Nutrient Timing: A Garage Door of Opportunity?

Nutrient timing involves manipulation of nutrient consumption at specific times in and around exercise bouts in an effort to improve performance, recovery, and adaptation. Its historical perspective centered on ingestion during exercise and grew to include pre- and post-training periods. As research continued, translational focus remained primarily on the impact and outcomes related to nutrient consumption during one specific time period to the exclusion of all others. Additionally, there seemed to be increasing emphasis on outcomes related to hypertrophy and strength at the expense of other potentially more impactful performance measures. As consumption of nutrients does not occur at only one time point in the day, the effect and impact of energy and macronutrient availability becomes an important consideration in determining timing of additional nutrients in and around training and competition. This further complicates the confining of the definition of “nutrient timing” to one very specific moment in time at the exclusion of all other time points. As such, this review suggests a new perspective built on evidence of the interconnectedness of nutrient impact and provides a pragmatic approach to help frame nutrient timing more inclusively. Using this approach, it is argued that the concept of nutrient timing is constrained by reliance on interpretation of an “anabolic window” and may be better viewed as a “garage door of opportunity” to positively impact performance, recovery, and athlete availability

Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201

The effects of TeaCrine® and caffeine on endurance and cognitive performance during a simulated match in high-level soccer players

Abstract Background Theacrine (1,3,7,9-tetramethyluric-acid) is a pure alkaloid with a similar structure to caffeine and acts comparably as an adenosine receptor antagonist. Early studies have shown non-habituating effects, including increases in energy and focus in response to Teacrine®, the compound containing pure theacrine. The purpose of this study was to determine and compare the effects of Teacrine® and caffeine on cognitive performance and time-to-exhaustion during a simulated soccer game in high-level male and female athletes. Methods Male and female soccer players (N = 24; MAge = 20.96 ± 2.05y, MMaleVO2max = 55.31 ± 3.39 mL/O2/kg, MFemaleVO2max = 50.97 ± 3.90 mL/O2/kg) completed a 90-min simulated treadmill soccer match over four randomized sessions (TeaCrine®, caffeine, TeaCrine® + caffeine, placebo). Cognitive testing at halftime and end-of-game including simple reaction time (SRT), choice RT (CRT), and cognitive-load RT with distraction questions (COGRT/COGRTWrong) was performed, with a run time-to-exhaustion (TTE) at 85% VO2max following end-of-game cognitive testing. Session times and pre-exercise nutrition were controlled. RM-MANOVAs with univariate follow-ups were conducted and significance was set at P < 0.05. Results TTE trended towards significance in TeaCrine® and TeaCrine® + caffeine conditions compared to placebo (P < 0.052). A condition main effect (P < 0.05) occurred with faster CRT in caffeine and TeaCrine® + caffeine compared to placebo. COGRTWrong showed a significant time main effect, with better accuracy at end-of-game compared to halftime (P < 0.05). A time x condition interaction in SRT (P < 0.05) showed placebo improved from halftime to end-of-game. Conclusions The 27–38% improvements in TTE reflect increased performance capacity that may have important implications for overtime scenarios. These findings suggest TeaCrine® favorably impacts endurance and the combination with caffeine provides greater benefits on cognitive function than either supplement independently

Effects of caffeine, methylliberine, and theacrine on vigilance, marksmanship, and hemodynamic responses in tactical personnel: a double-blind, randomized, placebo-controlled trial

