Addition of sodium alginate and pectin to a carbohydrate-electrolyte solution does not influence substrate oxidation, gastrointestinal comfort, or cycling performance.

Eight well-trained cyclists ingested 68 g·h-1 of a carbohydrate-electrolyte solution with sodium alginate and pectin (CHO-ALG) or a taste and carbohydrate type-matched carbohydrate-electrolyte solution (CHO) during 120 min of cycling at 55% maximal power followed by an ∼20 min time trial. Oxygen uptake, carbon dioxide production, blood glucose concentration, substrate oxidation, gastrointestinal symptoms, and time trial performance (CHO-ALG: 1219 ± 84 s, CHO: 1267 ± 102 s; P = 0.185) were not different between trials. Novelty Inclusion of sodium alginate and pectin in a carbohydrate drink does not influence blood glucose, substrate oxidation, gastrointestinal comfort, or performance in cyclists.

A single mega dose of vitamin D3 improves selected physical variables in vitamin D-deficient young amateur soccer players: a randomized controlled trial.

This randomized controlled trial aimed to test whether vitamin D (VD) supplementation affects measures of physical performance in VD-deficient, mildly trained children. Thirty-six recreationally soccer player boys were randomly assigned to single dose (200 000 IU) of VD3 (n = 19) or placebo (n = 17). Plasma 25-hydroxyvitamin D (25-OHD) was assessed and measures of physical performance (i.e., vertical and standing broad jumps, triple hop, 10-m and 30-m sprints, shuttle run) were performed before and 12 weeks after the loading dose. Mixed ANCOVA models were performed and effect size was estimated by partial eta squared (ηp2). Baseline 25-OHD and physical variables were equivalent in the 2 groups. Twelve weeks after VD loading, plasma 25-OHD increased and physical variables improved only in the VD group. There was a significant interaction effects for group by time for vertical jump (F = 14.9, p = 0.001, ηp2 = 0.394), triple hop jump (F = 24.2, p < 0.001, ηp2 = 0.513), 10-m (F = 4.46, p = 0.046, ηp2 = 0.162) and 30-m (F = 6.56, p = 0.017, ηp2 = 0.222) sprints, and shuttle run (F = 13.4, p = 0.001, ηp2 = 0.369). In conclusion, a single bolus of VD3 resulted in significant improvements in jumping ability, agility, and running speed in mildly trained children that are deficient in VD. The findings suggest that correcting VD deficit might be beneficial for physical performance. Novelty A mega dose of VD3 improves jumping ability, agility, and running speed in VD-deficient, mildly trained children. Effect of VD on measures of physical performance is noticeable 3 months after the loading dose.

The effect of general duty police ensemble on graded exercise and simulated work performance.

This 2-part study examined the impact of general duty police ensemble on selected cardiopulmonary responses during incremental treadmill exercise and on simulated work performance in 25 healthy young male and female participants. Part I comprised randomly ordered treadmill tests in 2 experimental conditions: physical training (PT; undergarments, shorts, t-shirt, and running shoes) and police duty ensemble (PDE; undergarments, body armour, patrol uniform, boots, duty belt with required equipment, radio, and weapons). The PDE added 10.3 kg (SD 0.4) or 14% (SD 2) body mass. Participants walked at 5.6 km·h-1, starting at 0% grade with 2% increases in grade every 2 min. The 4% stage was 6 min in duration to achieve physiological steady state. Subsequently, the 2-min increments continued to exhaustion. Part II evaluated performance time on a recognized job-related work simulation circuit, in 3 experimental conditions: (i) PT, (ii) weighted belt (WB; PT plus a 7.5 kg weighted belt), and (iii) PDE. In Part I, physiological responses (e.g., oxygen uptake, ventilation, heart rate) were elevated (p < 0.05) with PDE during submaximal exercise but peak values were unchanged. Test duration and peak power output were significantly reduced with PDE. In Part II, circuit completion time was increased in PDE but not WB when compared with PT (p < 0.05). Heart rate and perceived exertion were similar in all conditions and perceived dyspnea was higher in PDE. Novelty Police duty ensemble negatively affected exercise performance more than would be expected due to load mass alone. Specificity must be considered when simulating occupational load carriage.

Velocity-based resistance training: impact of velocity loss in the set on neuromuscular performance and hormonal response.

