RESUMO
This study aimed to evaluate the influence of hamstrings and quadriceps strength on the hamstrings-to-quadriceps conventional (H:Qcon) and functional (H:Qfun) ratios in male soccer players. Quadriceps concentric peak torque (PT) and hamstrings concentric and eccentric PT were assessed with isokinetic dynamometry at 60°/s in 101 players (202 legs). The cut-points of 0.50, 0.55 and 0.60 were used to assess muscle imbalance through the H:Qcon ratio, while 0.80, 0.85 and 0.90 were used for H:Qfun ratio. Legs with lower H:Qcon ratio had decreased hamstrings concentric PT (p < 0.01; moderate and large effect sizes) and increased quadriceps concentric PT (p < 0.01; moderate effect sizes) in all cut-points. Legs with lower H:Qfun ratio had decreased hamstrings eccentric PT (p < 0.01; large effect sizes) for all cut-points, and controversial results for quadriceps concentric PT (p < 0.01 only for 0.80 cut-point; small effect sizes). H:Qcon ratio presented only weak correlations with quadriceps (r = -0.37) and hamstrings (r = 0.45) concentric PT, while H:Qfun ratio had a negligible correlation with quadriceps concentric PT (r = -0.30) and a moderate correlation with hamstrings eccentric PT (r = 0.66). In conclusion, our findings support that hamstrings strength deficit is the key factor for low H:Q ratios in male soccer players, especially those with poor H:Qfun ratio.
Assuntos
Futebol , Humanos , Masculino , Futebol/fisiologia , Torque , Força Muscular/fisiologia , Fenômenos Biomecânicos , Músculo Quadríceps/fisiologia , Músculo Esquelético/fisiologiaRESUMO
This study investigated the effects of concurrent training performed either with repetitions to failure or not to failure in muscle power, muscle quality (MQ), peak oxygen uptake (VO2peak), and visceral fat in older men. This is an ancillary analysis of a randomized controlled trial. 36 older men (mean age ± SD; 67.1 ± 5.1 years) were randomized into three groups: one performing repetitions to failure (RFG, n = 13), another performing repetitions not to failure and 50% of the repetitions of the RFG (NFG, n = 12), and third performing repetitions not to failure with equal training volume of the RFG (ENFG, n = 11). The training was performed twice a week for 20 weeks at intensities ranging from 65 to 80% of maximal strength. In each session, the individuals started with strengthening exercises and then performed aerobic exercise (i.e., walking) on a treadmill. The primary endpoint was change from baseline to post-20 wk of absolute and relative muscle power output during squat and countermovement jump, ultrasound measurements for MQ using quadriceps echo intensity, and visceral fat thickness, as well as their VO2peak through a maximal incremental test on a treadmill. All training groups improved similarly and significantly jump height (ranging from 9 to 16%) and all their muscle power outcomes (mean change ranging from 2 to 7%) (P < .001). In addition, all groups significantly decreased visceral fat thickness (ranging from -11 to -21%) (P < .001), and significantly increased VO2peak (ranging from 4 to 8%) (P < .01), with no differences between groups. No changes were observed in the MQ outcomes. Concurrent training performed using repetitions to failure or not to failure promoted similar gains in the muscle power output, aerobic capacity, and visceral fat in healthy older men.
Assuntos
Fatores de Risco Cardiometabólico , Treinamento Resistido , Idoso , Exercício Físico , Humanos , Masculino , Força Muscular , Músculo EsqueléticoRESUMO
This study compared the effects of 20 weeks of concurrent training with and without repetitions to failure on neuromuscular and functional adaptations in older men. METHODS: Thirty-six older men (67.1 ± 5.1 years) were randomized into three groups: one performing repetitions to failure (RFG, n = 13), another performing repetitions not to failure and 50% of the repetitions of the RFG (NFG, n = 12), and a third performing repetitions not to failure with equal training volume of the RFG (ENFG, n = 11). Training was performed twice a week for 20 weeks at intensities ranging from 65% to 80% of maximal strength. In each session, the individuals started with strengthening exercises and then performed aerobic exercise on a treadmill. Before and after the intervention, individuals were assessed for their one repetition maximum (1RM) for leg press (LP) and knee extension (KE) exercises, knee extensors' isometric peak torque (PTiso ), and rate of torque development (RTD) at 50 ms, 100 ms, and 250 ms, muscle thickness of the quadriceps, as well as functional performance on sit-to-stand, and timed up and go tests. RESULTS: After training, there were significant (P < 0.001) increases in the LP and KE 1RM, PTiso , and RTD outcomes in all groups. Also, there were significant increases in muscle thickness of the quadriceps and in the sit-to-stand test (P < 0.05) in all groups. No significant differences were observed between groups in any outcome. CONCLUSION: Concurrent training using repetitions to concentric failure did not promote additional benefits for neuromuscular function, muscle thickness, or functional capacity of older individuals.
Assuntos
Exercício Físico , Força Muscular , Músculo Esquelético/fisiologia , Treinamento Resistido , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , TorqueRESUMO
PURPOSE: The purpose of this study was to investigate the effects of photobiomodulation therapy (PBMT) combined with resistance training on knee extensors muscle mass, strength and functional capacity in elderly men. METHODS: In this randomized double-blinded placebo-controlled trial, healthy elderly men (age 60-80 years) completed 12 weeks of resistance training (2×/week) with application of placebo (n = 13) or active PBMT (n = 11) on quadriceps muscles (850 nm, 240 J per limb) before each training session. Leg press and knee extension one-repetition maximum (1RM) tests, isometric and concentric peak torques, rectus femoris (RF) and vastus lateralis (VL) muscle thickness, timed up-and-go (TUG) and chair rise-to-standing (CRS) tests were performed before and after the intervention period. RESULTS: There were significant improvements in all outcomes for both groups (p < 0.05), except for RF muscle thickness for the placebo group (p = 0.09). Large effect sizes (ES > 0.8) were observed for leg press and leg extension 1RM and CRS tests for both groups, as well as for TUG test for PBMT group. Isokinetic peak torque for both groups and TUG for placebo group had moderate increases (ES > 0.5). Muscle thicknesses and isometric peak torque had small increases (ES > 0.2) in both groups. Both null hypothesis analysis and magnitude-based inference support similar effects of PBMT and placebo treatments. CONCLUSION: Different than previously evidenced in young subjects, PBMT with the parameters used in this study did not provide any additional benefits in comparison to placebo application on muscle mass, strength and functional capacity of healthy elderly men engaged in a resistance training program.