title: Effects of Coffee and Caffeine Anhydrous Intake During Creatine Loading.
abstract: The purpose of this study was to determine the effect of 5 days of creatine (CRE) loading alone or in combination with caffeine anhydrous (CAF) or coffee (COF) on upper-body and lower-body strength and sprint performance. Physically active males (n = 54; mean ± SD; age = 20.1 ± 2.1 years; weight = 78.8 ± 8.8 kg) completed baseline testing, consisting of 1 repetition maximum (1RM) and repetitions to fatigue with 80% 1RM for bench press and leg press, followed by a repeated sprint test of five, 10-second sprints separated by 60-second rest on a cycle ergometer to determine peak power (PP) and total power (TP). At least 72 hours later, subjects were randomly assigned to supplement with CRE (5 g of CRE monohydrate, 4 times per day; n = 14), CRE + CAF (CRE +300 mg·d of CAF; n = 13), CRE + COF (CRE +8.9 g of COF, yielding 303 mg of CAF; n = 13), or placebo (PLA; n = 14) for 5 days. Serum creatinine (CRN) was measured before and after supplementation, and on day 6, participants repeated pretesting procedures. Strength measures were improved in all groups (p ≤ 0.05), with no significant time × treatment interactions. No significant interaction or main effects were observed for PP. For TP, a time × sprint interaction was observed (p ≤ 0.05), with no significant interactions among treatment groups. A time × treatment interaction was observed for serum CRN values (p ≤ 0.05) that showed increases in all groups except PLA. Four subjects reported mild gastrointestinal discomfort with CRE + CAF, with no side effects reported in other groups. These findings suggest that neither CRE alone nor in combination with CAF or COF significantly affected performance compared with PLA.
authors.affiliation: 1Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, North Carolina; 2Human Movement Sciences, Department of Allied Health Sciences, University of North Carolina, Chapel Hill, North Carolina; and 3School of Pharmacy, Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Eric T
authors.initials: ET
authors.lastname: Trexler
authors.forename: Abbie E
authors.initials: AE
authors.lastname: Smith-Ryan
authors.forename: Erica J
authors.initials: EJ
authors.lastname: Roelofs
authors.forename: Katie R
authors.initials: KR
authors.lastname: Hirsch
authors.forename: Adam M
authors.initials: AM
authors.lastname: Persky
authors.forename: Meredith G
authors.initials: MG
authors.lastname: Mock
mesh_terms: D000293:Adolescent; D000328:Adult; D002110:Caffeine / Q000008:administration & dosage*; D003069:Coffee; D003401:Creatine / Q000008:administration & dosage* / Q000097:blood; D019587:Dietary Supplements; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000187:drug effects / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D012420:Running / Q000502:physiology; D055815:Young Adult
chemical_list: D003069:Coffee; D002110:Caffeine; D003401:Creatine