Caffeine has a small effect on 5-km running performance of well-trained and recreational runners

The purpose of this study was to investigate if caffeine ingestion improves 5-km time-trial performance in well-trained and recreational runners. Using a double-blind placebo-controlled design, 15 well-trained and 15 recreational runners completed two randomized 5-km time-trials, after ingestion of either 5mgkg(-1) of caffeine or a placebo. Caffeine ingestion significantly improved 5-km running performance in both the well-trained and recreational runners. In comparison to the placebo trial, the caffeine trial resulted in 1.1% (90% CI 0.4-1.6) and 1.0% (0.2-2%) faster times for the well-trained and recreational runners. Reliability testing of the recreational runners indicated a test-retest error of measurement of 1.4%. We conclude that caffeine ingestion is likely to produce small but significant gains in 5-km running performance for both well-trained and recreational runners.     

Sodium phosphate loading improves laboratory cycling time-trial performance in trained cyclists

Sodium phosphate loading has been reported to increase maximal oxygen uptake (6–12%), however its influence on endurance performance has been ambiguous. The aim of this study was to examine the influence of sodium phosphate loading on laboratory 16.1 km cycling time-trial performance. Six trained male cyclists ( peak, 64.1 ± 2.8 ml kg⁻¹ min⁻¹; mean ± S.D.) took part in a randomised double-blind crossover study. Upon completion of a control trial (C), participants ingested either 1 g of tribasic dodecahydrate sodium phosphate (SP) or lactose placebo (P) four times daily for 6 days prior to performing a 16.1 km (10 mile) cycling time-trial under laboratory conditions. Power output and heart rate were continually recorded throughout each test, and at two points during each time-trial expired air samples and capillary blood samples were taken. There was a 14-day period between each of the supplemented time-trials. After SP loading mean power was greater than for P and C (C, 322 ± 15 W; P, 317 ± 16 W; SP, 347 ± 19 W; ANOVA, P < 0.05) and time to complete the 16.1 km was shorter than P, but not C (ANOVA, P < 0.05). During the SP trial, relative to the P, mean changes were mean power output +9.8 ± 8.0% (±95% confidence interval); time −3.0 ± 2.9%. There was a tendency towards higher after SP loading (ANOVA, P = 0.07). Heart rate, , RER and blood lactate concentration were not significantly affected by SP loading. Sodium phosphate loading significantly improved mean power output and 16.1 km time-trial performance of trained cyclists under laboratory conditions with functional increases in oxygen uptake.     

The influence of external ankle braces on subjective and objective parameters of performance in a sports-related agility course

With lateral ankle sprains being the most frequent sports-related injury, there is an evident demand for the preventive measures in active individuals with chronic ankle instability. Braces are commonly used for prevention and treatment of ankle injuries. Various investigations—mostly performed with healthy subjects—focused on this problem, yet they often compared only a few models or used only limited testing procedures. However, controversy exists whether braces affect sports performance. The purpose of the present study was to compare the effects of ten different ankle braces—one rigid, five semirigid, four soft models—in a comprehensive evaluation with multiple testing procedures in 34 subjects with self-reported chronic ankle instability. The multiple testing procedures evaluated objective performance-related parameters and subjective parameters related to comfort and stability. The subjects performed an agility course with maximal effort. The course included a vertical jump and a cutting maneuver, both on a force platform, a single leg hopping test on level and inclined plates, a combined straight and curve sprint and sidesteps. Three valid trials were measured and averaged for each brace and every subject. Subjective aspects were evaluated with a questionnaire about handling, perceived restrictions, support and comfort; it was completed after each brace was worn and tried. With regard to the objective parameters, no significant differences were found between the braces except for the rigid brace which showed decreased values for the vertical jump and longer times for the other tests compared to all other braces. The subjective evaluation of the braces revealed significant differences with respect to comfort and handling and therefore, permitted a distinction between semirigid and soft braces. Although significant differences between braces were found in subjective performance restriction, no significant differences were revealed in the objective evaluation. From that point of view, patients could choose a brace model according to their individual needs. A comfortable brace might have a positive influence on the athletes state of mind although other aspects like the braces stabilizing effect play an additional role and should also be taken into account for recommendation of braces.     

Effet d’une hyperventilation volontaire préexercice sur la performance lors de l’épreuve de Wingate

Aim

To determine the effect of a preexercise hyperventilation (HV) on performance measured during the Wingate test.

