Performance Changes and Recovery Time in U20 and Older Handball Players after a High-Intensity Sprint Exercise

This study used a single bout of repeated high-intensity sprint exercise as a variable to compare the performance and recovery time of handball players within a typical age range for team sport athletes. Two test groups (U20 players, n = 12, mean age = 18 years; senior players, n = 17, mean age = 27 years) were observed during and after their performance of a high-intensity interval exercise consisting of four sets of 6 × 40 m all-out change-of-direction sprints. U20 players outperformed senior players in all sprint sets. The groups’ physiological responses and perceived exertion and stress levels were measured immediately before and after the exercise and also after 24, 48, and 72 h. Repeated measures ANOVAs revealed no interaction effects between age and measurement time points on jump height, muscle soreness, and perceived stress levels after the high-intensity interval exercise. However, the U20 athletes showed marginally, but not statistically significant lower creatine kinase (CK) values than the seniors 72 h after the exercise. The vagal heart rate variability (HRV) parameter rMSSD indicated a faster recovery for the U20 athletes compared to the senior players 24 h after the sprint intervals. Overall, the results demonstrate that repeated sprint intervals do not differently affect the physical performance ability (i.e., jump height) of U20 and senior players. Single parameters related to the players’ ability to recover, such as CK and HRV values, show some variations as a function of age. Based on this, coaches may want to consider a longer recovery period after a high-intensity exercise for senior players compared to younger ones.

Effects of Pyruvate Supplementation on High-intensity Interval Exercise Induced Metabolic Acidosis and Repeated Sprint Exercise Performance of College Soccer Athletes

Background: The effects of pyruvate on metabolic acidosis and oxidative metabolism had been studied. The ability to attenuate acidosis and improve oxidative system contribution are critical to the performance of team sport athletes during perform multiple high-intensity exercise over a limited period of time. This study aimed to investigate the impact of pyruvate supplementation on energy metabolism and metabolic acidosis during high-intensity interval exercise (HIIE), as well as to evaluate its role on repeated sprint exercise (RSE) performance.Methods: 14 well-trained male college soccer athletes (age: 20 ± 2 years, body fat: 13.11 ± 3.50 %) were studied in a randomized, double-blind, cross-over study. The participants ingested either 0.1g/kg/d of pyruvate or a placebo for 1-week. Metabolic acidosis was induced by HIIE after the supplement period, and RSE ability in the acidosis state was assessed. Venous blood pH, bicarbonate (HCO3-) and base excess (BE) were measured at baseline, pre-HIIE, post-HIIE, pre-RSE and post-RSE. Finger-stick blood lactate were collected at baseline, immediately after each bout of HIIE and 3, 5, 7, 10 min after HIIE. The energy systems contribution during HIIE were estimated. Results: Blood pH, HCO3- and BE were significantly lower than baseline after HIIE (p < 0.01) in both pyruvate group (PYR) and placebo group (PLA). Compared to PLA, the blood pH, HCO3- and BE were significantly improved in PYR at pre-HIIE (p < 0.01), post-HIIE (p < 0.01) and pre-RSE (p < 0.01). Furthermore, blood BE remained higher in PYR than PLA till end of RSE (p < 0.05). The contribution of oxidative system in the fourth bout of HIIE was higher in PYR than PLA (p < 0.05). In PLA, the ratio of total anaerobic energy contribution during HIIE was higher than that of aerobic (oxidative) (p < 0.01), but not in PYR (p > 0.05). Relative peak power (RPP) of first, fifth sprint, relative average power (RAP) of fifth sprint, the average of RPP and RAP during RSE were significantly improved in PYR compared with PLA (p < 0.05). While no significant changes in the PD% of each bout (p > 0.05) or average PD% (p > 0.05) were observed between the two groups. Conclusion: Pyruvate supplementation for 1-week enhances oxidative system energy contribution and buffers metabolic acidosis during HIIE, and improves RSE performance in acidosis.

Symbolic Analysis of the Heart Rate Variability During the Plateau Phase Following Maximal Sprint Exercise

Cardiac autonomic control is commonly assessed via the analysis of fluctuations of the temporal distance between two consecutive R-waves (RR). Cardiac regulation assessment following high intensity physical exercise is difficult due to RR non-stationarities. The very short epoch following maximal sprint exercise when RR remains close to its lowest value, i.e., the PLATEAU, provides the opportunity to evaluate cardiac regulation from stationary RR sequences. The aim of the study is to evaluate cardiac autonomic control during PLATEAU phase following 60-m maximal sprint and compare the results to those derived from sequences featuring the same length as the PLATEAU and derived from pre-exercise and post-exercise periods. These sequences were referred to as PRE and POST sequences. RR series were recorded in 21 subjects (age: 24.9 ± 5.1 years, 15 men and six women). We applied a symbolic approach due to its ability to deal with very short RR sequences. The symbolic approach classified patterns formed by three RRs according to the sign and number of RR variations. Symbolic markers were compared to more classical time and frequency domain indexes. Comparison was extended to simulated signals to explicitly evaluate the suitability of methods to deal with short variability series. A surrogate test was applied to check the null hypothesis of random fluctuations. Over simulated data symbolic analysis was able to separate dynamics with different spectral profiles provided that the frame length was longer than 10 cardiac beats. Over real data the surrogate test indicated the presence of determinism in PRE, PLATEAU, and POST sequences. We found that the rate of patterns with two variations with unlike sign increased during PLATEAU and in POST sequences and the frequency of patterns with no variations remained unchanged during PLATEAU and decreased in POST compared to PRE sequences. Results indicated a sustained sympathetic control along with an early vagal reactivation during PLATEAU and a shift of the sympathovagal balance toward vagal predominance in POST compared to PRE sequences. Time and frequency domains markers were less powerful because they were dominated by the dramatic decrease of RR variance during PLATEAU.

