Dr. Gymbro
Fitness General Nutrition Recovery Science & Research supplements Trending: supplements sports nutrition creatine pre workout resistance training
A landscape editorial photograph of a trail runner's moment of rest on a misty forest trail at early morning, shot at shallow depth of field. In the foreground, a rustic ceramic bowl in muted slate blue sits on a weathered wooden fence post, filled with plump, dusty-blue fresh blueberries with a few loose berries scattered on the wood grain. A small scatter of fine, deep-purple blueberry powder dusts the post beside the bowl, with a worn wooden spoon resting nearby. Soft dew clings to the berries and catches the light. In the soft-focus midground and background, a lone trail runner in a sage green technical jacket and charcoal shorts descends a winding dirt path through tall evergreens and ferns, captured mid-stride, slightly blurred with gentle motion. Golden sunrise light filters through the trees in warm diagonal beams, creating a hazy atmosphere with light mist hanging between the trunks. The palette is harmonious and calm: deep indigo and dusty blue from the berries, moss greens, warm amber light, and soft cream highlights. Composition follows the rule of thirds, with the blueberry bowl anchored in the lower left third and the runner small in the upper right, leaving negative space in the misty background for headline overlay. Natural film-like grain, muted tones, subtle vignette, and a clean, contemporary magazine aesthetic similar to a health and science feature in a modern online journal. Crisp detail on the berries, creamy bokeh behind. No text, no logos, no futuristic elements.
Fitness

Tjedan jagoda ubrzao trail trkače — evo zašto

Power Brett · · 3 min read

Tjedan jagoda ubrzao trail trkače — evo zašto

Kratki opis – devet iskusnih trkača dovršilo je simuliranu trail utrku od 22,2 km brže nakon što su sedam dana prije utrke uzimali zamrznuto‑sušeni prah visokoborovnih borovnica, dok je kontrolna faza koristila placebo. Brzina otkucaja srca i percipirani napor tijekom trčanja nisu se razlikovali, a trkači su sljedeći dan pokazali bolji rezultat u eksplozi‑skoku, što sugerira brži oporavak.

Rezultati potječu iz randomiziranog kontroliranog istraživanja koje su proveli Giles i suradnici, objavljeno u International Journal of Sport Nutrition and Exercise Metabolism (PubMed; DOI).

Što su istraživači testirali

Trail trčanje, osobito s velikim udarcima nizbrdo, izaziva mikropoškođene mišiće, oksidativni stres i upalu – sve faktore koji doprinose zamoru. Borovnice su poznate po visokom sadržaju antioksidansa, pa su autori postavili pitanje može li kratkotrajna suplementacija ublažiti te negativne učinke i poboljšati izvedbu.

Dizajn studije

  • Sudionici: devet iskusnih trkača (s redovitim treninzima i prethodnim iskustvom u trailu).
  • Intervencije: 7 dana uzimanja zamrznuto‑sušenog praha od visokoborovnih borovnica (BLU) i, u zasebnoj fazi, 7 dana placeba (PLA). Svaki trkač je sudjelovao u obje faze, što je omogućilo unutar‑subjektnu analizu.
  • Utrka: simulirana trail dionica od 22,2 km, uključujući tehnike uspona i spusta.
  • Mjeri: prije utrke, odmah nakon i 24 h kasnije – simptomi i bol u mišićima, srčani ritam i varijabilnost (HRV), indeks reaktivne snage, visina skoka s pada, plućna funkcija (FEV1/FVC), salivarni kortizol, imunoglobulin A i izdisani dušikov oksid.

Tijekom same utrke pratili su brzinu otkucaja srca i ocjene percipiranog napora za noge i pluća.

Glavni rezultat: brže bez dodatnog napora

Vrijeme dovršetka utrke bilo je značajno kraće uz borovnice (p = 0,003). Međutim, ni brzina otkucaja srca ni percipirani napor (RPE) se nisu razlikovali između uvjeta. To znači da su trkači trčali brže, a da nisu osjećali veći napor ili veći srčani teret.

