Chih-Yin Tai

Ingesting a pre-workout supplement containing caffeine, B-vitamins, amino acids, creatine, and beta-alanine before exercise delays fatigue while improving reaction time and muscular endurance

BackgroundThe purpose of this study was to determine the effects of the pre-workout supplement Assault™ (MusclePharm, Denver, CO, USA) on upper and lower body muscular endurance, aerobic and anaerobic capacity, and choice reaction time in recreationally-trained males. Subjective feelings of energy, fatigue, alertness, and focus were measured to examine associations between psychological factors and human performance.MethodsTwelve recreationally-trained males participated in a 3-week investigation (mean +/- SD, age: 28 +/- 5 y, height: 178 +/- 9 cm, weight: 79.2 +/- 15.7 kg, VO2max: 45.7 +/- 7.6 ml/kg/min). Subjects reported to the human performance laboratory on three separate occasions. All participants completed a baseline/familiarization day of testing that included a maximal graded exercise test for the determination of aerobic capacity (VO2max), one-rep maximum (1-RM) for bench and leg press to determine 75% of 1-RM, choice reaction tests, and intermittent critical velocity familiarization. Choice reaction tests included the following: single-step audio and visual, one-tower stationary protocol, two-tower lateral protocol, three-tower multi-directional protocol, and three-tower multi-directional protocol with martial arts sticks. Subjects were randomly assigned to ingest either the supplement (SUP) or the placebo (PL) during Visit 2. Subjects were provided with the cross-over treatment on the last testing visit. Testing occurred 20 min following ingestion of both treatments.ResultsSignificant (p < 0.05) main effects for the SUP were observed for leg press (SUP: 13 ± 6 reps, PL: 11 ± 3 reps), perceived energy (SUP: 3.4 ± 0.9, PL: 3.1 ± 0.8), alertness (SUP: 4.0 ± 0.7, PL: 3.5 ± 0.8), focus (SUP: 4.1 ± 0.6, PL: 3.5 ± 0.8), choice reaction audio single-step (SUP: 0.92 ± 0.10 s, PL: 0.97 ± 0.11 s), choice reaction multi-direction 15 s (SUP: 1.07 ± 0.12 s, PL: 1.13 ± 0.14 s), and multi-direction for 30 s (SUP: 1.10 ± 0.11 s, PL: 1.14 ± 0.13 s).ConclusionsIngesting the SUP before exercise significantly improved agility choice reaction performance and lower body muscular endurance, while increasing perceived energy and reducing subjective fatigue. These findings suggest that the SUP may delay fatigue during strenuous exercise.

Ingesting a preworkout supplement containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days is both safe and efficacious in recreationally active men

The purpose of this study was to determine the safety and efficacy of consuming a preworkout supplement (SUP) containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days. We hypothesized that little to no changes in kidney and liver clinical blood markers or resting heart rate and blood pressure (BP) would be observed. In addition, we hypothesized that body composition and performance would improve in recreationally active males after 28 days of supplementation. In a double-blind, placebo-controlled study, participants were randomly assigned to ingest one scoop of either the SUP or placebo every day for 28 days, either 20 minutes before exercise or ad libitum on nonexercise days. Resting heart rate and BP, body composition, and fasting blood samples were collected before and after supplementation. Aerobic capacity as well as muscular strength and endurance were also measured. Significant (P < .05) main effects for time were observed for resting heart rate (presupplementation, 67.59 ± 7.90 beats per minute; postsupplementation, 66.18 ± 7.63 beats per minute), systolic BP (presupplementation, 122.41 ± 11.25 mm Hg; postsupplementation, 118.35 ± 11.58 mm Hg), blood urea nitrogen (presupplementation, 13.12 ± 2.55 mg/dL; postsupplementation, 15.24 ± 4.47 mg/dL), aspartate aminotransferase (presupplementation, 34.29 ± 16.48 IU/L; postsupplementation, 24.76 ± 4.71 IU/L), and alanine aminotransferase (presupplementation, 32.76 ± 19.72 IU/L; postsupplementation, 24.88 ± 9.68 IU/L). Significant main effects for time were observed for body fat percentage (presupplementation, 15.55% ± 5.79%; postsupplementation, 14.21% ± 5.38%; P = .004) and fat-free mass (presupplementation, 70.80 ± 9.21 kg; postsupplementation, 71.98 ± 9.27 kg; P = .006). A significant decrease in maximal oxygen consumption (presupplementation, 47.28 ± 2.69 mL/kg per minute; postsupplementation, 45.60 ± 2.81 mL/kg per minute) and a significant increase in percentage of oxygen consumption per unit time at which ventilatory threshold occurred (presupplementation, 64.38% ± 6.63%; postsupplementation, 70.63% ± 6.39%) and leg press one-repetition maximum (presupplementation, 218.75 ± 38.43 kg; postsupplementation, 228.75 ± 44.79 kg) were observed in the SUP only. No adverse effects were noted for renal and hepatic clinical blood markers, resting heart rate, or BP. Supplements containing similar ingredients and doses should be safe for ingestion periods lasting up to 28 days in healthy, recreationally trained, college-aged men.

