Workout
Conditioning Intervals
An interval session that builds work capacity without eating the recovery your lifting needs, with the modality choice that decides interference.
The session 10 working sets
Warm-up — 8 min
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Easy cycling or rowingConversational pace. Genuinely easy. | 1 | 8 min | — |
Intervals — 8 rounds
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Bike or rower intervalsHard means you could not hold a conversation. Not a sprint. | 8 | 60 sec hard | 90 sec easy |
Cool-down
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Easy cycling or rowing | 1 | 5 min | — |
Conditioning is worth training and easy to overdo. This session is built to give you the aerobic benefit while costing as little as possible from your lifting.
The interference effect, in proportion
The claim that cardio kills your gains is overstated, but not invented. Concurrent training does show some interference, and three variables determine how much.
Modality. Running causes substantial eccentric muscle damage in the legs, competing directly with leg training. Cycling and rowing are mostly concentric and interfere far less. This is the single biggest lever.
Volume. Interference scales with how much you do. Two half-hour sessions is a different proposition from five hour-long runs.
Proximity. Doing hard intervals immediately before squatting is a bad idea. Separate them by a day, or by several hours.
Do all three sensibly and the interference is close to negligible.
Why 60 seconds on, 90 off
Sixty-second efforts sit in the range where the aerobic system is doing most of the work and the buffering demand is high, which is where conditioning gains come from for most people.
Shorter, harder efforts drift toward anaerobic power. Longer ones become a tempo session. Neither is wrong; this is the general-purpose middle.
Use the heart rate calculator to set the effort if you train by heart rate — this is roughly zone 4, remembering that heart rate lags at the start of each interval.
Keep the easy work easy
The warm-up and the recovery periods should be genuinely easy.
The most common mistake in conditioning is doing everything at a moderately hard effort — too hard to recover from, not hard enough to drive adaptation. Sharp contrast between the hard and easy portions is what makes intervals work.
Common questions
Will cardio kill my gains?
Not at these doses. The interference effect is real but depends on modality, volume and proximity to lifting. Two 30-minute cycling or rowing sessions a week, done on non-lifting days or several hours apart, has minimal effect on strength and hypertrophy.
Why cycling or rowing rather than running?
Running produces far more eccentric muscle damage in the legs, which competes directly with leg training for recovery. Cycling and rowing are largely concentric, which is why they show less interference in the research.
How hard should the intervals be?
Hard enough that you could not hold a conversation, not so hard that it is a sprint. Roughly zone 4 on the heart rate calculator. If round eight is dramatically slower than round one, you started too hard.