The effects of polyethylene glycosylated creatine supplementation on anaerobic performance measures and body composition

Maximal Number of Repetitions at Percentages of the One Repetition Maximum: A Meta-Regression and Moderator Analysis of Sex, Age, Training Status, and Exercise

The maximal number of repetitions that can be completed at various percentages of the one repetition maximum (1RM) [REPS ~ %1RM relationship] is foundational knowledge in resistance exercise programming. The current REPS ~ %1RM relationship is based on few studies and has not incorporated uncertainty into estimations or accounted for between-individuals variation. Therefore, we conducted a meta-regression to estimate the mean and between-individuals standard deviation of the number of repetitions that can be completed at various percentages of 1RM. We also explored if the REPS ~ %1RM relationship is moderated by sex, age, training status, and/or exercise. A total of 952 repetitions-to-failure tests, completed by 7289 individuals in 452 groups from 269 studies, were identified. Study groups were predominantly male (66%), healthy (97%), < 59 years of age (92%), and resistance trained (60%). The bench press (42%) and leg press (14%) were the most commonly studied exercises. The REPS ~ %1RM relationship for mean repetitions and standard deviation of repetitions were best described using natural cubic splines and a linear model, respectively, with mean and standard deviation for repetitions decreasing with increasing %1RM. More repetitions were evident in the leg press than bench press across the loading spectrum, thus separate REPS ~ %1RM tables were developed for these two exercises. Analysis of moderators suggested little influences of sex, age, or training status on the REPS ~ %1RM relationship, thus the general main model REPS ~ %1RM table can be applied to all individuals and to all exercises other than the bench press and leg press. More data are needed to develop REPS ~ %1RM tables for other exercises.

The effects of phosphocreatine disodium salts plus blueberry extract supplementation on muscular strength, power, and endurance

BACKGROUND

Numerous studies have demonstrated the efficacy of creatine supplementation for improvements in exercise performance. Few studies, however, have examined the effects of phosphocreatine supplementation on exercise performance. Furthermore, while polyphenols have antioxidant and anti-inflammatory properties, little is known regarding the influence of polyphenol supplementation on muscular strength, power, and endurance. Thus, the purpose of the present study was to compare the effects of 28 days of supplementation with phosphocreatine disodium salts plus blueberry extract (PCDSB), creatine monohydrate (CM), and placebo on measures of muscular strength, power, and endurance.

METHODS

Thirty-three men were randomly assigned to consume either PCDSB, CM, or placebo for 28 days. Peak torque (PT), average power (AP), and percent decline for peak torque (PT%) and average power (AP%) were assessed from a fatigue test consisting of 50 maximal, unilateral, isokinetic leg extensions at 180°·s^- 1 before and after the 28 days of supplementation. Individual responses were assessed to examine the proportion of subjects that exceeded a minimal important difference (MID).

RESULTS

The results demonstrated significant (p < 0.05) improvements in PT for the PCDSB and CM groups from pre- (99.90 ± 22.47 N·m and 99.95 ± 22.50 N·m, respectively) to post-supplementation (119.22 ± 29.87 N·m and 111.97 ± 24.50 N·m, respectively), but no significant (p = 0.112) change for the placebo group. The PCDSB and CM groups also exhibited significant improvements in AP from pre- (140.18 ± 32.08 W and 143.42 ± 33.84 W, respectively) to post-supplementation (170.12 ± 42.68 W and 159.78 ± 31.20 W, respectively), but no significant (p = 0.279) change for the placebo group. A significantly (p < 0.05) greater proportion of subjects in the PCDSB group exceeded the MID for PT compared to the placebo group, but there were no significant (p > 0.05) differences in the proportion of subjects exceeding the MID between the CM and placebo groups or between the CM and PCDSB groups.

CONCLUSIONS

These findings indicated that for the group mean responses, 28 days of supplementation with both PCDSB and CM resulted in increases in PT and AP. The PCDSB, however, may have an advantage over CM when compared to the placebo group for the proportion of individuals that respond favorably to supplementation with meaningful increases in muscular strength.

Nutrition and physical activity interventions for the general population with and without cardiometabolic risk: a scoping review

OBJECTIVE

The objective of this scoping review was to examine the research question: In the adults with or without cardiometabolic risk, what is the availability of literature examining interventions to improve or maintain nutrition and physical activity-related outcomes? Sub-topics included: (1) behaviour counseling or coaching from a dietitian/nutritionist or exercise practitioner, (2) mobile applications to improve nutrition and physical activity and (3) nutritional ergogenic aids.

