Peak Height Velocity Research Articles

Strength Proxies Explain Balance Task Performance by Proximity to Peak Height Velocity in Young Acrobatic Gymnasts

Background: Balance tasks are critical for performance in acrobatic gymnastics, where athletes often train and compete in mixed-age groups with varying maturational stages. To improve individualized training, in this cross-sectional study, the relationship was examined between strength capacity and balance task performance in female gymnasts at two maturational stages based on peak height velocity (PHV). Methods: Circa-PHV (n = 17, 11.92 ± 1.7 years) and post-PHV (n = 17, 16.47 ± 1.8 years) participants performed static balance tasks (standing on blocks, tandem stance, headstand) while center of pressure (CoP) excursion was recorded, and a proactive balance task (time to stabilization after landing, TTS). Strength assessments included isometric mid-thigh pull, handgrip, countermovement jump (CMJ), and push-up tests. Results: Correlational, regression, and inter-group analyses highlighted differences in strength–balance relationships across groups. Maximal isometric strength and CMJ power were the strongest predictors of static standing balance, with greater predictive strength in the circa-PHV group, underscoring the role of maturation in strength–balance interactions. The results also revealed that strength parameters influenced balance differently depending on the task, suggesting that specific balance types (static–proactive) and tasks (standing–inverted) require distinct strength capacities. Conclusions: Strength’s influence on balance varies by maturational stage, emphasizing the need for tailored training programs to enhance balance and optimize performance in young gymnasts.

Sprint and jump performance are determined by localized BIA - an ecological study in track and field adolescent athletes

BackgroundRaw data obtained through bioelectrical impedance analysis (BIA) have been applied in different populations to assess body fluids and cell integrity. Assessing raw BIA parameters in specific muscles is an emerging method for evaluating muscle function. We investigated the associations of the BIA-derived variables of resistance (R), reactance (Xc) and phase angle (PhA) measured through whole-body (WB) and muscle-localized (ML) methods with performance in the countermovement jump (CMJ) and 50-meter (m) sprint.MethodsThirty-one male track and field athletes (16.5 ± 1.6 years) were assessed. Fat-free mass (FFM) and Fat mass percentage (%FM) were determined by skinfold thickness. BIA at 50 kHz was employed to obtain the WB and ML (right thigh) parameters. The WB and ML-BIA parameters were adjusted by height (R/H, Xc/H) and segment length (R/L, Xc/L). The CMJ assessment was conducted via a contact mat; the software recorded the jump height. The 50-m sprint time was measured via two sets of photocells. Pearson’s correlation and linear multiple regression were performed.ResultsML-PhA was inversely related to the 50-m sprint (β=-0.56) and by itself explained 29% of the sprint time variation. It remained a significant predictor even after adjusting for age, height, FFM and peak height velocity (PHV). ML-R/L was directly related to 50-m sprint (β = 0.48) and inversely related to CMJ performance (β=-0.54), explaining 20% and 27% of the variation in 50-m sprint and CMJ performance, respectively. Similarly, it remained a significant predictor in the adjusted models. Correlations between WB-BIA (PhA, R/H) and performance tests were found to be dependent on covariates.ConclusionsIn this sample, the ML-BIA parameters of R/L and PhA were significantly associated with performance independent of age, height, FFM and PHV. Higher ML-PhA values were associated with better sprint times, whereas higher ML-R/L values were associated with worse sprint times and CMJ performance.

Percentile Values of Specific Physical Performances in Tunisian Basketball Players Aged 9 to 21: Considering Maturity Status

Background: Success in basketball is influenced by various factors, including biological maturation. Peak height velocity (PHV) is a key indicator of maturation, playing an important role in assessing the performance of basketball players. This study aimed to analyze the effects of maturational status, chronological age, and gender on anthropometric characteristics and physical performance parameters in Tunisian basketball players and to establish local percentile reference values for physical performance. Methods: A total of 470 basketball players (240 males and 230 females) were categorized into three maturity status groups: pre-PHV (n = 111), circa-PHV (n = 170), and post-PHV (n = 189). Anthropometric and physical fitness parameters were assessed to provide percentile reference values. Results: Our findings revealed significantly higher anthropometric and physical performance values in the post-PHV athletes compared to those in the pre- and circa-PHV groups. Additionally, male athletes outperformed females in most measured variables. Basketball-specific skills appeared to be more dependent on chronological age than on pubertal status. Conclusions: Percentile values were established for both boys and girls, offering valuable references for trainers to quantify and individualize training programs. These findings may assist practitioners in identifying potentially talented basketball players based on their maturation status.

Association of childhood obesity with pubertal development in boys: A systematic review and meta-analysis.

