Is your endurance training lagging despite logging endless miles on the treadmill or long sessions on the elliptical? Improving your conditioning isn’t as straightforward as extended durations on cardio machines. There’s more science to it than brute force.
In early December 2024, Dr. Gommaar D’Hulst, a senior scientist at ETH Zurich, Switzerland, shared actionable strategies to enhance conditioning. He addressed common concerns and outlined key principles to improve training.
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Exercise Training Non-Responders
Dr. D’Hulst referenced the “Family HERITAGE Study,” an older research project that examined the effects of exercise training on genetically related individuals. (1) Over 20 weeks, researchers implemented progressive overload training using various exercise equipment. Findings highlighted the following differences in individual training responses:
- Some participants experienced significant improvements in their VO2 max, an indicator of the body’s ability to absorb and utilize oxygen.
- Others showed little to no improvement, with some experiencing a decline in their oxygen uptake, categorizing them as non-responders or low responders. Conversely, some high responders showed exceptional fitness gains.
- Most participants saw an average increase in oxygen uptake ranging from 200 to 500 milliliters, representing the largest segment of the study group.
Since this influential study, researchers have attributed these variations to human genetic differences, suggesting that some individuals can undergo extensive training yet achieve minimal fitness improvements due to inherent biological factors.
Study Debunked
Another study debunked that notion of genetics. The counter-study emphasized that, with proper training, everyone can benefit from exercise. (2) Eighty-seven young, healthy individuals with no prior training participated. Baseline assessments, including VO2 and VO2 max measurements, were conducted through an incremental test to exhaustion.
Some individuals who trained once, twice, or even three times per week showed no improvement in their VO2 max levels, indicating they didn’t respond to the initial exercise routines.
Participants in the groups training four or five times a week experienced full benefits. Researchers advised non-responders to increase their training frequency by doubling their sessions.
Those who initially trained once per week increased to three sessions, while those training twice a week increased to four. Similarly, participants training three times per week increased to five sessions. After rest, the adjustments significantly boosted training volume of all non-responders.
Following another six weeks of training at these higher intensities, every group showed marked improvements in VO2 max. This demonstrates a clear takeaway: individuals can effectively enhance their VO2 max over time by increasing weekly training frequency.
What Does This Mean for Training?
According to Dr. D’Hulst, functional fitness participants who aim to enhance their aerobic conditioning should follow the following steps:
- Track progress consistently by performing a functional threshold power (FTP) test, a VO2 max assessment, and a time trial (e.g., run or row 10 kilometers every 10 to 12 weeks).
- Track training volume using the TRIMP formula (training impulse), calculated as rate of perceived exertion (RPE) multiplied by training duration.
- Gradually increase training volume by 10-15% through progressive overload.
Functional athletes involved in CrossFit or HYROX who aim to increase their training volume and improve conditioning can benefit from block periodization, which prioritizes a specific training area.
For HYROX athletes, the season can be strategically divided based on competition goals. Early phases can focus on low-intensity, long-duration aerobic conditioning to build a strong base endurance. As the season progresses and competitions draw near, training can shift to higher-intensity efforts.
“If you’re struggling with conditioning, monitor your training load and up the training volume in a block-periodized way,” D’Hulst recommended. “That is the way to go to improve overall conditioning while maintaining functional fitness.”
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References
- Bouchard, C., An, P., Rice, T., Skinner, J. S., Wilmore, J. H., Gagnon, J., Pérusse, L., Leon, A. S., & Rao, D. C. (1999). Familial aggregation of VO(2max) response to exercise training: results from the HERITAGE Family Study. Journal of applied physiology (Bethesda, Md. : 1985), 87(3), 1003–1008. https://doi.org/10.1152/jappl.1999.87.3.1003
- Montero, D., & Lundby, C. (2017). Refuting the myth of non-response to exercise training: ‘non-responders’ do respond to higher dose of training. The Journal of physiology, 595(11), 3377–3387. https://doi.org/10.1113/JP273480
Featured image via Shutterstock/Lucky Business
