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This study compared the acute and long-term effects of intermittent and continuous static stretching training on straight leg raise range of motion (ROM). Seventy-seven preadolescent female gymnasts were divided into a stretching (n = 57), and a control group (n = 20). The stretching group performed static stretching of the hip extensors of both legs, three times per week for 15 weeks. One leg performed intermittent (3 × 30 s with 30 s rest) while the other leg performed continuous stretching (90 s). ROM pre- and post-stretching was measured at baseline, on weeks 3, 6, 9, 12, 15 and after 2 weeks of detraining. ROM was increased during both intermittent and continuous stretching training, but remained unchanged in the control group. Intermittent stretching conferred a larger improvement in ROM compared to both continuous stretching and control from week 3, until the end of training, and following detraining (p = 0.045 to 0.001 and d = 0.80 to 1.41). During detraining, ROM after the intermittent protocol decreased (p = 0.001), while it was maintained after the continuous protocol (p = 0.36). Acute increases in ROM following the intermittent stretching were also larger than in the continuous (p = 0.038). Intermittent stretching was more effective than continuous, for both long-term and acute ROM enhancement in preadolescent female athletes.

The purposes of the study were to track weightlifters' barbell acceleration with a portable accelerometer over three training sessions to examine test-retest reliability and to compare peak barbell acceleration at different training intensities. Twelve nationally ranked weightlifters volunteered for this study. The portable accelerometer was attached to the right side of the barbell to measure barbell resultant acceleration during the snatch lift at a sampling frequency of 100 Hz. The data were collected over three training sessions at intensity levels of 80%, 85%, and 90% of one repetition maximum. The data were analyzed using intra-class correlation coefficients (ICCs) for the three training sessions and one-way repeated measure ANOVA to compare the difference in peak barbell acceleration at three intensities. Results showed that the device was highly reliable with an ICC of 0.88 and 95% confidence interval of 0.81-0.93. There were significant differences in peak barbell acceleration at various lifting intensities, indicating a decline of the acceleration as the mass of the barbell became heavier. The portable accelerometer seems useful in measuring barbell acceleration data, which can be analyzed in future studies to monitor a weightlifter's performance in a practical setting instead of testing at a laboratory.

The aim of this study was to investigate the acute effects of a vibration-assisted static stretching intervention on enhancing split range of motion in gymnasts matched on initial range of motion. Twenty-two female artistic gymnasts (mean age 13.8 years, s=2.3) matched for age (±6 months) and competitive level were randomly assigned to a static stretching intervention with or without simultaneous vibration. The test consisted of adopting a forward split position with the rear leg bent to 90° and held vertically against a matted block while the pelvis remained perpendicular to the lines of the two legs. The gymnast was instructed to descend into the lowest split position of her comfortable pain tolerance. Positions were videotaped and digitized creating an angle between the split legs. The stretching intervention consisted of a forward split position with emphasis on the front leg hamstring muscle group, followed by a forward lunge position with emphasis on the rear leg quadriceps muscle group. In...

Currently, whole-body vibration is being used to promote enhanced performance. Many coaches and athletes believe that it can acutely enhance explosive performance and power output. However, the scientific literature is unclear as to whether this enhancement occurs. The purpose of this study was to examine the acute effects of whole-body vibration on static jump performance, including jump height, peak force, rate of force development, and peak power. Fourteen recreationally active individuals (5 females, 9 males) participated in three separate randomized treatment sessions. Treatment 1 consisted of no vibration while treatment 2 and treatment 3 incorporated whole-body vibration. The whole-body vibration protocol consisted of three 30-s bouts of vibration performed at 30 Hz and low amplitude (~3 mm) with a 30-s rest between bouts. Treatment 1 was identical in duration to both treatments 2 and 3, but did not contain any vibration. Five minutes after each treatment, the participants performed the st...

The purpose of this study was to assess the acute effects of vibration and stretching on passive and active forward split range of motion in elite adult female synchronized swimmers. Eleven athletes performed a passive forward split test measuring the height of the anterior superior iliac spine on both sides and an active split test on both sides by adopting an inverted split position. Then athletes were assigned randomly by right or left leg to receive vibration on one leg while stretching. The contralateral leg was stretched but did not receive vibration and served as the control. The treatment involved a 40-s exposure to vibration of the forward leg in a split and 40 s of vibration to the rear leg in a split. The athletes were then post-tested using the same protocols. The results indicated that the vibration had a statistically significant influence on passive forward split flexibility, but not active split flexibility. The results of this study confirm earlier work and further demonstrate th...

