Does the Repeated-Bout Effect Influence Post-Activation Performance Enhancement in Recreational Runners?

Purpose: This study examined how a low dose of an eccentric-oriented lunge exercise could induce the repeated-bout effect (RBE) and affect the subsequent post-activation performance enhancement (PAPE) in recreational runners. Methods: Twenty male recreational runners (32.1 ± 2.8 years; 173.4 ± 6.1 cm; 73.3 ± 11.5 kg; 57.8 ± 7.2 mL·kg-1·min-1) were divided into control (N = 10) and experimental (N = 10) groups. In the first and fourth weeks, the groups were assessed for jump capacity, dynamic balance, and submaximal running kinematics before and after an incremental shuttle-run test until exhaustion. The experimental group was also submitted to two sessions of the eccentric-oriented lunge exercise (3 sets of 10 repetitions with 2 min of passive recovery) in the second and third weeks. Results: We observed that the first session promoted muscle damage, which was significantly (p < .05) reduced after the second training session, thus indicating an RBE. Meanwhile, there was no effect of the RBE on dynamic balance and submaximal running kinematics in the post-intervention. However, there was a significant increase in countermovement jump height (p = .008) for the experimental group when compared to the control group, although no PAPE was observed. Conclusions: The current results demonstrate that a simple, low-dose eccentric-oriented exercise may induce an RBE, leading to reduced muscle damage and a possibly improved lower limbs' muscle power in recreational runners. However, the absence of PAPE effects suggests that the RBE may not directly influence the potentiation/fatigue balance after fatiguing running exercises.

The Repeated Bout Effect of Multiarticular Exercises on Muscle Damage Markers and Physical Performances: A Systematic Review and Meta-Analyses.

ABSTRACT: Doma, K, Matoso, B, Protzen, G, Singh, U, and Boullosa, D. The repeated bout effect of multiarticular exercises on muscle damage markers and physical performances: a systematic review and meta-analyses. J Strength Cond Res 37(12): 2504-2515, 2023-This systematic review and meta-analysis compared muscle damage markers and physical performance measures between 2 bouts of multiarticular exercises and determined whether intensity and volume of muscle-damaging exercises affected the outcomes. The eligibility criteria consisted of (a) healthy male and female adults; (b) multiarticular exercises to cause muscle damage across 2 bouts; (c) outcome measures were compared at 24-48 hours after the first and second bouts of muscle-damaging exercise; (d) at least one of the following outcome measures: creatine kinase (CK), delayed onset of muscle soreness (DOMS), muscle strength, and running economy. Study appraisal was conducted using the Kmet tool, whereas forest plots were derived to calculate standardized mean differences (SMDs) and statistical significance and alpha set a 0.05. After screening, 20 studies were included. The levels of DOMS and CK were significantly greater during the first bout when compared with the second bout at T24 and T48 (p < 0.001; SMD = 0.51-1.23). Muscular strength and vertical jump performance were significantly lower during the first bout compared with the second bout at T24 and T48 (p ≤ 0.05; SMD = -0.27 to -0.40), whereas oxygen consumption and rating of perceived exertion were significantly greater during the first bout at T24 and T48 (p < 0.05; SMD = 0.28-0.65) during running economy protocols. The meta-analyses were unaffected by changes in intensity and volume of muscle-damaging exercises between bouts. Multiarticular exercises exhibited a repeated bout effect, suggesting that a single bout of commonly performed exercises involving eccentric contractions may provide protection against exercise-induced muscle damage for subsequent bouts.

Energy demands in high-intensity intermittent taekwondo specific exercises.

Background: Taekwondo is an intermittent Olympic combat sport, which shows an aerobic predominance in matches and high participation of alactic metabolism for actions that determine competitive success. However, there is no information on energetic contribution systems in different high-intensity intermittent exercises for metabolic conditioning with specific movements. The study aimed to measure the physiological demands, mainly the energy expenditure, in taekwondo-specific high-intensity intermittent exercises (HIIE). Methods: This study recruited ten male black belt athletes with a mean age of 20.2 ± 4 years, body mass of 62.8 ± 10.5 kg and height of 170.6 ± 7.8 cm, and total practice time of 11.8 ± 5.4 years. Subjects performed an incremental specific test and three different HIIE protocols on nonconsecutive days, and all comprised three 2-min rounds and 1 min of recovery between rounds. Heart rate, oxygen consumption, and blood lactate were measured. Energetic expenditure of aerobic, alactic, and lactic metabolisms was estimated through oxygen consumption, excess post-exercise oxygen consumption, and peak blood lactate after each round. Results: For the mean of the three rounds, the TKDtest100 resulted in higher absolute and relative contribution from the aerobic metabolism (52.4 ± 4%; p = 0.01) and lower than the 35:5 relative alactic contribution (48.7 ± 5.4%; p = 0.03). Conclusion: The mean of the three rounds for 35:5 and 15:10:5 presented similar absolute and relative contributions of aerobic and alactic metabolisms, whereas the TKDtest100 was a predominantly aerobic activity. We emphasize that aerobic metabolism was predominant from the second round in the 15:10:5 and 100%TKDtest protocols and in the last round of the 35:5 protocol.

Inclusion of sprints during moderate-intensity continuous exercise enhances post-exercise fat oxidation in young males.

