Compatibility of Concurrent Aerobic and Strength Training for Skeletal Muscle Size and Function: An Updated Systematic Review and Meta-Analysis
Sample
43 studies (PRISMA search to 15 March 2021; PROSPERO CRD42020203777). Inclusion: healthy adults of any sex and age; supervised concurrent aerobic + strength training for at least 4 weeks; comparison = identical strength prescription with no aerobic training; outcomes = maximal strength, explosive strength, muscle hypertrophy.
Key Findings
Maximal strength: SMD −0.06 (95% CI −0.20 to 0.09; p = 0.446) — not compromised
Explosive strength: SMD −0.28 (95% CI −0.48 to −0.08; p = 0.007) — attenuated by concurrent training
Muscle hypertrophy: SMD −0.01 (95% CI −0.16 to 0.18; p = 0.919) — not compromised
Moderator, session timing: attenuation of explosive strength was more pronounced when aerobic and strength work were in the same session (p = 0.043) than when sessions were separated by at least 3 h (p > 0.05)
No significant moderation by type of aerobic training (cycling vs running), frequency of concurrent training (> 5 vs < 5 weekly sessions), training status (untrained vs active) or mean age (< 40 vs > 40 years)
Authors' conclusion: concurrent training does not compromise hypertrophy or maximal strength; explosive-strength gains may be attenuated, especially with same-session training; effects appeared independent of aerobic modality, frequency, training status and age
Practical Application
Across 43 controlled trials in healthy adults, adding aerobic training to an identical strength programme left maximal strength (SMD −0.06) and hypertrophy (SMD −0.01) untouched but attenuated explosive strength (SMD −0.28, p = 0.007), and the loss was concentrated in same-session designs (p = 0.043) rather than sessions ≥3 h apart; cycling vs running, weekly frequency, training status and age made no difference — the interference that survives meta-analysis is small, specific to power/explosive gains, and largely a scheduling problem.
≥3 h separation between aerobic and strength work is the meta-analytic condition under which the explosive-strength penalty stopped being significant; if power matters, do not stack them in one session.
Do not choose cycling over running (or vice versa) to "reduce interference" on this evidence — modality was not a significant moderator here.
Not from this paper: the 24-h separation guidance for endurance-priority athletes lives in REF-329 (Doma 2019).
Limitations
Studies underpowered to detect small-to-moderate interference in specific sub-populations
Heterogeneous definitions of "concurrent"; trials of at least 4 weeks, so long-term effects are not covered
Population is healthy adults, untrained to active — not trained endurance athletes; transfer to a cyclist with a large aerobic volume is untested by this pooling
Individual-level EIMD response not modelled
How this entry was checked and changed
Content correction 2026-09-27
"Running shows larger interference than cycling", "interference larger when frequency high" -> the meta-analysis found no significant moderation by aerobic modality (cycling vs running), frequency, training status or age; the cyclists-tolerate-tighter-scheduling bullet was deleted.
"≤20 min between" -> not in the abstract; same session vs ≥3 h apart is the comparison reported. Pooled SMDs (−0.06 / −0.28 / −0.01) and CIs added.
Sport line "cycling, running, swimming" -> cycling, running, strength (population: healthy adults, not swimmers).
Full text (checked 2026-10-12)
The 43 studies included 1090 participants, 590 doing combined aerobic and strength training and 500 doing strength training alone; cycling was the aerobic mode in 24 studies and running in 16 (full text).
"Same session" was defined as ≤ 20 min between aerobic and strength training, and in that subgroup explosive strength showed SMD − 0.31 (95% CI − 0.62 to − 0.01; p = 0.043), with no significant interference when sessions were separated by at least 3 h (full text).
Within the cycling subgroup, explosive strength initially showed SMD − 0.44 (p = 0.043), but after removing the overly influential study by Mikkola et al. it became − 0.27 (p = 0.086); low frequency similarly went from − 0.45 (p = 0.039) to − 0.25 (p = 0.059) (full text).
The pooled analysis found no order-specific effect (aerobic before strength vs strength before aerobic) (full text).
The frequency subgroups were 4.1 ± 0.3 vs 6.1 ± 1.6 weekly sessions, and the "active" training-status group included studies describing participants as recreationally active, trained or well-trained (full text).
Pooled datasets were 37 studies for maximal strength (525 vs 442 participants), 18 for explosive strength (270 vs 208) and 15 for hypertrophy (201 vs 188) (full text).
Mean PEDro score was 4.3 ± 0.9 (medium quality), seven studies were low quality, and aerobic exercise intensity could not be analysed as a moderator because reporting was inconsistent (full text).