Purpose The intensity of active recovery (AR) for performance recovery is often determined using breath gas analyzers and other special equipment. However, such procedures are difficult to perform in ...the field or where facilities are inadequate. Although several AR methods using simple patient-derived information have been proposed, only a few have specifically addressed their immediate effects. The present study aimed to quantify the immediate effects of AR, which was determined using the maximum exercise capacity calculated using a physical fitness test without specialized devices. Participants and Methods Thirty-two healthy male participants were equally divided into AR and control groups. Each group performed squat jumps, followed by a recovery intervention of jogging at a set intensity in the AR group or rest in a seated position in the control group. Standing long jumps performed before and after the squat jumps as well as after the intervention were analyzed. Results The recovery rate for standing long jumps was significantly higher in the AR group than in the control group. Conclusion The results of this pilot study indicate that the implementation of AR based on maximum exercise capacity may enhance performance recovery and requires further validation in larger studies.
Purpose This study aimed to investigate cardiovascular responses, including heart rate (HR) and heart rate variability (HRV), to various hyperlactatemia–passive exercise interactions. Participants ...and Methods Nine healthy male participants performed upper limb passive cycling movement, and their HR and HRV were assessed while their blood lactate levels were manipulated by sustained handgrip exercise at control, 15% maximum voluntary contraction (MVC), and 30% MVC, followed by postexercise circulatory occlusion. Results HR and root mean squared standard difference (rMSSD) of HRV response remained constant at all blood lactate levels during passive exercise (HR: control, 75.8 ± 3.4 bpm; 15% MVC, 76.9 ± 2.7 bpm; and 30% MVC, 77.0 ± 3.7 bpm; rMSSD: control, 33.2 ± 6.9 ms; 15% MVC, 36.3 ± 7.3 ms; and 30% MVC, 37.3 ± 8.9 ms). Conclusion Manipulating metaboreflex activation did not significantly alter HR or HRV during passive exercise. These results suggest that, in healthy participants, the interactions between mechanical and metabolic stimuli do not affect HR and HRV responses, implying that passive exercise may be safely implemented.
: The hyperbolic form of the power-duration relationship is rigorous and highly conserved across species, forms of exercise, and individual muscles/muscle groups. For modalities such as cycling, the ...relationship resolves to two parameters, the asymptote for power (critical power CP) and the so-called W' (work doable above CP), which together predict the tolerable duration of exercise above CP. Crucially, the CP concept integrates sentinel physiological profiles-respiratory, metabolic, and contractile-within a coherent framework that has great scientific and practical utility. Rather than calibrating equivalent exercise intensities relative to metabolically distant parameters such as the lactate threshold or V˙O2max, setting the exercise intensity relative to CP unifies the profile of systemic and intramuscular responses and, if greater than CP, predicts the tolerable duration of exercise until W' is expended, V˙O2max is attained, and intolerance is manifested. CP may be regarded as a "fatigue threshold" in the sense that it separates exercise intensity domains within which the physiological responses to exercise can (<CP) or cannot (>CP) be stabilized. The CP concept therefore enables important insights into 1) the principal loci of fatigue development (central vs. peripheral) at different intensities of exercise and 2) mechanisms of cardiovascular and metabolic control and their modulation by factors such as O2 delivery. Practically, the CP concept has great potential application in optimizing athletic training programs and performance as well as improving the life quality for individuals enduring chronic disease.
Introduction
Repeated sprints exercise (RSE) performed in hypoxia (RSH) induce greater performance improvement than in normoxia (Brocherie et al., 2017). It has been previously argued that RSH ...efficiency depend on the oxidative-glycolytic balance which is influenced by sprint duration and exercise-to-rest-ratio (E:R). Indeed, we recently showed that long sprint duration (e.g. 20 s vs 10 s or 5 s) blunts the additional impact of hypoxia on RSH with a constant large E:R of 1:22. However, E:R also influence acute response to RSH. Therefore, this study aims to compare acute responses during RSE to exhaustion with a short E:R (1:6) in normoxia (RSN) and hypoxia (FiO2 = 0.13) and the same sprint durations (5, 10 or 20 s) previously used.
