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Background: Often, pressure overload–induced myocardial remodeling does not undergo complete reverse remodeling after decreasing afterload. Recently, mitochondrial abnormalities and oxidative stress have been successively implicated in the pathogenesis of several chronic pressure overload cardiac diseases. Therefore, we aim to clarify the myocardial energetic dysregulation in (reverse) remodeling, mainly focusing on the mitochondria. Methods: Thirty-five Wistar Han male rats randomly underwent sham or ascending (supravalvular) aortic banding procedure. Echocardiography revealed that banding induced concentric hypertrophy and diastolic dysfunction (early diastolic transmitral flow velocity to peak early-diastolic annular velocity ratio, E/E′: sham, 13.6±2.1, banding, 18.5±4.1, P =0.014) accompanied by increased oxidative stress (dihydroethidium fluorescence: sham, 1.6×10 8 ±6.1×10 7 , banding, 2.6×10 8 ±4.5×10 7 , P Results: Two weeks later, hypertrophy decreased with the decline of oxidative stress (dihydroethidium fluorescence: banding, 2.6×10 8 ±4.5×10 7 , debanding, 1.96×10 8 ±6.8×10 7 , P P =0.029). The reduction of energetic demands imposed by overload relief allowed the mitochondria to reduce its activity and myocardial levels of phosphocreatine, phosphocreatine/ATP, and ATP/ADP to normalize in debanding towards sham values (phosphocreatine: sham, 38.4±7.4, debanding, 35.6±8.7, P =0.71; phosphocreatine/ATP: sham, 1.22±0.23 debanding, 1.11±0.24, P =0.59; ATP/ADP: sham, 6.2±0.9, debanding, 5.6±1.6, P =0.66). Despite the decreased mitochondrial area, complex III and V expression increased in debanding compared with sham or banding. Autophagy and mitophagy-related markers increased in banding and remained higher in debanding rats. Conclusions: During compensatory and maladaptive hypertrophy, mitochondria become more active. However, as the disease progresses, the myocardial energetic demands increase and the myocardium becomes energy deficient. During reverse remodeling, the concomitant attenuation of cardiac hypertrophy and oxidative stress allowed myocardial energetics, left ventricle hypertrophy, and diastolic dysfunction to recover. Autophagy and mitophagy are probably involved in the myocardial adaptation to overload and to unload. We conclude that these mitochondrial reversible changes underlie diastolic function adaptations during myocardial (reverse) remodeling.

This study aimed to analyze the physiological demands of match play for different playing positions in elite male team handball. Time motion (N = 30) and heart rate (HR; N = 70) data were recorded throughout 10 official matches. The mean distance covered by backcourt players (4.96 ± 0.64 km) was greater (p ≤ 0.02) than for wings and pivots (4.23 ± 0.52 and 3.91 ± 0.51 km, respectively). Backcourt players spent less time standing still and walking (∼76%) than wings and pivots (∼80%) (p ≤ 0.03), and wings spent more time sprinting than the other playing positions. Backcourt players (122.9 ± 17.0) and pivots (126.8 ± 33.0) performed more high-demanding actions per game than wings (54.6 ± 15.6) (p = 0.01). The time spent by pivots in high-intensity activities decreased from the first to the second half (4.1 ± 2.4 to 2.7 ± 0.9%; p ≤ 0.01), while backcourt players showed a decrease in high-demanding playing actions (p ≤ 0.05). Backcourt players and pivots had higher mean (84 ± 9 and 83 ± 9% vs. 79 ± 10%; p ≤ 0.03) and peak effective HR, and percentage of total time at intensities >80% maximal HR (HRmax) than wings. The fraction of total time spent at intensities >80% HRmax decreased for all outfield playing positions in the second half (from 39-76 to 30-46%). Competitive team handball involves position-specific differences in the physiological demands. Furthermore, exercise intensity decreases from the first to the second half for all outfield playing positions suggesting that these players experience neuromuscular fatigue. Training of elite handball players should comprise high-intensity position-specific exercises aiming at improving the ability to maintain a high exercise intensity throughout the game.