Protocol

Seven subjects realized the Wingate test whether in normal condition or after the realization of six maximal respiration cycles realized in 30 s. Gas exchanges were recorded breath by breath throughout the test.

Results

Pic power measured during the test was not significantly different after HV. In opposite, the fatigability index (FI) was significantly higher after HV.

Conclusion

A HV does not affect maximal power, but seems to reduce aerobic contribution, which may explain the higher FI observed after HV.     

The shoulder endurance test (SET): A reliability and validity and comparison study on healthy overhead athletes and sedentary adults

ObjectivesThe primary purpose was to examine the reliability of a new shoulder physical performance test -the Shoulder Endurance Test (SET)- in young healthy overhead athletes and sedentary adults and to provide preliminary reference values. The secondary objective was to determine whether there are differences on SET scores based on groups, sides and days. The third objective was to evaluate the relationship between the SET and shoulder rotational isometric strength in both groups.DesignReliability and validity study.SettingLaboratory setting.ParticipantsA total sample of 92 participants volunteered to participate in this study (30 healthy overhead athletes - 62 sedentary adults).Main outcome measuresWe used a two-session measurement design separated by seven days to evaluate the reliability. We calculated intraclass correlation coefficients to determine relative reliability and used standard error of measurement and minimal detectable change to quantify absolute reliability.Systematic differences in SET scores between groups, days and sides were analysed with a two-way analysis of variance (ANOVA) for repeated measures. To check for systematic differences within groups between day 1 and day 2, a Wilcoxon Signed Rank Test was performed. Relationship between shoulder rotational isometric strength and the SET was determined using the Spearman Rank test (r_s).ResultsRelative reliability was high to very high in both groups (intraclass correlation coefficient [2,1] range = 0.78–0.93) and absolute reliability was clinically acceptable. The standard error of measurement varied from 10.7 s to 16.45 s. The minimal detectable change ranged from 29.6 s to 45.6 s. Weak correlations were found between the SET and isometric shoulder rotational strength (r_s range = 0.309–0.431).Resultsof the ANOVA for repeated measures showed a significant two-way interaction effect for day x groups (p = 0.020) and a significant main effect for side (p= < 0.001). Results of the Wilcoxon Signed Rank Test showed no systematic differences in group 1 between day 1 and day 2 for both sides (p = 0.79 dominant side; p = 0.66 non-dominant side).ConclusionsThe SET is a reliable clinically applicable shoulder physical performance test in young adult overhead athletes and sedentary adult.     

Four men in a boat: Ultra-endurance exercise alters the gut microbiome

ObjectivesCompositional and functional adaptions occur in the gut microbiome in response to habitual physical activity. The response of the gut microbiome to sustained, intense exercise in previously active individuals, however, is unknown. This study aimed to prospectively explore the gut microbiome response of four well-trained male athletes to prolonged, high intensity trans-oceanic rowing, describing changes in microbial diversity, abundance and metabolic capacity.DesignA prospective, repeated-measures, within-subject report.MethodsSerial stool samples were obtained from four male athletes for metagenomic whole-genome shotgun sequencing to record microbial community structure and relevant functional gene profiles before, during and after a continuous, unsupported 33-day, 5000 km transoceanic rowing race. Calorific intake and macronutrient composition were recorded by validated food frequency questionnaire and anthropometry was determined by body composition analysis and cardiorespiratory testing.ResultsMicrobial diversity increased throughout the ultra-endurance event. Variations in taxonomic composition included increased abundance of butyrate producing species and species associated with improved metabolic health, including improved insulin sensitivity. The functional potential of bacterial species involved in specific amino and fatty acid biosynthesis also increased. Many of the adaptions in microbial community structure and metaproteomics persisted at three months follow up.ConclusionsThese findings demonstrate that prolonged, intense exercise positively influences gut microbial diversity, increases the relative abundance of some bacterial species and up-regulates the metabolic potential of specific pathways expressing microbial gene products. These adaptions may play a compensatory role in controlling the physiological stress associated with sustained exertion as well as negating the deleterious consequences accompanying endurance exercise.     

Establishing a relationship between the effect of caffeine and duration of endurance athletic time trial events: A systematic review and meta-analysis

Objectives

Caffeine has well-documented benefits on endurance athletic performance. Because of caffeine’s ergogenic effects of reducing perceived fatigue, it is hypothesized that as duration of athletic event increases, so will the effect size of caffeine upon performance. This study aims to examine the relationship between duration of endurance athletic event and the effect size of caffeine compared to placebo for athletic performance.

