Commercially available compression garments or electrical stimulation do not enhance recovery following a sprint competition in elite cross-country skiers

This study investigated whether commercially available compression garments (COMP) exerting a moderate level of pressure and/or neuromuscular electrical stimulation (NMES) accelerate recovery following a cross-country sprint skiing competition compared with a control group (CON) consisting of active recovery only. Twenty-one senior (12 males, 9 females) and 11 junior (6 males, 5 females) Swedish national team skiers performed an outdoor sprint skiing competition involving four sprints lasting ～3–4 min. Before the competition, skiers were matched by sex and skiing level (senior versus junior) and randomly assigned to COMP (n?=?11), NMES (n?=?11) or CON (n?=?10). Creatine kinase (CK), urea, countermovement jump (CMJ) height, and perceived muscle pain were measured before and 8, 20, 44 and 68?h after competition. Neither COMP nor NMES promoted the recovery of blood biomarkers, CMJ or perceived pain post-competition compared with CON (all P?>?.05). When grouping all 32 participants, urea and perceived muscle pain increased from baseline, peaking at 8?h (standardised mean difference (SMD), [95% confidence intervals (CIs)]): 2.8 [2.3, 3.2]) and 44?h (odds ratio [95% CI]: 3.3 [2.1, 5.1]) post-competition, respectively. Additionally, CMJ was lower than baseline 44 and 68?h post-competition in both males and females (P?相似文献   

Agreement in Body Fat Estimates Between a Hand-Held Bioelectrical Impedance Analyzer and Skinfold Thicknesses in African American and Caucasian Adolescents

Purpose: The aim of this study was to examine the effect of active versus passive recovery on 6 repeated Wingate tests (30-s all-out cycling sprints on a Velotron ergometer). Method: Fifteen healthy participants aged 29 (SD = 8) years old (body mass index = 23 [3] kg/m²) participated in 3 sprint interval training sessions separated by 3 to 7 days between each session during a period of 1 month. The 1st visit was familiarization to 6 cycling sprints; the 2nd and 3rd visits involved a warm-up followed by 6 30-s cycling sprints. Each sprint was followed by 4 min of passive (resting still on the ergometer) or active recovery (pedaling at 1.1 W/kg). The same recovery was used within each visit, and recovery type was randomized between visits. Results: Active recovery resulted in a 0.6 W/kg lower peak power output in the second sprint (95% confidence interval [CI] [ ? 0.2, ? 0.8 W/kg], effect size = 0.50, p < .01) and a 0.4 W/kg greater average power output in the 5th and 6th sprints (95% CI [+0.2,+0.6 W/kg], effect size = 0.50, p < .01) compared with passive recovery. There was little difference between fatigue index, total work, or accumulated work between the 2 recovery conditions. Conclusions: Passive recovery is beneficial when only 2 sprints are completed, whereas active recovery better maintains average power output compared with passive recovery when several sprints are performed sequentially (partial eta squared between conditions for multiple sprints = .38).     

Repeated-sprint training in hypoxia induced by voluntary hypoventilation improves running repeated-sprint ability in rugby players

Purpose: The goal of this study was to determine the effects of repeated-sprint training in hypoxia induced by voluntary hypoventilation at low lung volume (VHL) on running repeated-sprint ability (RSA) in team-sport players.

Methods: Twenty-one highly trained rugby players performed, over a 4-week period, seven sessions of repeated 40-m sprints either with VHL (RSH-VHL, n?=?11) or with normal breathing (RSN, n?=?10). Before (Pre-) and after training (Post-), performance was assessed with an RSA test (40-m all-out sprints with a departure every 30?s) until task failure (85% of the reference velocity assessed in an isolated sprint).

