A Comparative Study: Cardioprotective Effects of High-Intensity Interval Training Versus Ischaemic Preconditioning in Rat Myocardial Ischaemia-Reperfusion.

(1) Background: Years of research have identified ischemic preconditioning (IPC) as a crucial endogenous protective mechanism against myocardial ischemia-reperfusion injury, enhancing the myocardial cell's tolerance to subsequent ischemic damage. High-intensity interval training (HIIT) is promoted by athletes because it reduces exercise duration and improves metabolic response and cardiopulmonary function. Our objective was to evaluate and compare whether HIIT and IPC could reduce myocardial ischemia and reperfusion injury in rats. (2) Methods: Male Sprague-Dawley rats were divided into four groups: sham surgery, coronary artery occlusion (CAO), high-intensity interval training (HIIT), and ischemic preconditioning (IPC). The CAO, HIIT, and IPC groups experienced 40 min of coronary artery occlusion followed by 3 h of reperfusion to induce myocardial ischemia-reperfusion injury. Subsequently, the rats were sacrificed, and blood samples along with cardiac tissues were examined. The HIIT group received 4 weeks of training before surgery, and the IPC group underwent preconditioning before the ischemia-reperfusion procedure. (3) Results: The HIIT and IPC interventions significantly reduced the extent of the myocardial infarction size and the levels of serum troponin I and lactate dehydrogenase. Through these two interventions, serum pro-inflammatory cytokines, including TNF-α, IL-1ß, and IL-6, were significantly decreased, while the anti-inflammatory cytokine IL-10 was increased. Furthermore, the expression of pro-apoptotic proteins PTEN, caspase-3, TNF-α, and Bax in the myocardium was reduced, and the expression of anti-apoptotic B-cell lymphoma 2 (Bcl-2) was increased, ultimately reducing cellular apoptosis in the myocardium. In conclusion, both HIIT and IPC demonstrated effective strategies with potential for mitigating myocardial ischemia-reperfusion injury for the heart.

Effect of Lactobacillus plantarum PS128 on neuromuscular efficiency after a half-marathon.

Introduction: Lactobacillus plantarum PS128 (PS128) could be considered an antioxidant supplement to reduce muscle fatigue and improve exercise capacity recovery after vigorous exercise. Purpose: The purpose of this study is to investigate the effect of PS128 on muscle fatigue and electromyography (EMG) activity after a half-marathon (HM). Methods: The experimental design used a repeated-measures design with a double-blind approach. The participants either took two capsules of PS128 for 4 weeks as the PS128 group (PSG, n = 8) or took two capsules of a placebo for 4 weeks as the placebo group (PLG, n = 8) to ensure counterbalancing. The time points of the maximal voluntary isometric contraction (MVIC) and EMG activity test were set before probiotics were taken (baseline), 48 h before HM (Pre), and immediately at 0 h, 3 h, 24 h, 48 h, 72 h, and 96 h after HM. Results: EMG activity included median power frequency (MDF), integrated EMG (iEMG), and neuromuscular efficiency (peak torque/iEMG). The MVICs of knee extensors, analyzed by using an isokinetic dynamometer, showed a decrease from the Pre to 0 h (p = 0.0001), 3 h (p < 0.0001), 24 h (p < 0.0001), 48 h (p < 0.0001), 72 h (p = 0.0002), and 96 h (p = 0.0408) time points in the PLG. Sidak's multiple comparisons tests showed that the PLG was significantly lower than the PSG at 0 h (p = 0.0173), 3 h (p < 0.0001), 24 h (p < 0.0001), 48 h (p < 0.0001), 72 h (p < 0.0001), and 96 h (p = 0.0004) time points. The MDF of vastus medialis oblique (VMO) in the PLG was significantly decreased 24 h after HM and significantly lower than that in the PSG at all times points after HM. The iEMG of VMO in the PLG was significantly decreased 48 h after HM and significantly lower than that in the PSG at 0 h, 3 h, 24 h, 48 h, and 72 h after HM. Conclusion: The PS128 supplementation may prevent the decrease in MDF, iEMG, and peak torque after vigorous exercise. Recreational runners may consider implementing a probiotic supplementation regimen as a potential strategy to mitigate muscle fatigue following HM.

Effects of swimming training on myocardial protection in rats.

Swimming is important for promoting and maintaining health, as it can increase the efficiency of the cardiovascular system and decrease the occurrence of cardiovascular diseases. The objective of the present study was to examine whether swimming training could decrease myocardial injury in rats caused by myocardial ischemia/reperfusion (I/R). Sprague-Dawley rats were randomized into four groups, namely the Sham, coronary artery occlusion, swimming training and ischemic preconditioning (IPC) groups. Myocardial I/R was induced in anesthetized male Sprague-Dawley rats by a 40-min occlusion followed by a 3-h reperfusion of the left anterior descending coronary artery. The rats were sacrificed after surgery and their hearts were examined. The results demonstrated that the number of TUNEL-positive nuclei and degree of caspase-3 activation were both significantly increased in the myocardium following myocardial I/R in rats, indicating increased cardiomyocyte apoptosis. On the other hand, swimming training decreased the serum levels of creatine phosphokinase, lactate dehydrogenase and cardiac troponin I, and was associated with reduced histological damage and myocardial infarct size. Furthermore, swimming training also reduced TNF-α levels, caspase-3 activation and enhanced Bcl-2 activation, which decreased the number of apoptotic cells in the myocardium. The findings of the present study showed that swimming training and IPC could similarly decrease myocardial injury following myocardial I/R, and may therefore be used as exercise training to effectively prevent myocardial injury.