This study aimed to compare the effects of 2 resistance training (RT) programs with different velocity losses (VLs) allowed in each set: 10% (VL10%) versus 30% (VL30%) on neuromuscular performance and hormonal response. Twenty-five young healthy males were randomly assigned into 2 groups: VL10% (n = 12) or VL30% (n = 13). Subjects followed a velocity-based RT program for 8 weeks (2 sessions per week) using only the full-squat (SQ) exercise at 70%-85% 1-repetition maximum (1RM). Repetition velocity was recorded in all training sessions. A 20-m running sprint, countermovement jump (CMJ), 1RM, muscle endurance, and electromyogram (EMG) during SQ exercise and resting hormonal concentrations were assessed before and after the RT program. Both groups showed similar improvements in muscle strength and endurance variables (VL10%: 7.0%-74.8%; VL30%: 4.2%-73.2%). The VL10% resulted in greater percentage increments in CMJ (9.2% vs. 5.4%) and sprint performance (-1.5% vs. 0.4%) than VL30%, despite VL10% performing less than half of the repetitions than VL30% during RT. In addition, only VL10% showed slight increments in EMG variables, whereas no significant changes in resting hormonal concentrations were observed. Therefore, our results suggest that velocity losses in the set as low as 10% are enough to achieve significant improvements in neuromuscular performance, which means greater efficiency during RT. Novelty The VL10% group showed similar or even greater percentage of changes in physical performance compared with VL30%. No significant changes in resting hormonal concentrations were observed for any training group. Curvilinear relationships between percentage VL in the set and changes in strength and CMJ performance were observed.

The effects of a pre-exercise meal on postexercise metabolism following a session of sprint interval training.

Sprint interval training (SIT) has demonstrated reductions in fat mass through potential alterations in postexercise metabolism. This study examined whether exercising in the fasted or fed state affects postexercise metabolism following acute SIT. Ten active males performed a bout of modified SIT (8 × 15-s sprints; 120 s recovery) in both a fasted (FAST) and fed (FED) state. Gas exchange was collected through 3 h postexercise, appetite perceptions were measured using a visual analog scale, and energy intake was recorded using dietary food logs. There was no difference in energy expenditure between conditions at any time point (p > 0.329) or in total session energy expenditure (FED: 514.8 ± 54.9 kcal, FAST: 504.0 ± 74.3 kcal; p = 0.982). Fat oxidation at 3 h after exercise was higher in FED (0.110 ± 0.04 g·min-1) versus FAST (0.069 ± 0.02 g·min-1; p = 0.013) though not different between conditions across time (p > 0.340) or in total postexercise fat oxidation (FED: 0.125 ± 0.04 g·min-1, FAST: 0.105 ± 0.02 g·min-1; p = 0.154). Appetite perceptions were lower in FED (-4815.0 ± 4098.7 mm) versus FAST (-707.5 ± 2010.4 mm, p = 0.022); however, energy intake did not differ between conditions (p = 0.429). These results demonstrate the fasted or fed state does not augment postexercise metabolism following acute SIT in a way that would favour fat loss following training. Novelty Energy expenditure was similar between conditions, while fat oxidation was significantly greater in FED at 3 h after exercise. Appetite perceptions were significantly lower in FED; however, energy intake was not different between conditions. Current findings suggest that performing SIT in the fed or fasted state would not affect fat loss following training.

Caffeine increases peripheral fatigue in low- but not in high-performing cyclists.

The influence of cyclists' performance levels on caffeine-induced increases in neuromuscular fatigue after a 4-km cycling time trial (TT) was investigated. Nineteen cyclists performed a 4-km cycling TT 1 h after ingesting caffeine (5 mg·kg-1) or placebo (cellulose). Changes from baseline to after exercise in voluntary activation (VA) and potentiated 1 Hz force twitch (Qtw,pot) were used as markers of central and peripheral fatigue, respectively. Participants were classified as "high performing" (HP, n = 8) or "low performing" (LP, n = 8) in accordance with their performance in a placebo trial. Compared with placebo, caffeine increased the power, anaerobic mechanical power, and anaerobic work, reducing the time to complete the trial in both groups (p < 0.05). There was a group versus supplement and a group versus supplement versus trial interaction for Qtw,pot, in which the postexercise reduction was greater after caffeine compared with placebo in the LP group (Qtw,pot = -34% ± 17% vs. -21% ± 11%, p = 0.02) but not in the HP group (Qtw,pot = -22% ± 8% vs. -23% ± 10%, p = 0.64). There was no effect of caffeine on VA, but there was a group versus trial interaction with lower postexercise values in the LP group than in the HP group (p = 0.03). Caffeine-induced improvement in 4-km cycling TT performance seems to come at the expense of greater locomotor muscle fatigue in LP but not in HP cyclists. Novelty Caffeine improves exercise performance at the expense of a greater end-exercise peripheral fatigue in low-performing athletes. Caffeine-induced improvement in exercise performance does not affect end-exercise peripheral fatigue in high-performing athletes. High-performing athletes seem to have augmented tolerance to central fatigue during a high-intensity time trial.