Background Tactical athletes require fast reaction times (RT) along with high levels of vigilance and marksmanship performance. Caffeine has been shown to improve these measures but also results in increased blood pressure and jitteriness. Research on other purine alkaloids, such as methylliberine and theacrine, has suggested they do not increase blood pressure or jitteriness to the same extent, but their impact on tactical performance is unknown. Methods A between-subjects, randomized, placebo-controlled design was used to test the effects of placebo (PLA), 300 mg caffeine (CAF), and a combination of 150 mg caffeine, 100 mg methylliberine, and 50 mg theacrine (CMT) on RT and marksmanship along with hemodynamic and arousal measures following a sustained vigilance task in tactical personnel (n = 48). Following consumption of the supplement, participants underwent a 150-min protocol consisting of two rounds. Each round began with leisurely reading followed by a 30-min vigilance task before beginning two trials of movement and marksmanship tasks. Hemodynamics and felt arousal were assessed throughout the protocol. Composite Z-scores were calculated for overall performance measures at each timepoint, and mixed-effects models were used to assess differences in RT, accuracy, and composite Z-scores along with hemodynamics and felt arousal. An α-level of 0.05 was used to determine statistical significance, and Cohen’s d was used to quantify effect sizes. Results A Group-by-Time interaction for vigilance RT (P = 0.038) indicated improvements for both CAF and CMT from round 1 to round 2 (P  0.20). Group main effects for systolic (SBP; P = 0.001) and diastolic blood pressure (DBP; P = 0.028) indicated higher SBP in CAF (P = 0.003, d= 0.84) and CMT (P = 0.007, d= 0.79) compared to PLA but only higher DBP in CAF (P = 0.025, d= 0.74). No Group-by-Time interaction or Group main effect was found for felt arousal (P > 0.16). Conclusions These findings suggest similar benefits on RT during a vigilance task between CAF, containing 300 mg caffeine, and CMT above PLA, though CAF resulted in slightly less favorable hemodynamic changes. This study is the first to provide data showing similar efficacy of combined caffeine, methylliberine, and theacrine compared to double the caffeine dose consumed alone on vigilance RT but without a significant rise in DBP above PLA in tactical personnel

Effects of fucoidan supplementation on inflammatory and immune response after high-intensity exercise

Introduction High-intensity exercise (HIE) can damage the musculotendon complex and impact the immune response, resulting in post-exercise inflammation. Sufficient rest and recovery will improve muscular resilience against future damaging bouts; however, HIE with minimal durations of rest is common in athletic competitions that facilitate persistent inflammation and immune dysregulation. Fucoidans are fucose-rich sulfated polysaccharides with demonstrated anti-inflammatory and pro-immune responses. Fucoidans may improve inflammation and immune responses, which may prove beneficial for individuals who regularly engage in repeated HIE. The research purpose was to investigate the safety and efficacy of fucoidans on inflammatory and immune markers following HIE. Methods Eight male and eight female participants were randomized into a double-blind, placebo-controlled, counterbalanced, crossover design study and supplemented with 1 g/day fucoidan from Undaria pinnatifida (UPF) or placebo (PL) for 2 weeks. Supplementation periods concluded with HIE testing, followed by 1 week of washout. HIE involved one > 30 s Wingate anaerobic test (WAnT) and eight 10 s WAnT intervals. Blood was drawn pre-exercise, immediately post-exercise, 30 min, and 60 min post-exercise to assess immune and inflammatory markers. Blood markers, peak power (PP), and mean power (MP) were analyzed using a 2 (condition) × 4 (time) design. Significance was set at α = .05. Results A time-by-condition interaction was observed for interleukin-6 (p = .01) and interleukin-10 (p = .008). Post hoc analysis revealed greater interleukin-6 and interleukin-10 concentrations at 30 min post HIE with UPF supplementation (p = .002 and p = .005, respectively). No effects of condition were observed for all blood markers or performance outcomes with UPF supplementation (p > .05). Main effects of time were observed for white blood cells, red blood cells, red cell distribution width, mean platelet volume, neutrophils, lymphocytes, monocytes, eosinophils, basophils, natural killer cells, B and T-lymphocytes, CD4 and CD8 cells (p < .05). Discussion No adverse events were reported throughout the study period, indicating a positive safety profile of UPF. While notable changes in biomarkers occurred up to 1 hr post HIE, few differences were observed between supplementation conditions. There did appear to be a modest effect of UPF on inflammatory cytokines potentially warranting further investigation. However, fucoidan supplementation did not influence exercise performance