Childhood obesity leads to early puberty development in girls, but its effect in boys remains unclear. We conducted a systematic review and meta-analysis to study the association between childhood obesity and puberty development in boys. We included 14 cohort studies with 114,822 boys. Meta-analysis showed that childhood overweight (RR, 1.44; 95%CI, 1.08-1.93; the number of studies [N] = 4) and obesity (RR, 1.35; 95%CI, 1.11-1.64; N = 5) were associated with the earlier occurrence of testicular volume ≥4mL (Tanner stage 2). Age reaching Tanner stage 2 in overweight boys was earlier than normal-weight boys (mean difference: -0.23 years, 95% CI: -0.37 to -0.08; N = 2); a similar trend was observed in obese boys, but the effect estimate did not reach significance level (mean difference: -0.27 years, 95% CI: -0.59 to 0.05; N = 3). Similarly, the age at pubarche in boys with overweight/obesity was earlier than those with normal weight. Qualitative analysis shows first nocturnal emission; change in voice and peak height velocity in boys with overweight/obesity appeared to develop earlier than those with normal weight. These findings suggest overweight/obesity is associated with earlier pubertal development in boys. Due to the limited number of studies identified in this review, further studies are warranted to confirm these associations.

A comparative analysis of axial and appendicular skeletal maturity staging systems through assessment of longitudinal growth and curve modulation after VBT surgery.

Appendicular skeleton markers are commonly used for maturity assessment for Adolescent Idiopathic Scoliosis (AIS) patients. Traditionally, Risser has been a standard skeletal maturity assessment method. More recently, Sanders classification (SSMS), as a more comprehensive system, became popular, especially in decision-making for Vertebral Body Tethering (VBT). Thumb-Ossification Composite Index (TOCI), using ossification of thumb epiphyses, has been claimed to more accurately stage patients around their peak height velocity. However, growth peaks may occur separately at lower limbs and trunk. Hence, Cervical Vertebral Maturity (CVM), using cervical spine morphology, possesses a potential to better estimate spinal growth as it uses axial skeleton markers instead of appendicular skeleton markers. The aim of the study was to compare various axial and appendicular skeletal maturity assessment methods for longitudinal growth and curve modulation after VBT. A retrospective analysis of prospectively collected data was conducted. Skeletal maturity was determined using Risser, SSMS, TOCI and CVM for each patient. Crosstabulations of axial vs. appendicular markers were formed to analyze their concordance and discordance. Logistic and logarithmic regression models were run to assess longitudinal growth (postoperative height gain and leg-length growth) and curve modulation (follow-up instrumented Cobb correction after index operation), respectively. Models were compared using Akaike information criterion (AIC). 34 patients (32F/2M, mean age: 12.8 ± 1.5 years, mean follow-up: 47.7 (24-80) months) were included. The median preoperative maturity stages were: Risser: 1 (-1-4), SSMS: 4 (1-7), TOCI: 6 (1-8) and CVM: 4 (1-6). At latest follow-up, all patients reached skeletal maturity. Concordance and discordance were observed between axial vs. appendicular systems that demonstrated a range of possible distributions of CVM, where trunk peak height velocity occurred before, simultaneously with or after the standing height peak height velocity. R-squared values for Risser, SSMS, TOCI and CVM were 0.701, 0.783, 0.810 and 0.811, respectively, for prediction of final height; 0.759, 0.821, 0.831 and 0.775 for final leg-length, and 0.507, 0.588, 0.668 and 0.673 for curve modulation. Delta AIC values demonstrated that different skeletal maturity assessment methods provided distinctive information regarding follow-up height gain, leg-length growth and curve behavior. Risser score provided considerably less information for all three outcome variables. TOCI and SSMS provided substantial information regarding remaining leg-length assessments, while in terms of assessment of total height gain and curve modulation after surgery, CVM and TOCI offered substantial information and SSMS offered strong information. Mutual use of axial and appendicular markers may provide valuable insight concerning timing of surgery and magnitude of surgical correction.

Gut Microbiota and Tryptophan Metabolism in Pathogenesis of Ischemic Stroke: A Potential Role for Food Homologous Plants.

The intestinal flora is involved in the maintenance of human health and the development of diseases, and is closely related to the brain. As an essential amino acid, tryptophan (TRP) participates in a variety of physiological functions in the body and affects the growth and health of the human body. TRP catabolites produced by the gut microbiota are important signaling molecules for microbial communities and host-microbe interactions, and play an important role in maintaining health and disease pathogenesis. The review first demonstrates the evidence of TRP metabolism in stroke and the relationship between gut microbiota and TRP metabolism. Furthermore, the review reveals that food homologous plants (FHP) bioactive compounds have been shown to regulate various metabolic pathways of the gut microbiota, including the biosynthesis of valine, leucine, isoleucine, and vitamin B6 metabolism. The most notable metabolic alteration is in TRP metabolism. The interaction between gut microbiota and TRP metabolism offers a plausible explanation for the notable bioactivities of FHP in the treatment of ischemic stroke (IS). This review enhances the comprehension of the underlying mechanisms associated with the bioactivity of FHP on IS.