The Short Performance Physical Battery Is Associated with One-Year Emergency Department Visits and Hospitalization.

Les outils cliniques employés dans les établissements de soins peuvent fournir des informations pronostiques importantes aux professionnels de la santé. Dans cette étude observationnelle prospective d'un an, nous avons examiné l'association entre les scores au Short Performance Physical Battery (SPPB), d'une part, et les consultations à l'urgence et les hospitalisations au cours de l'étude, d'autre part. Au total, 191 patients ayant été nouvellement référés à une clinique gériatrique externe de Hamilton (Ontario) ont été contactés, et parmi eux, 120 pris part à l'étude. Le SPPB et d'autres évaluations ont été réalisés dans le cadre de consultations de routine. Les dossiers médicaux électroniques ont été examinés pour déterminer le nombre de consultations à l'urgence et d'hospitalisations dans l'année qui a suivi l'évaluation de base. Des analyses de régression logistique ont été utilisées pour identifier des prédicteurs des consultations à l'urgence et des hospitalisations. Le score moyen au SPPB dans la cohorte étudiée (moyenne d'âge = 80,6 ans, écart-type = 6,3 ans ; 53 % de femmes) était de 6,3 (écart-type = 3,2). Au cours de cette période d'un an, le score au SPPB était associé au nombre de consultations à l'urgence [RR = 0,90 (0,78-1,03)] et d'hospitalisations [RR = 0,84 (0,72-0,97)], après ajustement pour l'âge, le sexe et les comorbidités.Tools applied at the point of care can provide valuable prognostic information for practitioners. In this one-year, prospective observational study, we examined the association of the short performance physical battery (SPPB) and one-year emergency department (ED) visits and hospitalizations. Overall, 191 new referrals attending an outpatient geriatric clinic in Hamilton, Ontario, were approached, and 120 were enrolled. SPPB and other assessments were completed during the routine clinical visit. ED visits and hospitalizations within one year of the baseline assessment were abstracted from electronic medical records. Logistic regression analyses were used to determine ED visits and hospitalization predictors. The mean SPPB score in the study cohort (mean age 80.6, SD 6.3 years; 53% female) was 6.3 (SD 3.2). SPPB score was associated with a one-year ED visit (OR = 0.90 [0.78­1.03]) and hospitalization (OR = 0.84 [0.72­0.97]) after adjusting for age, sex, and co-morbidities.

Acetaminophen ingestion improves muscle activation and performance during a 3-min all-out cycling test.

Acute acetaminophen (ACT) ingestion has been shown to enhance cycling time-trial performance. The purpose of this study was to assess whether ACT ingestion enhances muscle activation and critical power (CP) during maximal cycling exercise. Sixteen active male participants completed two 3-min all-out tests against a fixed resistance on an electronically braked cycle ergometer 60 min after ingestion of 1 g of ACT or placebo (maltodextrin, PL). CP was estimated as the mean power output over the final 30 s of the test and W' (the curvature constant of the power-duration relationship) was estimated as the work done above CP. The femoral nerve was stimulated every 30 s to measure membrane excitability (M-wave) and surface electromyography (EMGRMS) was recorded continuously to infer muscle activation. Compared with PL, ACT ingestion increased CP (ACT: 297 ± 32 W vs. PL: 288 ± 31 W, P < 0.001) and total work done (ACT: 66.4 ± 6.5 kJ vs. PL: 65.4 ± 6.4 kJ, P = 0.03) without impacting W' (ACT: 13.1 ± 2.9 kJ vs. PL: 13.6 ± 2.4 kJ, P = 0.19) or the M-wave amplitude (P = 0.66) during the 3-min all-out cycling test. Normalised EMGRMS amplitude declined throughout the 3-min protocol in both PL and ACT conditions; however, the decline in EMGRMS amplitude was attenuated in the ACT condition, such that the EMGRMS amplitude was greater in ACT compared with PL over the last 60 s of the test (P = 0.04). These findings indicate that acute ACT ingestion might increase performance and CP during maximal cycling exercise by enhancing muscle activation.

High doses of sodium nitrate prior to exhaustive exercise increases plasma peroxynitrite levels in well-trained subjects: randomized, double-blinded, crossover study.

