Cardio is too broad a label to explain a stalled lift. Start with the outcome comparison, then look at your main goal, demanding sessions and recovery across the week.
Which gain are you trying to protect?
| Outcome | What the updated review found | What it means for a mixed program |
|---|---|---|
| Muscle size | No significant average difference. | Check your own progress; a pooled result is not a personal guarantee. |
| Maximal strength | No significant average difference. | Track your important lifts separately. |
| Explosive strength | Smaller gains; same-session concern. | Give jumps, sprints or other power work deliberate placement if that is the main goal. |
| Aerobic fitness | Not the review’s outcome. | Track aerobic progress separately rather than treating muscle results as the whole program. |
The 2022 Schumann review pooled 43 supervised studies in healthy adults for at least four weeks, comparing added cardio with matched strength training alone.
Why do older studies sound more alarming?
Hickson’s 1980 experiment deliberately combined a demanding schedule: strength training five days weekly and endurance training six days weekly for ten weeks. The combined group initially gained leg strength, then leveled off and declined late in the program, while its aerobic gains remained similar to endurance training alone.
That result showed that interference can occur under a high combined workload. It does not establish that two walks added to a recreational lifting plan have the same effect.
A 2012 meta-analysis of 21 studies also reported smaller average effects for some strength, size and power comparisons, and its subgroup analysis implicated running more than cycling. Its running-versus-cycling finding was not confirmed in 2022.
Different study sets complicate direct comparisons.
Does the six-hour spacing rule apply to everyone?
A 2016 trial randomized 58 amateur rugby players to strength only, a control group, or combined training with zero, six or 24 hours between strength and aerobic sessions over seven weeks. Its comparison gives a reason to consider more recovery between demanding sessions in that sport and protocol.
The trial did not establish a universal six-hour cutoff for every person, cardio intensity or muscle-building goal. The newer review’s separated-session subgroup used at least three hours; this was not an exact personal clock.
Two illustrative weeks, organized by the main goal
These are editorial examples, not programs tested in the studies above. Keep session effort and the total weekly workload within your own capacity, and change the plan if the next important session repeatedly suffers.
| Day | Strength-first example | Endurance-first example |
|---|---|---|
| Monday | Primary strength session | Primary aerobic session |
| Tuesday | Easy aerobic session or walk | Strength maintenance session |
| Wednesday | Recovery or easy movement | Easy aerobic session |
| Thursday | Second strength session | Recovery or easy movement |
| Friday | Moderate aerobic session | Second primary aerobic session |
| Saturday | Optional easy movement | Second strength session |
| Sunday | Rest or comfortable movement | Rest or comfortable movement |
The two columns keep the demanding sessions visible and place lighter or recovery days around them. A coach may choose a different order for a sport, available days or a specific power goal; our concurrent-training programming guide goes deeper into how training volume and session order interact.
If lifting performance stalls after adding aerobic work, review whether the aerobic sessions became harder or longer, whether important lifts are now done while tired, and whether sleep and food intake support the added work. A registered dietitian can help with individual nutrition needs; a single protein or calorie number is not needed to answer this myth.
Where does the Controlled Chaos video fit?
Coach Sean Hayes presents “Controlled Chaos Day 3” as a session mixing strength and athletic work. It is a training vlog, not a trial comparing that exact routine with strength-only or endurance-only programs.
Its useful question is how to combine qualities without losing sight of the outcome that matters most to you. The evidence table above gives you three separate measures to watch rather than a promise that one mixed session builds all of them equally.
Watch the original video
Sources
- Schumann et al. (2022), 43-study updated concurrent-training review.
- Wilson et al. (2012), 21-study concurrent-training meta-analysis.
- Hickson (1980), ten-week strength and endurance experiment.
- Robineau et al. (2016), recovery-duration trial in amateur rugby players.
This article is general training information, not an individualized sports or medical program. If you have a heart condition, injury or medical concern, ask a qualified clinician or coach how to adapt demanding sessions.
