Title Akutni učinak tri različite doze kofeina na izvedbu balističkih pokreta, jakost i mišićnu izdržljivost Title (english) The acute effects of three different doses of caffeine on ballistic performance, strength and muscular endurance Author Filip Sabol Mentor Pavle Mikulić (mentor)Committee member Cvita Gregov (predsjednik povjerenstva)Committee member Zvonimir Šatalić (član povjerenstva)Committee member Daniel Bok (član povjerenstva)Granter University of Zagreb Defense date and country 2020-12-16, Croatia Scientific / art field, SOCIAL SCIENCES Universal decimal classificationUDC ) 796/799 - Sport Abstract Cilj: Primarni cilj ovog randomiziranog, dvostruko slijepog, placebom kontroliranog istraživanja s ukriženim ustrojem bio je ispitati akutne učinke tri doze kofeina (2, 4, i 6 mg/kg) na izvedbu balističkih pokreta, jakost i mišićnu izdržljivost mišića gornjeg i donjeg dijela tijela kod muškaraca iskusnih u treningu s otporom. Sekundarni cilj bio je usporediti akutne učinke navedenih doza kofeina između osoba s niskim (≤100 mg/dan) i umjereno do visokim (>100 mg/dan) habitualnim unosom kofeina.
Metode: Testovima bacanje medicinke iz sjeda i vertikalni objenožni skok procijenjena je izvedba balističkih pokreta, testovima jednog maksimalnog ponavljanja (1 repetition maximum, 1RM) u potisku s ravne klupe i stražnjem čučnju procijenjena je jakost, a testovima maksimalnog broja ponavljanja (s 60% 1RM) do trenutnog mišićnog otkaza u potisku s ravne klupe i stražnjem čučnju procijenjena je mišićna izdržljivost. Uzorak ispitanika varirao je kroz testove između n=20 (dob (AS ± SD): 25 ± 5 god) i n=28 (dob (AS ± SD): 25 ± 6 god). Svi testovi provedeni su u četiri različita dolaska kroz četiri uvjeta: konzumacija placeba, 2, 4 i 6 mg/kg kofeina 60 minuta prije početka testiranja. Habitualni unos kofeina sudionika u istraživanju procijenjen je korištenjem upitnika.
Rezultati: Značajno poboljšanje izvedbe bacanja medicinke iz sjeda u odnosu na placebo uočeno je samo za dozu kofeina od 6 mg/kg, dok je kod vertikalnog objenožnog skoka značajno poboljšanje uočeno za sve 3 doze (2, 4 i 6 mg/kg) kofeina. U usporedbi s placebom, doza od 2 mg/kg kofeina pokazala se učinkovitom za poboljšanje jakosti mišića donjeg dijela tijela, a sve tri doze kofeina poboljšale su mišićnu izdržljivost mišića donjeg dijela tijela. Za mišićnu jakost i mišićnu izdržljivost mišića gornjeg dijela tijela nisu uočeni značajni učinci kofeina u pogledu poboljšanja izvedbe. Usporedba akutnih učinaka kofeina na tjelesnu izvedbu između dvije skupine habitualnih konzumenata kofeina nije ukazala na značajne razlike u izvedbi ni u jednom provedenom testu.
Zaključak: Konzumacija kofeina može akutno poboljšati izvedbu balističkih pokreta mišića gornjeg i donjeg dijela tijela kao i jakost i mišićnu izdržljivost mišića donjeg dijela tijela u osoba iskusnih u treningu s otporom. Akutni učinak kofeina je, čini se, naglašeniji kod izvedbe vježbi koje uključuju mišiće donjeg naspram gornjeg dijela tijela. Opažene su velike
varijacije između ispitanika u odgovorima na kofein. Habitualna konzumacija kofeina, čini se, nema utjecaj na akutne učinke kofeina na tjelesnu izvedbu, iako ovaj nalaz traži potvrdu u budućim istraživanjima.
Abstract (english) Purpose: The primary aim of this randomized, double-blind, placebo-controlled, crossover study was to examine the acute effects of three doses of caffeine (2, 4, 6 mg/kg) on upper- and lower-body ballistic exercise performance, strength, and muscular endurance in a sample of resistance-trained men. The secondary aim was to compare the acute effects of the mentioned caffeine doses among low (≤100 mg/day) vs. moderate to high (>100 mg/day) habitual caffeine users.
Methods: Seated medicine ball throw and vertical jump tests were used to assess the performance of ballistic exercise, tests of one maximum repetition (1 repetition maximum, 1RM) in bench press and back squat tests were used to assess strength, and tests of maximum number of repetitions (with 60% 1RM) until momentary muscular failure in bench press and back squat used to assess muscular endurance. The sample of the participants varied through tests between n= 20 (age (mean ± SD): 25 ± 5 y) and n= 28 (age (mean ± SD): 25 ± 6 y). All tests were performed during four separate sessions under four conditions: placebo, 2, 4, and 6 mg/kg of caffeine ingested 60 minutes prior to testing. Habitual caffeine intake was evaluated using a standardized questionnaire.
Results: Analysis of ballistic exercise performance indicated that, compared to placebo, significant improvement in seated medicine ball throw test was evident only with a 6 mg/kg dose of caffeine. However, all three doses (2, 4, and 6 mg/kg) of caffeine were ergogenic for the vertical jump performance. Compared to placebo, a dose of 2 mg/kg caffeine was shown to be effective in improving lower-body muscular strength, and all three doses of caffeine improved lower-body muscular endurance. For upper-body muscular strength and muscular endurance, no significant effects of caffeine on performance were found (compared to placebo). Comparison between the two groups of habitual caffeine users indicated no differences in performance following acute caffeine ingestion.
Conclusion: Caffeine ingestion may acutely enhance upper- and lower-body ballistic exercise performance as well as lower-body muscular strength and muscular endurance in resistance-trained men. The acute effect of caffeine seems to be generally more pronounced
for the lower-body exercises as compared to the exercises involving the upper body. Large inter-individual variations in responses to caffeine were observed. Habitual caffeine intake does not seem to affect the acute effects of caffeine on exercise performance, although this needs confirmation in future studies.
Keywords
kofein
izvedba balističkih pokreta
jakost
mišićna izdržljivost
habitualni unos kofeina
Keywords (english)
caffeine
ballistic exercise performance
strength
muscular endurance
habitual caffeine intake
Language croatian URN:NBN urn:nbn:hr:117:371928 Promotion 2021 Study programme Title: postgraduate doctoral study of kinesiology Type of resource Text Extent 112 str. File origin Born digital Access conditions Open access Terms of use Created on 2021-01-28 13:26:28