The aim of this study was to investigate the effect of different doses of pre-workout sodium nitrate supplementation on nitric oxide, peroxynitrite levels, and performance parameters. Ten well-trained male subjects participated in a randomized, double-blinded, crossover study. They ingested 8, 16, and 24 mmol sodium nitrate or placebo (NaCl) dissolved in water at 2.5 h before an incremental exercise test. Respiratory gases (oxygen consumption, carbon dioxide production, respiratory exchange ratio) were measured throughout the exercise trials and 3 blood samples (pre-ingestion, 2.5 h post-ingestion and postexercise) were taken to analyze nitrate/nitrite (NOx) and peroxynitrite levels. Data were analyzed using repeated-measures ANOVA at significance level of P < 0.05. NOx levels significantly increased following sodium nitrate ingestion compared with placebo (placebo: 40.86 ± 10.7 µmol/L, 8 mmol: 203.69 ± 25.1 µmol/L, 16 mmol: 289.41 ± 30.1 µmol/L, and 24 mmol: 300.95 ± 42.4 µmol/L, respectively) (P = 0.0001). However, this did not induce any significant change in oxygen consumption (P = 0.351), blood lactate concentration (P = 0.245), and time-to-exhaustion (P = 0.147). Peroxynitrite levels were similar compared with placebo when participants ingested 8 and 16 mmol of inorganic nitrate but a significant increase was observed after exercise at maximal intensity when participants were supplemented with 24 mmol (mean = 14.60 ± 1.3 µmol/L, P = 0.001). Pre-workout ingestion of high dose of sodium nitrate (24 mmol) induced peroxynitrate formation, a marker of oxidative stress. Caution must be taken regarding administration of higher doses before benefits or adverse effects are established in this population.

Effects of caffeine on endurance capacity and psychological state in young females and males exercising in the heat.

Acute caffeine ingestion is considered effective in improving endurance capacity and psychological state. However, current knowledge is based on the findings of studies that have been conducted on male subjects mainly in temperate environmental conditions, but some physiological and psychological effects of caffeine differ between the sexes. The purpose of this study was to compare the physical performance and psychological effects of caffeine in young women and men exercising in the heat. Thirteen male and 10 female students completed 2 constant-load walks (60% of thermoneutral peak oxygen consumption on a treadmill until volitional exhaustion) in a hot-dry environment (air temperature, 42 °C; relative humidity, 20%) after caffeine (6 mg·kg-1) and placebo (wheat flour) ingestion in a double-blind, randomly assigned, crossover manner. Caffeine, compared with placebo, induced greater increases (p < 0.05) in heart rate (HR) and blood lactate concentrations in both males and females but had no impact on rectal or skin temperatures or on walking time to exhaustion in subjects of either gender. Caffeine decreased (p < 0.05) ratings of perceived exertion and fatigue in males, but not in females. In females, but not in males, a stronger belief that they had been administered caffeine was associated with a shorter time to exhaustion. In conclusion, acute caffeine ingestion increases HR and blood lactate levels during exercise in the heat, but it has no impact on thermoregulation or endurance capacity in either gender. Under exercise-heat stress, caffeine reduces ratings of perceived exertion and fatigue in males but not in females.

Whole-body active warm-up and inspiratory muscle warm-up do not improve running performance when carrying thoracic loads.

Whole-body active warm-ups (AWU) and inspiratory muscle warm-up (IMW) prior to exercise improves performance on some endurance exercise tasks. This study investigated the effects of AWU with and without IMW upon 2.4-km running time-trial performance while carrying a 25-kg backpack, a common task and backpack load in physically demanding occupations. Participants (n = 9) performed five 2.4-km running time-trials with a 25-kg thoracic load preceded in random order by (i) IMW comprising 2 × 30 inspiratory efforts against a pressure-threshold load of 40% maximal inspiratory pressure (PImax), (ii) 10-min unloaded running (AWU) at lactate turnpoint (10.33 ± 1.58 km·h-1), (iii) placebo IMW (PLA) comprising 5-min breathing using a sham device, (iv) AWU+IMW, and (v) AWU+PLA. Pooled baseline PImax was similar between trials and increased by 7% and 6% following IMW and AWU+IMW (P < 0.05). Relative to baseline, pooled PImax was reduced by 9% after the time-trial, which was not different between trials (P > 0.05). Time-trial performance was not different between any trials. Whole-body AWU and IMW performed alone or combination have no ergogenic effect upon high-intensity, short-duration performance when carrying a 25-kg load in a backpack.

