Dr. Andy Galpin on exercise-science: what the evidence says · JRE #996

What the evidence says 01 / RECORD

Galpin describes an internal lab result in which every subject improved 20-30% under one restriction-training condition and got worse under another; no peer-reviewed publication matching this exact result (a uniform 20-30% gain in literally every subject) could be located, and it appears to be an unpublished, anecdotal account of in-house data rather than a citable study. Published research on related training modalities shows real but variable effects rather than uniform ones: a systematic review and meta-analysis of inspiratory muscle training (a category that includes restricted-breathing devices like the O2 Trainer) found a significant average improvement in maximal inspiratory pressure with high between-study heterogeneity (I-squared 75%), a non-significant average change in VO2max with very high heterogeneity (I-squared 95%), and a significant reduction in blood lactate with low heterogeneity (I-squared 16%) - a mixed picture of inconsistent individual/study-level responses rather than a universal effect. Similarly, a 2024 systematic review and meta-analysis of blood-flow-restriction training in 542 athletes found moderate-to-large average improvements in strength, power, speed and endurance, again reported as average effect sizes across variable individual responses, with no mention in that review of a restriction protocol that reliably makes performance worse as Galpin describes for an alternate condition. Because the specific internal study is not published or independently verifiable, the precise "every single person, 20-30%" figure cannot be checked against public data; the general concept that restriction-based training can improve performance is supported in principle, but the magnitude and universality Galpin describes go beyond what published evidence establishes.