Sex Differences in Response to Listening to Self-Selected Music during Repeated High-Intensity Sprint Exercise

The purpose of this study was to examine possible sex differences in high-intensity exercise performance, fatigue, and motivational responses to exercise while listening to music. Physically active males and females (ages 18–24) were recruited to participate. Participants completed two separate repeated sprint exercise trials each with a different condition: (1) no music (NM) (2) self-selected music (SSM). During each trial, participants completed 3 × 15 s Wingate anaerobic tests (WAnTs) while listening to NM or SSM separated by 2 min of active recovery. Following each WAnT, rate of perceived exertion (RPE) and motivation to exercise were assessed. Relative power output, fatigue index, RPE, and motivation were analyzed. There were no significant sex differences for relative power between music conditions (p = 0.228). Fatigue index was significantly lower in females while listening to SSM (p = 0.032) versus NM while no differences were observed for males (p = 0.246). RPE was lower while listening to SSM versus NM in females (p = 0.020), but not for males (p = 0.277). Lastly, motivation to exercise increased in the SSM condition versus NM in females (p = 0.006) but not in males (p = 0.090). Results indicate that listening to SSM music did not result in superior anaerobic performance in either sex, but females responded more favorably to subjective outcomes (i.e., RPE and motivation) while listening to SSM, which may have in turn influenced indices of fatigue during the tests. These results suggest that females may respond more positively than males to exercise-induced fatigue while listening to SSM music during repeated bouts of high-intensity exercise.

Effects of Reduced Carbohydrate Intake after Sprint Exercise on Breath Acetone Level

Assessment of breath acetone level may be an alternative procedure to evaluate change in fat metabolism. The purpose of the present study was to investigate the effect of insufficient carbohydrate (CHO) intake after sprint exercise on breath acetone level during post-exercise. Nine subjects conducted two trials, consisting of either reduced CHO trial (LOW trial) or normal CHO trial (NOR trial). In each trial, subjects visited to laboratory at 7:30 following an overnight fast to assess baseline breath acetone level. They commenced repeated sprint exercise from 17:00. After exercise, isoenergetic meals with different doses of CHO (LOW trial; 18% for CHO, 27% for protein, 55% for fat, NOR trial; 58% for CHO, 14% for protein, 28% for fat) were served. Breath acetone level was also monitored immediately before and after exercise, 1 h, 3 h, 4 h, and 15 h (on the following morning) after completing exercise. A significant higher breath acetone level was observed in LOW trial than in NOR trial 4 h after completion of exercise (NOR trial; 0.66 ppm, LOW trial; 0.9 ppm). However, breath acetone level did not differ on the following morning between two trials. Therefore, CHO intake following an exhaustive exercise affects breath acetone level during early phase of post-exercise.

The methylome and comparative transcriptome after high intensity sprint exercise in human skeletal muscle

The methylome and transcriptome signature following exercise that is physiologically and metabolic relevant to sporting contexts such as team sports or health prescription scenarios (e.g. high intensity interval training/HIIT) has not been investigated. To explore this, we undertook two different sport/exercise relevant high-intensity sprint running protocols in humans using a repeated measures design of: 1) Change of direction (COD) versus; 2) straight line (ST) sprint exercise. We took skeletal muscle biopsies from the vastus lateralis 30 minutes and 24 hours post exercise followed by 850K methylation arrays and comparative analysis with recent sprint and acute aerobic exercise meta-analysis transcriptomes. Despite matched intensity (speed x distance and number of accelerations/decelerations) between COD and ST exercise, COD exercise elicited greater movement (GPS Playerload™), physiological (HR), metabolic (lactate) as well as central and peripheral (differential RPE) loading compared with ST exercise. The exercise response alone across both conditions evoked extensive alterations in the methylome immediately post and 24 hrs after exercise, particularly in MAPK, AMPK and axon guidance pathways. COD evoked a considerably greater hypomethylated signature across the genome compared with ST sprint exercise, particularly enriched in: Protein binding, MAPK, AMPK, insulin, and axon guidance pathways. A finding that was more prominent immediately post exercise. Comparative methylome analysis with sprint running transcriptomes identified considerable overlap, with 49% of the genes altered at the expression level also differentially methylated after COD exercise. After differential methylated region analysis, we discovered that VEGFA and its downstream nuclear transcription factor, NR4A1 had enriched hypomethylation within their promoter regions. VEGFA and NR4A1 were also significantly upregulated in the sprint transcriptome and meta-analysis of exercise transcriptomes. We confirmed increased mRNA expression of VEGFA, and considerably larger increases in the expression of canonical metabolic genes, PGC1-α and NR4A3, 3 hrs post COD vs. ST exercise. Overall, we demonstrate that increased physiological load via change of direction sprint exercise in human skeletal muscle evokes considerable epigenetic modifications that are associated with changes in expression of genes responsible for adaptation to exercise. These data imply that introducing changes in direction into high intensity running protocols could serve as an important modulator of a favourable epigenomic and transcriptomic landscape in response to exercise in athletes and trigger greater skeletal muscle remodelling through enhanced gene expression.