Napomena: sažetak ne navodi veličinu razlike u minutama, pa se ne može izravno zaključiti koliko je vrijeme uštedjeno – p‑vrijednost samo potvrđuje da je razlika bila statistički značajna u ovom malom uzorku.

Znakovi bržeg oporavka

Nekoliko sekundarnih parametara pokazalo je povoljniji ishod uz borovnice:

  • Supinacija pulsa (niža) – BLU (p = 0,031).
  • Osjećaj umora – BLU (p = 0,005).
  • FEV1/FVC (omjer plućne funkcije) – BLU (p = 0,023).
  • Visina skoka s pada – opala je 24 h nakon utrke kod PLA (p = 0,022), dok je ostala nepromijenjena kod BLU.

Skok s pada je osjetljiv pokazatelj eksplozi‑snage i funkcije donjih ekstremiteta, što je posebno važno nakon intenzivnog nizbrdo trčanja. Održavanje ove sposobnosti sljedeći dan sugerira bolji oporavak mišića.

Praktični zaključci

  • Doza: Sažetak ne otkriva točnu količinu u gramima; potrebno je pogledati puni rad za detalje. Korišten je zamrznuto‑sušeni prah visokoborovnih borovnica, a ne svježe voće niti ekstrakt.
  • Vremenski okvir: Suplementacija je trajala 7 dana uzastopno prije utrke. Procjene su napravljene odmah nakon utrke i 24 h kasnije, što ukazuje na kratkoročni učinak, a ne na jedinstvenu „pre‑trening“ dozu.
  • Tko bi mogao imati korist: Iskusni trail trkači koji se pripremaju za natjecanje s mnogo uspona i padina, gdje su mišićna oštećenja i zamor sljedećeg dana relevantni.
  • Tko treba biti oprezan: Osobe s alergijom na voće, probavnim problemima ili kroničnim zdravstvenim stanjima koja zahtijevaju strogu kontrolu ugljikohidrata trebaju se konzultirati s liječnikom ili dijetetičarem. Početnici i ne‑trkači nisu zastupljeni u ovoj studiji.

Važnost veličine uzorka

Samo devet sudionika čini ovaj pokus iznimno mali. Takvi rezultati su skloniji preuveličavanju učinaka i ne mogu se generalizirati na žene, starije trkače, početnike ili duže utrke. Također, simulirana utrka ne odražava sve stressore pravog natjecanja.

Sažetak ne ističe razlike u salivarnoj razini kortizola ili imunoglobulina A, pa tvrdnja da „nije povećan fiziološki ili perceptivni stres“ znači da ti parametri nisu pokazali pogoršanje, a ne da su potpuno eliminirani.

Zaključak

Istraživanje pruža zanimljive, ali preliminarne dokaze da tjedan suplementacije zamrznuto‑sušenim prahom visokoborovnih borovnica može poboljšati izvedbu trail utrke, smanjiti osjećaj umora i očuvati eksplozi‑snagu sljedeći dan, bez dodatnog percipiranog napora. Ako ste zdravi trkač i volite borovnice, eksperimentiranje s ovakvom suplementacijom predstavlja nisku razinu rizika, ali preporučuje se čekati veće i dobro dizajnirane studije prije nego što se odlučite na redovitu primjenu.

Izvor: Giles et al., “Seven Days of Highbush Blueberry Supplementation Improves Trail Running Performance in Experienced Runners Without Elevating Physiological or Perceptual Stress Markers,” Int J Sport Nutr Exerc Metab. PubMed 42521198.

Original study

Read the original research on pubmed.ncbi.nlm.nih.gov →

This article summarizes published research for general information. It is not medical advice.

Share XFacebookLinkedInRedditWhatsApp
PB

Written by

Power Brett

Power Brett writes for Dr. Gymbro: science-backed fitness, nutrition & performance.