A multi-ingredient, pre-workout supplement is apparently safe in healthy males and females

Background Pre-workout supplements (PWS) have become increasingly popular with recreational and competitive athletes. While many ingredients used in PWS have had their safety assessed, the interactions when combined are less understood. Objective The purpose of this study was to examine the safety of 1 and 2 servings of a PWS. Design Forty-four males and females (24.4±4.6 years; 174.7±9.3 cm; 78.9±18.6 kg) from two laboratories participated in this study. Subjects were randomly assigned to consume either one serving (G1; n=14) or two servings (G2; n=18) of PWS or serve as an unsupplemented control (CRL; n=12). Blood draws for safety panels were conducted by a trained phlebotomist before and after the supplementation period. Results Pooled data from both laboratories revealed significant group×time interactions (p<0.05) for mean corpuscular hemoglobin (MCH; CRL: 30.9±0.8–31.0±0.9 pg; G1: 30.7±1.1–30.2±0.7 pg; G2: 30.9±1.2–30.9±1.1 pg), MCH concentration (CRL: 34.0±0.9–34.4±0.7 g/dL; G1: 34.1±0.9–33.8±0.6 g/dL; G2: 34.0±1.0–33.8±0.8 g/dL), platelets (CRL: 261.9±45.7–255.2±41.2×103/µL; G1: 223.8±47.7–238.7±49.6×103/µL; G2: 239.1±28.3–230.8±34.5×103/µL), serum glucose (CRL: 84.1±5.2–83.3±5.8 mg/dL; G1: 86.5±7.9–89.7±5.6 mg/dL; G2: 87.4±7.2–89.9±6.6 mg/dL), sodium (CRL: 137.0±2.7–136.4±2.4 mmol/L; 139.6±1.4–140.0±2.2 mmol/L; G2: 139.0±2.2–138.7±1.7 mmol/L), albumin (CRL: 4.4±0.15–4.4±0.22 g/dL; G1: 4.5±0.19–4.5±0.13 g/dL; G2: 4.6±0.28–4.3±0.13 g/dL), and albumin:globulin (CRL: 1.8±0.30–1.8±0.28; G1: 1.9±0.30–2.0±0.31; G2: 1.8±0.34–1.8±0.34). Each of these variables remained within the clinical reference ranges. Conclusions The PWS appears to be safe for heart, liver, and kidney function in both one-serving and two-serving doses when consumed daily for 28 days. Despite the changes observed for select variables, no variable reached clinical significance.

Caloric Expenditure of Aerobic, Resistance, or Combined High-intensity Interval Training Using a Hydraulic Resistance System in Healthy Men

