The Influence of Competitive Level on Stretch-Shortening Cycle Function in Young Female Gymnasts.
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ABSTRACT:
SUBMITTER: Moeskops S
PROVIDER: S-EPMC9323029 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Muscle architecture is an important component of muscle function, and recent studies have shown changes in muscle architecture with fatigue. The stretch-shortening cycle is a natural way to study human locomotion, but little is known about how muscle architecture is affected by this type of exercise. This study investigated potential changes in medial gastrocnemius (MG) muscle architecture after exhaustive stretch-shortening cycle exercise. Male athletes (n = 10) performed maximal voluntary contractions (MVC) and maximal drop jump (DJ) tests before and after an exercise task consisting of 100 maximal DJs followed by successive rebound jumping to 70% of the initial maximal height. The exercise task ceased upon failure to jump to 50% of maximal height or volitional fatigue. Muscle architecture of MG was measured using ultrasonography at rest and during MVC, and performance variables were calculated via a force plate and motion analysis. After SSC exercise, MVC (-13.1%; p = 0.005; dz = 1.30), rebound jump height (-14.8%, p = 0.004; dz = 1.32), and ankle joint stiffness (-26.3%; p = 0.008; dz = 1.30) decreased. Ankle joint range of motion (+20.2%; p = 0.011; dz = 1.09) and MG muscle-tendon unit length (+12.0%; p = 0.037; dz = 0.91) during the braking phase of DJ, the immediate drop-off in impact force (termed peak force reduction) (?27.3%; p = 0.033; dz = 0.86), and lactate (+9.5 mmol/L; p < 0.001; dz = 3.58) increased. Fascicle length increased at rest (+4.9%; p = 0.013; dz = 1.16) and during MVC (+6.8%; p = 0.048; dz = 0.85). Pennation angle decreased at rest (-6.5%; p = 0.034, dz = 0.93) and during MVC (-9.8%; p = 0.012; dz = 1.35). No changes in muscle thickness were found at rest (-2.6%; p = 0.066; dz = 0.77) or during MVC (-1.6%; p = 0.204; dz = 0.49). The greater MG muscle-tendon stretch during the DJ braking phase after exercise indicates that muscle damage likely occurred. The lower peak force reduction and ankle joint stiffness, indicative of decreased active stiffness, suggests activation was likely reduced, causing fascicles to shorten less during MVC.
| S-EPMC6933009 | biostudies-literature
Project description:Adolescent high-performance gymnasts are considered to be at risk for low energy intake. The aim of the present study was to determine the effects of implementing a nutritional education program during the sports season on the nutritional status and nutrition knowledge of the female artistic gymnasts from the Technification Center of the Balearic Islands (n = 24; age, 14.1 ± 2.3 years). A quasi-experimental intervention design was applied, which consisted of implementing a nutritional education program of seven sessions given during eight months. Measurements of nutritional intake, nutrition knowledge, and anthropometric parameters, as well as hematological and biochemical blood parameters, were performed. Gymnasts reported low energy and carbohydrate intakes, with significant increases during the study (energy, 28.3 ± 1.4 vs. 32.8 ± 1.4 kcal kg-1, p = 0.015, carbohydrate 3.2 ± 0.2 vs. 3.9 ± 0.2 g kg-1, p = 0.004). The average values for parameters such as hemoglobin, ferritin, lipoprotein, and vitamin C and E levels in the plasma were within normal ranges. Low intakes of most of the food groups were observed during the study, with similar initial and final values. Nutrition knowledge did not change as a result of the study (28.0 ± 1.7 vs. 31.1 ± 1.3, p = 0.185). In conclusion, gymnasts reported low energy intakes. However, blood markers and most of the anthropometrical parameters measured were within normal ranges. The nutrition education program implemented did not produce significant improvements in the dietary habits or nutritional knowledge of gymnasts.
| S-EPMC8143314 | biostudies-literature
Project description:The aim of this study was to analyze dietary intake and body composition in a group of elite-level competitive rhythmic gymnasts from Spain. We undertook body composition and nutritional analysis of 30 elite gymnasts, divided into two groups by age: pre-teen (9-12 years) (n = 17) and teen (13-18 years) (n = 13). Measures of height, weight, and bioimpedance were used to calculate body mass index and percent body fat. Energy and nutrient intakes were assessed based on 7-day food records. The two groups had similar percentages of total body fat (pre-teen: 13.99 ± 3.83% vs. teen: 14.33 ± 5.57%; p > 0.05). The energy availability values for pre-teens were above the recommended values (>40 kcal/FFM/day) 69.38 ± 14.47 kcal/FFM/day, while those for the teens were much lower (34.7 ± 7.5 kcal/FFM/day). The distribution of the daily energy intake across the macronutrients indicates that both groups ingested less than the recommended level of carbohydrates and more than the recommended level of fat. Very low intakes of calcium and vitamin D among other micronutrients were also noted. The main finding is that teenage gymnasts do not consume as much energy as they need each day, which explains their weight and development. Moreover, they are at a high risk of developing low energy availability that could negatively impact their performance and future health.
