Sprint Exercise Research Articles

The Effect of Exercise Training Type on Paraoxonase-1 and Lipid Profile in Rats

Background: Paraoxonase-1 (PON1) is an anti-atherosclerotic enzyme that protects high-density lipoprotein (HDL) and low-density lipoprotein (LDL) against oxidation. There are contradictory studies about the effects of exercise training on PON1 activity. Objectives: The purpose of the present study was to elucidate the effects of sprint and endurance exercise training on serum PON1 activity and lipid profile in rats. Methods: Twenty-four Albino Wistar rats were divided to sedentary control (SC), endurance training (ET), and sprint training (ST) groups. The animals were subjected to endurance (at a speed of 27 m/minute) and sprint (at a speed of 40 to 54 m/minute) training on a treadmill for 6 weeks, 6 days per week. Using commercial kits, PON1 activity and lipid profile levels were measured by spectrophotometry and enzymatic methods, respectively. The data were analyzed by one-way analysis of variance followed by Tukey’s post-hoc test at P < 0.05 level. Results: Both ET and ST regimens increased PON1 activity in the serum, and the alteration was greater following ST than ET (F1, 23 = 17.87, P = 0.001). In contrast, neither ST nor ET changed significantly the serum levels of triglyceride (F1, 23 = 0.288, P = 0.753), total cholesterol (F1, 23 = 0.385, P = 0.685), LDL (F1, 23 = 1.07, P = 0.361), and HDL (F1, 23 = 1.36, P = 0.277). In addition, serum PON1 activity was positively correlated with serum HDL levels in rats (R = 0.44, P = 0.032). Conclusions: Despite the lack of change in serum lipid profile, sprint training can lead to greater protection against lipid peroxidation than endurance training through increases in serum PON1 activity.

Performance and Muscle Damage Responses during Repeated Sprint Exercise in Hypoxia among Athletes

Performance and Muscle Damage Responses during Repeated Sprint Exercise in Hypoxia among Athletes

Impact of time and work:rest ratio matched sprint interval training programmes on performance: A randomised controlled trial.

The aim of this study was to examine the effects of a short training intervention using two repeated sprint protocols matched for total sprint duration and work:rest ratio. Randomised-controlled trial. Thirty physically active males were randomly allocated to one of two sprint training groups: a 6s group, a 30s group or a non-exercising control. The training groups were matched for work:rest ratio and total sprint time per session, and completed 6 training sessions over a 2-week period. Before and after the 2 week training period, participants completed a VO2max test and a 10km time trial on a cycle ergometer. Time trial performance increased significantly by 5.1% in 6s (630±115s to 598±92s; p<0.05) and 6.2% in 30s (579±68s to 543±85s; p<0.05) from baseline testing, but there was no significant change in the control group (p>0.05), and no significant difference between exercise groups (p>0.05). The 6s group increased peak power output by 9.0% (from 1092±263W to 1181±248W; p<0.05) from sprint session 1 to 6, and the 30s group by 20.0% (1041±161W to 1237±159W; p<0.05). This study indicates that both 6 and 30s bouts of repeated sprint exercise, matched for total sprint duration and W:R can improve athletic performance.

Endurance, aerobic high-intensity, and repeated sprint cycling performance is unaffected by normobaric "Live High-Train Low": a double-blind placebo-controlled cross-over study.