Results: The number of sprints completed during the RSA test was significantly increased after the training period in RSH-VHL (9.1?±?2.8 vs. 14.9?±?5.3; +64%; p?p?=?.74). Maximal velocity was not different between Pre- and Post- in both groups whereas the mean velocity decreased in RSN and remained unchanged in RSH-VHL. The mean SpO₂ recorded over an entire training session was lower in RSH-VHL than in RSN (90.1?±?1.4 vs. 95.5?±?0.5%, p?Conclusion: RSH-VHL appears to be an effective strategy to produce a hypoxic stress and to improve running RSA in team-sport players.     

Upper and lower body responses to repeated cyclical sprints

Purpose: To compare the physiological and perceptual responses of the upper and lower body to all-out cyclical sprints with short or long rest periods between sprints.

Methods: Ten recreationally trained males completed four 10?×?10?s sprint protocols in a randomized order: upper body with 30?s and 180?s of rest between sprints, and lower body with 30?s and 180?s of rest between sprints. Additionally, maximum voluntary contractions (MVC) were measured at pre-sprint and post-sprints 5 and 10. Normalized (% of first sprint) peak power, MVC, heart rate (HR) and rating of perceived exertion (RPE) were compared between upper and lower body within the same recovery period, and absolute values (Watts, bpm, RPE scores) were compared within the same body part and between recovery periods.

Results: Trivial differences were identified in normalized peak power, HR and RPE values between the upper and lower body in both recovery conditions (<2%, d?≤?0.1), but MVC forces were better maintained with the upper body (～9.5%, d?=?1.0) in both recovery conditions. Absolute peak power was lower (～147?Watts, d?=?1.3), and HR was higher (～10?bpm, d?=?0.73) in the 30?s compared to 180?s condition in both the upper and lower body whereas RPE scores were similar (<0.6?RPE units, d?≤?0.1). Despite the reductions in peak power, MVC forces were better maintained in the 30?s condition in both upper (2.5?kg, d?=?0.4) and lower (7.5?kg, d?=?0.7) body.

Conclusions: Completing a commonly used repeated sprint protocol with the upper and lower body results in comparable normalized physiological and perceptual responses.     

Repeated sprint ability in young basketball players: one vs. two changes of direction (Part 2)

The aim of this study was to compare the training effects based on repeated sprint ability (RSA) (with one change of direction) with an intensive repeated sprint ability (IRSA) (with two changes of direction) on jump performance and aerobic fitness. Eighteen male basketball players were assigned to repeated sprint ability and intensive repeated sprint ability training groups (RSAG and IRSAG). RSA, IRSA, squat jump (SJ), countermovement jump (CMJ) and Yo-Yo intermittent recovery level 1 test were assessed before and after four training weeks. The RSA and IRSA trainings consisted of three sets of six sprints (first two weeks) and eight sprints (second two weeks) with 4-min sets recovery and 20-s of sprints recovery. Four weeks of training led to an overall improvement in most of the measures of RSA, but little evidence of any differences between the two training modes. Jump performance was enhanced: CMJ of 7.5% (P < 0.0001) and 3.1% (P = 0.016) in IRSAG and RSAG respectively. While SJ improved of 5.3% (P = 0.003) for IRSAG and 3.4% (P = 0.095) for RSAG. Conversely the Yo-Yo distance increased 21% (P = 0.301) and 34% (P = 0.017) in IRSAG and RSAG respectively. Therefore, short-term repeated sprint training with one/two changes of direction promotes improvements in both RSA and IRSA respectively but the better increase on jump performance shown a few changes on sprint and endurance performances.     

Effects of coffee and caffeine anhydrous on strength and sprint performance

Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, 10-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300?mg flat dose; yielding 3–5?mg/kg bodyweight), COF (8.9?g; 303?mg caffeine), or placebo (PLA; 3.8?g non-caloric flavouring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p?=?.04), but not PLA (p?=?.99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p?>?.05). There were no sprint?×?treatment interactions for PP or TW (p?>?.05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise.     