Consensus on maturity-related injury risks and prevention in youth soccer: A Delphi study.

The aim of this study was to achieve consensus from leading sport and exercise science practitioners in professional soccer academies surrounding (i) motivations for maturity-related data collection (ii) maturity-related injury risk factors (iii) how maturity-related data informs injury prevention practices and (iv) the use of bio-banding as an alternative injury prevention strategy. The study adopted an iterative three round online Delphi method, where a series of statements were rated by expert panellists. Consensus agreement was set at ≥70% for all statements. Nine panellists participated in all three rounds (69% response rate). Consensus was achieved for a total of sixteen statements. Panellists agreed that the period during and 12-months post peak height velocity, muscle strength/flexibility imbalances and maturity status (% predicted adult height) as the most important maturity-related injury risk factors. Panellists also agreed that maturity-related data collection is important for injury prevention as well as physical and performance-related purposes, but not for recruitment or retain/release purposes. It was also evident that variability and misunderstanding of key language terms used within the growth and maturation literature exists. It was agreed that practitioners who are responsible for conducting maturational assessments require additional training/education to enhance their application, delivery and outcomes. The findings indicate that maturity-related data collection is part of a multidisciplinary process, dedicated towards the long-term development of players. Greater training and education are required along with increased dissemination of research findings surrounding the full uses for bio-banding. This study provides guidance on maturity-related injury risks and prevention in youth soccer for practitioners.

The role of cuproptosis in gastric cancer.

As a biologically essential transition metal, copper is widely involved in various enzymatic reactions and crucial biological processes in the body. It plays an increasingly important role in maintaining normal cellular metabolism and supporting the growth and development of the human body. As a trace element, copper maintains the dynamic balance of its concentration in body fluids through active homeostatic mechanisms. Both excess and deficiency of copper ions can impair cell function, ultimately leading to cell damage and death. Cuproptosis is a novel form of cell death where copper ions cause cell death by directly binding to the lipoylated components of the citric acid cycle (CAC) in mitochondrial respiration and interfering with the levels of iron-sulfur cluster (Fe-S cluster) proteins, ultimately causing protein toxic stress. Its primary characteristics are Cu2+ concentration dependence and high expression in mitochondrial respiratory cells. Recent research has revealed that, compared to other forms of programmed cell death such as apoptosis, necrosis, and autophagy, cuproptosis has unique morphological and biochemical features. Cuproptosis is associated with the occurrence and development of various diseases, including cancer, neurodegenerative diseases, and cardiovascular diseases. This article focuses on a review of the relevance of cuproptosis in gastric cancer (GC).

Interactions between fungi and other microorganisms for better fungal products: a review

Under natural conditions, substrates are occupied by sets of different micro-organisms that interact with one another in synergistic or antagonistic relationships. These interactions can influence the growth, development, and biochemistry of economically important fungi, enhance their beneficial properties, stimulate the growth of fruiting bodies, or accelerate the growth of mycelium used for the production of various products and biotechnology processes where fungi are involved. The paper presents a literature review covering known interactions between fungi and bacteria, fungi and actinomycetes, and between different fungi that can be used to promote the production of fungal products or that need to be taken into account in order to avoid production losses. A brief overview of fungi and micro-organism co-culture strategies is provided as well.

Identifying Key Factors for Predicting the Age at Peak Height Velocity in Preadolescent Team Sports Athletes Using Explainable Machine Learning.

Maturation is a key factor in sports participation and often determines the young athletes' characterization as a talent. However, there is no evidence of practical models for understanding the factors that discriminate children according to maturity. Hence, this study aims to deepen the understanding of the factors that affect maturity in 11-year-old Team Sports Athletes by utilizing explainable artificial intelligence (XAI) models. We utilized three established machine learning (ML) classifiers and applied the Sequential Forward Feature Selection (SFFS) algorithm to each. In this binary classification task, the logistic regression (LR) classifier achieved a top accuracy of 96.67% using the seven most informative factors (Sitting Height, Father's Height, Body Fat, Weight, Height, Left and Right-Hand Grip Strength). The SHapley Additive exPlanations (SHAP) model was instrumental in identifying the contribution of each factor, offering key insights into variable importance. Independent sample t-tests on these selected factors confirmed their significance in distinguishing between the two classes. By providing detailed and personalized insights into child development, this integration has the potential to enhance the effectiveness of maturation prediction significantly. These advancements could lead to a transformative approach in young athletes' pediatric growth analysis, fostering better sports performance and developmental outcomes for children.