The aim was to investigate whether 6weeks of normobaric "Live High-Train Low" (LHTL) using altitude tents affect highly trained athletes incremental peak power, 26-km time-trial cycling performance, 3-min all-out performance, and 30-s repeated sprint ability. In a double-blinded, placebo-controlled cross-over design, seven highly trained triathletes were exposed to 6weeks of normobaric hypoxia (LHTL) and normoxia (placebo) for 8h/day. LHTL exposure consisted of 2 weeks at 2500m, 2weeks at 3000m, and 2weeks at 3500m. Power output during an incremental test, ~26-km time trial, 3-min all-out exercise, and 8 × 30s of all-out sprint was evaluated before and after the intervention. Following at least 8weeks of wash-out, the subjects crossed over and repeated the procedure. Incremental peak power output was similar after both interventions [LHTL: 375 ± 74 vs. 369 ± 70W (pre-vs-post), placebo: 385 ± 60 vs. 364 ± 79W (pre-vs-post)]. Likewise, mean power output was similar between treatments as well as before and after each intervention for time trial [LHTL: 257 ± 49 vs. 254 ± 54W (pre-vs-post), placebo: 267 ± 57 vs. 267 ± 52W (pre-vs-post)], and 3-min all-out [LHTL: 366 ± 68 vs. 369 ± 72W (pre-vs-post), placebo: 365 ± 66 vs. 355 ± 71W (pre-vs-post)]. Furthermore, peak- and mean power output during repeated sprint exercise was similar between groups at all time points (n = 5). In conclusion, 6weeks of normobaric LHTL using altitude tents simulating altitudes of 2500-3500m conducted in a double-blinded, placebo-controlled cross-over design do not affect power output during an incremental test, a ~26-km time-trial test, or 3-min all-out exercise in highly trained triathletes. Furthermore, 30s of repeated sprint ability was unaltered.

The Effect of Previous Wingate Performance Using one Body Region on Subsequent Wingate Performance Using a Different Body Region.

The 30 second Wingate Anaerobic Test (WAnT) is the gold standard measure of anaerobic performance. The present investigation aimed to determine if a previous WAnT using one body region significantly affected a subsequent WAnT using a different body region. Twelve male university students (n = 12, 23 ± 2 years, 84 ± 16.1 kg, 178.5 ± 7.4 cm) volunteered to complete two repeated WAnT protocols (either lower body WAnT followed by an upper body WAnT or vice versa) on two separate testing occasions. The upper body WAnT was conducted on a modified electromagnetically braked cycle ergometer using a flywheel braking force corresponding to 5% bodyweight. The lower body WAnT was conducted on an electronically braked cycle ergometer using a flywheel braking force corresponding to 7.5% bodyweight. Participants had a 1 minute rest period for transition between WAnTs. Data are reported as mean ± standard deviation. No significant differences were identified in power indices for the lower body between 30 s WAnTs. When the upper body WAnT was performed 2nd, absolute peak power (p < 0.01), mean power (p < 0.001) and relative mean power (p < 0.001) were significantly lower compared to when the upper body WAnT was performed 1st. The value of maximum revolutions per minute was significantly lower (p < 0.001) when the upper body WAnT was performed after the lower body WAnT, compared to when it was performed 1st (193.3 ± 11.4 1st vs 179.8 ± 14.4 2nd). Previous upper body sprint exercise does not significantly affect lower body sprint exercise; however, previous lower body sprint exercise severely compromises subsequent upper body sprint performance.

Cerebral blood flow, frontal lobe oxygenation and intra-arterial blood pressure during sprint exercise in normoxia and severe acute hypoxia in humans

Cerebral blood flow (CBF) is regulated to secure brain O2 delivery while simultaneously avoiding hyperperfusion; however, both requisites may conflict during sprint exercise. To determine whether brain O2 delivery or CBF is prioritized, young men performed sprint exercise in normoxia and hypoxia (PIO2 = 73 mmHg). During the sprints, cardiac output increased to ∼22 L min−1, mean arterial pressure to ∼131 mmHg and peak systolic blood pressure ranged between 200 and 304 mmHg. Middle-cerebral artery velocity (MCAv) increased to peak values (∼16%) after 7.5 s and decreased to pre-exercise values towards the end of the sprint. When the sprints in normoxia were preceded by a reduced PETCO2, CBF and frontal lobe oxygenation decreased in parallel (r = 0.93, P < 0.01). In hypoxia, MCAv was increased by 25%, due to a 26% greater vascular conductance, despite 4–6 mmHg lower PaCO2 in hypoxia than normoxia. This vasodilation fully accounted for the 22 % lower CaO2 in hypoxia, leading to a similar brain O2 delivery during the sprints regardless of PIO2. In conclusion, when a conflict exists between preserving brain O2 delivery or restraining CBF to avoid potential damage by an elevated perfusion pressure, the priority is given to brain O2 delivery.