Abstract Falcone, PH, Tai, C-Y, Carson, LR, Joy, JM, Mosman, MM, McCann, TR, Crona, KP, Kim, MP, and Moon, JR. Caloric expenditure of aerobic, resistance, or combined high-intensity interval training using a hydraulic resistance system in healthy men. J Strength Cond Res 29(3): 779–785, 2015—Although exercise regimens vary in content and duration, few studies have compared the caloric expenditure of multiple exercise modalities with the same duration. The purpose of this study was to compare the energy expenditure of single sessions of resistance, aerobic, and combined exercise with the same duration. Nine recreationally active men (age: 25 ± 7 years; height: 181.6 ± 7.6 cm; weight: 86.6 ± 7.5 kg) performed the following 4 exercises for 30 minutes: a resistance training session using 75% of their 1-repetition maximum (1RM), an endurance cycling session at 70% maximum heart rate (HRmax), an endurance treadmill session at 70% HRmax, and a high-intensity interval training (HIIT) session on a hydraulic resistance system (HRS) that included repeating intervals of 20 seconds at maximum effort followed by 40 seconds of rest. Total caloric expenditure, substrate use, heart rate (HR), and rating of perceived exertion (RPE) were recorded. Caloric expenditure was significantly (p ⩽ 0.05) greater when exercising with the HRS (12.62 ± 2.36 kcal·min−1), compared with when exercising with weights (8.83 ± 1.55 kcal·min−1), treadmill (9.48 ± 1.30 kcal·min−1), and cycling (9.23 ± 1.25 kcal·min−1). The average HR was significantly (p ⩽ 0.05) greater with the HRS (156 ± 9 b·min−1), compared with that using weights (138 ± 16 b·min−1), treadmill (137 ± 5 b·min−1), and cycle (138 ± 6 b·min−1). Similarly, the average RPE was significantly (p ⩽ 0.05) higher with the HRS (16 ± 2), compared with that using weights (13 ± 2), treadmill (10 ± 2), and cycle (11 ± 1). These data suggest that individuals can burn more calories performing an HIIT session with an HRS than spending the same amount of time performing a steady-state exercise session. This form of exercise intervention may be beneficial to individuals who want to gain the benefits of both resistance and cardiovascular training but have limited time to dedicate to exercise.

Sport-specific reaction time after dehydration varies between sexes

Methods Ten women and eleven men between the ages of eighteen and thirty-five volunteered to participate in the study (27 +/4yr, 78.7 +/14.8 kg, 174.0 +/7.5 cm). Subjects reported to the lab in a fasted and normally hydrated state and completed a two-minute, multi-directional sportspecific reaction time test. Subjects then ran on a treadmill at 80% estimated max HR for 30 minutes, followed by multiple 15 minute sessions in a dry sauna at approximately 150 degrees F. After reaching a 2% (+/0.4%) reduction in dry body weight subjects completed the same procedures as pre-dehydration. Reaction times were separated into quartiles (each quartile being a 30-second interval of the two minutes) and averaged to examine the data within each test. Consent to publish the results was obtained from all participants.

Safety of 28 days consumption of a pre-workout supplement

Background In recent years, the consumption of multi-ingredient supplements in the pre-exercise time period in order to obtain ergogenic benefits has become increasingly popular. Ingesting pre-workout supplement(s) (PWS) is one approach used by athletes and recreational populations to aid performance and maximize training adaptations. Purported benefits include increases in strength, improved focus, and sustained energy during exercise. While research exists on the ergogenic benefits of PWS, less is known regarding the safety and potential side effects of chronic consumption. Therefore, the purpose of this study was to examine the safety of consuming a PWS containing caffeine, nitrates, and amino acids over a 28 day period.

The Effect of Mild Dehydration Induced by Heat and Exercise on Cognitive Function

Background: Past studies have demonstrated cognitive impairment after dehydration, though results are not always consistent. Methodological differences may account for these discrepancies. Therefore, the purpose of the present study was to determine the effects of mild dehydration on various domains of cognitive function. Methods: Twenty-seven men (n=14; 26.9±4.6 years; 176.3±6.6 cm; 79.1±9.0 kg) and women (n=13; 27.3±4.3 years; 171.0±6.5 cm; 66.5±4.5 kg) participated in the study. Subjects were dehydrated to approximately 2% body mass loss via treadmill running and sauna. Measurements were collected prior to and after dehydration. Cognitive function tests included: Finger tapping, symbol digit coding, Stroop, and shifting attention tests. Results: Reaction time during the shifting attention test was significantly lower from pre-testing to post-testing (PRE: 882.67±126.59 ms; POST: 830.00±105.83 ms; p=0.0012). The Stroop reaction time was significantly lower from pre-testing to post-testing (PRE: 712.56±97.52 ms; POST: 671.63±97.21 ms; p=0.02). No significant changes were observed in any other measurements. Conclusion: Dehydration may enhance cognitive functioning in the areas of Stroop reaction time and reaction time during the shifting attention test.

Bioimpedance And Dxa Total Body Water Estimations In The Elderly: A Deuterium Oxide Comparison.

