World Cup fever? How different climates will affect performance

No matter who’s playing, the first game of a World Cup is always special – full of excitement, anticipation and hope for tournament filled with skills, goals and drama. This time, hosts Brazil take on a solid Croatian side in Sao Paulo, in a match suited to Brazilian flair and, most importantly, a glut of goals. Around 20 hours later, Mexico and Cameroon will jog out onto the pitch 1,400 miles north in Natal to begin their warm-up. Despite the momentum created by the opening fixture, this game has the potential to be a flop – not because of the quality of the two teams but because of when and where they’re playing.</p

The sport science regime that helped boxer Kell Brook become a world champion

Now if you’re not a boxing fan you may not be familiar with Brook but he’s the first British boxer in 28 years to win a world title in the US from an unbeaten American fighter, Shawn “Showtime” Porter. Brook’s victory was the culmination of 20 years of hard work and support – and of course a sprinkling of science courtesy of his team from Sheffield Hallam University. I’ve been Brook’s sports scientist for two years.</p

Effect of hand cooling on body temperature, cardiovascular and perceptual responses during recumbent cycling in a hot environment

The purpose of this study was to quantify physiological and perceptual responses to hand immersion in water during recumbent cycling in a hot environment. Seven physically active males (body mass 79.8 ± 6.3 kg; stature 182 ± 5 cm; age 23 ± 3 years) immersed their hands in 8, 14 and 34°C water whilst cycling at an intensity (W) equivalent to 50% (Formula presented.)O2peak for 60 min in an environmental chamber (35°C, 50% relative humidity). 8 and 14°C water attenuated an increase in body temperature, and lowered cardiorespiratory and skin blood flow demands. These effects were considered to be practically beneficial (standardised effect size > 0.20). There was a tendency for 8 and 14°C to extend exercise duration versus 34°C (>7%). Heart rate, intestinal, mean skin and mean body temperature were less in 8°C compared to 14°C; these differences were considered practically beneficial. Augmented heat loss at the palm-water surface might enable cooler blood to return to the body and limit physiological strain. These findings provide a mechanistic basis for continuous hand cooling and indicate that endurance exercise in hot environments could be improved using this method. Future research should investigate its effectiveness during cycling and running performanc

Alleviating Heat Strain During Exercise: Hand Cooling and Thermoregulation

Exercise capacity and performance are impaired in hot and humid environments, principally due to an increased body temperature and cardiovascular strain. Strategies that alleviate heat strain and improve exercise capability are therefore meaningful from a safety and performance perspective. These strategies are often assessed using core body temperature as a primary outcome, usually derived from inside the rectum, but increasingly from the intestinal tract using gastrointestinal telemetry pill systems. The reliability of intestinal temperature, however, was unclear. Therefore, the purpose of study 1 was to investigate the inter-day reliability of intestinal temperature during an exercise-heat challenge. Gastrointestinal temperature demonstrated good reliability but researchers and practitioners should be aware of potential heteroscedasticity as the magnitude of error increases with temperature. This information is useful when examining the effectiveness of strategies to alleviate heat strain and improve performance. Indeed, there are many interventions designed for this purpose, however, few are practical enough to be used during continuous exercise in hot environments. The objective of study 2 was to systematically identify and meta-analyse the effect of practical cooling strategies applied during exercise in hot environments. Cooling during fixed-intensity exercise before a self-paced performance trial improves endurance performance in the heat. These improvements are most likely mediated by an improved rating of perceived exertion and heat strain but not by attenuating an increase in body temperature. A potentially effective site for limiting increases in body temperature during exercise is the hands. Therefore, the purpose of study 3 was to quantify the physiological and perceptual responses to hand immersion in water during recumbent cycling in a hot environment. Hand immersion in cold water attenuated an increase in body temperature compared to a thermoneutral control and elicited beneficial effects on heart rate, skin temperature and skin blood flow. The aim of study 4 was to extend these findings to investigate the effects of prototype cooling gloves worn during exercise in a hot environment. The cooling gloves decreased indices of intestinal and skin temperature as well as heart rate. Beneficial effects were also observed for rating of perceived exertion, thermal comfort and thermal sensation. The findings from these studies have practical implications for assessments of interventions using gastrointestinal temperature, the choice of practical cooling strategy used during exercise in the heat and the application of hand cooling strategies. Future research should aim to improve the ergonomics of the cooling gloves designed in study 4 and investigate their impact on exercise capability in hot environments

Effects of creatine and sodium bicarbonate co-ingestion on multiple indices of mechanical power output during repeated wingate tests in trained men