The Effects of a Single Whole-Body Cryotherapy Exposure on Physiological, Performance, and Perceptual Responses of Professional Academy Soccer Players After Repeated Sprint Exercise.

Russell, M, Birch, J, Love, T, Cook, CJ, Bracken, RM, Taylor, T, Swift, E, Cockburn, E, Finn, C, Cunningham, D, Wilson, L, and Kilduff, LP. The effects of a single whole-body cryotherapy exposure on physiological, performance, and perceptual responses of professional academy soccer players after repeated sprint exercise. J Strength Cond Res 31(2): 415-421, 2017-In professional youth soccer players, the physiological, performance, and perceptual effects of a single whole-body cryotherapy (WBC) session performed shortly after repeated sprint exercise were investigated. In a randomized, counterbalanced, and crossover design, 14 habituated English Premier League academy soccer players performed 15 × 30 m sprints (each followed by a 10 m forced deceleration) on 2 occasions. Within 20 minutes of exercise cessation, players entered a WBC chamber (Cryo: 30 seconds at -60° C, 120 seconds at -135° C) or remained seated (Con) indoors in temperate conditions (∼25° C). Blood and saliva samples, peak power output (countermovement jump), and perceptual indices of recovery and soreness were assessed pre-exercise and immediately, 2-hour and 24-hour postexercise. When compared with Con, a greater testosterone response was observed at 2-hour (+32.5 ± 32.3 pg·ml, +21%) and 24-hour (+50.4 ± 48.9 pg·ml, +28%) postexercise (both P = 0.002) in Cryo (trial × treatment interaction: P = 0.001). No between-trial differences were observed for other salivary (cortisol and testosterone/cortisol ratio), blood (lactate and creatine kinase), performance (peak power output), or perceptual (recovery or soreness) markers (all trial × treatment interactions: P > 0.05); all of which were influenced by exercise (time effects: all P ≤ 0.05). A single session of WBC performed within 20 minutes of repeated sprint exercise elevated testosterone concentrations for 24 hours but did not affect any other performance, physiological, or perceptual measurements taken. Although unclear, WBC may be efficacious for professional soccer players during congested fixture periods.

A2 Milk Enhances Dynamic Muscle Function Following Repeated Sprint Exercise, a Possible Ergogenic Aid for A1-Protein Intolerant Athletes?

Hyperaminoacidemia following ingestion of cows-milk may stimulate muscle anabolism and attenuate exercise-induced muscle damage (EIMD). However, as dairy-intolerant athletes do not obtain the reported benefits from milk-based products, A2 milk may offer a suitable alternative as it lacks the A1-protein. This study aimed to determine the effect of A2 milk on recovery from a sports-specific muscle damage model. Twenty-one male team sport players were allocated to three independent groups: A2 milk (n = 7), regular milk (n = 7), and placebo (PLA) (n = 7). Immediately following muscle-damaging exercise, participants consumed either A2 milk, regular milk or PLA (500 mL each). Visual analogue scale (muscle soreness), maximal voluntary isometric contraction (MVIC), countermovement jump (CMJ) and 20-m sprint were measured prior to and 24, 48, and 72 h post EIMD. At 48 h post-EIMD, CMJ and 20-m sprint recovered quicker in A2 (33.4 ± 6.6 and 3.3 ± 0.1, respectively) and regular milk (33.1 ± 7.1 and 3.3 ± 0.3, respectively) vs. PLA (29.2 ± 3.6 and 3.6 ± 0.3, respectively) (p < 0.05). Relative to baseline, decrements in 48 h CMJ and 20-m sprint were minimised in A2 (by 7.2 and 5.1%, respectively) and regular milk (by 6.3 and 5.2%, respectively) vs. PLA. There was a trend for milk treatments to attenuate decrements in MVIC, however statistical significance was not reached (p = 0.069). Milk treatments had no apparent effect on muscle soreness (p = 0.152). Following muscle-damaging exercise, ingestion of 500 mL of A2 or regular milk can limit decrements in dynamic muscle function in male athletes, thus hastening recovery and improving subsequent performance. The findings propose A2 milk as an ergogenic aid following EIMD, and may offer an alternative to athletes intolerant to the A1 protein.

