Skeletal muscle interaction synergetic effects during a complex acyclic motor action performing

The study showed the sambo wrestlers’ muscle synergies’ spatial-temporal structure, extracted using the PCA method. We considered the individual periods of the "leg grabbing" throw coordination structure. It was revealed the electrical activity of extensive synergies changes depending on registered muscular efforts values, typical for different periods of the performed movement. The synergetic effects of skeletal muscle interaction demonstrate plasticity, manifested in typical patterns of spatial and temporal activation of revealed muscle synergies, which ensures reliable control of motor function in various periods of complex movement coordination performing. Key words: muscle synergies; synergetic effects; intermuscular coordination; motion control, skeletal muscle.

Effect of Muscle Energy Technique on Kicking Speed in Football Players with Hamstring Tightness - An Experimental Study

Background: Football is a dynamic sport that requires athlete to perform many different movements and skills such as rapid acceleration and deceleration, jumping, kicking, and sliding, quick changes of directions. Hamstring muscle injury being the commonest injury is due to hamstring tightness. Prevalence of hamstring injury is common in football players because of its tightness. Muscle energy technique helps in increasing Hamstring flexibility of football players with hamstring tightness. Purpose of Study: The purpose of this study was to find out the effect of Muscle energy technique on kicking speed in football players with hamstring tightness. The players were given 6 days Muscle energy technique on hamstring muscle to improve its flexibility. Kicking speed time was checked pre and post Muscle energy technique. Materials and Methodology: Football players with hamstring tightness [n=40] were included in this study. Muscle energy technique was given for hamstring tightness for 6 days. Pre and post kicking speed time of the players were noted. Result: There was decrease in kicking speed time of the players when compared with pre [0.785] and post [0.4450] Muscle energy technique was proved statistically significant [p=0.000]. Conclusion: It is concluded that Muscle energy technique helps in decreasing the kicking speed time i.e. the ball will cover the given distance in shorter period of time in football players with hamstring tightness and hence helps in bringing out their best performance on field. Key words: Muscle energy technique [MET], Hamstring tightness, kicking speed time.

Short-term changes of the static stretching, electromyoestimulation and whole-body vibration on the flexibility of hamstrings

Aim. The purpose of this study was to investigate the acute effects of the static stretching (SS), neuromuscular electrical stimulation (NEMS), wholebody vibration (WBV) and the combination of all these protocols (WBV+NEMS) on the flexibility of hamstrings. Methods. Fifteen males received four stretching protocols in a crossover design, one protocol per week: static stretching (SS); stretching with superimposed NEMS; stretching combined with WBV; and stretching with superimposed NEMS combined with WBV (WBV+NEMS). All protocols lasted one minute. The flexibility was assessed by both the Back Saver Sit and Reach (BSSR) and the Active Knee Extension (AKE) test. Flexibility measurements were performed before (baseline), immediately after the protocol (post) and 1, 3, 5 and 10 min post protocol. Outcomes. The BSSR at post was greater than the baseline value for NEMS (18.3%, p<0.001), WBV (10.1%, p<0.05), and WBV+NMES (14.9%, p<0.01). Ten minutes after the application of each protocol the BSSR was higher in respect to baseline value for SS (12.0%, p<0.001), NMES (18.8%, p<0.001), WBV (12.7%, p<0.01), and WBV+NEMS (13.6%, p<0.001). All protocols improved AKE in the same way. Conclusion. Our data indicates that SS, NEMS, WBV and the combination of both methods are effective to improve the flexibility of hamstrings. Furthermore, this improvement may be maintained for at least 10 min after the cessation of the exercise, irrespectively of the stretching protocol. Key words: Muscle stretching exercises, proprioception, training, electric stimulation, vibration.

Interaction of amino acids and insulin in the regulation of protein metabolism in growing animals

Young animals utilize their dietary amino acids more efficiently for growth because they are capable of a greater increase in tissue protein synthesis in response to feeding than older animals. This response to feeding is particularly profound in skeletal muscle. The feeding-induced stimulation of protein synthesis in skeletal muscle is uniquely and independently regulated by both insulin and amino acids. In most visceral tissues, the stimulation of protein synthesis by feeding is mediated by amino acids alone and not by insulin. The stimulation of protein synthesis by nutrition and hormones is regulated by alterations in the expression and activity of components of the intracellular signaling pathways that control the initiation of translation. Key words: Muscle, pigs, neonate, protein synthesis, insulin, amino acids

Ultra-sound Imaging for Precision Implantation of a Multi Sensor Temperature Probe in Skeletal Muscle Tissue

A technique for implanting multi sensor temperature probes in muscle tissue was developed to optimize the accuracy of the tissue temperature measurements and the internal localization of the probe. Real time ultra-sound imaging was used to (a) determine the best perpendicular insertion tract, (b) guide the insertion of the probe in order to avoid major blood vessels, and (c) verify the insertion point relative to discernable anatomic reference structures such as arteries and bone. Key words: muscle temperature, temperature transients, heat content

Variability in Estimating Eccentric Contraction-Induced Muscle Damage and Inflammation in Humans

