REF-431 · Mann et al., 2014 · Sports Medicine, Vol. 44, pp. 1113-1124 · Paper

High Responders and Low Responders: Factors Associated with Individual Variation in Response to Standardized Training

B+moderate evidenceMeasured on a mixed groupWritten before October 2026, being re-checked

Synthesis Framework

The review's premise: the group mean is usually taken as the typical response, but individuals show a wide range of responses to the same standardized endurance-type training. Factors the review associates with this variation:

1

Genetic influences — an important contribution to variation in certain training responses; supported by heritability estimates and, more recently, links between some responses and specific single nucleotide polymorphisms

2

Pre-training phenotype — hereditary influences are often expressed through the pre-training phenotype; some parameters show heredity in the baseline phenotype but not in the training response. In most cases the pre-training phenotype predicts only a small amount of the variation in response

3

Pre-training autonomic activity — the exception: its relationship with the subsequent VO2max response shows relatively stronger predictive potential

4

Characteristics of the training program — prescription by relative intensity and duration does not guarantee an equivalent homeostatic stress; some relative-intensity methods equalise the stimulus between individuals better than others, so individuals experience a different "stimulus" from the same program

5

Recovery between sessions — varies with training status, sleep, psychological stress and habitual physical activity; an imbalance between overall stress and recovery can produce fatigue and even maladaptation

6

Nutrition — some evidence that timing and composition of dietary intake modulate the training response

7

Measurement error — a share of the apparent individual variation is measurement error, which future studies should account for

Key Findings (from the abstract)

Individuals commonly show a wide range of responses to standardized endurance-type training rather than a similar response.
In most cases the pre-training phenotype predicts only a small amount of the variation in the subsequent training response; the relationship between pre-training autonomic activity and the subsequent maximal oxygen uptake response shows relatively stronger predictive potential.
Variation not explained by genetics may relate to the training program (how well relative-intensity prescription equalises homeostatic stress), recovery between sessions, nutrition, and measurement error.
The authors conclude that more studies are required to clarify and quantify the role of these factors.

Key Distinctions

The review contrasts "high responders" and "low responders" to the same standardized program but gives no fixed percentages for these groups
Not from this paper; the base's own practice: the 15/70/15 split (Naturals / Realists / Workers) is a practitioner heuristic from REF-436, not a finding of this review

Practical Decision Tree (the base's own practice, built on the review's factor list — not from the paper)

```

Athlete shows minimal response to a training block?

├── Check recovery: sleep, psychological stress, habitual activity, training status → if poor, address first

├── Check baseline phenotype → if already highly trained, expect smaller gains

├── Check the stimulus: was the prescribed relative intensity actually equivalent for this athlete? (HR/lactate/RPE drift)

├── Check nutrition timing and composition around sessions

├── Check measurement noise → repeat the test before labelling (REF-430)

└── Then change the stimulus: intensity, block structure or modality (REF-995 for intensity, in untrained adults; REF-136)

```

Practical Application

Individuals vary widely in their response to the same standardized endurance training; the review attributes this to genetics (often expressed through the baseline phenotype), how the relative-intensity prescription actually lands on each person, recovery between sessions (training status, sleep, stress, habitual activity), nutrition — and to measurement error — a poor response is a prompt to check these factors, not a fixed label
Pre-training autonomic activity (resting HRV-type measures) is the baseline variable with the strongest predictive signal for the VO2max response in this review — a reason to log it before a block
Not from this paper; the base's own practice: do not label an athlete a non-responder after one block; repeat the test and adjust the stimulus first
Not from this paper; the base's own practice: track several outcomes (not only VO2max — also threshold power, durability, body composition), since heredity and response differ by parameter

Limitations

Review, not original data; no systematic search
Pre-2014 — does not cover newer block periodization or HRV-guided literature
Does not quantify modulator effect sizes; the authors call for studies to clarify and quantify these factors
How this entry was checked and changed
Why this level

regraded 2026-09-27 from A: narrative review without systematic method, from an established training-monitoring group

Content correction 2026-09-27
"~47% of trainability variance", "last 12 weeks", "~15% / ~70% / ~15%", "8-12 weeks", "4-6 weeks", "2-3 training cycles" -> none are in the abstract; removed or relabelled as the base's own practice. The 15/70/15 split is now attributed to the practitioner framework REF-436 (the old cross-ref pointed at REF-433, which is the ACTN3 entry).
Six invented "factor categories" (incl. "dose response sensitivity — block periodization") -> replaced with the factors the abstract actually lists, including pre-training autonomic activity and measurement error.
Level A -> B+ (narrative review); added Tier/Sport lines.
2026-09-28: added Key Findings from the abstract (Europe PMC PMID 24807838).
2026-10-01: cross-reference to SYNTH-13 no longer names an archetype — that model was retired as an unvalidated composite.
2026-10-02: decision-tree pointer repointed from the unverified composite REF-432 to REF-995 (Reuter 2023), which covers the intensity step only and only in untrained adults.