Dietary nitrate supplementation improves sprint and high-intensity intermittent running performance

The influence of dietary nitrate (NO3−) supplementation on indices of maximal sprint and intermittent exercise performance is unclear. PurposeTo investigate the effects of NO3− supplementation on sprint running performance, and cognitive function and exercise performance during the sport-specific Yo-Yo Intermittent Recovery level 1 test (IR1). MethodsIn a double-blind, randomized, crossover study, 36 male team-sport players received NO3−-rich (BR; 70 mL·day−1; 6.4 mmol of NO3−), and NO3−-depleted (PL; 70 mL·day−1; 0.04 mmol NO3−) beetroot juice for 5 days. On day 5 of supplementation, subjects completed a series of maximal 20-m sprints followed by the Yo-Yo IR1. Cognitive tasks were completed prior to, during and immediately following the Yo-Yo IR1. ResultsBR improved sprint split times relative to PL at 20 m (1.2%; BR 3.98 ± 0.18 vs. PL 4.03 ± 0.19 s; P < 0.05), 10 m (1.6%; BR 2.53 ± 0.12 vs. PL 2.57 ± 0.19 s; P < 0.05) and 5 m (2.3%; BR 1.73 ± 0.09 vs. PL 1.77 ± 0.09 s; P < 0.05). The distance covered in the Yo-Yo IR1 test improved by 3.9% (BR 1422 ± 502 vs. PL 1369 ± 505 m; P < 0.05). The reaction time to the cognitive tasks was shorter in BR (615 ± 98 ms) than PL (645 ± 120 ms; P < 0.05) at rest but not during the Yo-Yo IR1. There was no difference in response accuracy. ConclusionsDietary NO3− supplementation enhances maximal sprint and high-intensity intermittent running performance in competitive team sport players. Our findings suggest that NO3− supplementation has the potential to improve performance in single-sprint or multiple-sprint (team) sports.

Effect of Carbohydrate Intake on Maximal Power Output and Cognitive Performances.

The present study aimed to assess the beneficial effect of acute carbohydrate (7% CHO) intake on muscular and cognitive performances. Seventeen high levels athletes in explosive sports (fencing and squash) participated in a randomized, double-blind study consisting in series of 6 sprints (5s) with a passive recovery (25s) followed by 15 min submaximal cycling after either maltodextrine and fructose (CHO) or placebo (Pl) intake. Cognitive performances were assessed before and after sprint exercise using a simple reaction time (SRT) task at rest, a visual scanning task (VS) and a Go/Nogo task (GNG) during a submaximal cycling exercise. Results showed a beneficial effect of exercise on VS task on both conditions (Pl: −283 ms; CHO: −423 ms) and on SRT only during CHO condition (−26 ms). In the CHO condition, SRT was faster after exercise whereas no effect of exercise was observed in the Pl condition. According to a qualitative statistical method, a most likely and likely positive effect of CHO was respectively observed on peak power (+4%) and tiredness (−23%) when compared to Pl. Furthermore, a very likely positive effect of CHO was observed on SRT (−8%) and a likely positive effect on visual scanning (−6%) and Go/Nogo tasks (−4%) without any change in accuracy. In conclusion acute ingestion of 250 mL of CHO, 60 min and 30 min before exercise, improve peak power output, decrease muscular tiredness and speed up information processing and visual detection without changing accuracy.

Is salivary cortisol moderating the relationship between salivary testosterone and hand-grip strength in healthy men?