DESIGN

The current study is a scoping review. A literature search of the Medline Complete, CINAHL Complete, Cochrane Database of Systematic Reviews and other databases was conducted to identify articles published in the English language from January 2005 until May 2020. Data were synthesised using bubble charts and heat maps.

SETTING

Out-patient, community and workplace.

PARTICIPANTS

Adults with or without cardiometabolic risk factors living in economically developed countries.

RESULTS

Searches resulted in 19 474 unique articles and 170 articles were included in this scoping review, including one guideline, thirty systematic reviews (SR), 134 randomised controlled trials and five non-randomised trials. Mobile applications (n 37) as well as ergogenic aids (n 87) have been addressed in several recent studies, including SR. While primary research has examined the effect of individual-level nutrition and physical activity counseling or coaching from a dietitian/nutritionist and/or exercise practitioner (n 48), interventions provided by these practitioners have not been recently synthesised in SR.

CONCLUSION

SR of behaviour counseling or coaching provided by a dietitian/nutritionist and/or exercise practitioner are needed and can inform practice for practitioners working with individuals who are healthy or have cardiometabolic risk.

Impact of Six Consecutive Days of Sprint Training in Hypoxia on Performance in Competitive Sprint Runners

Kasai, N, Mizuno, S, Ishimoto, S, Sakamoto, E, Maruta, M, Kurihara, T, Kurosawa, Y, and Goto, K. Impact of six consecutive days of sprint training in hypoxia on performance in competitive sprint runners. J Strength Cond Res 33(1): 36-43, 2019-The purpose of this study was to determine the effects of 6 successive days of repeated sprint (RS) training in moderate hypoxia on anaerobic capacity in 100-200-m sprint runners. Eighteen male sprint runners (age, 20.0 ± 0.3 years; height, 175.9 ± 1.1 cm; and body mass, 65.0 ± 1.2 kg) performed repeated cycling sprints for 6 consecutive days in either normoxic (NOR; fraction of inspired oxygen [FiO2], 20.9%; n = 9) or hypoxic conditions (HYPO; FiO2, 14.5%; n = 9). The RS ability (10 × 6-second sprints), 30-second maximal sprint ability, maximal oxygen uptake ((Equation is included in full-text article.)max), and 60-m running time on the track were measured before and after the training period. Intramuscular phosphocreatine (PCr) content (quadriceps femoris muscle) was measured by P-magnetic resonance spectroscopy (P-MRS) before and after the training period. Both groups showed similar improvements in RS ability after the training period (p < 0.05). Power output during the 30-second maximal sprint test and (Equation is included in full-text article.)max did not change significantly after the training period in either group. Running time for 0-10 m improved significantly after the training period in the HYPO only (before, 1.39 ± 0.01 seconds; after, 1.34 ± 0.02 seconds, p < 0.05). The HYPO also showed a significant increase in intramuscular PCr content after the training period (before, 31.5 ± 1.3 mM; after, 38.2 ± 2.8 mM, p < 0.05). These results suggest that sprint training for 6 consecutive days in hypoxia or normoxia improved RS ability in competitive sprint runners.

Examination of a Multi-ingredient Preworkout Supplement on Total Volume of Resistance Exercise and Subsequent Strength and Power Performance

Bergstrom, HC, Byrd, MT, Wallace, BJ, and Clasey, JL. Examination of a multi-ingredient preworkout supplement on total volume of resistance exercise and subsequent strength and power performance. J Strength Cond Res 32(6): 1479-1490, 2018-This study examined the acute effects of a multi-ingredient preworkout supplement on (a) total-, lower-, and upper-body volume of resistance exercise and (b) the subsequent lower-body strength (isokinetic leg extension and flexion), lower-body power (vertical jump [VJ] height), upper-body power (bench throw velocity [BTv]), and cycle ergometry performance (critical power and anaerobic work capacity). Twelve men completed baseline strength and power measures before 2 experimental visits, supplement (SUP) and placebo (PL). The experimental visits involved a fatiguing cycling protocol 30 minutes after ingestion of the SUP or PL and 15 minutes before the beginning of the resistance exercise protocol, which consisted of 4 upper-body and 4 lower-body resistance exercises performed for 4 sets to failure at 75% 1 repetition maximum. The exercise volume for the total, lower, and upper body was assessed. The VJ height and BTv were measured immediately after the resistance exercise. Postexercise isokinetic leg extension and flexion strength was measured 15 minutes after the completion of a second cycling protocol. There was a 9% increase in the total-body volume of exercise and a 14% increase in lower-body volume of exercise for the SUP compared with the PL, with no effect on exercise volume for the upper body between the SUP and PL. The increased lower-body volume for the SUP did not result in greater lower-body strength and power performance decrements after exhaustive exercise, compared with the PL. These findings suggested the potential for the SUP to increase resistance exercise volume, primarily related to an increased lower-body volume of exercise.

