Block Periodization and Intensity Distribution for Endurance

The sources on this entry studied how endurance and strength training is periodized and how training intensity is distributed: one meta-analysis, five systematic reviews, seven trials, two comparative training studies and four narrative or critical reviews. Mølmen 2019 (meta-analysis, 20 studies, 6 pooled) reports small favourable effects of block over traditional periodization for VO2max (SMD 0.40) and maximal power output (SMD 0.28), with moderate-to-large effects for threshold workloads, and concludes that block periodization is an adequate alternative to traditional periodization, with results to be viewed cautiously given low methodological quality (mean PEDro 3.7/10). Trials in trained athletes point the same way: Rønnestad 2014 (randomised trial) reports VO2max +4.6%, peak power +2.1% and power at 2 mmol/L lactate +10% and suggests that block periodization provides “superior adaptations to traditional organization” over a 4-week period despite similar volume and intensity; Rønnestad 2016 (randomised trial) reports larger gains in peak power output (4% versus -3%) and power at 4 mmol/L (11% versus 2%) with block periodization, while the traditional group showed no change; Rønnestad 2018 (randomised trial in well-trained ice-hockey players) reports larger improvements in knee-extension peak torque (6.6% versus -4.2%) and VO2max (5.1% versus 1.1%); García-pallarés 2010 (kayakers) reports similar VO2peak gains under both models (11% and 8.1%) with larger gains in peak paddling speed, power and stroke rate with half the endurance training volume, and concludes that block periodization may be more effective than traditional; Manchado 2018 (high-level female handball players) reports significantly greater improvements in jump, handgrip, bench press, sprint and throwing velocity with block periodization, no difference in half-squat or VO2max, and concludes that it may be more effective; Bartolomei 2014 (randomised trial) reports that block periodization may enhance upper-body power expression more than traditional with equal volume, with no differences for lower-body performance; Painter 2012 (non-randomised trial) reports that the block model required 35% less volume load and 52% fewer repetitions for similar strength gains than a daily undulating model. Against this, Galán-Rioja 2023 (systematic review, 7 studies, 161 participants) reports that no evidence is currently available favouring a specific periodization model over 8 to 12 weeks in trained road cyclists, and Conlon 2016 and Conlon 2017 (randomised trials) report that periodized and non-periodized resistance training produced improvements with no between-group differences in untrained older adults, so periodization does not appear necessary in the initial stages. On intensity distribution, Kenneally 2017 (systematic review, 16 studies) reports pyramidal and polarized training as more effective than threshold training for running performance, though threshold is used by some of the “best marathon runners”; Casado 2022 (systematic review, 10 articles) reports that highly trained and elite distance runners typically follow a pyramidal distribution, marathoners more pyramidal and 1500-m runners more polarized; and González-Ravé 2021 (systematic review, 9 studies) reports that highly trained swimmers follow volume and intensity distribution based on their primary event. The narrative reviews set out the case for block periodization: Issurin 2010, Issurin 2016 and Issurin 2018 describe limitations of traditional periodization and the block model as an alternative, with Issurin 2018 reporting that studies confirmed gains in maximal oxygen uptake and maximal power output under block periodization; Api 2022 reports that block periodization appears more efficient for advanced athletes, while for novices the chosen model does not seem to affect development; Sahabuddin 2025 (systematic review) reports enhancement of aerobic capacity by up to 10% and muscle strength by approximately 8% using block and non-linear periodization.