This study examined the moderating effect of cortisol (C) on the relationship between testosterone (T) and hand-grip strength (HGS) in healthy young men. Sixty-five males were monitored for salivary T, C and HGS before and 15 min after a short bout (5 × 6-s trials) of sprint cycling exercise. Sprint exercise promoted (p < .05) positive changes in T (6.1 ± 24.9%) and HGS (3.4 ± 7.5%), but a negative C response (−14.4 ± 33.1%). The T and C measures did not independently predict HGS, but a significant T × C interaction was found in relation to these outcomes. Further testing revealed that pre-test T and HGS were negatively associated (p < .05), but only in men with high C levels. The exercise changes in T and HGS were also negatively related in men with low C levels (p < .05), but no relationship was seen in men with high C levels. In summary, complex relationships between T and HGS emerged when considering C as a moderating variable. The pre-test combination of high C and low T levels favoured absolute HGS, whereas low pre-test C levels and a smaller T change were linked to larger HGS changes. These associations suggest that, in the current format, T is not necessarily anabolic to muscle strength in healthy young men. Such complexities could also explain some of the inconsistent T relationships with physical performance in lesser trained male populations.

The Effect of Green Tea Ingestion and Interval Sprinting Exercise on the Body Composition of Overweight Males: A Randomized Trial.

The combined effect of green tea ingestion and interval sprinting exercise on body and abdominal fat of overweight males was investigated. Participants were randomly assigned into control (C), green tea (GT), interval sprinting exercise (ISE), and green tea and ISE (GT + ISE) groups. The GT, GT + ISE, and C groups consumed three GT capsules daily. The ISE and GT + ISE groups completed 36 ISE sessions over 12 weeks. Forty eight overweight males with a mean BMI of 28.5 ± 0.92 kg/m2 and age of 26 ± 0.7 years acted as participants. There was a significant reduction in total and abdominal fat mass for the ISE and GT + ISE groups, p < 0.05, however, total and abdominal fat mass did not significantly change in the GT and C groups. There was a significant increase in total lean mass, p < 0.05, after the intervention for the ISE and GT + ISE groups only. There was a significant increase in fat oxidation during submaximal aerobic exercise, p < 0.05, after the intervention for the ISE, GT + ISE, and GT groups with no change for the C group. Following the 12-week intervention the ISE and GT + ISE groups, compared to C, recorded a significantly greater decrease in body and abdominal fat, and a significant increase in total lean mass. Ingestion of green tea by itself, however, did not result in a significant decrease in body or abdominal fat, but increased fat utilization during submaximal exercise. The combination of 12 weeks of GT ingestion and ISE did not result in greater total and abdominal fat reduction compared to 12 weeks of ISE alone.

Effects of Beetroot Juice on Recovery of Muscle Function and Performance between Bouts of Repeated Sprint Exercise.

This study examined the effects of beetroot juice (BTJ) on recovery between two repeated-sprint tests. In an independent groups design, 20 male, team-sports players were randomized to receive either BTJ or a placebo (PLA) (2 × 250 mL) for 3 days after an initial repeated sprint test (20 × 30 m; RST1) and after a second repeated sprint test (RST2), performed 72 h later. Maximal isometric voluntary contractions (MIVC), countermovement jumps (CMJ), reactive strength index (RI), pressure-pain threshold (PPT), creatine kinase (CK), C-reactive protein (hs-CRP), protein carbonyls (PC), lipid hydroperoxides (LOOH) and the ascorbyl free radical (A•−) were measured before, after, and at set times between RST1 and RST2. CMJ and RI recovered quicker in BTJ compared to PLA after RST1: at 72 h post, CMJ and RI were 7.6% and 13.8% higher in BTJ vs. PLA, respectively (p < 0.05). PPT was 10.4% higher in BTJ compared to PLA 24 h post RST2 (p = 0.012) but similar at other time points. No group differences were detected for mean and fastest sprint time or fatigue index. MIVC, or the biochemical markers measured (p > 0.05). BTJ reduced the decrement in CMJ and RI following and RST but had no effect on sprint performance or oxidative stress.

Exercise training comprising of single 20-s cycle sprints does not provide a sufficient stimulus for improving maximal aerobic capacity in sedentary individuals.