Creatine Supplementation and Upper Limb Strength Performance: A Systematic Review and Meta-Analysis

BACKGROUND

Creatine is the most widely used supplementation to increase performance in strength; however, the most recent meta-analysis focused specifically on supplementation responses in muscles of the lower limbs without regard to upper limbs.

OBJECTIVE

We aimed to systematically review the effect of creatine supplementation on upper limb strength performance.

METHODS

We conducted a systematic review and meta-analyses of all randomized controlled trials comparing creatine supplementation with a placebo, with strength performance measured in exercises shorter than 3 min in duration. The search strategy used the keywords 'creatine', 'supplementation', and 'performance'. Independent variables were age, sex and level of physical activity at baseline, while dependent variables were creatine loading, total dose, duration, time interval between baseline (T0) and the end of the supplementation (T1), and any training during supplementation. We conducted three meta-analyses: at T0 and T1, and on changes between T0 and T1. Each meta-analysis was stratified within upper limb muscle groups.

RESULTS

We included 53 studies (563 individuals in the creatine supplementation group and 575 controls). Results did not differ at T0, while, at T1, the effect size (ES) for bench press and chest press were 0.265 (95 % CI 0.132-0.398; p < 0.001) and 0.677 (95 % CI 0.149-1.206; p = 0.012), respectively. Overall, pectoral ES was 0.289 (95 % CI 0.160-0.419; p = 0.000), and global upper limb ES was 0.317 (95 % CI 0.185-0.449; p < 0.001). Meta-analysis of changes between T0 and T1 gave similar results. The meta-regression showed no link with characteristics of population or supplementation, demonstrating the efficacy of creatine independently of all listed conditions.

CONCLUSION

Creatine supplementation is effective in upper limb strength performance for exercise with a duration of less than 3  min, independent of population characteristics, training protocols, and supplementary doses or duration.

Creatine Use in Sports

Context:

The use of creatine as a dietary supplement has become increasingly popular over the past several decades. Despite the popularity of creatine, questions remain with regard to dosing, effects on sports performance, and safety.

Evidence Acquisition:

PubMed was searched for articles published between 1980 and January 2017 using the terms creatine, creatine supplementation, sports performance, and dietary supplements. An additional Google search was performed to capture National Collegiate Athletic Association–specific creatine usage data and US dietary supplement and creatine sales.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Short-term use of creatine is considered safe and without significant adverse effects, although caution should be advised as the number of long-term studies is limited. Suggested dosing is variable, with many different regimens showing benefits. The safety of creatine supplementation has not been studied in children and adolescents. Currently, the scientific literature best supports creatine supplementation for increased performance in short-duration, maximal-intensity resistance training.

Conclusion:

While creatine appears to be safe and effective for particular settings, whether creatine supplementation leads to improved performance on the field of play remains unknown.

Creatine supplementation does not alter neuromuscular recovery after eccentric exercise

INTRODUCTION

The purpose of this study was to investigate the effects of creatine (CR) supplementation on recovery after eccentric exercise (ECC).

METHODS

Fourteen men were assigned randomly to ingest 0.3 g/kg of CR or placebo (PL) before and during recovery (48 hours) from 6 sets of 8 repetitions of ECC. Maximal voluntary contraction (MVC), voluntary activation (VA), muscle thickness (MT), electromyography (EMG), contractile properties, and soreness were assessed.

RESULTS

MVC, evoked twitch torque, and rate of torque development decreased for both groups immediately after ECC and recovered at 48 hours. MT increased and remained elevated at 48 hours for both groups. Soreness increased similarly for both groups. EMG activation was higher for CR versus PL only at 48 hours. There were no group differences for torque, total work, or fatigue index during ECC.

CONCLUSIONS

CR supplementation before and during recovery from ECC had no effect on strength, voluntary activation, or indicators of muscle damage. Muscle Nerve 54: 487-495, 2016.

