Research has demonstrated that caffeine ingestion improves physical performance. Caffeinated chewing gum is commercially available for consumption and the use of such products to enhance cycling performance may appeal to competitive cyclists. Stay Alert™ chewing gum (100mg caffeine/piece) offers a quick and effective delivery of caffeine via the buccal mucosa. PURPOSE:The purpose of the current investigation was twofold: 1) to determine if caffeine administered in chewing gum (Stay Alert™) enhances cycling performance, 2) to identify whether timing of administration impacts subsequent performance. METHODS:Eight male cyclists participated in five separate laboratory sessions, with a one week washout period between sessions. During the first visit, subjects underwent a graded exercise test on an Excalibur 1300Wcycle ergometer to determine maximal oxygen consumption (VO2max) and were allotted time to practice the cycle time trial (TT). For each of the next four visits, 3 pieces of chewing gum [caffeine (CAFF) or placebo (PLA)] were administered at 3 time points, 120 min pre exercise (-120), 60 min pre exercise (-60), and 5 min pre exercise (-5). In 3 of the 4 experimental trials, CAFF was administered at one of the three time points and PLA at the other two time points. During the control trial (CON), PLA gum was administered at all three time points. The order in which participants completed the experimental trials was randomized. Following baseline measurements, time allotted for gum administration, and a standard warmup, participants cycled at 75% VO2max (constant Wattage) for 15 min then completed a 7 kj·kg -1 TT.) or PL ingestion 1h prior to the trial (counterbalanced). Exercises were performed to failure (2 minutes recovery between sets/exercises). RPE (0-10 Omni scale) was recorded after every set and Session-RPE (S-RPE) was recorded 20min after each trial. RESULTS:For total repetitions, a 2 (trial) x 4 (sets) repeated measures ANOVA revealed a significant difference for bench press (p=0.02) but no not for lat pulldown, shoulder press, bicep curl, tricep pushdown, or leg press (CA vs. PL). CA resulted in a non-significant (p=0.24) 1.7% increase in total repetitions for all exercises (CA 2111 ± 2, PL 2076 ± 2) and sets combined compared to PL. Post-hoc analyses revealed significantly greater repetitions (p=0.003) for bench press (set 4) and approached significant (p=0.06) for shoulder press (set 1) with CA. However, no significant difference was found for any other set (p>0.05). No significant difference was shown for RPE (p>0.05) or S-RPE (p=0.44) with CA (8.1 ± 0.8) vs. PL (7.9 ± 0.9). Three participants exceeded the effect size for total repetitions (>20 reps) showing a 10-18% improvement with CA. Other participants showed no response (n=4) or a decrement (n=3) in performance with CA. CONCLUSIONS:Results indicate CA may influence resistance training performance but is highly variable among subjects. More research is needed to clarify reasons for deviant individual responses.
METHODS: Seven healthy male university soccer players (mean ± SD: age 23 ± 2.9 years, height 1.7 ± 0.04 m, BM 62.7 kg ± 6.7) took part in two main trials, a water trial (PLA) and a carbohydrate trial (CHO), each separated by at least 7 days. Each participant was individually assessed to establish both their pretraining hydration status and their fluid consumption during the training session. Participants performed the skill tests (Loughborough Soccer Passing Test) before and after 60 min of soccer-specific training. Tc, blood lactate and blood glucose were monitored before, every 15 min during and after exercise. Participants were prescribed either water (PLA) or a 6.6% CHO-electrolyte drink (CHO) and consumed 2ml/Kg BM every 15 min during the training session. RESULTS:There were no differences in Tc values between trials at any of the measurement stages during and after the training session. Blood glucose levels were significantly increased in CHO (5.14 ± 2.57 mmol/L) following the completion of soccer-specific training, when compared to PLA (4.51 ± 0.78 mmol/L). Blood lactate levels were increased from resting levels at all measurement points in both trials. Percentage dehydration and change in BM loss were greater in the CHO trial (p<0.05) (BM loss. PLA: 0.47 ± 0.17 kg, CHO: 0.69 ± 0.20 kg. % Dehydration: PLA: 0.75 ± 0.26%, CHO: 1.10 ± 0.30). There was no difference between soccer skill scores in PLA and CHO.CONCLUSIONS: 60 min of soccer-specific exercise in the heat does not impact Tc responses to a level where subsequent soccer skill performance is adversely affected and can maintain or slightly increase soccer skill performance when hydration levels are kept <~2% BM loss. (No relationships reported)Although acute changes in body mass (BM) and urine color (UC) are used as simple field measures, their accuracy to predict static hydration status (HYD) is not as clear. PURPOSE:To compare changes in HYD biomarkers in free-living (FL) and imposed euhydration (EU) and 24 hr fluid restriction (FR) during warm weather.METHODS: 15 female and 12 male subjects (25 ± 6 yrs) participated in morning (am) and afternoon (pm) laboratory visits while otherwise remaining physically inactive over three days (mean peak daily temperature = 32 ± 4 ºC). After the first day of FL, 24 hr of EU and dehydration via FR were imposed on subsequent days. BM, plasma osmolality (POsm) via fingerstick samples, urine osmolality (UOsm), UC, and urine specific gravity (USG) were recorded. RESULTS:The % of subjects exhibiting dehydration "thresholds" during am and pm FL were 59 and 41% for USG (>1.020); 78 and 41% for UC (>4); and 63 and 59% for UOsm (> 700 mOsmol/kg), respectively. During EU, four subjects had UC > 4 whereas no subjects had UOsm >700 or USG>1.020. FR at 24 h resulted in 2.0 ± 0.8% reduction in BM from EU (p < .001) for all subjects (females=1.9%; males= 2.2%). UOsm and POsm were the only measures sensitive enough to detect progressively higher values at 16 and 24 h of FR (942 ± 110 vs. 1020 ± 99 mOsmol/kg, p < .001 and 291 ± 6 v...
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