| S-EPMC8233987 | biostudies-literature
Project description:Introduction: Although figure skating attracts several hundred thousand participants worldwide, there is little knowledge about physical health and sports injuries among young skaters. The present study aimed to describe the health status of a geographically defined Swedish population of licensed competitive figure skaters and to examine injury determinants. Methods: All licensed competitive skaters in the southeastern region of Sweden were in April 2019 invited to participate in a cross-sectional study using an online questionnaire. Multiple binary logistic regression was used for the examination of injury determinants. The primary outcome measure was the 1-year prevalence of a severe sports injury episode (time loss >21 days). The secondary outcome measure was the point prevalence of an ongoing injury. The determinants analyzed were age, skating level, relative energy deficiency indicators, and training habits. Results: In total, 142 (36%) skaters participated, 137 (96%) girls [mean (SD) age: 12.9 (SD 3.0) years]. Participating boys (n = 5) were excluded from further analysis. The 1-year prevalence of a severe sports injury episode was 31%. The most common injury locations for these injuries were the knee (25%), ankle (20%), and hip/groin (15%). In the multiple model, having sustained a severe injury episode was associated with older age (OR 1.2, 95% CI 1.1-1.4; p = 0.002) and an increased number of skipped meals per week (OR 1.1, 95% CI 1.0-1.3; p = 0.014). The point prevalence of an ongoing injury episode was 19%. The most common locations were the knee (24%), ankle (24%), and foot (24%). Having an ongoing injury episode was associated with older age (OR 1.4, 95% CI 1.2-1.7; p < 0.001) and an increased number of skipped meals per week (OR 1.1, 95% CI 1.0-1.3; p = 0.049). Conclusion: One-third of young female Swedish competitive figure skaters had sustained a severe injury episode during the past year, and a fifth reported an ongoing episode. Older age and an increased number of skipped meals per week were associated with a sports injury episode. Long-term monotonous physical loads with increasing intensity and insufficient energy intake appear to predispose for injury in young female figure skaters. Further examination of injury determinants among competitive figure skaters is highly warranted.
| S-EPMC8253259 | biostudies-literature
Project description:Gymnastics has a history of high injury incidence rates. However, little is known about the injury pathology in young gymnasts. The purpose of this study was to fill gaps in the literature by providing insight into the injury pathology in gymnasts aged 6 to 17 years. This study was retrospective in design, where injury data were collected using a Qualtrics questionnaire and distributed via social media. The findings revealed that the most common injury site was the lower limb (60.5%), in particular, the ankle/foot (49%) and knee (27%). Overuse injuries and sprains were most prevalent among the lower limb (25% and 18.4%, respectively), and gymnasts seemed to have a tendency to train through injury with modifications to training. In conclusion, lower limb joint sprain and overuse injuries accounted for the majority of injuries in youth gymnasts. These injuries were more frequently reported in girls in the years associated with peak height velocity and beyond.
| S-EPMC9955164 | biostudies-literature
Project description:This study examined the influence of the elongation of attached crossbridges and residual force enhancement on joint torque enhancement by the stretch-shortening cycle (SSC). Electrically evoked submaximal tetanic plantar flexions were adopted. Concentric contractions were evoked in the following three conditions: after 2 s isometric preactivation (ISO condition), after 1 s isometric then 1 s eccentric preactivation (ECC condition), and after 1 s eccentric then 1 s isometric preactivation (TRAN condition). Joint torque and fascicle length were measured during the concentric contraction phase. While no differences in fascicle length were observed among conditions at any time points, joint torque was significantly higher in the ECC than TRAN condition at the onset of concentric contraction. This difference would be caused by the dissipation of the elastic energy stored in the attached crossbridges induced by eccentric preactivation in TRAN condition due to 1 s transition phase. Furthermore, joint torques observed 0.3 and 0.6 s after concentric contraction were significantly larger in the ECC and TRAN conditions than in the ISO condition while no difference was observed between the ECC and TRAN conditions. Since the elastic energy stored in the attached crossbridges would have dissipated over this time frame, this result suggests that residual force enhancement induced by eccentric preactivation also contributes to joint torque enhancement by the SSC.
