Caffeine Supplementation as an Ergogenic Aid for Muscular Strength and Endurance: A Recommendation for Coaches and Athletes

Caffeine (1, 3, 7-trimethylxanthine) which can be ubiquitously found in energy drinks, sodas, coffee, and supplements, is one of the principal legal drugs consumed worldwide. Caffeine based ergogenic aids are utilized prolifically within training and competition for an ergogenic benefit to enhance sporting performance by both recreational and elite athletes. The evidence of caffeine's ability to enhance endurance performance is well established, however, evidence of an ergogenic benefit for muscular endurance and strength-based tasks is limited. Moreover, the limited evidence for caffeine’s ergogenic benefit in muscular endurance and strength is equivocal, and therefore, practical recommendations for the implementation of caffeine supplementation in training and competition for coaches, and practitioners is difficult. Indeed, it is currently not known if, and how caffeine may improve muscular endurance and/or strength based tasks. Variability in the findings could be due to several factors including muscles tested, participant characteristics, exercise protocol, type and dose of caffeine used. This brief review will discuss the current literature relating to the potential efficacy of caffeine to enhance muscular endurance and strength based performance, and provides evidence based recommendations for athletes and coaches to implement

Acute Effects of Caffeine on Strength Performance in Trained and Untrained Individuals

Objective: The primary aim of this study was to compare the acute effects of a caffeine based supplement on the strength performance of trained and untrained individuals with a secondary investigation into the effects of a placebo. Method: Seven resistance trained (>6 months) and seven untrained (<6 months) males (mean ± SD: age: 21 ± 3 y, mass: 75.2 ± 11.3 kg, height: 176 ± 6 cm) consumed either caffeine (CAF) (5 mg.kg.bw-1), placebo (PLA) or nothing (CON) 60 minutes prior to 1 RM squat measurements in a double-blinded, repeated measures design. A two way repeated measures ANOVA was applied to test for the main effects of condition (CAF, PLA, CON) and group (Trained, Untrained), and the interaction effect (condition x group). Results: A significant interaction effect (F(2,11)=4.38, p=0.024) for 1 RM was observed. In the untrained group there was significant difference between CON and PLA (p<0.001). On average 1 RM in the untrained group was 12% lower in the CON trial (92.1 kg) compared to the PLA (102.9 kg; 95% CI=-5.3 to -16.1 kg), and 9% lower compared to CAF (p=0.005; 95% CI=-2.7 to 14.5 kg). There was no significant difference in 1 RM in the untrained group between PLA and CAF (p=0.87, 95% CI -3.2 to 7.5 kg). Additionally, there were no significant differences for the trained group between conditions. There was also a significant main effect for condition for 1 RM (F(2,11)=12.81, p<0.001) . Overall the CON trial was 6% lower (p=0.001, 95% CI=-3.0 to -10.6 kg) than the PLA trial (117.9 kg; 95% CI 97.6 to 124.6 kg), and 5% lower (p=0.12, 95% CI=-1.2 to -9.5 kg) than the CAF trial (116.4 kg; 95% CI 105.0 to 127.8 kg). There was no significant difference between PLA and CAF (p=0.951). Finally, there was a significant main effect for group (F(1,12)=8.79, p=0.12). On average 1 RM was 25% higher in the trained group (131.7 kg; 95% CI=114.5 to 148.9 kg) compared to the untrained group (98.6 kg; 95% CI=81.4 to 115.8 kg). Conclusion: These findings suggest that both a caffeine supplementation and placebo improve 1 RM in untrained individuals but do not improve performance in resistance trained athletes. No significant differences between caffeine and placebo, suggests placebo induced mechanisms also need to be considere

Is It Time We Changed How We Measure Length of Stay for Hip and Knee Arthroplasty?