Association of plasma 25-hydroxyvitamin D with physical performance in physically active children.

Vitamin D is thought to regulate skeletal muscle function and boost physical performance. The aim of this study was to assess the relationship between vitamin D and physical performance in physically active children. This cross-sectional study included 125 children who practice football as a leisure activity. Plasma 25-hydroxyvitamin D (25-OHD) was assessed using a chemiluminescence immunoassay method. Vitamin D inadequacy was defined as 25-OHD < 20 ng/mL. Physical performance testing included measurements of muscle strength (maximal isometric contraction), jumping ability (vertical jump, standing broad jump, triple hop test), linear sprint (10 m and 20 m), and agility (9 × 4-m shuttle run). Plasma 25-OHD concentrations were positively correlated with muscle strength (r = 0.539; p < 0.001), vertical jump (r = 0.528; p < 0.001), and standing broad jump (r = 0.492; p < 0.001) but inversely correlated with sprint performance (r = -0.539; p < 0.001). In multivariate analysis models, plasma 25-OHD concentrations were associated with each physical performance parameter independently of age, maturity status, body mass index, fat mass, and protein and calcium intakes. In conclusion, a low plasma 25-OHD level was associated with decreased muscle strength, agility, and jumping and sprinting abilities in physically active children. Vitamin D inadequacy may limit exercise performance. Further research should verify whether correction of vitamin D deficiency enhances physical performance.

Fitness, body composition and blood lipids following 3 concurrent strength and endurance training modes.

This study investigated changes in physical fitness, body composition, and blood lipid profile following 24 weeks of 3 volume-equated concurrent strength and endurance training protocols. Physically active, healthy male and female participants (aged 18-40 years) performed strength and endurance sessions on different days (DD; men, n = 21; women, n = 18) or in the same session with endurance preceding strength (ES; men, n = 16; women, n = 15) or vice versa (SE; men, n = 18; women, n = 14). The training volume was matched in all groups. Maximal leg press strength (1-repetition maximum (1RM)) and endurance performance (maximal oxygen consumption during cycling), body composition (dual-energy X-ray absorptiometry), and blood lipids were measured. 1RM and maximal oxygen consumption increased in all groups in men (12%-17%, p < 0.001; and 7%-18%, p < 0.05-0.001, respectively) and women (13%-21%, p < 0.01-0.001; and 10%-25%, p < 0.01-0.001, respectively). Maximal oxygen consumption increased more in DD vs. ES and SE both in men (p = 0.003-0.008) and women (p = 0.008-0.009). Total body lean mass increased in all groups (3%-5%, p < 0.01-0.001). Only DD led to decreased total body fat (men, -14% ± 15%, p < 0.001; women, -13% ± 14%, p = 0.009) and abdominal-region fat (men, -18% ± 14%, p = 0.003; women, -17% ± 15%, p = 0.003). Changes in blood lipids were correlated with changes in abdominal-region fat in the entire group (r = 0.283, p = 0.005) and in DD (r = 0.550, p = 0.001). In conclusion, all modes resulted in increased physical fitness and lean mass, while only DD led to decreases in fat mass. Same-session SE and ES combined training is effective in improving physical fitness while volume-equated, but more frequent DD training may be more suitable for optimizing body composition and may be possibly useful in early prevention of cardiovascular and metabolic diseases.

Maximal power output during incremental cycling test is dependent on the curvature constant of the power-time relationship.

The aim of this study was to investigate whether the maximal power output (Pmax) during an incremental test was dependent on the curvature constant (W') of the power-time relationship. Thirty healthy male subjects (maximal oxygen uptake = 3.58 ± 0.40 L·min(-1)) performed a ramp incremental cycling test to determine the maximal oxygen uptake and Pmax, and 4 constant work rate tests to exhaustion to estimate 2 parameters from the modeling of the power-time relationship (i.e., critical power (CP) and W'). Afterwards, the participants were ranked according to their magnitude of W'. The median third was excluded to form a high W' group (HIGH, n = 10), and a low W' group (LOW, n = 10). Maximal oxygen uptake (3.84 ± 0.50 vs. 3.49 ± 0.37 L·min(-1)) and CP (213 ± 22 vs. 200 ± 29 W) were not significantly different between HIGH and LOW, respectively. However, Pmax was significantly greater for the HIGH (337 ± 23 W) than for the LOW (299 ± 40 W). Thus, in physically active individuals with similar aerobic parameters, W' influences the Pmax during incremental testing.