Related Articles

A wide landscape editorial photograph of a clean, sunlit kitchen counter in soft morning light, shot from a slightly elevated three-quarter angle with shallow depth of field. In the foreground, a small matte ceramic dish holds a handful of pale cream-colored supplement capsules, with a few spilled casually onto a pale oak surface. Beside them sits an unlabeled amber glass bottle with its cap off. A folded gray linen napkin and a glass of water with delicate condensation add a calm, everyday feel. In the softly blurred midground, a pair of well-worn running shoes in muted sage green rests beside a rolled yoga mat in dusty terracotta. A small notebook lies open with a pencil resting across it, its pages showing faint hand-drawn bar charts that are nearly flat, with one or two slightly taller bars. The charts are suggestive rather than legible. The background is a bright window with sheer white curtains, casting long, gentle shadows across the counter. A potted eucalyptus sprig in a simple white vase adds a touch of organic green. The palette is restrained and modern: warm creams, soft sage, terracotta, muted oatmeal, and pale wood tones, with subtle highlights on the glass and ceramic. The mood is thoughtful, skeptical, and quietly informative, like a contemporary health and science magazine feature. Natural film-like grain, soft contrast, and generous negative space on the right third of the frame leave room for headline text. There are no people, no logos, no text, and no futuristic elements, only a minimalist, trendy, lifestyle-journal aesthetic.
fitness

2 g karnizina dnevno 12 tjedana: Ispitivanje na 299 osoba uglavnom ne pokazuje učinak

BY IRON MARCUS ·

Tablete karnizina reklamiraju se kao dodatak koji povećava izdržljivost mišića. Nedavno je, nasumično, placebom kontrolirano istraživanje na 299 sudionika testiralo tu tvrdnju, a većina rezultata bila je bez značajnih razlika. Dva signala pojavila su se u podgrupama, no potrebno ih je tumačiti s oprezom, bez pretjeranog hvaljenja.
A overhead flat-lay photograph in a modern editorial style, shot on a pale oatmeal-colored linen surface with soft, diffused natural window light coming from the upper left, casting gentle, elongated shadows. Three ceramic bowls in matte, muted tones sit in a loose, balanced triangle composition: one in dusty sage green holding fine pale-green pea protein powder, one in warm cream holding silky ivory whey powder, and one in soft terracotta holding golden-yellow egg protein powder. Each bowl has a small wooden scoop resting against its rim, with a few powder specks scattered naturally across the linen. Around the bowls, subtle ingredient cues add storytelling without clutter: a handful of fresh green peas in their open pod beside the sage bowl, a small glass bottle of milk with a faint condensation sheen near the cream bowl, and two brown speckled eggs, one whole and one cracked open to reveal a bright yolk, near the terracotta bowl. A sprig of dried wheat or pampas grass enters the frame from the top right corner for texture and height. Three glass tumblers of smoothie-like shakes in slightly different hues, soft green, creamy white, and pale apricot, stand along the upper edge of the frame, slightly out of focus, creating depth and a gentle rhythm. A thin brass spoon and a folded sand-colored napkin add a refined touch in the lower left. The palette is warm and earthy: sage, cream, terracotta, butter yellow, and soft beige, with tiny accents of brass. Negative space is left on the right third of the composition for possible title overlay, keeping the layout airy and uncluttered. The overall mood is calm, thoughtful, and approachable, like a contemporary wellness magazine or minimalist food journal, with crisp focus on the bowls, shallow depth of field toward the edges, subtle film-like grain, and a clean, sophisticated, slightly matte finish.
fitness

Whey vs grašak vs jaje: 51 studija rangirala proteine po tome koji najviše potiče rast mišića nakon treninga