PurposeSprint interval training (SIT) provides a potent stimulus for improving maximal aerobic capacity ({dot{text{V}}text{O}}_{ 2} { hbox{max} }), which is among the strongest markers for future cardiovascular health and premature mortality. Cycling-based SIT protocols involving six or more ‘all-out’ 30-s Wingate sprints per training session improve {dot{text{V}}text{O}}_{ 2} { hbox{max} }, but we have recently demonstrated that similar improvements in {dot{text{V}}text{O}}_{ 2} { hbox{max} } can be achieved with as few as two 20-s sprints. This suggests that the volume of sprint exercise has limited influence on subsequent training adaptations. Therefore, the aim of the present study was to examine whether a single 20-s cycle sprint per training session can provide a sufficient stimulus for improving {dot{text{V}}text{O}}_{ 2} { hbox{max} }.MethodsThirty sedentary or recreationally active participants (10 men/20 women; mean ± SD age: 24 ± 6 years, BMI: 22.6 ± 4.0 kg m−2, {dot{text{V}}text{O}}_{ 2} { hbox{max} }: 33 ± 7 mL kg−1 min−1) were randomised to a training group or a no-intervention control group. Training involved three exercise sessions per week for 4 weeks, consisting of a single 20-s Wingate sprint (no warm-up or cool-down). {dot{text{V}}text{O}}_{ 2} { hbox{max} } was determined prior to training and 3 days following the final training session.ResultsMean {dot{text{V}}text{O}}_{ 2} { hbox{max} } did not significantly change in the training group (2.15 ± 0.62 vs. 2.22 ± 0.64 L min−1) or the control group (2.07 ± 0.69 vs. 2.08 ± 0.68 L min−1; effect of time: P = 0.17; group × time interaction effect: P = 0.26).ConclusionAlthough we have previously demonstrated that regularly performing two repeated 20-s ‘all-out’ cycle sprints provides a sufficient training stimulus for a robust increase in {dot{text{V}}text{O}}_{ 2} { hbox{max} }, our present study suggests that this is not the case when training sessions are limited to a single sprint.

Low-Volume Intense Exercise Elicits Post-exercise Hypotension and Subsequent Hypervolemia, Irrespective of Which Limbs Are Exercised.

Introduction: Exercise reduces arterial and central venous blood pressures during recovery, which contributes to its valuable anti-hypertensive effects and to facilitating hypervolemia. Repeated sprint exercise potently improves metabolic function, but its cardiovascular effects (esp. hematological) are less well-characterized, as are effects of exercising upper versus lower limbs. The purposes of this study were to identify the acute (<24 h) profiles of arterial blood pressure and blood volume for (i) sprint intervals versus endurance exercise, and (ii) sprint intervals using arms versus legs.Methods: Twelve untrained males completed three cycling exercise trials; 50-min endurance (legs), and 5*30-s intervals using legs or arms, in randomized and counterbalanced sequence, at a standardized time of day with at least 8 days between trials. Arterial pressure, hemoglobin concentration and hematocrit were measured before, during and across 22 h after exercise, the first 3 h of which were seated rest.Results: The post-exercise hypotensive response was larger after leg intervals than endurance (AUC: 7540 ± 3853 vs. 3897 ± 2757 mm Hg·min, p = 0.049, 95% CI: 20 to 6764), whereas exercising different limbs elicited similar hypotension (arms: 6420 ± 3947 mm Hg·min, p = 0.48, CI: −1261 to 3896). In contrast, arterial pressure at 22 h was reduced after endurance but not after leg intervals (−8 ± 8 vs. 0 ± 7 mm Hg, p = 0.04, CI: 7 ± 7) or reliably after arm intervals (−4 ± 8 mm Hg, p = 0.18 vs. leg intervals). Regardless, plasma volume expansion at 22 h was similar between leg intervals and endurance (both +5 ± 5%; CI: −5 to 5%) and between leg and arm intervals (arms: +5 ± 7%, CI: −8 to 5%).Conclusions: These results emphasize the relative importance of central and/or systemic factors in post-exercise hypotension, and indicate that markedly diverse exercise profiles can induce substantive hypotension and subsequent hypervolemia. At least for endurance exercise, this hypervolemia may not depend on the volume of post-exercise hypotension. Finally, endurance exercise led to reduced blood pressure the following day, but sprint interval exercise did not.