Patient length of stay (LOS) for lower limb arthroplasty is a frequently quoted outcome measure. However, the use of mean values in days is prone to being skewed by outliers. Between January 2013 and December 2015, patient LOS for primary hip and knee replacement was collected in 1,168 patients. There were two groups: pre- and postinstitution of the Rapid Recovery Program. The hypothesis was that reducing LOS would highlight proportionate differences when using hours as the measuring unit. Statistical analysis confirmed a significant reduction in LOS between the Enhanced Recovery Program and Rapid Recovery Program ( < 0.001). Use of the median LOS reduces the impact of outliers. Use of hours as the unit of measure of LOS enabled analysis of the time of day of discharge. With decreasing LOS and day-case arthroplasty, a measurement in median hours should become the standard to allow for the detection of subtle changes

Reproducibility of measurement techniques used for creatine kinase, interleukin-6 and high-sensitivity C-reactive protein determination over a 48 h period in males and females

To examine the reproducibility of three measurement techniques used to determine creatine kinase, interleukin-6 and high-sensitivity C-reactive protein, 50 participants had blood samples taken on two occasions. Fingertip plasma samples were analysed using the Reflotron for CK determination. Venous blood samples collected into serum separator tubes were used for IL-6 and hs-CRP analyses. IL-6 was measured using an enzyme linked immune assay development kit. The hs-CRP was measured by an in-house ELISA method. Dependent t-tests showed no systematic bias between samples. The interdian CV was 20.0% for CK, 15.3% for IL-6 and 44.2% for hs-CRP. The intraclass correlation coefficient was 0.90 for CK, 0.98 for IL-6 and 0.70 for hs-CRP. The 95% limits of agreement were ?69.7 to 63.5 IU/L for CK, ?1.48 to 1.80?pg/ml for IL-6 and ?1.10 to 0.91??g/L for hs-CRP. The results demonstrate low absolute reproducibility, which may obscure a true experimental effect. ? 2018, ? 2018 Taylor & Francis.Association of Anaesthetists of Great Britain and Ireland, University of Western Sydney, Aspetar Orthopaedic and Sports Medicine Hospital, Central Manchester University Hospitals NHS Foundation Trust, Loughborough University, College of Arts and Sciences, Boston University, University of Hul

Sleep Medication and Athletic Performance—The Evidence for Practitioners and Future Research Directions

Opinion piece

The Importance of Monitoring Sleep within Adolescent Athletes: Athletic, Academic, and Health Considerations

Opinion piece

Physical fitness and physical self-concept of male and female young adults in Qatar

Background Physical inactivity is high within the Qatari population, particularly within females, and school-based environments, contributing to increased morbidity and mortality. School-based physical activity (PA) outcomes may be mediated by physical self-concept. Low physical self-concept may negatively impact PA engagement, compromising childhood and adolescent physical fitness, which may translate into adulthood. Normative physical fitness data for the Qatari population is unavailable. Stratifying normative physical fitness appears prudent, to not only allow comparisons to be made worldwide, but enable informed decisions for public health policy and future interventions in the Qatari population.Scopu

Hypoxia mediated release of endothelial microparticles and increased association of S100A12 with circulating neutrophils

Microparticles are released from the endothelium under normal homeostatic conditions and have been shown elevated in disease states, most notably those characterised by endothelial dysfunction. The endothelium is sensitive to oxidative stress/status and vascular cell adhesion molecule-1 (VCAM-1) expression is upregulated upon activated endothelium, furthermore the presence of VCAM-1 on microparticles is known. S100A12, a calcium binding protein part of the S100 family, is shown to be present on circulating leukocytes and is thought a sensitive marker to local inflammatory process, which may be driven by oxidative stress. Eight healthy males were subjected to breathing hypoxic air (15% O2, approximately equivalent to 3000 metres altitude) for 80 minutes in a temperature controlled laboratory and venous blood samples were processed immediately for VCAM-1 microparticles (VCAM-1 MP) and S100A12 association with leukocytes by flow cytometry. A pre-hypoxic blood sample was used for comparison. Both VCAM-1 MP and S100A12 association with neutrophils were significantly elevated post hypoxic breathing later declining to levels observed in the pre-test samples. A similar trend was observed in both cases and a correlation may exist between these two markers in response to hypoxia. These data offer evidence using novel markers of endothelial and circulating blood responses to hypoxia