This study investigated the effects of creatine and sodium bicarbonate co-ingestion on mechanical power during repeated sprints. Nine well-trained men (age = 21.6 ± 0.9 yr, stature = 1.82 ± 0.05 m, body mass = 80.1 ± 12.8 kg) participated in a double-blind, placebo-controlled, counterbalanced, crossover study using six 10-s repeated Wingate tests. Participants ingested either a placebo (0.5 g·kg-1 of maltodextrin), 20 g·d-1 of creatine monohydrate + placebo, 0.3 g·kg-1 of sodium bicarbonate + placebo, or co-ingestion + placebo for 7 d, with a 7 d washout between conditions. Participants were randomised into two groups with a differential counterbalanced order. Creatine conditions were ordered first and last. Indices of mechanical power output (W), total work (J) and fatigue index (W·s-1) were measured during each test and analysed using the magnitude of differences between groups in relation to the smallest worthwhile change in performance. Compared to placebo, both creatine (effect size (ES) = 0.37-0.83) and sodium bicarbonate (ES = 0.22-0.46) reported meaningful improvements on indices of mechanical power output. Co-ingestion provided small meaningful improvements on indices of mechanical power output (W) compared to sodium bicarbonate (ES = 0.28-0.41), but not when compared to creatine (ES = -0.21-0.14). Co-ingestion provided a small meaningful improvement in total work (J) (ES = 0.24) compared to creatine. Fatigue index (W·s-1) was impaired in all conditions compared to placebo. In conclusion, there was no meaningful additive effect of creatine and sodium bicarbonate co-ingestion on mechanical power during repeated sprints

Considerations for the scientific support process and applications to case studies

Case studies are vehicle to bridge the gap between science and practice because they provide opportunities to blend observations and interventions that have taken place in real-world environments with scientific rigour. The purpose of this invited commentary is to present considerations for those providing applied sport science support to athletes with the intention of broadcasting this information to the scientific community. We present a four phased approach (1: Athlete overview; 2: Needs analysis; 3: Intervention planning; 4: Results,evaluation and conclusion) for scientific support to assist practitioners in the development and implementation of scientific support. These considerations are presented in the form of ‘performance questions’ designed to guide and critically evaluate the scientific support process and aid the transfer of this knowledge via case studies

The Effectiveness of Two Methods of Prescribing Load on Maximal Strength Development: A Systematic Review

Background: Optimal prescription of resistance exercise load (kg) is essential for the development of maximal strength. Two methods are commonly used in practice with no clear consensus on the most effective approach for the improvement of maximal strength. Objective: The primary aim of this review was to compare the effectiveness of percentage 1RM (% 1RM) and repetition maximum targets (RM) as load prescription methods for the development of maximal strength. Methods: Electronic database searches of MEDLINE, SPORTDiscus, Scopus, and CINAHL Complete were conducted in accordance with PRISMA guidelines. Studies were eligible for inclusion if a direct measure of maximal strength was used, a non-training control group was a comparator, the training intervention was > 4 weeks in duration and was replicable, and participants were defined as healthy and between the ages of 18–40. Methodological quality of the studies was evaluated using a modified Downs and Black checklist. Percentage change (%) and 95% confidence intervals (CI) for all strength-based training groups were calculated. Statistical significance (p < 0.05) was reported from each study. Results: Twenty-two studies comprising a total of 761 participants (585 males and 176 females) were found to meet the inclusion criteria. 12 studies were returned for % 1RM, with 10 for RM. All studies showed statistically significant improvements in maximal strength in the training groups (31.3 ± 21.9%; 95% CI 33.1–29.5%). The mean quality rating for all studies was 17.7 ± 2.3. Four studies achieved a good methodological rating, with the remainder classified as moderate. Conclusions: Both % 1RM and RM are effective tools for improving maximal strength. % 1RM appears to be a better prescriptive method than RM potentially due to a more sophisticated management of residual fatigue. However, large heterogeneity was present within this data. Lower body and multi-joint exercises appear to be more appropriate for developing maximal strength. Greater consensus is required in defining optimal training prescriptions, physiological adaptations, and training status

Aging and aerobic fitness affect the contribution of noradrenergic sympathetic nerves to the rapid cutaneous vasodilator response to local heating

Sedentary aging results in a diminished rapid cutaneous vasodilator response to local heating. We investigated whether this diminished response was due to altered contributions of noradrenergic sympathetic nerves; assessing 1) the age-related decline and, 2) the effect of aerobic fitness. We measured skin blood flow (SkBF)(laser-Doppler flowmetry) in young (24±1 yr) and older (64±1 yr) endurance-trained and sedentary men (n=7 per group) at baseline and during 35 min of local skin heating to 42 °C at three forearm sites: 1) untreated; 2) bretylium tosylate (BT), preventing neurotransmitter release from noradrenergic sympathetic nerves; and 3) yohimbine and propranolol (YP), antagonising α- and β-adrenergic receptors. SkBF was converted to cutaneous vascular conductance (CVC) (SkBF/mean arterial pressure) and normalized to maximal CVC (%CVCmax) achieved by skin heating to 44 °C. Pharmacological agents were administered using microdialysis. In the young trained, the rapid vasodilator response was reduced at the BT and YP sites (P0.05) but treatment with BT did (P>0.05). Neither BT nor YP treatments affected the rapid vasodilator response in the older sedentary group (P>0.05). These data suggest that the age-related reduction in the rapid vasodilator response is due to an impairment of sympathetic-dependent mechanisms, which can be partly attenuated with habitual aerobic exercise. Rapid vasodilation involves noradrenergic neurotransmitters in young trained men, and non-adrenergic sympathetic cotransmitters (e.g., neuropeptide Y) in young sedentary and older trained men, possibly as a compensatory mechanism. Finally, in older sedentary men, the rapid vasodilation appears not to involve the sympathetic system