Upper-body repeated-sprint training in hypoxia in international rugby union players

Abstract

This study investigated the effects of upper-body repeated-sprint training in hypoxia vs. in normoxia on world-level male rugby union players’ repeated-sprint ability (RSA) during an international competition period. Thirty-six players belonging to an international rugby union male national team performed over a 2-week period four sessions of double poling repeated-sprints (consisting of 3 × eight 10-s sprints with 20-s passive recovery) either in normobaric hypoxia (RSH, simulated altitude 3000 m, n?=?18) or in normoxia (RSN, 300 m; n?=?18). At pre- and post-training intervention, RSA was evaluated using a double-poling repeated-sprint test (6 × 10-s maximal sprint with 20-s passive recovery) performed in normoxia. Significant interaction effects (P?<?0.05) between condition and time were found for RSA-related parameters. Compared to Pre-, peak power significantly improved at post- in RSH (423?±?52 vs. 465?±?69 W, P?=?0.002, η²=0.12) but not in RSN (395?±?65 vs. 397?±?57 W). Averaged mean power was also significantly enhanced from pre- to post-intervention in RSH (351?±?41 vs. 388?±?53 W, P?<?0.001, η²=0.15), while it remained unchanged in RSN (327?±?49 vs. 327?±?43 W). No significant change in sprint decrement (P?=?0.151, η²?=?0.02) was observed in RSH (?17?±?2% vs. ?16?±?3%) nor RSN (?17?±?2% vs. ?18?±?4%). This study showed that only four upper-body RSH sessions were beneficial in enhancing repeated power production in international rugby union players. Although the improvement from RSA to game behaviour remains unclear, this finding appears of practical relevance since only a short preparation window is available prior to international games.     

Endurance and sprint benefits of high-intensity and supramaximal interval training

Abstract

This study examined the effect of two different interval training programs–high-intensity interval training (HIT) and supramaximal interval training (SMIT)–on measures of sprint and endurance performance. Physically active individuals (Females: n=32; age 19.3, s=2.2 years; mass 67.6, s=9.1 kg; stature 172.7, s=6.6 cm. Males: n=23; age 20.0, s=2.7 years; mass 71.3, s=8.3 kg; stature 176.6, s=5.8 cm) completed pre-testing that comprised (1) 3000 m time-trial, (2) 40 m sprint, and (3) repeated sprint ability (RSA–6×40 m sprints, 24 s active recovery) performance. Participants were then matched for average 3000 m running velocity (AV) and randomly assigned to one of three groups: (i) HIT, n=19, 4 min at 100% AV, 4 min passive recovery, 4–6 bouts per session; (ii) SMIT, n=20, 30 s at 130% AV, 150 s passive recovery, 7–12 bouts per session; and (iii) control group, n=16, 30 min continuous running at 75% AV. Groups trained three times per week for six weeks. When time to complete each test were compared among groups: (i) improvements in 3000 m time trial performance were greater following SMIT than continuous running, and (ii) improvements in 40 m sprint and RSA performance were greater following SMIT than HIT and continuous running. In addition, a gender effect was observed for the 3000 m time trial only, where females changed more following the training intervention than males. In summary, for concurrent improvements in endurance, sprint and repeated sprint performance, SMIT provides the greatest benefits for physically active individuals.     

Influence of a caffeine mouth rinse on sprint cycling following glycogen depletion

Attenuated performance during intense exercise with limited endogenous carbohydrate (CHO) is well documented. Therefore, this study examined whether caffeine (CAF) mouth rinsing would augment performance during repeated sprint cycling in participants with reduced endogenous CHO. Eight recreationally active males (aged 23?±?2?yr, body mass 84?±?4?kg, stature 178?±?7?cm) participated in this randomized, single-blind, repeated-measures crossover investigation. Following familiarization, participants attended two separate evening glycogen depletion sessions. The following morning, participants completed five, 6?s sprints on a cycle ergometer (separated by 24?s active recovery), with mouth rinsing either (1) a placebo solution or (2) a 2% CAF solution. During a fifth visit, participants completed the sprints without prior glycogen depletion. Repeated-measures ANOVA identified significant main effect of condition (CAF, placebo, and control [P?P?P?P?P?P?相似文献   