Salivary testosterone responses to a physical and psychological stimulus and subsequent effects on physical performance in healthy adults.

To address the rapid influence of testosterone (T) on neuromuscular performance, we compared the T and physical performance responses of adults exposed to a physical and psychological stimulus. A group of healthy men (n=12) and women (n=14) each completed three treatments using a randomised, crossover design: exercise involving five × ten-second cycle sprints, viewing a video clip with aggressive content and a control session. Salivary T concentrations, hand-grip strength (HGS) and countermovement jump peak power (CMJ PP) were assessed before and 15 minutes after each session. The relative changes in T (17±29%) and CMJ PP (-0.1±4.4%) following sprint exercise were superior to the aggressive video (-6.3±19%, -2.2±5.9%) and control (-4.8±23%, -2.8±4.4%) treatments, respectively (p ≤0.05). Pre-treatment T levels correlated (r= -0.58 to -0.61, p <0.05) with the T responses of men (sprint exercise) and women (sprint exercise, aggressive video), but no variables were significantly correlated with the relative changes in HGS or CMJ PP. Sprint exercise promoted a general rise in T and maintained CMJ PP, relative to the video and control treatments. In both sexes, those individuals with higher pre-test T levels tended to produce smaller T responses to one or more treatments. These data highlight the importance of stimulus selection and individual predispositions when attempting to acutely modify T and associated physical performance.

Are the oxygen uptake and heart rate off-kinetics influenced by the intensity of prior exercise?

The aim of this study was to investigate the effect of prior exercise on the heart rate (HR) and oxygen uptake (VO2) off-kinetics after a subsequent high-intensity running exercise. Thirteen male futsal players (age 22.8±6.1years) performed a series of high-intensity bouts without prior exercise (control), preceded by a prior same intensity continuous exercise (CE+CE) and a prior sprint exercise (SE+CE). The magnitude of excess post-exercise oxygen consumption (EPOCm−4.25±0.19 vs. 3.69±0.20Lmin−1 in CE+CE and 3.62±0.18Lmin−1 in control; p<0.05) and the parasympathetic reactivation (HRR60s−33±3 vs. 37±3bpm in CE+CE and 42±3 bpm in control; p<0.05) in the SE+CE were higher and slower, compared with another two conditions. The EPOCτ (time to attain 63% of total response; 53±2s) and the heart rate time-course (HRτ−86±5s) were significantly longer after the SE+CE condition than control transition (48±2s and 69±5s, respectively; p<0.05). The SE+CE induce greater stress on the metabolic function, respiratory system and autonomic nervous system regulation during post-exercise recovery than CE, highlighting that the inclusion of sprint-based exercises can be an effective strategy to increase the total energy expenditure following an exercise session.

Protein-Pacing from Food or Supplementation Improves Physical Performance in Overweight Men and Women: The PRISE 2 Study.

We recently reported that protein-pacing (P; six meals/day @ 1.4 g/kg body weight (BW), three of which included whey protein (WP) supplementation) combined with a multi-mode fitness program consisting of resistance, interval sprint, stretching, and endurance exercise training (RISE) improves body composition in overweight individuals. The purpose of this study was to extend these findings and determine whether protein-pacing with only food protein (FP) is comparable to WP supplementation during RISE training on physical performance outcomes in overweight/obese individuals. Thirty weight-matched volunteers were prescribed RISE training and a P diet derived from either whey protein supplementation (WP, n = 15) or food protein sources (FP, n = 15) for 16 weeks. Twenty-one participants completed the intervention (WP, n = 9; FP, n = 12). Measures of body composition and physical performance were significantly improved in both groups (p < 0.05), with no effect of protein source. Likewise, markers of cardiometabolic disease risk (e.g., LDL (low-density lipoprotein) cholesterol, glucose, insulin, adiponectin, systolic blood pressure) were significantly improved (p < 0.05) to a similar extent in both groups. These results demonstrate that both whey protein and food protein sources combined with multimodal RISE training are equally effective at improving physical performance and cardiometabolic health in obese individuals.

