The Evidence on Teaching

Familial aggregation of VO2max response to exercise training: results from the HERITAGE Family Study

Bouchard C, An P, Rice T, Skinner JS, Wilmore JH, Gagnon J, Pérusse L, Leon AS, Rao DC · 1999

grade Cquasi-experimentindependentunreplicatednumbers spot-checked
Sample
481 sedentary adults from 98 two-generation families
Population
Sedentary white adults (parents + offspring), ages 17-65; 20-wk supervised cycle ergometer training
Design
Single-arm family training study, no control group. 'Maximal heritability' is an upper bound including shared household. VO2max measured twice by cycle ergometry pre and post. Baseline figure from companion, Med Sci Sports Exerc 30:252-258, 1998.
Key findings
The trainability claim, and its limits. Under an identical supervised 20-week program, VO2max gains ranged from ~0 to >1,000 ml/min, with 2.5x more response variance BETWEEN families than within, and a heritability of the RESPONSE reported as 47%. CRITICAL CAVEAT: that 47% is an explicit 'MAXIMAL heritability' — an upper bound from a two-generation FAMILY design (not twins) that cannot separate genes from shared household (a 28% maternal-transmission model also fit), with NO non-exercise control arm. Downgraded to C: it establishes familial aggregation of training response, not a clean heritability of trainability. See renwick-2024-individual-response-vo2max for the control-arm corrective.
Genetic confound
Family (not twin) design conflates genes with shared household; no control arm, so the partitioned response variance also contains measurement error and within-subject random variation.

Effects

OutcomeMetricValueMeasureTimingVsHorizonClass
VO2max gain after standardized 20-wk endurance trainingheritability (max)47% (age/sex-adjusted); maternal transmission 28% in one modelstandardizedpost-20-wk training (pre-post change)nonenot-applicablehealth
Family clustering of training responsevariance ratio2.5x more variance between families than within familiesstandardizedpost-20-wk trainingnonenot-applicablehealth
Mean VO2max change and low/high responder spreadml/minmean +~400 ml/min; low responders near 0, high responders >1,000 ml/minstandardizedpost-20-wk trainingnoneend-of-treatmenthealth
Baseline VO2max in sedentary state (Bouchard 1998 companion, n=429, 86 families)heritability (max)>=50%; maternal heritability ~30%standardizedbaseline, untrainednonenot-applicablehealth

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