paper by Gaskill et al. (1999) in cross-country skiers which got me thinking and raised a lot of questions. ⛷️pubmed.ncbi.nlm.nih.gov/10449026/

While half the group improved with traditional high-volume, low-intensity training; the other half didn’t. Switching non-responders to a lower volume, more intensified program in year 2 drove performance gains.

But why did one group thrive on traditional training methods while the other needed less volume and more intensity? Was there a way to predict this in advance to fast track the trial-and-error process?

After starting working with the Australian Rowing Team in the Rio 2016 Cycle, I continued to see the same trend: one-size-fits-all squad-based training program, wildly different individual results. 🚣‍♂️

This ignited our quest to better understand individual training responses. Humans show up to 40% differences in adaptation to identical stimuli. Group programs often fail for many athletes because they ignore this biological variability.

Balance is key: Too much stress (volume and/or intensity) without adequate recovery leads to maladaptation, and performance stagnates. Adaptations occur when you nail the dose - frequency, volume, intensity, specificity. And recovery time varies between athletes.

Many sports demand a heavy blend of both aerobic and anaerobic systems, but individuals responses can vary considerably. For example, @Ana_C_Holt et al., (2016) showed aerobic contribution to 6-min rowing performance ranged from 79 to 91%. 🚣‍♂️

How do we tackle this in training? For example, there's the volume vs. intensity debate: polarised training works for many endurance athletes, but some may need a vastly different approach - e.g., ⬇️ volume ⬆️ intensity - to optimise their performance, as in Gaskill’s study. ⛷️

High Intensity Interval Training can enhance both energy systems, but responses (acute and chronic) can differ vastly between athletes. Some excel with short, supramaximal intervals; others with longer submaximal efforts - but group means reported within research often mask this.

Could physiological profiles be the missing puzzle piece? Muscle fibre type, energetic contributions, anaerobic speed/power reserve, fractional utilisation, blood measures (e.g., peak lactate, bicarbonate depletion, H+ accumulaiton)? Could these help explain individual responses?

@Phil_Bellinger et al. (2020) showed that muscle fiber type contributes to the variability in performance responses to training. Athletes with more type I fibers maintained performance in response to an overload training period and achieved ⬆️ performance supercompensation.

Using APR to prescribe HIIT has been shown to ⬆️ consistency in training responses in soccer, rugby, running, rowing & kayaking. Accounting for athlete profiles ⬇️ variability in physiological, cardiovascular & hormonal responses, enhancing adaptations & performance. ⚽🏉🏃‍♂️🚣

Another approach from @ingvillodden et al. (2024) showed that fractional utilisation (LT2 %VO2max; which varies widely between athletes: SD ~7% in runners) can predict time spent >90% VO2max during HIIT - important for stimulating endurance training adaptations.

A higher LT2 %VO2max allows athletes to achieve more time >90% VO2max during longer, submaximal intervals, whilst a lower % may require shorter, higher intensity efforts. These profiling methods (and others) can be used to guide training and enhance responses across athletes.

Our team then set out to look at the influence of physiological profile on training responses in our Rowing group. We found that physiological profiling, using many of the methods above, modified responses to interval training.

Long intervals (8-20 min @ ~LT2 W) improved 6-min TT performance by 3.7%. While shorter HIIT (30s-3.5 min) was less effective overall (2.7%), rowers with a more "anaerobic" profile benefited more from short intervals, showing the need to tailor by physiology.

These learnings transformed our training: profile comprehensively - energetics, APR, W', fractional utilisation, blood measures - and tailor training accordingly. Less trial & error, more precision. It's not weaknesses vs. strengths - it's the right dose for the right physiology.

We saw far more consistent performance progression within the group, showing that an individualised approach far outperformed generic, squad-based training. And the athletes loved training to a program they knew was tailored to their specific needs.

I'm sure many of you have had similar experiences, journeys, and perspectives, so I would love to hear your thoughts. Comment below!