| S-EPMC5367297 | biostudies-literature
Project description:Multiple cues have been suggested as the mechanical stimulus for the heart's hypertrophic response. Our work has previously suggested that the amount of cyclic shortening in cardiomyocytes controls myocyte shape and the amount of stretch controls myocyte size. To identify gene expression changes that occur in response to these mechanical perturbations, we used microarray analysis of papillary muscles cultured for 12 h at physiological or reduced levels of cyclic shortening and physiological or reduced mean stretch. Overall, genes related to extracellular matrix (ECM) were surprisingly prominent in our analysis. Connective tissue growth factor was among a small group of genes regulated by the amount of cyclic shortening regardless of the level of mean stretch, and many more ECM genes were regulated by shortening with reduced amounts of stretch. When we compared our results to gene expression data from an in vivo model of pressure overload (PO), which also decreases myocyte shortening, we found the genes that were commonly regulated in PO and our decreased shortening groups were most significantly enriched for ontology terms related to the ECM, followed by genes associated with mechanosensing and the cytoskeleton. The list of genes regulated in PO and our decreased shortening groups also includes genes known to change early in hypertrophy, such as myosin heavy chain 7, brain natriuretic peptide, and myosin binding protein C. We conclude that in intact myocardium, the amount of cyclic shortening may be an important regulator not only of myocyte genes classically associated with hypertrophy but also of ECM genes.
| S-EPMC3921349 | biostudies-literature
Project description:It has been suggested that successful young gymnasts are a highly select group in terms of the physique. This review summarizes the available literature on elite female gymnasts' anthropometric characteristics, somatotype, body composition and biological maturation. The main aims were to identify: (i) a common physique and (ii) the differences, if any, among competitive/performance levels. A systematic search was conducted online using five different databases. Of 407 putative papers, 17 fulfilled all criteria and were included in the review. Most studies identified similar physiques based on: physical traits (small size and low body mass), a body type (predominance of ecto-mesomorphy), body composition (low fat mass), and maturity status (late skeletal maturity as well as late age-at-menarche). However, there was no consensus as to whether these features predicted competitive performance, or even differentiated between gymnasts within distinctive competitive levels. In conclusion, gymnasts, as a group, have unique pronounced characteristics. These characteristics are likely due to selection for naturally-occurring inherited traits. However, data available for world class competitions were mostly outdated and sample sizes were small. Thus, it was difficult to make any conclusions about whether physiques differed between particular competitive levels.
| S-EPMC5548172 | biostudies-other
Project description:ObjectiveNutritional status is important for health and competitive achievement. This area remains understudied among elite-level female athletes and is appropriate for research. We examined nutritional status and cardiovascular health markers of two groups of female athletes of the same age and competition period, involved in weight-bearing and a non-weight-bearing sport: gymnasts (n = 17) and swimmers (n = 14); mean age 17.4 and 16.6 years.MethodsBody composition and dietary intake were assessed by bioelectrical impedance and Food Frequency Questionnaire. The concentrations of serum micronutrients (B12, 25-hydroxyvitamin D (25 (OH) D), calcium, magnesium, phosphorus, potassium, and iron), blood lipids, and blood pressure (BP) were measured. Setting and Participants. A cross-sectional study of 31 athletes from Slovenia.ResultsGymnasts had higher body mass index (21.5 vs. 20.1 kg/m2, p=0.043) and lower fat free mass (42.4 vs. 46.6 kg, p=0.024) than swimmers and comparable body fat percentage (22.5 vs. 22.8%). Both groups had low intake of carbohydrates, fibre, polyunsaturated fats, protein (only gymnasts), and micronutrients (11/13 micronutrients gymnasts and 4/13 swimmers) and high intake of free sugars and saturated fats. Both groups also had significantly lower-than-recommended serum levels of 25 (OH) D. All cardiovascular risk factors were within recommended ranges. Gymnasts had higher LDL cholesterol (2.7 vs. 2.2 mmol/L, p < 0.011), and swimmers had higher systolic BP (126 vs. 107 mmHg, p < 0.001).ConclusionsDietary intake especially in gymnasts was suboptimal, which may reflect in anthropometric and cardiovascular marker differences between gymnasts and swimmers.
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Project description:How males and females contribute to joint reproductive success has been a long-standing question in sexual selection. Under postcopulatory sexual selection, paternity success is predicted to derive from complex interactions among females engaging in cryptic female choice and males engaging in sperm competition. Such interactions have been identified as potential sources of genetic variation in sexually selected traits but are also expected to inhibit trait diversification. To date, studies of interactions between females and competing males have focused almost exclusively on genotypes and not phenotypic variation in sexually selected traits. Here, we characterize within- and between-sex interactions in Drosophila melanogaster using isogenic lines with heritable variation in both male and female traits known to influence competitive fertilization. We confirmed, and expanded on, previously reported genotypic interactions within and between the sexes, and showed that several reproductive events, including sperm transfer, female sperm ejection, and sperm storage, were explained by two- and three-way interactions among sex-specific phenotypes. We also documented complex interactions between the lengths of competing males' sperm and the female seminal receptacle, which are known to have experienced rapid female-male co-diversification. Our results highlight the nonindependence of sperm competition and cryptic female choice and demonstrate that complex interactions between the sexes do not limit the ability of multivariate systems to respond to directional sexual selection.
| S-EPMC7523561 | biostudies-literature