Five brutal days. Then rest. You’ll climb better.

Study: Solli et al. 2025. Well-trained cyclists did a 6-day block with five 30/15 HIT sessions, then a 6-day active recovery. Compared with time-matched regular training that still included HIT, the block group improved last-minute ramp power and 10 s sprint. VO2max did not change. Net effect is a quick top-end sharpen without central gains.

Short intervals are not new. What is new is the use-case. This study tests a tight 6-day microcycle against a realistic control that already has HIT, then builds the unload into the intervention. It shows you can lift race-useful power in 12 days when you protect recovery after the block.

What it adds beyond the classic 30/15 papers

• Comparator quality. Earlier work mainly pitted short vs long intervals. Here the block beats a regular-training control that still hits intensity. That makes translation to amateurs cleaner.
• Block plus planned unload. Earlier 1-week “shock” studies standardised post-block days. Solli formalises a 6-day active recovery as part of the prescription. Treat the rest week as stimulus, not an afterthought.
• Outcomes that fit racing. No VO2max change, yet better last-minute ramp power and small sprint gains. This reframes expectation for a 12-day window. You sharpen without chasing central adaptations.
• Mechanistic alignment. Acute physiology shows 30/15 yields the highest time near VO2max across sexes and muscle phenotypes. The block extends that logic into a short, scheduled overload.

How to run it with amateurs

Who: Trained riders with a base. Not for beginners.

Days 1–6 block (5 sessions):

• Each HIT session: 5 × 8.75 min of 30 s on / 15 s off, 3–4 min easy between sets.
• “On” is very hard but smooth. Strong breathing. Hold form.
• Keep the other day very easy. Limit extra volume.

Days 7–12 unload:

• Mostly Zone 1–2. One light opener mid-week only. Protect sleep and carbs.

Pairing: Keep your usual endurance rides small in the block. Skip strength work this week.

Monitor:

• Peak 1-min power in a ramp or step test, 10 s sprint power, and a short TT or hard finish set after the unload.
• HRV and mood. If either tanks, drop one set or one session.

Coach notes

• Expect a sharper finish and better last-minute power. Do not expect VO2max to move in 12 days.
• The 30/15 block slots well 10–21 days out from a target or after a stale period.
• For athletes who do better with moderate intensity, note that a 2025 crossover trial found a similar block pattern with moderate-intensity intervals also beats regular training when you protect the unload. The pattern may be the lever. Choose intensity by athlete profile.

On my mindJust rest

Sometimes all the signs point to needing a break. Motivation drops. That race next weekend doesn’t sound exciting. It takes longer to get ready and out the door. You can’t even finish the ride you started.

And it’s totally normal. In cycling we sometimes squeeze a little of tomorrow’s motivation and joy out of today’s ride. That debt needs to be paid back.

Be kind to yourself and take the break, for as long as it takes to rest and reset. You’ll come back ready and eager. Let it run its course.

Damian