The influence of playing surface on physiological and performance responses during and after soccer simulation

The aim of this study was to investigate the effect of playing surface on physiological and performance responses during and in the 48 h after simulated soccer match play. Blood lactate, single-sprint, repeated-sprint and agility of eight amateur soccer players were assessed throughout a 90-min soccer-simulation protocol (SSP) completed on natural turf (NT) and artificial turf. Counter-movement jump, multiple-rebound jump, sprint (10 m, 60 m), L-agility run (L-AR), creatine kinase (CK) and perception of muscle soreness (PMS) were measured before, immediately after, 24 h and 48 h after exercise. Analyses revealed significant changes in blood lactate and single-sprint performance (both P < 0.05) during the SSP but with no significant differences between surfaces. Conversely, repeated-sprint performance demonstrated an interaction effect, with reductions in performance evident on NT only (P < 0.05). Whilst L-AR and 10-m sprint performance remained unchanged, 60-m sprint and multiple-rebound jump performance were impaired, and PMS and CK were elevated immediately following the SSP (all P < 0.05) but with no surface effects. Although performance, CK and PMS were negatively affected to some degree in the 48 h after the SSP, there was no surface effect. For the artificial and natural surfaces used in the present study, physiological and performance responses to simulated soccer match play appear to be similar. Whilst a potential for small differences in performance response exists during activity, surface type does not affect the pattern of recovery following simulated match play.     

Creatine kinase,neuromuscular fatigue,and the contact codes of football: A systematic review and meta-analysis of pre- and post-match differences

Physiological or performance tests are routinely utilised to assess athletes’ recovery. At present, the ideal tool to assess recovery remains unknown. Therefore, the aim of this systematic review was to examine the change in creatine kinase (CK) and neuromuscular function as measured via a countermovement jump (CMJ) following a match in the contact codes of football. A comprehensive search of databases was undertaken with RevMan (V 5.3) used for statistical analysis. Our results demonstrated that CK pre- versus post-match (standardised mean difference (SMD)?=?0.90, 95% CI?=?0.50 to 1.31, p?p?p?p?=?.03), and pre- versus 24?h post-match (SMD?=??0.80, 95% CI?=??1.31 to ?0.28, p?=?.002) decreased significantly. There was a significant relationship between the change in CK and the change in CMJ PP from immediately pre to immediately post (r?=??0.924, p?=?.025), and between CMJ immediately following a match and 24?h CK change (r?=??0.983, p?=?.017). In conclusion, CK levels increase and performance in the CMJ decreases following a match of a contact code of football. The identification of this relationship may allow coaching staff to implement a standalone measure of recovery.     

Effects of inertia correction and resistive load on fatigue during repeated sprints on a friction-loaded cycle ergometer

Abstract

Seven 6 s sprints with 30 s recovery between sprints were performed against two resistive loads: 50 (L50) and 100 (L100) g · kg^?1 body mass. Inertia-corrected and -uncorrected peak and mean power output were calculated. Corrected peak power output in corresponding sprints and the drop in peak power output relative to sprint 1 were not different in the two conditions, despite the fact that mean power output was 15–20% higher in L100 (P < 0.01). The effect of inertia correction on power output was more pronounced for the lighter load (L50), with uncorrected peak power output in sprint 1 being 42% lower than the corresponding corrected peak power output, while this was only 16% in L100. Fatigue assessed by the drop in uncorrected peak and mean power output in sprint 7 relative to sprint 1 was less compared with that obtained by corrected power values, especially in L50 (drop in uncorrected vs. corrected peak power output: 13.3 ± 2.2% vs. 23.1 ± 4.1%, P < 0.01). However, in L100, the difference between the drop in corrected and uncorrected mean power output in sprint 7 was much smaller (24.2 ± 3.1% and 21.2 ± 2.7%, P < 0.01), indicating that fatigue may be safely assessed even without inertia correction when a heavy load is used. In conclusion, when inertia correction is performed, fatigue during repeated sprints is unaffected by resistive load. When inertia correction is omitted, both power output and the fatigue profile are underestimated by an amount dependent on resistive load. In cases where inertia correction is not possible during a repeated sprints test, a heavy load may be preferable.     

