Six weeks of high-intensity interval training with and without beta-alanine supplementation for improving cardiovascular fitness in women.

The purpose of the present study was to evaluate the effects of cycle ergometry high-intensity interval training (HIIT) with and without beta-alanine supplementation on maximal oxygen consumption rate (VO2 peak), cycle ergometer workload at the ventilatory threshold (VT W), and body composition. Forty-four women (mean +/- SD age = 21.8 +/- 3.7 years; height = 166.5 +/- 6.6 cm; body mass (BM) = 65.9 +/- 10.8 kg; VO2 peak = 31.5 +/- 6.2 ml x kg(-1) x min(-1)) were randomly assigned to 1 of 3 groups: beta-alanine (BA, n = 14) 1.5 g + 15 g dextrose powder; placebo (PL, n = 19) 16.5 g dextrose powder; or control (CON, n = 11). Testing was conducted at baseline (week 0), after 3 weeks (week 4), and after 6 weeks (week 8). VO2 peak (ml x kg(-1) x min(-1)) and VT W were measured with a metabolic cart during graded exercise tests on a corival cycle ergometer, and body composition (percent fat = % fat and fat-free mass = FFM) were determined by air displacement plethysmography. High-intensity interval training was performed on a corival cycle ergometer 3 times per week with 5 2-minute work intervals and 1-minute passive recovery with undulating intensities (90-110% of the workload recorded at VO2 peak) during each training session. VO2 peak increased (p 0.05) for the CON group. VT W increased (p

Acute effects of a thermogenic nutritional supplement on cycling time to exhaustion and muscular strength in college-aged men.

BACKGROUND: The purpose of the present study was to examine the acute effects of a thermogenic nutritional supplement containing caffeine, capsaicin, bioperine, and niacin on muscular strength and endurance performance. METHODS: Twenty recreationally-active men (mean +/- SD age = 21.5 +/- 1.4 years; stature = 178.2 +/- 6.3 cm; mass = 76.5 +/- 9.9 kg; VO2 PEAK = 3.05 +/- 0.59 L/min-1) volunteered to participate in this randomized, double-blinded, placebo-controlled, cross-over study. All testing took place over a three-week period, with each of the 3 laboratory visits separated by 7 days (+/- 2 hours). During the initial visit, a graded exercise test was performed on a Lode Corival cycle ergometer (Lode, Groningen, Netherlands) until exhaustion (increase of 25 W every 2 min) to determine the maximum power output (W) at the VO2 PEAK (Parvo Medics TrueOne(R) 2400 Metabolic Measurement System, Sandy, Utah). In addition, one-repetition maximum (1-RM) strength was assessed using the bench press (BP) and leg press (LP) exercises. During visits 2 and 3, the subjects were asked to consume a capsule containing either the active supplement (200 mg caffeine, 33.34 mg capsaicin, 5 mg bioperine, and 20 mg niacin) or the placebo (175 mg of calcium carbonate, 160 mg of microcrystalline cellulose, 5 mg of stearic acid, and 5 mg of magnesium stearate in an identical capsule) 30 min prior to the testing. Testing included a time-to-exhaustion (TTE) ride on a cycle ergometer at 80% of the previously-determined power output at VO2 PEAK followed by 1-RM LP and BP tests. RESULTS: There were no differences (p > 0.05) between the active and placebo trials for BP, LP, or TTE. However, for the BP and LP scores, the baseline values (visit 1) were less than the values recorded during visits 2 and 3 (p

Effects of creatine monohydrate and polyethylene glycosylated creatine supplementation on muscular strength, endurance, and power output.

The purpose of this study was to examine the effects of a moderate dose of creatine monohydrate (CM) and two smaller doses of polyethylene glycosylated (PEG) creatine on muscular strength, endurance, and power output. Fifty-eight healthy men (mean +/- SD: age, 21 +/- 2 years; height, 176 +/- 6 cm; body mass [BM], 75 +/- 14 kg) volunteered and were randomly assigned to 1 of 4 groups: (a) placebo (PL; 3.6 g of microcrystalline cellulose; n = 15), (b) CM (5 g of creatine; n = 13), (c) small-dose PEG creatine (1.25 g of creatine: PEG1.25; n = 14), or (d) moderate-dose PEG creatine (2.50 g of creatine: PEG2.50; n = 16). Testing was conducted before (pre-) and after (post-) a 30-day supplementation period. Measurements included body mass, countermovement vertical jump (CVJ) height, power output during the Wingate test (peak power [PP] and mean power [MP]), 1 repetition maximum bench press (1RMBP), 1RM leg press (1RMLP) strength, and repetitions to failure at 80% of the 1RM for bench press (REPBP) and leg press (REPLP). BM and MP (W) increased (p

Acute effects of a thermogenic nutritional supplement on energy expenditure and cardiovascular function at rest, during low-intensity exercise, and recovery from exercise.