Bioimpedance techniques have the ability to estimate total body water (TBW) and include single frequency bioimpedance (BIA), bioimpedance spectroscopy (BIS), and multiple-frequency bioimpedance (MFBIA). In addition, dual-energy X-ray absorptiometry (DXA) can predict TBW by using fat-free mass and a constant hydration status of 0.737%. However, the validity of the aforementioned methods has not been established in a healthy elderly population. PURPOSE: Compare BIA, BIS, MFBIA, and DXA TBW estimations in elderly men and women to a criterion deuterium oxide (D2O) TBW measurement. METHODS: Thirty-four women and twenty-four men over the age of sixty-five participated in the study (71 +/5yr, 68.8 +/12.0kg, 167.0 +/8.5 cm). Subjects reported to the lab in a fasted state and provided a urine sample before ingesting approximately 11 grams of D2O. Four hours later the subjects provided another urine sample for the calculation of TBW using a standard isotope dilution method. During the four hour equilibration period the subjects had TBW measured using BIA, MFBIA, BIS, and DXA in no particular order. RESULTS: For men, all methods produced similar and high r values (0.890.95) as well as low standard error of the estimate (SEE) values (1.26-1.52 L) with BIA producing the only nonsignificant mean difference (0.29 L, p=0.31). The MFBIA produced the largest mean difference between D2O and over predicted TBW by 3.43 L. DXA and BIS also both significantly over predicted TBW with mean differences of 1.74 and 2.10 L respectively (p<0.001). For women, all methods produced nearly identical and high r values (0.90-0.91) as well as low standard error of the estimate (SEE) values (0.94-1.02 L). All methods significantly (p<0.001) over estimated TBW, but mean differences were low for DXA (0.92 L) and BIA (0.89 L) compared to BIS (2.37 L) and MFBIA (2.47 L). CONCLUSIONS: The added frequencies used in the MFBIA and the complex Cole models of the BIS did not increase the validity of TBW estimation in elderly men and women as the BIA outperform both devices and uses a single frequency of 50 kHz. However, all methods demonstrated high r values and low SEE values and have the potential to accurately estimate TBW in the current population. However, based on the current results the BIA method used in the current study resulted in the most valid estimations of TBW for elderly men and women compared to D2O.

Reliability of an interactive sport-specific choice reaction time device.

Methods Twelve recreationally trained males participated in Part a, which consisted of two visits (mean +/SD, 3.7 +/1.3 days); a familiarization testing day (V1a), followed by a subsequent testing day (V1b), and was conducted over a three week investigation period (28 +/5 yr, 178 +/9 cm, 79.15 +/15.7 kg, 17.5 +/6.6 % body fat). Part a was composed of nine choice reaction time testing protocols, including single step audio (CRA); single step visual (CRV); 15/30s single tower unidirectional [CRS(15s) (30s)]; 15/30s two tower lateral-directional [CRL(15s), (30s)]; 15/30s three tower multi-directional [CRM (15s), (30s)]; and a three tower, 2-minute stick hit test (stick hits). Seventeen recreationally trained males participated in Part b, which consisted of two visits (4.9 +/1.9 days) following a familiarization day (V1b and V2b), and was conducted over a two week investigational period (21.5 +/4.7 y, 181.1 +/6.1 cm, 85.2 +/17 kg, 14.5 +/11 % body fat). Part b comprised the same choice reaction time testing protocols as Part a. Part c consisted of a pooled mean of 62 tests taken from Part a and Part b, which examined data within choice reaction testing days between V1a, V2a, V1b, and V2b, except the 2-minute Stick Hits data. Results Mean (+/SD) time (seconds) values for Part a, Part b, and Part c were 0.87, 0.91 and 0.86 for Day/Trial 1 respectively, and 0.81, 0.89, and 0.85 for Day/Trial 2 which resulted in no significant differences from Day/Trial 1 to Day/Trial 2 for Part a, b, and c (p > 0.05). However, all times between testing days/trials decreased (a: -0.071 sec, b: -0.021 sec, c: -0.010). Differences in days from Part b (-0.02 sec) and Trials for Part c (-0.01 sec) resulted in similar findings, suggesting a familiarization session between testing days may result in similar reliability to that of within-day trials (p = 1.00). Two testing batteries showed a significant decrease in time between Day 1 and Day 2 after familiarization: CRL15 (Mean difference = -0.07, p = 0.036) and CRM30 (Mean difference = -0.05, p = 0.022).