We studied five young healthy volunteers who performed a "damage protocol" consisting of 240 (24 sets x 10 repetitions/set) maximal isokinetic eccentric muscle contractions (30°/s) on each leg one week apart. Biopsies were taken from the vastus lateralis on two occasions. Two biopsies were taken from within the same muscle 24 h following the damage protocol. On a second occasion a single biopsy was taken from the contralateral leg at 24 h following the same damage protocol. Biopsies at all three sites showed Z-band disruption, much greater (i.e., ∼14-fold) than is typically observed in resting biopsies, with no significant differences (ANOVA) according to site location (within legs or between legs). The within-leg coefficient of variation (CV) was, however, 41 ± 30%, and the between-leg CVs were 57 ± 36% and 68 ± 36%. Macrophage cells were also detected within the muscle, and cell numbers were not statistically different between biopsy sites. However, the within-biopsy CV = 52 ± 19% and the between-biopsy CVs of 34 ± 24% and 48 ± 27%. We conclude that eccentric contraction-induced Z-band streaming and inflammatory cell response, as detected in muscle biopsy samples from humans, is highly variable with a CV of 40-70%. Key words: muscle damage; eccentric exercise; biopsy; coefficient of variation

Adaptation to Eccentric Exercise: Neutrophils and E-selectin During Early Recovery

The purpose was to determine the responses of blood neutrophils and E-selectin concentrations during early recovery (< 24 hr)from 2 bouts of eccentric exercise. Subjects (N = 9) completed 2 bouts of eccentric arm exercise using their non-dominant arm (Bout 1 and Bout 2) and 1 non-exercise control condition. The exercise bouts were separated by 4 weeks, and the control condition preceded Bout 1. Neutrophil concentrations were significantly higher at 3, 6, and 9 hr post-exercise for Bout 1 relative to Bout 2 and control. No significant changes in blood E-selectin concentrations were observed. Isometric strength deficit was similar for Bout 1 and Bout 2 at 5 min and 3 hr post-exercise and was significantly greater for Bout 1 relative to Bout 2 at 6, 9, and 24 hr post-exercise. The adaptation to eccentric exercise is associated with a lower concentration of blood neutrophils during early recovery. The neutrophilia associated with novel eccentric arm exercise precedes secondary changes in isometric strength and is not associated with changes in the concentration of blood E- selection. Key Words: muscle inflammation, muscle damage, leukocyte adhesion

Adaptations in the Muscle Cell to Training: Role of the Na+-K+-Atpase

The plasticity of skeletal muscle is evident following the onset of regular contractile activity where extensive adaptations can be observed at all levels of organization. Among the properties subject to altered regulation is the Na+-K+-ATPase, an integral membrane protein distributed throughout the sarcolemma and t-tubule, which functions to maintain high Na+ and K+ transmembrane gradients. This protein is uniquely positioned to control muscle excitation and contraction processes, metabolic flux rates, and contractility. Pronounced and rapid upregulation in the Na+-K+-ATPase content can be observed within the first days of exercise and well before the other major ATPase proteins involved in Ca2+ and actomyosin cycling. Moreover, the Na+-K+-ATPase is subject to complex messenger regulation, involved both in the accommodation and the adaptive responses to contractile activity. This emphasizes that adaptive responses can be mediated soon after the onset of training and may have profound affects on muscle contractility and other cellular adaptations. Key Words: muscle, strain, exercise, adaptation, accommodation

Sample Size Required for the Accurate Determination of Fiber Area and Capillarity of Human Skeletal Muscle

This study aimed to determine the skeletal muscle fiber sample size required for a reliable, valid representation of an individual's average fiber area and capillary contacts (CC) per fiber. Biopsies were obtained from the biceps brachii of 11 college-age, recreational resistance-trained men in conjunction with a study investigating how muscle morphology changed after 12 weeks of resistance training. The effect of additional measurements on the rolling cumulative means for fiber area and CC per fiber was evaluated using sequential estimation analysis. Results showed that group cumulative mean and standard deviation had stabilized by 50 fiber measurements per individual for type I and II fibers and CC per fiber. Significant correlations (.96-.99; p < .05) existed between the 50th and 95th/100th cumulative individual means. These results indicate that a typical skeletal muscle needle biopsy would be sufficient to characterize type I and II fiber areas and CC per fiber of an individual in most subject populations, although the required sample size for characterizing fiber subtypes might be different. Key words: muscle biopsy; sequential estimation analysis

Effects of Combined Training Loads on Relations Among Force, Velocity, and Power Development

The effects of different training programs on the force-velocity relation and the maximum power output from the elbow flexor muscles were examined in 12 male adults. The subjects were divided into two equal groups (G30 + 100 and G30 + 0), In the G30 + 100 group, training was performed with five, repetitions at 30% maximum strength (Fmax) and five isometric contractions (100% Fmax) and in the G30 + 0 group with five repetitions at 30% Fmax and five contractions with no load (0% Fmax). Training was performed 3 days a week for 11 weeks. Maximum power increased significantly in both groups after training. The power increase was significantly greater in the G30 + 100 group. Maximum strength was significantly higher only in the G30 + 100 group, while maximum velocity increased in both groups. No significant difference in strength or velocity gain was observed between the two groups. These results suggest that isometric training at maximum strength (100% Fmax) is a more effective form of supplementary training to increase power production than no load training at maximum velocity. Key words: muscle training, force-velocity relation, muscle power