INTER-LIMB FUNCTIONAL ASYMMETRY AFTER A FATIGUING BOUT OF EXERCISE IN HIGH-LEVEL SOCCER PLAYERS

BACKGROUND: Fatigue, sex, and asymmetries greater than 10% between limbs are factors that influence noncontact injury rates. The purpose of this study was to investigate the effects of a fatiguing bout of exercise on strength and power inter-limb functional asymmetries in elite soccer players. METHODS: 38 high-level soccer players (females n =20) completed the study (Mage= 21.2 ± 1.8y). The study consisted of two visits within a week. At the first visit, participants were familiarized with the jump tests and 5-RM single-leg press was determined. At the second visit, each participant executed performance tests pre and post a 90-minute simulated soccer game on a treadmill. This protocol was developed based on prior GPS data on elite soccer players. Performance tests included single-leg press at 90 % of their 5-RM till failure, countermovement jump (CMJ), unilateral countermovement jump (SLCMJ), drop jump (DJ), and unilateral drop jump (SLDJ) on force plates. Asymmetry index was measured for SLCMJ, SLDJ and single leg press. All metrics were analyzed using a paired t-test of pre vs. post and sex comparison analysis. Statistical significance was set at α=0.05. RESULTS: Significant decreases in jump heights pre vs post were observed in the overall sample for CMJ, DJ, SLMCMJ, and SLDJ (p\u3c0.05), as well as a significant reduction in repetitions for single-leg press (p\u3c0.05). Sex-specific analyses reveled differences between males and females for these reductions. CMJ (M: p=0.02; F: p=0.40), SLCMJ on R leg (M: p=0.05; F: p=0.41), SLCMJ on L leg (M: p=0.02; F: p=0.16), SLDJ on R leg (M: p\u3c0.001; F: p=\u3c0.001). and SLDJ on L leg (M: p\u3c0.001; F: p=0.004). In addition, decreases in strength were seen in both legs in the single leg press test (M: p=0.002, F: p=0.04 on R leg; M: p\u3c0.001, F: p=0.04 on L leg). Asymmetry indexes for SLCMJ, SLDJ, and single leg press were nonsignificant for both males and females (p\u3e0.05). CONCLUSION: A 90-minute exercised-induced fatigue protocol that simulated soccer physical demands decreased performance metrics of power and strength in elite soccer players. Even though fatigue was detrimental on performance for both genders, there were no significant changes in asymmetry index pre vs post. Men presented more significant changes in inter-limb asymmetries than females. More research is needed to develop a standardized method to measure inter-limb asymmetries and their influence on sports performance

THE EFFECTS OF A BRAND-SPECIFIC HEMP-DERIVED CANNABIDIOL PRODUCT IN HEALTHY ADULTS

BACKGROUND: Cannabidiol (CBD) is a non-psychoactive phyto-cannabinoid that has recently gained traction for its potential anti-inflammatory, immunomodulatory, psychological, and pain-relieving effects. This study aimed to investigate the effects of a brand-specific hemp-derived CBD product in healthy adults over 12 weeks, compared to a placebo product. METHODS: 54 healthy adults (27 women and 27 men, age=25±7y; BMI=24.82±3.25 kg/m2) participated in the study. Participants arrived after \u3e8 h of fasting and \u3e48 h without alcohol consumption and vigorous exercise. Following baseline measurements (height, weight, blood pressure, EKG, and blood work to ensure health status), participants were stratified by sex and randomized into a placebo or CBD (50 mg/mL) group. Participants were instructed to consume 2mL daily. Data were collected at baseline and days 30±3, 60±3, and 90±3. Urine samples calculated chronic pain according to the foundational pain index (FPI) developed by Ethos laboratory. Blood was drawn to assess serum TNF-α, IL-10, and IL-6 levels. Psychological states were assessed using psychometric questionnaires: Cohen\u27s Perceived Stress Scale, Pittsburgh Sleep Quality Index, Profile of Mood States, and a 10-item Likert scale for perceived pain. Daily surveys were completed to determine overall well-being. A Two-way ANOVA was used to determine group differences over time while adjusting for baseline values (α=0.05). RESULTS: There were no main effects of group or time or group-by-time interactions for serum TNF-α, IL-6, and IL-10 (p\u3e0.05). Similarly, there were no group-by-time interactions or main effects for perceptual measures and most profile of mood state subscales (p\u3e0.05). No significant differences were found between groups in the incidence and prevalence of “colds or flus” (p\u3e0.05). However, the sub-score for “vigor” decreased (p=0.007) from visit 3 to visit 5 (p=0.014). In addition, the placebo group exhibited greater pain scores than the CBD group (p=0.028). CONCLUSIONS: CBD appears safe and well tolerated in healthy adults over a 12-week period. Moreover, CBD supplementation may help improve pain in healthy adults. Vigor decreased across the intervention for both groups, this may be an effect of time due to the academic semester. The present dosing appears safe but minimally effective, higher doses may be required to elicit more pronounced anti-inflammatory, pain-relieving, and mood-altering effects in healthy populations