Sprint profile of professional female soccer players during competitive matches: Female Athletes in Motion (FAiM) study

Abstract The aim of this study was to determine sprint profiles of professional female soccer players and evaluate how various speed thresholds impact those outcomes. Seventy-one professional players competing in full matches were assessed repeatedly during 12 regular season matches using a Global Positioning System (GPS). Locomotion ≥18?km?·?h(-1) was defined as sprinting and each event was classified into: Zone 1: 18.0-20.9?km· h(-1); Zone 2: 21.0-22.9?km?·?h(-1); Zone 3: 23.0-24.9?km?·?h(-1) and Zone 4: >25?km?·?h(-1). Outcomes included: duration (s), distance (m), maximum speed (km?·?h(-1)), duration since previous sprint (min) and proportion of total sprint distance. In total 5,019 events were analysed from 139 player-matches. Mean sprint duration, distance, maximum speed and time between sprints were 2.3?±?1.5?s, 15.1?±?9.4?m, 21.8?±?2.3?km· h(-1), and 2.5?±?2.5?min, respectively. Mean sprint distances were 657?±?157, 447?±?185, and 545?±?217?m for forwards, midfielders and defenders, respectively (P?≤?0.046). Midfielders had shorter sprint duration (P = 0.023), distance (P?≤?0.003) and maximum speed (P?相似文献   

Muscle metabolism and performance improvement after two training programmes of sprint running differing in rest interval duration

Repeated-sprint training often involves short sprints separated by inadequate recovery intervals. The effects of interval duration on metabolic and performance parameters are unclear. We compared the effects of two training programmes, differing in rest interval duration, on muscle (vastus lateralis) metabolism and sprint performance. Sixteen men trained three times a week for 8 weeks, each training session comprising 2-3 sets of two 80-m sprints. Sprints were separated by 10 s (n = 8) or 1 min (n = 8). Both training programmes improved performance in the 100-, 200-, and 300-m sprints, but the improvement was greater in the 10-s group during the final 100 m of the 200- and 300-m runs. Independent of interval duration, training mitigated the drop of muscle ATP after two 80-m sprints. The drop in phosphocreatine and the increases in glucose-6-phosphate and fructose-6-phosphate after two 80-m sprints were greater in the 10-s group. In conclusion, training with a limited number of repeated short sprints (≤10 s) may be more effective in improving speed maintenance in 200- and 300-m runs when performed with a 1:1 rather than a 1:6 exercise-to-rest ratio. This may be due to a greater activation of glycolysis caused, in part, by the limited resynthesis of phosphocreatine during the very short rest interval.     

Sprint performance and mechanical outputs computed with an iPhone app: Comparison with existing reference methods

The purpose of this study was to assess validity and reliability of sprint performance outcomes measured with an iPhone application (named: MySprint) and existing field methods (i.e. timing photocells and radar gun). To do this, 12 highly trained male sprinters performed 6 maximal 40-m sprints during a single session which were simultaneously timed using 7 pairs of timing photocells, a radar gun and a newly developed iPhone app based on high-speed video recording. Several split times as well as mechanical outputs computed from the model proposed by Samozino et al. [(2015). A simple method for measuring power, force, velocity properties, and mechanical effectiveness in sprint running. Scandinavian Journal of Medicine & Science in Sports. https://doi.org/10.1111/sms.12490] were then measured by each system, and values were compared for validity and reliability purposes. First, there was an almost perfect correlation between the values of time for each split of the 40-m sprint measured with MySprint and the timing photocells (r?=?0.989–0.999, standard error of estimate?=?0.007–0.015?s, intraclass correlation coefficient (ICC)?=?1.0). Second, almost perfect associations were observed for the maximal theoretical horizontal force (F₀), the maximal theoretical velocity (V₀), the maximal power (P_max) and the mechanical effectiveness (DRF – decrease in the ratio of force over acceleration) measured with the app and the radar gun (r?=?0.974–0.999, ICC?=?0.987–1.00). Finally, when analysing the performance outputs of the six different sprints of each athlete, almost identical levels of reliability were observed as revealed by the coefficient of variation (MySprint: CV?=?0.027–0.14%; reference systems: CV?=?0.028–0.11%). Results on the present study showed that sprint performance can be evaluated in a valid and reliable way using a novel iPhone app.     