The purpose of present study was to examine the acute effects of a thermogenic nutritional supplement on energy expenditure (EE) and cardiovascular function at rest, during low-intensity exercise, and recovery from exercise. Twenty-eight healthy sedentary participants (mean +/- SD; age, 22.3 +/- 1.9 years; body mass index, 24.0 +/- 3.7) volunteered for this randomized, double-blinded, placebo-controlled, crossover study. Each experimental trial was divided into 4 phases: (a) 30 minutes of initial resting, followed by the placebo or thermogenic nutritional supplementation, (b) 50 minutes of postsupplementation resting, (c) 60 minutes of treadmill walking (3.2-4.8 km x h), and (d) 50 minutes of postexercise recovery. Gas exchange variables measured by indirect calorimetry and heart rate (HR) were recorded during all 4 phases, blood pressure was only measured at rest, and rating of perceived exertion (RPE) was only recorded during exercise. EE and oxygen consumption rate (Vo2) were greater for the supplement than the placebo at 50 minutes after supplementation. Also, during the postsupplementation period, diastolic blood pressure (DBP) was higher at all time periods, whereas the respiratory exchange ratio (RER) was higher at 20 and 30 minutes for the supplement. During exercise, only Vo2 and minute ventilation (VE) were greater for the supplement than the placebo, with HR being less than the placebo at 20 minutes for the men. Postexercise EE, Vo2, systolic blood pressure (SBP), DBP, and HR (men only) at 10, 20, 30, and 50 minutes were greater for the supplement than the placebo. These findings indicated that the thermogenic nutritional supplement increased resting EE and exercise Vo2 with only minimal effects on blood pressure and HR and no meaningful effects on RER or RPE. These results suggested that the combination of thermogenic ingredients in this nutritional supplement may be useful to help maintain a negative caloric balance but may not influence substrate use or perceived exertion.

The effects of beta-alanine supplementation and high-intensity interval training on neuromuscular fatigue and muscle function.

The purpose of this study was to determine the effects of beta-alanine supplementation and high-intensity interval training (HIIT) on electromyographic fatigue threshold (EMG(FT)) and efficiency of electrical activity (EEA). A total of 46 men completed four, 2-min work bouts on a cycle ergometer. Using bipolar surface electrodes, the EMG amplitude was averaged and plotted over the 2-min. The resulting slopes were used to calculate EMG(FT) and EEA. Following initial testing, all participants were randomly assigned to either placebo (PL; n = 18), beta-alanine (BA; n = 18) or control groups (CON; n = 10). Following randomization, participants engaged in 6 weeks of HIIT training. Significant improvements in EMG(FT) and EEA resulted for both training groups. In conclusion, HIIT appeared to be the primary stimulus effecting EMG(FT) or EEA, suggesting adaptations from HIIT may be more influential than increasing skeletal muscle carnosine levels on delaying fatigue in recreationally active men.

Effects of creatine loading on electromyographic fatigue threshold in cycle ergometry in college-age men.

The purpose of this study was to examine the effects of 5 d of creatine (Cr) loading on the electromyographic fatigue threshold (EMG FT) in college-age men. Sixteen men (age 22.4 +/- 2.6 yr, height 177.4 +/- 6.8 cm, weight 79.5 +/- 10.6 kg; M +/- SD) participated in this double-blind study and were randomly placed into either placebo (Pl; 10 g of flavored fructose powder per packet; n = 8) or Cr (5 g dicreatine citrate plus 10 g of flavored fructose powder per packet; n = 8) loading groups. Each participant ingested 1 packet 4 times/d, totaling 20 g/d for 5 days (loading). Before and after loading, each participant performed a discontinuous cycle-ergometer test to determine his EMG FT, using bipolar surface electrodes placed on the vastus lateralis of the right thigh. Four 60-s work bouts (ranging from 200 to 400 W) were completed. Adequate rest was given between bouts to allow for the participants' heart rate (HR) to drop within 10 beats of their resting HR. The EMG amplitude was averaged over 5-s intervals for each 60-s work bout. Resulting slopes from each successive work bout were used to calculate EMG FT. A 2-way ANOVA, Group (Cr vs. Pl) x Time (pre vs. post), resulted in a nonsignificant (p > .05) interaction for supplement and time. In addition, a significant increase (p = .009) in weight was observed in the Cr group. These data suggest that there was a minimal influence of Cr loading on EMG FT for the participants in this study.