Methods
On separate visits, 10 active participants completed in random order three RSH and three RSN sessions to exhaustion on a cycle-ergometer (Excalibur Sport, Lode) with three sprint durations and a constant short E:R of 1:6 (5:30; 10:60 and 20:120). Vastus lateralis muscle de-reoxygenation (Oxymon, Artinis Medical Systems) and power output were continuously recorded. Lower limb and breathing discomfort, blood lactate, and ratings of perceived exertion were evaluated immediately after exhaustion.
Results
Number of sprints and peak power output were higher while blood lactate was lower (all p < 0.001) during 5:30 compared to 10:60 or 20:120. No condition or interaction effects were reported for blood lactate and exercise-related sensation. Blood lactate and muscle deoxyhemoglobin increase (p < 0.001) and total hemoglobin decrease (p = 0.002) during sprint were more pronounced when sprint duration increased (no hypoxia effect).
Discussion
Similar deoxygenation changes during recovery were reported in hypoxia compared to normoxia suggesting that 1:6 ratio and the associated long recovery period seemed to allow myoglobin O2 store restauration, even with a FiO2 = 13%. Sprint effort should be interspersed by incomplete recovery making impossible the full O2 reloading myoglobin and PCr resynthesis. The increase in blood lactate and the concomitant decrease in muscle oxygenation during sprint with longer duration confirmed a switch in the oxidative-glycolytic balance for energy supply. Since short exercise-to-rest ratio blunt hypoxic effect during RSH due to too long recovery period, hypoxia did not participate to the switch from oxidative to glycolytic energy supply.
Conclusion
During RSE to exhaustion, a short exercise-to-rest ratio (i.e., 1:6) blunts the specific psychophysiological responses induced by hypoxia, probably due to too long of recovery period. Manipulating effort duration rather than hypoxic exposure is preferable to alter both anaerobic energy system solicitation and power produced during repeated cycling sprints to exhaustion using a short exercise-to-rest ratio.
References
Brocherie, F., Girard, O., Faiss, R., & Millet, G. P. (2017). Effects of repeated-sprint training in hypoxia on sea-level performance: A meta-analysis. Sports Medicine, 47, 1651-1660. https://doi.org/10.1007/s40279-017-0685-3
Background: Caffeine is considered as one of the most nutritional supplements and the most consuming stimulant among athletes. Objective: The purpose of this study was to investigate the effect of ...caffeine on blood lactate response following exhaustive activities in the chest and chest bite of young male swimmers. Methods: This quasi-experimental study was performed and 16 male young swimmers were randomly divided into two groups. At first, swimmers without caffeine took part in a 100-meter long chest and back chest for the purpose of initial recording. Then, after seven more refreshments, taking caffeine was recorded. Blood lactate samples were taken in three stages of the basal state, after the supplementation period and immediately after exercise. Data were analyzed using repeated measure ANOVA, Bonferroni and independent correlation T-test. Results: The results of repeated analysis of variance showed that the consumption of caffeine had a significant effect on blood lactate response after exhaustive activities compared with the control group (P < 0.001) and also improved the record performance of swimmers (P < 0.001). Conclusion: The results showed that consumption of caffeine in groups had a significant effect on blood lactate and swimmerschr('39') performance, but there was no significant difference between breast and back chest groups.
Maximal oxygen uptake (VO
2
max) is a widely used measure of cardiorespiratory fitness, aerobic function, and overall health risk. Although VO
2
max has been measured for almost 100 yr, no ...standardized criteria exist to verify VO
2
max attainment. Studies document that incidence of 'true' VO
2
max obtained from incremental exercise (INC) can be confirmed using a subsequent verification test (VER). In this study, we examined efficacy of VER in persons with spinal cord injury (SCI).
Repeated measures, within-subjects study.
University laboratory in San Diego, CA.
Ten individuals (age and injury duration = 33.3 ± 10.5 yr and 6.8 ± 6.2 yr) with SCI and 10 able-bodied (AB) individuals (age = 24.1 ± 7.4 yr).
Peak oxygen uptake (VO
2
peak) was determined during INC on an arm ergometer followed by VER at 105 percent of peak power output (% PPO).
Gas exchange data, heart rate (HR), and blood lactate concentration (BLa) were measured during exercise.
Across all participants, VO
2
peak was highly related between protocols (ICC = 0.98) and the mean difference was equal to 0.08 ± 0.11 L/min. Compared to INC, VO
2
peak from VER was not different in SCI (1.30 ± 0.45 L/min vs. 1.31 ± 0.43 L/min) but higher in AB (1.63 ± 0.40 L/min vs. 1.76 ± 0.40 L/min).