To assess the physiological demands of including high-intensity efforts during continuous exercise, we designed a randomized crossover study, in which 12 physically active young males executed 3 different exercises in random order: FATmax - continuous exercise at the highest fat oxidation zone; 2min-130% - FATmax interspersed by a 2-minute bout at 130% of the maximal oxygen uptake associated intensity (iV̇O2max); and 20s:10s-170% - FATmax interspersed by four 20-s bouts at 170%iV̇O2max interpolated by 10s of passive recovery. We measured oxygen uptake (V̇O2), blood lactate concentration ([LAC]), respiratory exchange rate (RER), and fat and carbohydrate (CHO) oxidation. For statistical analyses, repeated-measures ANOVA was applied. Although no differences were found for average V̇O2 or carbohydrate oxidation rate, the post-exercise fat oxidation rate was 37.5% and 50% higher during the 2min-130% and 20s:10s-170% protocols, respectively, compared with the FATmax protocol, which also presented lower values of RER during exercise compared with 2min-130% and 20s:10s-170% (p < 0.001 in both), and higher values post-exercise (p = 0.04 and p = 0.002, respectively). [LAC] was higher during exercise when high-intensity bouts were applied (p < 0.001 for both) and was higher at post-exercise during the intermittent bouts compared with FATmax (p = 0.016). The inclusion of high-intensity efforts during moderate-intensity continuous exercise promoted higher physiological demands and post-exercise fat oxidation. Novelty: The inclusion of 2-minute efforts modifies continuous exercise demands. Maximal efforts can increase post-exercise fat oxidation. 2-minute maximal efforts, continuous or intermittent, presents similar demands.

Physiological aspects and energetic contribution in 20s:10s high-intensity interval exercise at different intensities.

BACKGROUND: One of the most popular high-intensity interval exercises is the called "Tabata Protocol". However, most investigations have limitations in describing the work intensity, and this fact appears to be due to the protocol unfeasibility. Furthermore, the physiological demands and energetic contribution during this kind of exercise remain unclear. METHODS: Eight physically active students (21.8 ± 3.7 years) and eight well-trained cycling athletes (27.8 ± 6.4 years) were enrolled. In the first visit, we collected descriptive data and the peak power output (PPO). On the next three visits, in random order, participants performed interval training with the same time structure (effort:rest 20s:10s) but using different intensities (115%, 130%, and 170% of PPO). We collected the number of sprints, power output, oxygen consumption, blood lactate, and heart rate. RESULTS: The analysis of variance for multivariate test (number of sprints, power output, blood lactate, peak heart rate and percentage of maximal heart rate) showed significant differences between groups (F = 9.62; p = 0.001) and intensities (F = 384.05; p < 0.001), with no interactions (F = 0.94; p = 0.57). All three energetic contributions and intensities were different between protocols. The higher contribution was aerobic, followed by alactic and lactic. The aerobic contribution was higher at 115%PPO, while the alactic system showed higher contribution at 130%PPO. In conclusion, the aerobic system was predominant in the three exercise protocols, and we observed a higher contribution at lower intensities.

Effects of High-Intensity Interval Training in Combat Sports: A Systematic Review with Meta-Analysis.

Vasconcelos, BB, Protzen, GV, Galliano, LM, Kirk, C, and Del Vecchio, FB. Effects of high-intensity interval training in combat sports: A systematic review with meta-analysis. J Strength Cond Res 34(3): 888-900, 2020-Combat sports (CS) are intermittent by nature and high-intensity interval training (HIIT) has been used as a tool to maintain and improve physical fitness among CS athletes. The aim of this study was to perform a systematic review and meta-analysis about chronic effects of HIIT in CS athletes. An electronic search was performed in PubMed, Science Direct, and Google Scholar using the following Boolean criteria: ("CS" OR "martial arts" OR "judo" OR "taekwondo" OR "jiu jitsu" OR "boxing" OR "karate" OR "wrestling" OR "wushu" OR "kung fu") AND ("HIIT" OR "intermittent exercise" OR "sprint interval training" OR "repeated sprint training [RST]"). To be included, the studies needed to be original, involve CS athletes, present HIIT intervention protocol (HIIT, sprint interval training [SIT] or RST), and analyze chronic physiological outcomes. From 2,211 identified studies, after screening and eligibility evaluation, 12 studies were included in this review with meta-analysis. Aerobic (aerobic capacity, heart rate, and maximum oxygen uptake), anaerobic (peak and mean power in single and successive Wingate tests, and blood lactate concentration), and anthropometric outcomes (body mass and body fat percentage) were evaluated. Data of 255 subjects from 12 studies were assessed. Regarding methodological quality, 7 studies obtained 9-10/12 on the TESTEX scale. For the interventions, 5 studies used HIIT, 4 studies used RST protocols, one used SIT protocols, and one used an intermittent protocol that could not be classified. Relating to aerobic power, was found an increase in V[Combining Dot Above]O2max, with a mean difference (MD) of 2.83 ml·kg·min (CI 95% = 0.40-5.25; p < 0.001) for striking and 2.36 ml·kg·min (CI 95% = 1.05-3.66; p < 0.001) for grappling athletes. No differences on anaerobic peak power for striking (MD = 0.67 W; CI 95% = -0.43 to 1.77; p = 0.23) were found, and a statistical improvement for grappling athletes, (MD = 0.51 W; CI 95% = 0.03-0.98; p = 0.04) was found. Seven studies analyzed anthropometric variables, with differences for body mass in striking (MD = -0.93 kg; CI 95% = -1.68 to -0.19; p = 0.01) and no differences for grappling (MD = -0.09 kg; CI 95% = -2.80 to 2.62; p = 0.95). Differences in body fat percentage in striking (MD = 0.50%; CI 95% = 0.30-0.70; p < 0.001) and no differences in grappling (MD = -0.87%; CI 95% = -1.77 to 0.03; p = 0.06) were found. It was concluded that HIIT positively influences maximum oxygen uptake and anaerobic power in combat sport athletes, with a minor impact on body composition.