Post-activation Performance Enhancement after a Bout of Accentuated Eccentric Loading in Collegiate Male Volleyball Players.

The purpose of this study was to investigate the benefit of post-activation performance enhancement (PAPE) after accentuated eccentric loading (AEL) compared to traditional resistance loading (TR). Sixteen male volleyball athletes were divided in AEL and TR group. AEL group performed 3 sets of 4 repetitions (eccentric: 105% of concentric 1RM, concentric: 80% of concentric 1RM) of half squat, and TR group performed 3 sets of 5 repetitions (eccentric & concentric: 85% of 1RM). Countermovement jump (CMJ), spike jump (SPJ), isometric mid-thigh pull (IMTP), and muscle soreness test were administered before (Pre) exercise, and 10 min (10-min), 24 h (24-h), and 48 h (48-h) after exercise. A two-way repeated measures analysis of variance was used to analyze the data. Peak force and rate of development (RFD) of IMTP in AEL group were significantly greater (p < 0.05) than TR group. The height, peak velocity, and RFD of CMJ, height of SPJ, and muscle soreness showed no interaction effects (p > 0.05) groups x time. AEL seemed capable to maintain force production in IMTP, but not in CMJ and SPJ. It is recommended the use of accentuated eccentric loading protocols to overcome the fatigue.

Effect of Daily Oral Lactobacillus plantarum PS128 on Exercise Capacity Recovery after a Half-Marathon.

A half-marathon (HM) is a vigorous high-intensity exercise, which could induce lower extremity musculoskeletal injury risks for recreational runners. They usually consume nonsteroidal anti-inflammatory drugs (NSAIDs) in order to shorten their return to play but ignore the side effects, such as peptic ulcers and renal and vascular disorders. Lactobacillus plantarum PS128 (PS128) could improve inflammation and oxidative stress by modulating the gut microbiota, thus potentially improving muscle damage and recovery. However, few studies have addressed the PS128 exercise capacity recovery 96 h after HM. Thus, this study aimed to investigate the effect of PS128 on exercise capacity and physiological adaptation after HM. A double-blind, randomized, placebo-controlled, counterbalanced, crossover trial was used for the experiment. HM was conducted at the beginning and end of the 4-week nutritional supplement administration. Eight recreational runners took two capsules (3 × 1010 CFU/capsule) of PS128 each morning and evening before meals for 4 weeks as the PS128 treatment (LT), or they took two capsules of placebo for 4 weeks as the placebo treatment (PT). In both treatments, an exercise capacity test (lower extremity muscle strength, anaerobic power, lower extremity explosive force, and aerobic capacity) and blood test (muscle fatigue, muscle damage, oxidative stress, and renal injury) were performed before the administration of the nutritional supplement (baseline), 48 h before HM (pre), and 0 h (0 h post), 3 h (3 h post), 24 h (24 h post), 48 h (48 h post), 72 h (72 h post), and 96 h (96 h post) after HM. There was no significant difference in the total duration of HM between PT and LT, but PT was found to be significantly higher than LT at Stage 4 (15,751-21,000 m) of HM (3394 ± 727 s vs. 2778 ± 551 s, p = 0.02). The lower extremity muscle strength measured using an isokinetic dynamometer in PT was significantly lower than that in LT at 72 h after HM. The lower extremity explosive force from the countermovement jump (CMJ) in PT was significantly decreased compared to 24 h prior. There was no significant difference between anaerobic power and aerobic capacity between the two treatments after HM. After HM, LT had lower muscle damage indices, such as myoglobin (3 h post-PT vs. -LT: 190.6 ± 118 ng/mL vs. 91.7 ± 68.6 ng/mL, p < 0.0001) and creatine phosphokinase (24 h post-PT vs. -LT: 875.8 ± 572.3 IU/L vs. 401 ± 295.7 IU/L, p < 0.0001). Blood urea nitrogen recovered in 24 h (24 h pre- vs. post-LT, p > 0.05) and higher superoxide dismutase was found in LT (96 h post-PT vs. -LT: 0.267 ± 0.088 U/mL vs. 0.462 ± 0.122 U/mL, p < 0.0001). In conclusion, PS128 supplementation was associated with an improvement in muscle damage, renal damage, and oxidative stress caused by HM through microbiota modulation and related metabolites but not in exercise capacity.