The purpose of this study was to analyze the effects of an entire season on physical fitness parameters (PFPs) in male professional soccer players (N = 18). Performance in 5- and 30-m sprint (T5 and T30), countermovement jump (CMJ), agility (T-test), knee extensor (KE) and knee flexor (KF) isokinetic strength, hamstrings/quadriceps strength ratio (H/Q) and bilateral differences (BDs), and Yo-Yo intermittent endurance test 2 (YYIE2) was evaluated in 4 moments (E1�E4) throughout the season. Individual match playing time was quantified. Significant improvements in CMJ and YYIE2 from E1 to E2 were observed (p < 0.05�0.01). The T30 improved from E2 to E3 (p < 0.01). The CMJ decreased from E2 to E3 and E4, and YYIE2 from E2 to E4 (p < 0.05). There were increments in the H/Q ratio and Agility from E1 and E2 to E3 and E4 (p < 0.05�0.01). Significant correlations were found in all evaluation points between different PFPs and between changes in strength parameters and agility, T5 and T30, CMJ, and YYIE2 (p < 0.05�0.001). Influence of individual match playing time was correlated to changes in T5 (E1 to E3; r = -0.705), KE nondominant leg (KEND; E2 to E3; r = 0.786), and KF (E3 to E4; r = 0.575�0.590). The interrelationship between muscle strength (e.g., KE), sprint (e.g., T5), and jump abilities (CMJ) suggests the importance of muscle strength and power training for soccer. This study suggests that the systematic participation of the players in soccer matches favors the increase and maintenance of soccer players KE and KF muscle strength and sprint ability (T5). Thus, given the unique demands of actual match play, coaches should try to incorporate a competitive friendly match in the weekly training cycle of nonstarter players.

Rebelo, AN, Ascensao, AA, Magalhaes, JF, Bischoff, R, Bendiksen, M, and Krustrup, P. Elite futsal refereeing: activity profile and physiological demands. J Strength Cond Res 25(4): 980-987, 2011—The purpose of this study was to determine the physiological demands and to establish the relationship between activity profile and endurance capacity of futsal referees. Eighteen elite futsal referees (33.0 6 5.1 years, 173 6 5 cm, and 73.2 6 8.4 kg) were studied. Video filming (n = 18) and heart rate (HR) recordings were performed throughout games. Blood lactate (n = 14) was determined at rest and after the game. Endurance capacity was determined with the Yo-Yo IE2. The number of activity changes was as high as 1,395 6 218 (6SD). Total distance covered, high-intensity running (HIR), sprinting (SPR), and sideways running were 5.89 6 0.56, 0.96 6 0.29, 0.09 6 0.07, and 0.91 6 0.46 km, respectively. The number of HIR and SPR bouts was 129 6 41 and 9 6 8, respectively, with a mean duration of ;1.4 seconds. Blood lactate content was 1.0 6 0.3 and 1.5 6 0.5 mM before and after the game. The amount of HIR performed during the match correlated significantly (r = 0.77; p , 0.05) with the Yo-Yo IE2 performance. Considering the data obtained in the present study, the use of match-specific intermittent fitness tests to evaluate futsal referees seems to be required.

Magalhaes, J., R. Ferreira, F. Marques, E. Olivera, J. Soares, and A. Ascensko. Indoor Climbing Elicits Plasma Oxidative Stress. Med. Sci. Sports Exerc., Vol. 39, No. 6, pp. 955-963, 2007. Purpose: Indoor climbing is a worldwide sport with particular physiological and physical demands. The purpose of this study was to analyze the effect of sustained indoor climbing until exhaustion on plasma oxidative stress markers, and to relate it to whole-body dynamic exercise performed at the same percentage of maximal oxygen uptake (VO2max). Methods: Fourteen male indoor climbers continuously climbed a competition-style route until exhaustion. Oxygen consumption and heart rate were continuously monitored during the climbing exercise. One week later, subjects performed a treadmill running protocol with the same duration and percentage Of VO2max a. as that of climbing exercise. Blood samples were collected at rest, immediately after, and 1h after both exercise protocols to analyze plasma levels of reduced (GSH) and oxidized (GSSG) glutathione, malondialdehyde (MDA), protein sulfhydryl (-SH) and carbonyl (CG) groups, total antioxidant status (TAS) and uric acid (UA), and total blood leukocytes, neutrophil, and lymphocyte counts. Results: Compared with running, climbing significantly increased the %GSSG, MDA, CG, TAS, and UA and decreased the GSH and -SH content. Blood counts of total leukocytes and neutrophils increased immediately after and 1h after both running and climbing (P < 0.05), although counts were higher in climbing than in running (P < 0.05). Lymphocytes significantly increased from baseline to 0 h, although they decreased below baseline 1h after climbing (P < 0.05). Conclusion: Data demonstrate that indoor climbing induces plasma oxidative stress. Moreover, results suggest that an ischemia-reperfusion prooxidant-based mechanism related to climbers' sustained and intermittent isometric forearm muscle contractions might have significantly contributed to observed plasma oxidative stress.