Creatine Supplementation and Lower Limb Strength Performance: A Systematic Review and Meta-Analyses

BACKGROUND

Creatine is the most widely used supplementation to increase strength performance. However, the few meta-analyses are more than 10 years old and suffer from inclusion bias such as the absence of randomization and placebo, the diversity of the inclusion criteria (aerobic/endurance, anaerobic/strength), no evaluation on specific muscles or group of muscles, and the considerable amount of conflicting results within the last decade.

OBJECTIVE

The objective of this systematic review was to evaluate meta-analyzed effects of creatine supplementation on lower limb strength performance.

METHODS

We conducted a systematic review and meta-analyses of all randomized controlled trials comparing creatine supplementation with a placebo, with strength performance of the lower limbs measured in exercises lasting less than 3 min. The search strategy used the keywords "creatine supplementation" and "performance". Dependent variables were creatine loading, total dose, duration, the time-intervals between baseline (T0) and the end of the supplementation (T1), as well as any training during supplementation. Independent variables were age, sex, and level of physical activity at baseline. We conducted meta-analyses at T1, and on changes between T0 and T1. Each meta-analysis was stratified within lower limb muscle groups and exercise tests.

RESULTS

We included 60 studies (646 individuals in the creatine supplementation group and 651 controls). At T1, the effect size (ES) among stratification for squat and leg press were, respectively, 0.336 (95 % CI 0.047-0.625, p = 0.023) and 0.297 (95 % CI 0.098-0.496, p = 0.003). Overall quadriceps ES was 0.266 (95 % CI 0.150-0.381, p < 0.001). Global lower limb ES was 0.235 (95 % CI 0.125-0.346, p < 0.001). Meta-analysis on changes between T0 and T1 gave similar results. The meta-regression showed no links with characteristics of population or of supplementation, demonstrating the creatine efficacy effects, independent of all listed conditions.

CONCLUSION

Creatine supplementation is effective in lower limb strength performance for exercise with a duration of less than 3 min, independent of population characteristic, training protocols, and supplementary doses and duration.

Performance Enhancing Diets and the PRISE Protocol to Optimize Athletic Performance

The training regimens of modern-day athletes have evolved from the sole emphasis on a single fitness component (e.g., endurance athlete or resistance/strength athlete) to an integrative, multimode approach encompassing all four of the major fitness components: resistance (R), interval sprints (I), stretching (S), and endurance (E) training. Athletes rarely, if ever, focus their training on only one mode of exercise but instead routinely engage in a multimode training program. In addition, timed-daily protein (P) intake has become a hallmark for all athletes. Recent studies, including from our laboratory, have validated the effectiveness of this multimode paradigm (RISE) and protein-feeding regimen, which we have collectively termed PRISE. Unfortunately, sports nutrition recommendations and guidelines have lagged behind the PRISE integrative nutrition and training model and therefore limit an athletes' ability to succeed. Thus, it is the purpose of this review to provide a clearly defined roadmap linking specific performance enhancing diets (PEDs) with each PRISE component to facilitate optimal nourishment and ultimately optimal athletic performance.

A review of creatine supplementation in age-related diseases: more than a supplement for athletes

Creatine is an endogenous compound synthesized from arginine, glycine and methionine. This dietary supplement can be acquired from food sources such as meat and fish, along with athlete supplement powders. Since the majority of creatine is stored in skeletal muscle, dietary creatine supplementation has traditionally been important for athletes and bodybuilders to increase the power, strength, and mass of the skeletal muscle. However, new uses for creatine have emerged suggesting that it may be important in preventing or delaying the onset of neurodegenerative diseases associated with aging. On average, 30% of muscle mass is lost by age 80, while muscular weakness remains a vital cause for loss of independence in the elderly population. In light of these new roles of creatine, the dietary supplement's usage has been studied to determine its efficacy in treating congestive heart failure, gyrate atrophy, insulin insensitivity, cancer, and high cholesterol. In relation to the brain, creatine has been shown to have antioxidant properties, reduce mental fatigue, protect the brain from neurotoxicity, and improve facets/components of neurological disorders like depression and bipolar disorder. The combination of these benefits has made creatine a leading candidate in the fight against age-related diseases, such as Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, long-term memory impairments associated with the progression of Alzheimer's disease, and stroke. In this review, we explore the normal mechanisms by which creatine is produced and its necessary physiology, while paying special attention to the importance of creatine supplementation in improving diseases and disorders associated with brain aging and outlining the clinical trials involving creatine to treat these diseases.