Data show similar VO
2
peak between incremental and verification tests in SCI, suggesting that VER confirms VO
2
max attainment. However, in AB participants completing arm ergometry, VER is essential to validate appearance of 'true' VO
2
peak.
The aim of this study was to seek a possible significant correlation between post-competition blood lactate concentrations (BLc) and the times achieved in swimming events. The research was done among ...71 swimmers (44 men and 27 women) of the Bulgarian national swimming team. The average age of the participants was 17.48 ± 2.50 years (18.02 ± 2.62 for men and 16.59 ± 2.00 for women). Blood lactate concentrations were measured 3 to 6 min after the finals of all individual swimming events in official competitions and the time ranged between 653 and 898 FINA points. The total number of measurements was 280 (175 samples from men and 105 from women) collected during a 3-year period (2016 -2018). The results indicated that the highest mean values of BLc were obtained after sprint distances: men’s 100m freestyle (16.91 ± 4.32 mmol/L) and women’s 100 m butterfly (16.89 ± 2.35 mmol/L). The lowest mean values were measured after distance swimming of 1500 m freestyle: 7.14±3.34 mmol/L for the man and 5.10 mmol/L for the women. Statistically significant coefficients of correlation between swimming times and BLc were observed in men’s swimming events of 100 m butterfly (r = -0.484); 100 m backstroke (r = -0.721); 100 m freestyle (r = -0.854); 50 m freestyle (r = -0.891) and women’s swimming event of 50 m freestyle (r = -0.688). In conclusion, there is no statistically significant difference in the post-competitive BLc levels depending on gender; significant differences in mean values of BLc between breaststroke and all other strokes; in sprint swimming events (especially in 100 m freestyle) statistically significant correlations between BLc and swimming times were observed.
Background: Motocross riders’ performance is highly dependent on the characteristics of the motorcycles and the skills of the riders, and the actual environmental conditions. This study aims to ...describe the differences in anthropometric and physiological characteristics between internationally ranked adolescent males and nationally ranked motorcross (MX) peer competitors; Methods: Data obtained from young riders (n=14) were divided into internationally ranked G1 (n=5) and - nationally ranked G2 (n=9) young MX riders. We determined body composition and cardiorespiratory variables, and measured heart rate and movement-related data with Polar Team Pro system during the race; (3) Results: Blood lactate concentrations were evaluated before and after the race session. MX riders with an international ranking performed significantly better during both races (R1 and R2), which manifested itself in significantly shorter times per lap on average (difference for R1=14.8 s and for R2=16.7 s, respectively, p=0.017), more laps completed (G1 vs G2 approx.: 11.2 : 9.9 laps for R1 and R2, p=0.019) and points scored (difference: R1=9.3 pts and R2=9.0 pts, p=0.014). There were no statistically significant differences in age between the two compared groups (p=0.559) and other anthropometric and physiological characteristics tested, with an exception of muscle mass percent (p<0.001); Conclusions: Current results showed that motocross probably places a heavy burden on riders, who need to be fit enough to maintain their position in the field.
Badminton is the fastest racket game with action of short duration and high intensity. Purpose: to measure and compare blood lactate concentration, PRE, heart rate and blood pressure before and ...after repeated badminton matches. Method: Six national ranked players (age = 22.6 ± 5.3 years; height = 172.5 ± 3.2 cm, weight = 66.1 ± 5.3 kg) played four badminton matches in raw with recovery period of 30 minutes in which Heart Rate, Blood pressure and RPE were measured before and immediately after the end ofeach match. Additionally, blood lactate concentration was measured before and after 5 min from the end of the match. Result: the study indicates that blood lactate concentration and RPE were higher in the fourth match comparing to others with significant differences among them for both before F3, 15= 20.08, P=0.000, F3, 15= 14.80, P=0.000, and after the end of the matches F3, 15= 16.48, P=0.000. F3, 15= 13.71, P=0.000, respectively. No significant differences for heart rate and blood pressure were found. Conclusion: the repetitive badminton matches exerted high cardiovascular and psychophysiological stress on the players. Reconsidering the given recovery time and the number of games allowed per day during national and international tournaments is highly recommended.
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