BY COACH RYAN ·

Umjesto očekivanog jasnog pobjednika u duelu whey, graška i jajčnog proteina, analiza od 51 studije pokazala je da jedini statistički značajan rezultat postiže standardni whey. Ipak, razlike su male, a kvaliteta dokaza skromna – stoga su i grašak i jaje uvjerljive alternative uz pravilnu dozu od 18‑25 g proteina po treningu.
Wide landscape editorial photograph of a minimalist wooden table in soft morning light. At the center, a small ceramic dish holds a modest pile of pale golden ashwagandha root powder, with a few dried gnarled ashwagandha roots and a sprig of green leaves with tiny orange-red berries lying beside it. A single tiny capsule sits split open next to the dish, with a delicate dusting of powder spilling out, hinting at a very small dose. In the softly blurred background on the right, a pair of clean running shoes and a folded sage-green towel rest on a pale linen surface, suggesting endurance training and fitness without any people in frame. A small brass measuring spoon and a glass of water with subtle condensation add quiet detail on the left. The palette is warm and earthy: oat beige, muted sage green, terracotta, soft cream, and touches of burnt orange from the berries. Lighting is natural, diffused window light from the left, casting long gentle shadows and a subtle glow across the powder grains. Shallow depth of field with crisp focus on the powder and roots, creamy bokeh behind. Composition uses generous negative space on the right third for headline overlay, with a clean, calm, contemporary wellness-magazine aesthetic. Shot as if on a 50mm lens, fine film grain, matte finish, high-end editorial styling, tactile textures of ceramic, wood, and linen, with a restrained, thoughtful mood that hints at caution and careful consideration.
supplements

Samo 30 mg Ashwagandhe podiglo VO2max za 8 tjedana – pročitajte detalje

BY JAKE THE TITAN ·

Dodaci ashwegandhe najčešće se prodaju u stotinama miligrama. U novom istraživanju ispitana je doza od tek 30 mg dnevno. Prema sažetku, ta je doza bila dovoljna da značajno poboljša VO2max u usporedbi s placebom tijekom osam tjedana. To je iznenađujuće jer se u većini drugih studija koriste doze deset puta veće.
A softly lit, minimalist gym interior photographed in a modern editorial style. In the foreground, a muscular lifter in a fitted charcoal tank top is mid-set at a cable station, forearm and shoulder muscles defined, a light dusting of chalk on their hands. The frame is shot at a slight low angle with shallow depth of field, so the background gym equipment melts into creamy blur. On a matte concrete-textured bench beside them sits a clean, unbranded matte-white scoop container of white powder, a stainless steel shaker bottle, and a small analog stopwatch, arranged with careful, magazine-style composure. A few loose grains of white powder catch the light on the bench surface. Warm golden late-afternoon sunlight pours through tall industrial windows on the left, creating long diagonal light streaks, gentle lens flare, and a subtle haze of floating chalk dust that glows in the beams. The palette is restrained and sophisticated: warm sand, soft cream, muted terracotta, deep charcoal, and a single accent of sage green from a potted plant on a shelf. Rows of neatly racked dumbbells in dark metal repeat in the mid-ground, adding rhythm and depth. The composition follows the rule of thirds: the lifter and supplement still life occupy the right two-thirds, while the left third remains calm, with a smooth, softly blurred wall and window light, leaving generous negative space for headline text. Subtle film grain, natural color grading, and a slightly desaturated, high-end lifestyle photography look evoke a contemporary health and science journal. No text, logos, or graphics. Clean, aspirational, grounded, and tactile, with a sense of focused effort and quiet intensity.
nutrition

Beta‑alanin konačno funkcionira u teretani – ako trenirate na ovaj način

BY DR. GYMBRO ·

Beta‑alanin dugo ima nejasnu reputaciju u teretani, ali novi randomizirani kontrolirani pokus može razjasniti razloge. Kada su sportaši uzimali 6,4 g dnevno četiri tjedna, njihov ukupan broj ponavljanja porastao je 17,3 % na drop‑setovima i 18,2 % na bi‑setovima, dok placebo nije pokazao značajne dobitke. Perceptivni napor, motivacija i osjećaj nisu se razlikovali između skupina, pa je dobitak bio fizički, a ne psihološki. Evo doze, perioda učitavanja, kome podaci vrijede i tko bi trebao ostati skeptičan.

This page is available in

English العربيةবাংলাČeštinaDeutschEspañolفارسیFrançaisHausaहिन्दीHrvatskiBahasa IndonesiaItaliano日本語Basa Jawa한국어NederlandsਪੰਜਾਬੀPolskiPortuguêsRomânăРусскийSrpskiTürkçeУкраїнськаTiếng Việt中文