REF-640 · Izquierdo-Gabarren et al., 2010 · Medicine & Science in Sports & Exercise, · Paper · PubMed
Concurrent Endurance and Strength Training Not to Failure Optimizes Performance Gains
In trained rowers, moderate-volume lifting not to failure beat higher-volume to-failure lifting for upper-body strength, power and 20-min row power
Participants
n=43 trained male rowers, matched and randomly assigned to four groups performing the same endurance training but different resistance training:
4RF (n=14): four exercises to repetition failure (the higher-volume arm)
4NRF (n=15): four exercises not to failure (moderate volume)
2NRF (n=6): two exercises not to failure (low volume)
Control (n=8): endurance training only
Protocol
8 weeks of linear periodized concurrent strength + endurance training
Outcomes: 1RM and maximal muscle power in prone bench pull (BP); average power over a 20-min all-out row (W 20 min); row power at 4 mmol/L lactate (W 4 mmol); power in 10 maximal strokes (W 10 strokes)
Key Findings
| Outcome | 4NRF (moderate, not to failure) | 4RF (higher volume, to failure) | 2NRF (low, not to failure) | Control |
|---|---|---|---|---|
| BP 1RM | +4.6% | +2.1% | +0.6% | — |
| BP power | +6.4% | -1.2% | -0.6% | — |
| W 10 strokes | +3.6% | -0.1% | +5% | — |
| W 20 min | +7.6% | +4.6% | +9% | — |
| W 4 mmol | +6.2% | +5.3% | +6.8% | +4.5% (ns between groups) |
4NRF beat both 4RF and 2NRF for upper-body strength and power (bench-pull 1RM and power).
Both not-to-failure groups (4NRF and 2NRF) beat 4RF for 10-stroke power and 20-min all-out row power.
No group difference for power at 4 mmol/L — threshold rowing power improved similarly whatever the lifting, including in the control group.
The to-failure arm was the higher-volume arm; the low-volume not-to-failure arm (2NRF) improved rowing power but gained essentially no upper-body strength or power.
Practical Application
RCT, 43 trained male rowers, 8 weeks: four lifts at moderate volume stopped short of failure (4NRF) gained more bench-pull 1RM (+4.6% vs +2.1%) and power (+6.4% vs -1.2%) than the same lifts taken to failure at higher volume (4RF), and both not-to-failure groups improved 20-min all-out row power more (+7.6% and +9% vs +4.6%); power at 4 mmol/L lactate improved equally in every group. Alongside heavy rowing, stopping sets short of failure is what let the lifting add strength and race-length power instead of just fatigue.
Keep a moderate lifting volume: cutting to two exercises (2NRF) still helped rowing power but gave no upper-body strength gain — going lighter is not the same as going not-to-failure.
Do not expect lifting to move threshold power: W 4 mmol rose ~5-7% in all groups over the 8 weeks, control included.
Not from this paper: a specific reps-in-reserve target for these sets — the abstract does not give one; see REF-583 for strength-programming dosing.
Reserve failure-adjacent efforts for rare testing, not routine concurrent blocks.
Limitations
Trained men only, 8-week block; generalisation to women, juniors, masters and longer macrocycles untested.
Small and uneven groups (2NRF n=6, control n=8); strength outcomes are upper-body (bench pull) only.
"Not to failure" and "to failure" also differed in total volume, so proximity to failure and volume are confounded by design.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from A: parallel RCT, n=43, groups of 6-15
Content correction 2026-09-27
"Beat equated-volume to-failure training ... 10 km erg" -> to-failure was the HIGHER-volume arm, and the endurance outcome was a 20-min all-out row (plus 10-stroke power), not a 10 km erg.
"Not to failure (lower volume) greater strength" -> the moderate-volume 4NRF arm gained strength/power; the low-volume 2NRF arm did not (+0.6% / -0.6%).
"Leave 2-4 reps in reserve" -> not in the abstract; removed.
Added n=43, group sizes, all reported percentages, no group difference in W 4 mmol; Level A -> A- (RCT, n=43).