Build the Engine Now, Race On It Later: Five Science-Backed Fixes for Pre-Season

Pre-season is the least glamorous and most valuable block in the calendar. No results, no medals, no PBs - just weeks of heavy lifting, base miles and dark evenings, laying down the physiology that has to hold up when it matters.

It's also the block where most people quietly lose ground. Not because they don't work hard enough, but because the work outruns the recovery. Hypertrophy blocks are brutal in a specific way: the soreness lingers, the fuel tank never quite refills, the quality sessions start to slide, and by week six you're accumulating fatigue instead of adaptation.

Here are five problems that show up in almost every pre-season, and what the research on New Zealand blackcurrant extract says about each one.

1. The problem: You start every session under-fuelled

Glycogen - carbohydrate stored in muscle - is the fuel that decides whether a session is productive or survivable. In a heavy training block you're rarely starting fully topped up, and the sessions that suffer first are the ones you care about most: The last two sets, the final interval, the second half of a long ride.

What the research shows. A 2025 study at Liverpool John Moores University took muscle biopsies from ten trained men after seven days on 600mg CurraNZ or placebo. Before exercise, muscle glycogen sat at 493 mmol/kg dry weight on the extract versus 355 on placebo - roughly 39% more stored fuel going into the session (Jones et al., European Journal of Applied Physiology, 2025). The researchers describe the extract as improving carbohydrate storage in skeletal muscle, effectively enlarging the tank rather than simply sparing what's in it.

What to do with it. Load for seven days, with carbohydrate, before your hardest training week rather than starting on the morning of it. The glycogen effect is a consequence of consistent daily intake, not a pre-workout hit.

2. The problem: the recovery product undoing the training

This one catches out a lot of well-informed athletes. High-dose antioxidant vitamins - particularly vitamin C and vitamin E taken together in gram quantities - have repeatedly been shown to interfere with the cellular signalling that training adaptation depends on.

Norwegian work found daily vitamin C and E supplementation blunted markers of mitochondrial biogenesis after endurance training (Paulsen et al., PMC4001759), and a separate trial found it diminished specific skeletal muscle adaptations including TFAM and SOD (Morrison et al., Free Radical Biology and Medicine, 2015). A review of the wider literature concluded there is no convincing evidence that antioxidant supplementation improves training adaptation, and good reason to think it can impair it (Merry & Ristow, Journal of Physiology).

Why anthocyanins are a different proposition. Blackcurrant anthocyanins are polyphenols, not high-dose vitamin antioxidants, and they appear to work through a different route. Plant & Food Research, testing New Zealand blackcurrant extract taken an hour before exercise, concluded the benefits were "unlikely to be attributable to the antioxidant properties of the extract and more likely due to the blackcurrant extract activating adaptive defensive pathways in cells and tissues" (Plant & Food Research, 2019). Their five-week follow-up found that daily use over an extended period maintained rather than dulled the effect, and described the extract as priming the body so that exercise can switch on its own antioxidant, inflammatory and adaptive defences.

What to do with it. If you're in a block where adaptation is the entire point, be sceptical of high-dose antioxidant vitamin stacks and lean on polyphenols instead.

3. The problem: Hard sessions feel harder than they should

Blood flow is a genuine limiter. Getting oxygen and substrate to working muscle - and metabolites away from it - determines how a given wattage or a given load feels.

What the research shows. A collaboration between the universities of Chichester and Worcester tracked femoral artery response across a loading period and found blood flow improvements of around 8%, 25% and 45% at one, four and seven days of intake, through widening of the blood vessels (Journal of Dietary Supplements, 2021). That confirmed an earlier finding of a moderate-to-large 20–35% increase in blood flow during exercise after a week's intake (Cook et al., Nutrients, 2017).

The practical read-across comes from a 2025 exploratory running study, where participants with endurance-dominant muscle fibre types covered 17% more total distance and 15% more high-intensity distance — at the same heart rate and the same blood lactate (Willems et al., Muscles, 2025). More output, no extra physiological cost.

What to do with it. Allow at least four days of loading, ideally seven, before you expect to notice anything. This is not an on-the-day effect.

4. The problem: Soreness that eats the next three days

Hypertrophy blocks mean eccentric loading, and eccentric loading means delayed onset muscle soreness. The cost isn't the discomfort - it's the sessions you downgrade or skip while you wait for it to clear.

What the research shows. A University of Surrey trial gave 27 recreational exercisers 300mg CurraNZ or placebo for seven days before a damaging bout of bicep curls, an hour beforehand, and for four days afterwards (Hunt et al., Nutrients, 2021). The results:

·       Three times faster recovery of muscle function — the blackcurrant group regained strength within 24 hours, placebo took 72

·       47% and 49% less soreness at 24 and 48 hours

·       84% less creatine kinase at 96 hours, indicating markedly less secondary muscle damage

Study lead Dr Julie Hunt noted that the exercise protocol "caused significant muscle damage in the placebo group, but this response was absent in the New Zealand blackcurrant group."

Worth knowing: Most comparable anthocyanin interventions - beetroot, blueberry, tart cherry, pomegranate - have failed to move creatine kinase at all.

What to do with it. Take it before and after the sessions you know will hurt. The Surrey protocol continued for four days post-exercise, and that's the design the results came from.

5. The problem: Technique and focus collapse before the muscles do

Late in a heavy session, the thing that fails first is often attention. Form drifts, bar path wanders, and the last sets become risk rather than stimulus.

What the research shows. A 2026 crossover trial at Jacksonville State University tested 250mg and 600mg CurraNZ against both a placebo and a no-capsule control in 20 resistance-trained adults (Koozehchian et al., Nutrients, 2026). Leg press one-rep max improved by 37.2kg on the low dose versus control - around 13% - with bench press up roughly 4–5% on both doses, and total leg press volume substantially higher. Barbell power increased 26% for peak power and 22% for mean power.

Performance on the hardest section of the Stroop test, which measures mental control under pressure, improved with both doses relative to placebo, while the placebo itself did not beat the no-capsule control on that section.

What to do with it. If your block is strength- or power-dependent rather than aerobic, this is the most directly relevant evidence available — and notably, the smaller dose performed as well as or better than the larger one across most outcomes.

The bottom line

Pre-season doesn't reward heroics. It rewards accumulating quality sessions without accumulating damage - starting each one properly fuelled, finishing it able to go again, and keeping every adaptation you paid for.

Load CurraNZ for seven days before your next hard block starts and keep it running through it. Your February self will be able to tell.

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How to use it: dosing

Fuelling: Two capsules, 7 days loading.

Recovery

·       Under 70kg: 1 capsule (300mg extract, 105mg anthocyanins) daily

·       Over 70kg: 2 capsules daily

Timing

·       Take 1–2 hours before training, with food

·       Allow a minimum of four days, ideally seven, before your target session or race — the blood flow and glycogen effects build over a loading period and are not acute

·       Keep taking it on rest days. Continuous daily intake is how the effect is maintained; there's no need to cycle off

For back-to-back hard days

·       Take a second dose of 2 capsules after the session, alongside your recovery carbohydrate, to support overnight refuelling

·       Research at Liverpool John Moores University found New Zealand blackcurrant extract accelerated the rate of muscle glycogen resynthesis by around 10% following exhaustive exercise under sub-optimal carbohydrate intake — the situation most people are actually in after an evening session

For soreness-heavy blocks

·       Continue for up to four days after a heavily eccentric or unaccustomed session, following the University of Surrey recovery protocol

CurraNZ is certified by Informed Sport and listed Group B by the Australian Institute of Sport.