RESUMO
This study aimed to analyze the effect of different knee starting angles on jump performance, kinetic parameters, and intersegmental coupling coordination during a squat jump (SJ) and a countermovement jump (CMJ). Twenty male volleyball and basketball players volunteered to participate in this study. The CMJ was performed with knee flexion at the end of the countermovement phase smaller than 90° (CMJ(<90)), greater than 90° (CMJ(>90)), and in a preferred position (CMJ(PREF)), while the SJ was performed from a knee angle of 70° (SJ(70)), 90° (SJ(90)), 110° (SJ(110)), and in a preferred position (SJ(PREF)). The best jump performance was observed in jumps that started from a higher squat depth (CMJ(<90)-SJ(70)) and in the preferred positions (CMJ and SJ), while peak power was observed in the SJ(110) and CMJ(>90). Analysis of continuous relative phase showed that thigh-trunk coupling was more in-phase in the jumps (CMJ and SJ) performed with a higher squat depth, while the leg-thigh coupling was more in-phase in the CMJ(>90) and SJ(PREF). Jumping from a position with knees more flexed seems to be the best strategy to achieve the best performance. Intersegmental coordination and jump performance (CMJ and SJ) were affected by different knee starting angles.
Assuntos
Basquetebol/fisiologia , Fenômenos Biomecânicos/fisiologia , Articulação do Joelho/fisiologia , Destreza Motora/fisiologia , Desempenho Psicomotor/fisiologia , Amplitude de Movimento Articular/fisiologia , Voleibol/fisiologia , Aceleração , Adulto , Humanos , Masculino , Suporte de Carga/fisiologia , Adulto JovemRESUMO
This study aimed to investigate the acute effects of simulated judo matches on fatigue and muscle damage markers. Twenty male judo athletes participated in this study. The athletes performed three 5-minute judo matches separated by 15 minutes of passive rest between each match. The following measurements were performed before and after each match: shoulder external/internal rotation isokinetic torque and countermovement jump (CMJ). Blood samples were taken before the first match and after the third match for serum creatine kinase (CK) and lactate dehydrogenase (LDH) analysis. T-tests for dependent samples and analysis of variance for repeated measures were used to compare the variables over the time; the level of significance was set at 0.05. An overall effect of the successive matches on shoulder internal (PTIN) and external (PTEX) rotation peak torque and CMJ performance was observed. PTIN and PTEX showed significant decreases in postmatch 2 and postmatch 3 when compared with the baseline (p < 0.01). Also, CMJ height declined in postmatch 2 and postmatch 3 (p < 0.01) when compared with the baseline. Serum CK and LDH activity increased significantly after the third match (p < 0.01). It was concluded that 3 successive judo matches induced a decline of peak torque and muscle power in the upper and lower limbs, respectively, and also provoked an increase of muscle damage markers. These findings may provide important knowledge for coaches and physical trainers to improve judo-specific strength training in both the upper and lower limbs.
Assuntos
Creatina Quinase/sangue , L-Lactato Desidrogenase/sangue , Artes Marciais/fisiologia , Fadiga Muscular/fisiologia , Adolescente , Adulto , Biomarcadores/sangue , Humanos , Masculino , Movimento/fisiologia , Músculo Esquelético/patologia , Rotação , Torque , Adulto JovemRESUMO
The purpose of the study was to analyze the relationships among physiological and neuromuscular indices with the 200- and 400-m sprint running performance. Fourteen male sprinters performed the following tests: determination of 200- (P200) and 400-m (P400) running performance; determination of VO2max and the velocity associated at VO2max; squat jump (SJ) and countermovement jump (CMJ); and maximal accumulated oxygen deficit (MAOD). Significant correlations were observed between SJ (r = -0.53), CMJ (r = -0.69), and MAOD (r = -0.65) with P200. Countermovement jump (CMJ) and MAOD explained 70% of the P200. The MAOD was the only variable to correlate significantly with P400 (r = -0.56); VO2max and CMJ were also selected in the regression together and explained 79% of P400. The indicators of muscular power and anaerobic capacity are capable of explaining P200. In the 400 m, the performance was determined by indices of anaerobic capacity, in conjunction with the athletes' aerobic and muscular power.