Effect of the recovery duration of a repeated sprint exercise on the power output, jumping performance and lactate concentration in pre-pubescent soccer players

Summary Study aim: The aim of the present study was to examine the effect of two different recovery durations (2 min versus 5 min) on the physiological responses (power output, stretch-shortening cycle and lactate concentration) to a 5×6 s repeated cycling sprint exercise protocol in pre-pubescent soccer players. Materials and methods: Twelve male soccer players (age 12.23 ± 0.55 yrs, body mass 43.6 ± 5.5 kg and height 156.1 ± 5.8 cm) performed 5 × 6 s sprints on a cycle ergometer (Ergomedic 874E, Monark, Sweden) against 0.075 times their body mass resistance on two occasions within a week. In one session there was a 2 min recovery and in the other there was a 5 min recovery in a counterbalanced order. A squat jump (SJ) and a countermovement jump (CMJ) were tested before and after each trial, and the eccentric utilisation ratio (EUR) was calculated as CMJ/SJ. Results: No significant trial × recovery interaction was observed in the participants’ peak power (p = 0.891, η2 = 0.118), mean power (p = 0.910, η2 = 0.106), SJ (p = 0.144, η2 = 0.630), CMJ (p = 0.616, η2 = 0.347) and EUR (p = 0.712, η2 = 0.295). However, a main effect of the trial on the CMJ of a large magnitude (p = 0.006, η2 = 0.862) was found, in which a higher score was recorded in the third trial than in the first trial (23.3 versus 21.8 cm). No differences were found in the lactate concentrations examined 5 min after the end of the protocol between the two recovery conditions (6.7 ± 1.8 vs. 6.0 ± 1.6 mmol · L–1, in the 2 and 5 min recovery, respectively, Cohen’s d = 0.4). Conclusions: The duration of the passive recovery time (2 min vs. 5 min) in trials of repeated sprints did not induce important changes either to the indices of the jumping performance or to the power output in pre-pubescent participants.

Oral Essential Amino Acids, Sprint Exercise And Collagens In Human Skeletal Muscle

PURPOSE: To investigate the effects of oral ingestion of essential amino acids (EAA exercise on the global gene expression in skeletal muscle after sprint exercise. METHODS: Twelve healthy physically active subjects (age 20-30 years) performed three 30-s cycle sprints with maximal voluntary pedaling rate on a mechanically braked cycle ergometer with 20 min rest between the sprints. The braking force was set at 0.75 N/kg body weight. The subjects consumed either EAA + maltodextrin solution or flavored water (placebo) in a randomized order. A post exercise biopsy (m. vastus lateralis) was taken 200 minutes after the last cycle sprint. RNA was isolated from the frozen muscle biopsies using TRIzol protocol. Purification was executed using RNeasy Mini Kit (Qiagen). The RNA concentration was determined using the NanoDrop (Thermo Fischer Scientific) and quality assessed by Agilent (Agilent Technologies). The Affymetrix Gene Chip Whole Transcript (WT) Sense Target Labeling Assay Manual was used for complementary DNA (cDNA) generation, hybridization and array processing (GeneChip® Human Transcriptome Array 2.0). Differentially expressed genes in response to EEA in combination with the sprint exercise were analyzed using the Ingenuity Pathways Analysis (IPA) software application. To validate microarray data total RNA was reverse transcribed using random hexamer primers. Real-time PCR was applied to measure mRNA expression using RPS18 as reference to correct for potential variation in RNA loading. RESULTS: The IPA Network analysis showed an enrichment of activated genes related to collagen metabolism. Some of the genes in the pathway analysis were validated by the PCR analysis. The expression of COL15A1, COL1A1, COL2A1 and BGN was higher in the EEA condition compared to the placebo condition (P<0.05). CONCLUSION: Oral ingestion of EAA after sprint exercise increases expression of genes related to collagen metabolism. The functional role of an activation of collagen metabolism is not known, although it could be speculated that an altered collagen metabolism reflects an extracellular remodeling after exercise and that this process is enhanced by oral ingestion of EEA. SUPPORT: The study was supported by grants from the Swedish National Center for Research in Sports.