Effects of inertia correction and resistive load on fatigue during repeated sprints on a friction-loaded cycle ergometer

Seven 6 s sprints with 30 s recovery between sprints were performed against two resistive loads: 50 (L50) and 100 (L100) g x kg(-1) body mass. Inertia-corrected and -uncorrected peak and mean power output were calculated. Corrected peak power output in corresponding sprints and the drop in peak power output relative to sprint 1 were not different in the two conditions, despite the fact that mean power output was 15-20% higher in L100 (P < 0.01). The effect of inertia correction on power output was more pronounced for the lighter load (L50), with uncorrected peak power output in sprint 1 being 42% lower than the corresponding corrected peak power output, while this was only 16% in L100. Fatigue assessed by the drop in uncorrected peak and mean power output in sprint 7 relative to sprint 1 was less compared with that obtained by corrected power values, especially in L50 (drop in uncorrected vs. corrected peak power output: 13.3 +/- 2.2% vs. 23.1 +/- 4.1%, P < 0.01). However, in L100, the difference between the drop in corrected and uncorrected mean power output in sprint 7 was much smaller (24.2 +/- 3.1% and 21.2 +/- 2.7%, P < 0.01), indicating that fatigue may be safely assessed even without inertia correction when a heavy load is used. In conclusion, when inertia correction is performed, fatigue during repeated sprints is unaffected by resistive load. When inertia correction is omitted, both power output and the fatigue profile are underestimated by an amount dependent on resistive load. In cases where inertia correction is not possible during a repeated sprints test, a heavy load may be preferable.     

The effect of short-duration sprint interval exercise on plasma postprandial triacylglycerol levels in young men

Abstract

It is well established that regular exercise can reduce the risk of cardiovascular disease, although the most time-efficient exercise protocol to confer benefits has yet to be established. The aim of the current study was to determine the effects of short-duration sprint interval exercise on postprandial triacylglycerol. Fifteen healthy male participants completed two 2 day trials. On day 1, participants rested (control) or carried out twenty 6 s sprints, interspersed with 24 s recovery (sprint interval exercise – 14 min for total exercise session). On day 2, participants consumed a high-fat meal for breakfast with blood samples collected at baseline, 2 h and 4 h. Gas exchange was also measured at these time points. On day 2 of control and sprint interval exercise trials, there were no differences (P < 0.05) between trials in plasma glucose, triacylglycerol, insulin or respiratory exchange ratio (RER). The area under the curve for plasma triacylglycerol was 7.67 ± 2.37 mmol · l^–1.4 h^–1 in the control trial and 7.26 ± 2.49 mmol · l^–1.4 h^–1 in the sprint interval exercise trial. Although the sprint exercise protocol employed had no significant effect on postprandial triacylglycerol, there was a clear variability in responses that warrants further investigation.     

The effect of heavy resistance exercise on repeated sprint performance in youth athletes