EXAMINING COUNTER-MOVEMENT JUMP HEIGHT USING A DIGITAL CONTACT MAT COMPARED TO FORCE PLATES

BACKGROUND: Jump testing is commonly used to assess return to sport for those recovering from ACL injury and repair. In a previous study, this testing method was praised as it stated vertical jump performance as more representative of a metric for knee function in healthy individuals than horizontal hop performance. Previous research has found the Just Jump system to slightly overestimate jump height while still maintaining high correlation rates with the gold standard Force Plate and only slight variations reported in the twos height measurements. The purpose of this research was to assess differences in jump height using a digital contact mat (Just Jump System, Probotics, Huntsville, Alabama, USA) versus force plates (Hawkins Dynamic, ME, US). It was hypothesized that there would not be significant differences between devices given both use flight time to calculate jump height. METHODS: 38 high level soccer players (M: n=18, age (yrs)= 21.5 ± 1.6, %BF= 10.7 ± 3.5; W: n =20, age (yrs)= 20.9 ± 2.1, %BF= 20.4 ± 4.3) participated in this experimental study. Each participant executed power performance on a contact mat (Just Jump System, Probotics, Huntsville, Alabama, USA) and force plates (Hawkins Dynamic, ME, US). Testing measures included bilateral countermovement jumps (CMJ) and bilateral drop jumps (DJ). Participants repeated each jump twice, if the two jumps differed by greater than 10% a third jump was performed, and the best jump was used for analysis. All performance metrics were analyzed using a paired t-test and Pearson correlations between contact mat vs force plate. Statistical significance was set at α=0.05. RESULTS: Significant differences in jump height were observed in CMJ and DJ (P\u3c0.05) between the jump mat and force plate data with the Jump Mat data being higher on average (JM CMJ = 18.3 ± 3.2, FP CMJ = 12.3 ± 2.5; JM DJ = 18.5 ± 2.7, FP DJ = 11.6 ± 3.2). For both the CMJ and DJ, a strong correlation was found. More specifically, there was a strong positive linear relationship between the two testing methods for both CMJ and DJ (r=0.96 and r=0.68 respectively).DISCUSSION: The significant difference between the two testing methods paired with the strong positive relationship indicates strong reliability, albeit poor validity, of the digital contact mat compared to force plates. This means that these testing methods are not fully interchangeable in practice, as the digital contact mat continuously overestimates jump height compared to force plates. Given this, researchers should be cautious when selecting which method to use, particularly when absolute values are critical values in decision making or assessment. As for further investigations, the source of the significant difference between the two methods should be further evaluated as well as previously developed equations aimed at created a more equal comparison between devices

