REF-813 · Denadai et al., 2006 · Applied Physiology, Nutrition, and Metabolism, Vol. · Paper · PubMed

Interval training at 95% and 100% of the velocity at VO2max: effects on aerobic physiological indexes and running performance

Blimited evidenceMeasured on trained to highly trained athletesWritten before October 2026, being re-checked

Seventeen well-trained runners were tested (incremental treadmill test for VO2max, vVO2max and velocity at 3.5 mmol/L lactate (vOBLA); submaximal running economy; 1500 and 5000 m time trials on a 400 m track) and randomised to interval training at 95% or 100% vVO2max. For 4 weeks each group did 2 high-intensity interval sessions and 4 submaximal runs a week.

VO2max did not change in either group. vOBLA and 5000 m performance improved in both groups. vVO2max, running economy and 1500 m performance improved only in the 100% vVO2max group.

Participants

n = 17 well-trained runners, randomised into the 95% and 100% vVO2max groups (group sizes, sex and age are not given in the abstract).

Protocol

Pre and post: incremental treadmill test (VO2max, vVO2max, vOBLA at 3.5 mmol/L), submaximal constant-intensity test (running economy), 1500 m and 5000 m time trials on a 400 m track.
Training, 4 weeks: 2 HIT sessions per week at 95% or 100% vVO2max, plus 4 submaximal run sessions per week.
Interval work and recovery durations are not given in the abstract.

Key Results

VO2max did not change after training in either group.
vOBLA and 5000 m running performance improved significantly in both groups.
vVO2max, running economy and 1500 m performance improved significantly only in the 100% vVO2max group.
Authors' conclusion: 4 weeks of 2 HIT sessions (95% or 100% vVO2max) plus 4 submaximal runs a week improves vOBLA and 5000 m performance in well-trained runners; the gains in vVO2max, running economy and 1500 m performance seem to depend on training at 100% vVO2max.

Practical Application

"Should my intervals be at vVO2max or a bit slower?" — in a randomised trial in seventeen well-trained runners, four weeks of two interval sessions a week at either 95% or 100% of vVO2max improved 5000 m time and speed at 3.5 mmol/L lactate, but only the 100% group also improved vVO2max, running economy and 1500 m time; VO2max itself did not change in either group.
For a 5000 m goal, reps slightly below vVO2max did as well here as reps at vVO2max; for a 1500 m goal, run them at vVO2max.
Do not judge a short interval block by VO2max: it did not move, while speed-based markers and race times did.
Inference, not tested here: the 1500 m benefit at 100% may reflect training closer to that race's speed; the study did not test mechanisms.
Not from this paper; the base's own practice: the shape of a vVO2max interval session is in SYNTH-33; the session count per week for trained runners is in REF-005.

Limitations

Seventeen runners split into two groups; small and short (4 weeks).
No control group without interval training, so improvements cannot be separated from the effect of simply continuing training.
The abstract gives no magnitudes of change, interval durations or recoveries.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level

parallel RCT, n=17