This investigation assessed whether prior heavy resistance exercise would improve the repeated sprint performance of 16 trained youth soccer players (Age 17.05 ± 0.65 years; height 182.6 ± 8.9 cm; body mass 77.8 ± 8.2 kg). In session 1, individual 1 repetition max was measured utilising a squat movement. In sessions 2 and 3, participants performed a running-based repeated anaerobic sprint test with and without prior heavy resistance exercise of 91% of their 1 repetition max. Times were recorded for each of the 6 sprints performed in the repeated sprint test and summed to provide total time. T-tests compared the two exercise conditions via differences in corresponding sprint times and total time. Analysis revealed significantly reduced total time with use of heavy resistance exercise (33.48 (±1.27) vs. 33.59 (±1.27); P = 0.01). Sprints 1 (P = 0.05) and 2 (P = 0.02) were also faster in the heavy resistance exercise condition (5.09 (±0.16) vs. 5.11 (±0.16) and 5.36 (±0.24) vs. 5.45 (±0.26) seconds respectively) although no other differences were shown. Findings demonstrate improved sprint times of trained adolescent soccer players after heavy resistance exercise although benefits appear not as sustained as in adult participants.     

Effect of repeat-sprint training in hypoxia on post-exercise interleukin-6 and F2-isoprostanes

This investigation examined the oxidative stress (F₂-Isoprostane; F₂-IsoP) and inflammatory (interleukin-6; IL-6) responses to repeat-sprint training in hypoxia (RSH). Ten trained male team sport athletes performed 3(sets)*9(repetitions)*5?s cycling sprints in simulated altitude (3000?m) and sea-level conditions. Mean and peak sprint power output (MPO and PPO) were recorded, and blood samples were collected pre-exercise, and again at 8 and 60?min post-exercise. Both MPO and PPO were significantly reduced in hypoxia (compared to sea-level) in the second (MPO: 855?±?89 vs. 739?±?95?W, p?=?.006; PPO: 1024?±?114 vs. 895?±?112?W, p?=?.010) and third (MPO: 819?±?105 vs. 686?±?83?W, p?=?.008; PPO: 985?±?125 vs. 834?±?99?W, p?=?.008) sets, respectively. IL-6 was significantly increased from pre- to 1?h post-exercise in both hypoxia (0.7?±?0.2 vs. 2.4?±?1.4?pg/mL, p?=?.004) and sea-level conditions (0.7?±?0.2 vs. 1.6?±?0.3?pg/mL, p?d?=?0.80) suggesting higher IL-6 levels of post-hypoxia. F₂-IsoP was significantly lower 1?h post-exercise in both the hypoxic (p?=?.005) and sea-level (p?=?.002) conditions, with no differences between trials. While hypoxia can impact on exercise intensity and may result in greater post-exercise inflammation, it appears to have little effect on oxidative stress. These results indicate that team sport organisations with ready access to hypoxic training facilities could confidently administer RSH without significantly increasing the post-exercise inflammatory or oxidative stress response.     

Cold water immersion improves recovery of sprint speed following a simulated tournament

Abstract

It is a common requirement in tournament scenarios for athletes to compete multiple times in a relatively short time period, with insufficient recovery time not allowing full restoration of physical performance. This study aimed to develop a greater understanding of the physiological stress experienced by athletes in a tournament scenario, and how a commonly used recovery strategy, cold water immersion (CWI), might influence these markers. Twenty-one trained male games players (age 19?±?2; body mass 78.0?±?8.8?kg) were randomised into a CWI group (n?=?11) or a control group (n?=?10). To simulate a tournament, participants completed the Loughborough Intermittent Shuttle Test (LIST) on three occasions in five days. Recovery was assessed at specific time points using markers of sprint performance, muscle function, muscle soreness and biochemical markers of damage (creatine kinase, CK), inflammation (IL-6 and C-Reactive Protein) and oxidative stress (lipid hydroperoxides and activity of 6 lipid-soluble antioxidants). The simulated tournament was associated with perturbations in some, but not all, markers of physiological stress and recovery. Cold water immersion was associated with improved recovery of sprint speed 24?h after the final LIST (ES?=?0.83?±?0.59; p?=?.034) and attenuated the efflux of CK pre- and post-LIST 3 (p?<?.01). The tournament scenario resulted in an escalation of physiological stress that, in the main, cold water immersion was ineffective at managing. These data suggest that CWI is not harmful, and provides limited benefits in attenuating the deleterious effects experienced during tournament scenarios.