HEART RATE MEASURE AGREEMENT BETWEEN APPLE WATCH SERIES 8 AND POLARGRIT X COMPARED TO POLAR H10 SENSOR

BACKGROUND: Heart rate (HR) measure agreement between wrist-worn devices and the chest-worn Polar H10during non-steady-state exercise is unclear. PURPOSE: To assess agreement between wrist-based photoplethysmography (PPG) devices (Apple Watch Series 8 [AW], Polar Grit X [PX]compared to Polar H10 chest-worn electrocardiographic device (H10) estimated HR.METHODS: Following an initial visit to determine velocity at VO2max (vVO2max),participants (n=10 males, 10 females, ages 18-35) completed 2 testing days. Participants wore the PX, AW, and H10 during all exercise bouts. Day 1 consisted of two, 4-minute bouts on the treadmill at 50% and 75% of vVO2max followed by an 8-min interval effort (30:30) at 100-120% of vVO2max. Day 2 consisted of a high intensity functional training (HIFT) protocol comprised of 3 rounds of 5 exercises (kettlebell swings, box jumps, burpees, sit-ups, cycling sprint) with a 40:20 work:rest ratio. Agreement of average and max HR from wrist-based PPG devices and H10 were analyzed via inter-class correlation coefficient (ICC) with 95% confidence intervals. An alpha level of 0.05 was used to determine statistical significance.RESULTS: There were strong significant correlations for average and max HR between H10and AW during running intervals at 50% (Average: ICC=0.99, CI=0.98-1.00; P\u3c0.0001; Max:ICC= 0.97, CI=0.91-0.99; P\u3c0.0001), 75% (Average: ICC=0.84, CI=0.62-0.94; P\u3c0.0001; Max:ICC=0.97, CI= 0.91-0.99; P\u3c0.0001) and 100% (Average: ICC=0.95, CI=0.84-0.98; P\u3c0.0001;Max: ICC=0.97, CI=0.91-0.99; P\u3c0.0001) of vVO2max. In contrast, PX was moderately correlated with at H10 at 50% (Average: ICC=0.70, CI=0.18-0.89; P=0.0001; Max: ICC=0.79,CI=0.50-0.92; P\u3c0.0001) and 75% (Average: ICC=0.50, CI= 0.01,-0.80; P=0.005; Max:ICC=0.43, CI=-0.14-0.75; P=0.26), but not 100% (Average: ICC=0.17, CI=-0.19,-0.56; P=0.19;Max: ICC=0.24, CI= -0.18-0.63; P=0.14) of vVO2max. There was strong agreement betweenAW and H10 (ICC=0.92, CI =0.59-0.98; P\u3c0.0001), but not PX (ICC=0.19, CI =-0.11-0.55;P=0.05), during HIFT. CONCLUSION: While AW shows strong agreement across multiple exercise intensities and modalities, the PX PPG technology does not demonstrate as strong of agreement. The PX showed decreased agreement as running interval intensity increased, and poor agreement duringHIFT. While the non-invasive nature, affordability, and convenience of PPG shows promise for continued growth as a daily activity assessment tool without the need for a chest strap, consumers and researchers should take this information into account when selecting a PPG device. The novel inclusion of HIFT sets this study apart and indicates the need for agreement testing across multiple exercise modalities in the field

HEART RATE MEASUREMENT VIA WRIST-BASED PPG WHEN COMPARED TO POLAR 10 CHEST-BASED ECG DURING A TREADMILL VO2MAX TEST

BACKGROUND: Accurate heart rate (HR) measurements during physical activity are critical to infer clinical indications (i.e, tachycardia, cardiovascular health, etc), and are used to measure physical exertion within healthy, athletic populations. Traditional ECGs, the gold standard for HR monitoring, are difficult to use outside of a laboratory setting, while wrist-based watches using (photoplethysmography) PPG sensing are commercially available and increasing in popularity. The purpose of this study is to examine the agreement of heart rate measurement via PPG sensors compared to ECG during a VO2max test. METHODS: Participants (N=20, 10 female/10 male, aged 18-35) completed a treadmill graded exercise test using the Bruce Protocol (VO2max =46.36 ± 5.74 ml/kg/min). Participants wore an Apple Watch Series 8, Polar Grit X watch, and a Polar H10 Chest Strap for the entire duration of this visit. The brand of watch on each wrist was counterbalanced for every participant. The average heart rate from each device during the graded exercise test was calculated and agreement between both wrist-based PPG devices and the chest-based ECG were analyzed via intraclass correlation (ICC) with a 95% confidence intervals (CI). An alpha level of 0.05 was used to determine statistical significance. RESULTS: The Apple Watch Series 8 and the Polar H10 chest strap demonstrated strong agreement with an ICC of 0.95 (95% CI=0.88-0.98). This correlation was statistically significant (P=\u3c0.0001). The Polar Grit X showed poor agreement compared to the Polar H10 with an ICC of 0.27 (95% CI =-0.20-0.56; P=0.13). CONCLUSION: During a graded exercise test, the Apple Watch Series 8 is a comparable heart rate monitor to the Polar H10 chest strap, indicated by the significantly strong ICC. However, the Polar Grit X watch did not demonstrate the same agreement, despite using the same PPG technology. This suggests not all wrist-worn PPG devices are created equal and consumers should take then into account when selecting a fitness or activity monitor. Future studies are necessary to determine the reliability of PPG sensing from other commercially available devices, as well as the reliability of PPG during maximal effort exercise