Rønnestad · Scandinavian journal of medicine & science in sports 2015 · randomized controlled trial · n=16

Short intervals induce superior training adaptations compared with long intervals in cyclists - an effort-matched approach.

Cited 70 times in the scientific literature.

Level 2 - randomized trial

Randomized controlled trial

PubMed 24382021 · doi:10.1111/sms.12165 · record verified 2026-08-30

What was done

Sixteen cyclists were randomized to 10 weeks of either effort-matched short intervals (SI; n = 9) or long intervals (LI; n = 7). High-intensity interval sessions were conducted twice weekly alongside low-intensity training. Groups were comparable at pretest and matched for total training volume of both high- and low-intensity sessions.

What was found

The short-interval group achieved a significantly larger relative increase in VO2max than the long-interval group (8.7% ± 5.0% vs. 2.6% ± 5.2%, P ≤ 0.05). Relative improvements in performance parameters—mean power output across 30-s, 5-min, and 40-min all-out tests—demonstrated a moderate-to-large effect favoring short intervals over long intervals (effect size range 0.86–1.54).

Why it matters

The findings show that when volume and effort are matched, short-interval protocols may offer superior physiological and performance adaptations across a cyclist's power profile compared to traditional long intervals.

Limits

The sample size is extremely small (n = 16 total), limiting precision. The abstract does not specify participant sex, baseline training status, or the precise work-to-rest durations of the interval protocols.

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