In the floor exercise, a gymnast may receive a general composition score deduction associated with a lack of diverse tumbling sequences. Diversity in tumbling is defined as the ability to tumble both forward and backward, as well as twist and flip. A coach's ability to direct technical and physical training for these skill varieties is enhanced when thorough descriptions of the skills are available. The aim of this study was to describe and compare muscle activation of the lower extremity in various tumbling sequences characterized by differing body orientations. The stretch-shortening cycle actions during the take-off portion of four different tumbling sequences were analysed and the results compared across muscles and type of take-off (forward vs. backward, twisting vs. non-twisting). Thirteen female gymnasts performed three trials each of round-off flic-flac to backward layout and to backward layout with longitudinal axis twist, and front flic-flac to forward layout and to forward layout with longitudinal axis twist. Activation onset was assessed as an increase of the EMG of 200% above noise before initial floor contact. The EMG was normalized to peak values for each muscle bilaterally during each take-off. Results showed that muscle activation characteristics in the pre-activation and impact phase (contact to maximal floor depression) differed between tumbling series. Backward take-offs were characterized by longer contact times, greater relative activity of the gastrocnemius compared with the vastus lateralis during pre-activation, and greater biceps femoris activation during impact compared with forward take-offs. Twisting backward was associated with reduced muscle activity of the twisting limb, while twisting forward was associated with increased muscle activation on the twisting limb. These differential effects related to the specific nature of the take-off indicate that training to enhance the stretch-shortening cycle action in gymnasts must be specific to the orientation requirements of each specific skill.

Here, we demonstrate that elevation of intracellular cyclic AMP (cAMP) in vascular endothelial cells (ECs) by either a direct activator of adenylyl cyclase or endogenous cAMP-mobilizing G protein-coupled receptors inhibited the tyrosine phosphorylation of STAT proteins by an interleukin 6 (IL-6) receptor trans-signaling complex (soluble IL-6Ralpha/IL-6). This was associated with the induction of suppressor of cytokine signaling 3 (SOCS-3), a bona fide inhibitor in vivo of gp130, the signal-transducing component of the IL-6 receptor complex. Attenuation of SOCS-3 induction in either ECs or SOCS-3-null murine embryonic fibroblasts abolished the inhibitory effect of cAMP, whereas inhibition of SHP-2, another negative regulator of gp130, was without effect. Interestingly, the inhibition of STAT phosphorylation and SOCS-3 induction did not require cAMP-dependent protein kinase activity but could be recapitulated upon selective activation of the alternative cAMP sensor Epac, a guanine nucleotide exchange factor for Rap1. Consistent with this hypothesis, small interfering RNA-mediated knockdown of Epac1 was sufficient to attenuate both cAMP-mediated SOCS-3 induction and inhibition of STAT phosphorylation, suggesting that Epac activation is both necessary and sufficient to observe these effects. Together, these data argue for the existence of a novel cAMP/Epac/Rap1/SOCS-3 pathway for limiting IL-6 receptor signaling in ECs and illuminate a new mechanism by which cAMP may mediate its potent anti-inflammatory effects.

Biomechanical research into artistic gymnastics has grown substantially over the years. However, most research is still skill oriented with few tries at generalization. Consequently, our understanding of the principles and bases of the sport, although improved, is still marginal with gaps in knowledge about technique attributes throughout the sport. For that reason, this review begins with an attempt to identify important variables contributing to successful performance. The review is presented in clusters of work in similar apparatuses culminating in Tables offering an 'at a glance' summary of knowledge in each cluster. The last section of the review tries to give some direction to future biomechanical research in gymnastics in issues relating to data collection--two-dimensional or three-dimensional, image size, frame rate--and analysis, such as descriptive or explanatory, simulation and optimization, and statistical issues.

The aim of this study was to characterize sprint ability, anthropometry, and lower extremity power in the US National Team Skeleton athletes. Fourteen athletes (male n = 7; mean ± SD: height 1.794 ...