Qualités physiques requises pour la performance en sprint avec changements de directions types sports collectifs

Purpose

To explore qualities necessary to succeed in (swerve-sprinting) sprints with changes of direction.

Method

Two biometric measurements (body mass (MC); lean body mass (MM)) and three tests (20 m sprint two-point start 20 Da, 20 m swerve-sprint: 20Dc on track equipped with a force platform, and half squat) are carried out by nine players of team sports.

Results

The multiple linear regression shows that 44% of 20Dc performance are explained by relative maximum force (developed on the 20 Da) and the MM relative.

Conclusion

Coordination could represent 50% of unexplained 20Dc performance.     

Contribution à l’étude des effets d’un programme de réentraînement à l’effort sur les aptitudes physiques de patients atteints de bronchopneumopathie chronique obstructive

Aims

The purpose of this study was to evaluate the effect of a three-months’ training rehabilitation on the physical capacity of patients suffering from chronic obstructive pulmonary disease (COPD).

Methods

The aerobic and anaereobic capacity was evaluated in 36 patients (Stage 2) before and after a training rehabilitation period: (duration: three months, frequency: two sessions per week, intensity: 65% of aerobic threshold for 25 min, type: regular exercise on a bicycle).

Results

Training rehabilitation caused a statistically significant specific improvement of submaximal aerobic capacity and an increase of quadriceps and flexor of the fingers’ strength.     

Aerobic fitness and field test performance in elite Spanish soccer referees of different ages

The major aim of this study was to examine the physical fitness of elite Spanish soccer referees in relation to their age. A secondary aim was to assess the population criterion validity of the 12 min running test (12 MRT) against aerobic-fitness laboratory tests. Participants were 45 soccer referees (age 35.5 ± 4.4 years, height 178.3 ± 5.0 cm, body mass 75.1 ± 6.6 kg, body fat 11.3 ± 2.15%, VO_2max 54.9 ± 3.9 ml kg⁻¹ min⁻¹) who were enrolled in the Referees Technical Committee of the Royal Spanish Soccer Federation. They were divided into three age groups: young (Y, 27–32 years, n = 15), average (A, 33–38 years, n = 17) and old (O, 39–45 years, n = 13). No age-related effects were observed for VO_2max, 12 MRT or 200 m sprint performance in either the pooled or grouped data. However, age-related performance decrements were observed for 50 m sprint performance and the ventilatory threshold (VT) running speed. Twelve MRT performance was moderately related to VO_2max (r = 0.46, P = 0.002), VT (km h⁻¹) (r = 0.49, P < 0.001), and peak treadmill velocity (PTV) (r = 0.60, P < 0.001). The results showed that older elite-level referees may be able to limit the expected age-related performance decrements in both aerobic and anaerobic performance usually reported for sedentary people. Additionally, these results show that older referees are able to reach physical fitness levels that have been suggested to be appropriate for coping with match demands.     

The effect of lower limb occlusion on recovery following sprint exercise in academy rugby players

Objectives

The effects of vascular occlusion on recovery of physiological and neuromuscular markers over 24 h, and hormonal reactivity to subsequent exercise were investigated.

Development of the Butterfly Agility Test

ObjectivesTo develop a PPT that incorporates multiple components of athletic ability and to assess its reliability.DesignTest-retest experimental design.SettingIndoor basketball court in southern Alabama, USA.ParticipantsA convenient sample of 21 asymptomatic subjects (14 male, 7 female).Main outcome measuresSubjects performed the Butterfly Agility Test (BAT), the modified Star Excursion Balance Test (mSEBT), a standing double-legged broad jump (BJ), the Pro Agility Test (PAT), and a forty-yard sprint (40 YS).ResultsOverall, the BAT was found to have good reliability (ICC = 0.89, 95 % CI = 0.023–0.97), strong correlation with the PAT (r = 0.73–0.77), moderate correlations with the BJ and 40 YS (r = 0.50–0.60), and moderate correlations with the mSEBT (r = 0.37–0.62).ConclusionThe BAT appears to be a promising composite assessment of athletic ability among young asymptomatic adults, but it is not recommended for clinical use at this time.Level of evidence3b.