The physiological stress response to anaerobic exercise is altered following sodium bicarbonate supplementation

Sodium bicarbonate (NaHCO3) is a nutritional aid that is proposed to enhance performance by reducing the state of exercise induced acidosis, however research is currently equivocal. Despite this, most research still focuses on its effects upon performance, and not whether the reduced acidosis impacts upon any other factors related to exercise. There is some research to suggest that such a reduction in [H+] can attenuate a number of physiological stress pathways such as stress hormones (1, 4), heat shock protein 72 (HSP72) and oxidative stress (3), suggesting a potential role in exercise recovery. However there are some limitations with this previous research as work intensities were not controlled for, hence making comparisons between treatments difficult. Also limited markers of stress were measured despite the physiological stress response being multi-faceted. The aim of this study was to examine whether the ingestion of NaHCO3 would influence the expression of several markers of stress measured simultaneously, following a work controlled anaerobic exercise

The cytokine response to a 30 min downhill run

ISEI Abstract – 7 The cytokine response to a 30 min downhill run L TAYLOR1, CHRISMAS BCR1, CARROLL S2, SMITH A3, PEMBERTON P3, SIEGLER JC4 and MIDGLEY AW5. 1 Applied Sport and Exercise Physiology (ASEP) & Muscle Cellular and Molecular Physiology (MCMP) research groups, Institute of Sport and Physical Activity Research (ISPAR), Department of Sport & Exercise Sciences, University of Bedfordshire, Bedford, UK. 2Department of Sport, Health & Exercise Science, The University of Hull, Hull, UK. 3Department of Clinical Biochemistry, Central Manchester Foundation Trust, Manchester, UK. 4School of Science & Health, University of Western Sydney, Sydney, Australia. 5Department of Sport & Physical Activity, Edge Hill University, Ormskirk, UK. ABSTRACT Eccentric exercise has been ubiquitously shown to result in exericse induced muscle damage (EIMD), accompanied with delayed onset muscle soreness (DOMS). Although eccentric exercise may induce greater neuromuscular adaptation, functional performance may be impaired, and soreness may persist for several days following this type of exercise. This is primarily thought to be due to structural damage to the muscle fibres. In addition to the mechanical theory of EIMD, it has been suggested that an increased inflammatory response may be associated with DOMS. Furthermore, it is possible that the inflammatory response may play a role in mediating recovery, and adaptation following EIMD. However, the effects of EIMD on markers of inflammation have produced inconsistent results. PURPOSE: The main aim of the present study was to investigate the cytokine response to a 30 min downhill run. METHODS: Fifty (36 male, 14 female), apparently healthy participants performed a 30 min downhill run (-12.5%, 70% Vmax). Interleukin 6 (IL-6), high sensitivity C reactive protein (hs-CRP), and tumor necrosis factor alpha (TNF-α) were measured at 1 h, 24 h and 48 h post downhill run. Additionally, isometric maximum voluntary contraction (MVC), and perceived muscle soreness were measured at 24 h and 48 h post downhill run. RESULTS: Detectable levles of TNF-α were only present in three participants, and therefore, these data were excluded from the analysis. There was no significant difference in IL-6 or hs-CRP at any time point (p \u3e 0.10). However, there was a significant decrease in MVC (p ≤ 0.001). On average MVC decreased by 11% and 8% in the dominant and non-dominant leg at 24 h and 48 h respectively. Furthermore, there was a significant increase in muscle soreness (p \u3c 0.001). On average soreness increased by 49 mm and 51 mm 24 h and 48 h post downhill run. CONCLUSION: The significant increase in muscle soreness in the present study is indicative of EIMD. Furthermore, the significant decrement in MVC at 24 h and 48 h post downhill run, demonstrates that neuromuscular function was impaired. The lack of any significant increase in the cytokine response, supports the theory that mechanical damage is the primary mechanism associated with the EIMD and DOMS phenomenon. Nevertheless, when interpreting these results it is important to consider that due to the sampling times employed in the present study, an inflammatory response may have been missed