The effects of flexibility training on exercise-induced muscle damage in young men with limited hamstrings flexibility.

Adaptations to 6 weeks of supervised hamstring stretching training and its potential impact on symptoms of eccentric exercise-induced muscle damage (EIMD) were studied in 10 young, untrained men with limited hamstrings flexibility. Participants performed unilateral flexibility training (experimental leg; EL) on an isokinetic dynamometer, while the contralateral limb acted as control (CL). Hip range of motion (ROM), passive, isometric, and concentric torques, active optimum angle, and biceps femoris and semitendinosus muscle thickness and ultrasound echo intensity were assessed both before and after the training. Additionally, muscle soreness was assessed before and after an acute eccentric exercise bout in both legs (EL and CL) at post-training only. Hip ROM increased (P < .001) only in EL after the training (EL = 10.6° vs CL = 1.6°), but no changes (P > .05) in other criterion measurements were observed. After a bout of eccentric exercise at the end of the program, isometric and dynamic peak torques and muscle soreness ratings were significantly altered at all time points equally in EL and CL. Also, active optimum angle was reduced immediately, 48 and 72 hours post-exercise, and hip ROM was reduced at 48 and 72 hours equally in EL and CL. Finally, biceps femoris muscle thickness was significantly increased at all time points, and semitendinosus thickness and echo intensity significantly increased at 72 hours, with no significant differences between legs. The stretching training protocol significantly increased hip ROM; however, it did not induce a protective effect on EIMD in men with tight hamstrings.

Effects of intra-session exercise sequence during water-based concurrent training.

The aim was to investigate the effects of the intra-session exercise order during water-based concurrent training on the neuromuscular adaptations in young women. 26 women (25.1±2.9 years) were placed into 2 groups: resistance prior to (RA) or after (AR) aerobic training. Subjects performed resistance (sets at maximal effort) and aerobic training (exercises at heart rate corresponding to the second ventilatory threshold) twice a week over 12 weeks, performing both exercise types in the same training session. Upper (elbow flexion) and lower-body (knee extension) one-repetition maximum test (1RM) and peak torque (PT) were evaluated. The muscle thickness (MT) of upper (sum of MT of biceps brachii and brachialis) and lower-body (sum of MT of vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris) was determined by ultrasonography. Moreover, the maximal electromyographic activity (EMG) of upper (biceps brachii) and lower-body (sum of EMG of vastus lateralis and rectus femoris) was measured. Both RA and AR groups increased the upper and lower-body 1RM and PT, while the lower-body 1RM increases observed in the RA was greater than AR (43.58±14.00 vs. 27.01±18.05%). RA and AR showed MT increases in all muscles evaluated, while the lower-body MT increases observed in the RA were also greater than AR (10.24±3.11 vs. 5.76±1.88%). There were increases in the maximal EMG of upper and lower-body in both RA and AR, with no differences between groups. Performing resistance prior to aerobic exercise during water-based concurrent training seems to optimize the lower-body strength and hypertrophy.

Time course of neuromuscular adaptations to knee extensor eccentric training.

This study investigated the chronology of neural and morphological adaptations to knee extensor eccentric training and their contribution to strength gains in isometric, concentric and eccentric muscle actions. 20 male healthy subjects performed a 12-week eccentric training program on an isokinetic dynamometer, and neuromuscular evaluations of knee extensors were performed every 4 weeks. After 12 training weeks, significant increases were observed for: isometric (24%), concentric (15%) and eccentric (29%) torques; isometric (29%) and eccentric (33%) electromyographic activity; muscle thickness (10%) and anatomical cross-sectional area (19%). Eccentric and isometric torques increased progressively until the end of the program. Concentric torque and muscle mass parameters increased until the eighth training week, but did not change from this point to the twelfth training week. Eccentric and isometric activation increased at 4 and 8 training weeks, respectively, while no change was found in concentric activation. These results suggest that: 1) the relative increment in concentric strength was minor and does not relate to neural effects; 2) eccentric and isometric strength gains up to 8 training weeks are explained by the increased neural activation and muscle mass, whereas the increments in the last 4 training weeks seem to be associated with other mechanisms.

Aerobic capacity of male professional futsal players.

AIM: The aim of this study was to evaluate the aerobic capacity of male professional futsal players. METHODS: A total of 186 players (22 goalkeepers and 164 on-court players) of three Brazilian futsal teams from first division performed ergospirometric evaluations (incremental test protocol) in a motorized treadmill. Data from maximal oxygen uptake (VO2max) and second ventilatory threshold (VT2), as well as speed, heart rate (HR) and BORG scale were presented in relation to total of sample and isolated by two main futsal tactical positions: goalkeepers and on-court players. RESULTS: The mean values to VO2max and VT2 observed in futsal players were respectively 58.00±6.37 mL/kg/min and 51.25±5.84 mL/kg/min. Players reached the VO2max at 96.95±4.66% of HRmax and the VT2 at 90.07±5.02%. Goalkeepers presented higher values (P<0.01) of body mass and height than on-court players. On-court players presented higher VO2max and VT2 in comparison to goalkeepers, and reached these levels at higher exercise levels (speed) than goalkeepers. CONCLUSIONS: We conclude that goalkeepers are significantly differents than on-court players regarding aerobic capacity. In this perspective, these differences are relevant to coaches when planning aerobic training sessions in futsal teams.