Effects of Maturation on Plantar Flexor Activity and Achilles Tendon Stiffness in Vertical Jumping: Sex Differences.

The aim of this study was to investigate the effect of maturation on vertical jumping performance, in adolescent boys and girls, concerning plantar flexor activity and Achilles tendon (AT) stiffness. Thirty-nine adolescents were tested in a counter-movement jump (CMJ) at three different time points: 18 and 9 months before peak height velocity (PHV) and at PHV. The EMG activity of the medialis gastrocnemius (MG) and tibialis anterior (TA) muscles was evaluated, in relation to jump height. Boys showed higher jumping ability and AT stiffness than girls. Additionally, boys revealed increased eccentric (ecc) and concentric (con) MG activity, along with decreased ecc and con TA activity, near PHV. On the other hand, girls showed increased ecc and con TA/MG co-contraction compared to boys, mainly near PHV. In conclusion, a different mechanism of vertical jumping performance is adopted between early adolescent boys and girls. Nevertheless, no notable alterations in jumping capability were detected over time, indicating that the maturation process does not influence stretch-shortening cycle (SSC) performance.

Associations between birth characteristics, pubertal timing and adult height.

This study investigated the association between gestational age and birth size with pubertal timing, measured as peak height velocity, and adult height. This retrospective, population-based study was conducted in Sweden in 2023. A sub-group of the 1974 and 1990 GrowUp Gothenburg cohorts was used (n = 4700, 50% males). The subgroup consisted of healthy individuals with Nordic ethnicity, known parental heights and measured adult heights. Data on birth characteristics (gestational age, birth length, birth weight) were collected. Pubertal timing was assessed as age at peak height velocity. Univariable linear regression analysis and bivariate correlations were conducted to answer the research questions. Gestational age was not associated with age at peak height velocity or adult height. Birth length and weight could explain 12% and 8% (p ≤ 0.001) respectively of attained adult height. However, birth length and birth weight could only explain the variation in age at peak height velocity to a small degree. This study showed that gestational age is not associated with age at peak height velocity or adult height. A positive relationship was found between birth size, particularly birth length, and adult height. No strong associations were found between birth size and age at peak height velocity.

Lotus growth and development in artificial water bodies in the conditions of the Stavropol Upland

Relevance. The creation of a botanical collection of the lotus family made it possible to study the biology and adaptive features of a rare relict species of Nelumbo nucifera and its variety in the conditions of the Stavropol Upland.Methods. The main phases of development (the beginning of growth, budding, flowering) were recorded. Statistical processing was carried out by the method of variance analysis according to G.N. Zaitsev.Results. In 2010, Nelumbo nucifera seeds were purchased from the Volga River Delta and planted in a 100-liter container, which was located in a closed ground. From 2010 to 2014, the plant vegetated every year from the second decade of January to November, in November, vegetation was artificially stopped. With such agricultural techniques, the plant had no flowering and fruiting phases. In June 2014, rhizomes were planted and lotus seeds were sown in a pond made of butyl rubber film. In 2017, the first flowering was observed. During the study period, the plants did not reach natural indicators, on average, the diameter of the leaves is less by 18.5 ± 1.6 cm, the flowers are 2 ± 0.1 cm, the height is 1.0–1.5 m. The duration of flowering is 57 ± 4 days, which corresponds to the natural conditions of lotus growth from mid-July to early September. During the years of research, 495 seeds were obtained. Under the influence of abiotic factors, the nut-bearing lotus lives up to 8 years in the botanical garden. Nelumbo nucifera Betsy grows intensively, flowering occurred in the third year after sowing, leaf diameter 57 ± 3 cm, height above the water surface 78 ± 7 cm, flowering duration 73 ± 7 days, which is longer than that of the nut-bearing lotus, full-fledged seeds are formed.

No Impact of Anthropometric and Fitness Factors on Speed-Agility in Young Soccer Players: Is It a Cognitive Influence?

Agility in young soccer players has long been associated with physical attributes like strength, speed, and power. The aims of this study were toinvestigate the relationship between cognitive factors and agility performance in this unique population. 39 young soccer players age 13.56 (SD 0.58)years were assessed for leg-muscle function (jump tests) and maturation status (peak height velocity). TheY-Agility Test, which included decision making in players, was used to measure performance. Cognitive factors such as perceptual skillsand decision making were evaluated with theY-Agility Test. The linear regression showed an absence of significance between theY-Agility Test and drop-jump contact (P = .283), Y-Agility Testand drop-jump flight (P = .185), Y-Agility Test and squat jump (P = .868), and Y-Agility Test and countermovement jump (P = .310). The linear mixed-model analyses suggested a difference between early-average maturers (P = .009) and early-late maturers (P = .005) but did not show a difference between average-late subjects (P = 1.000). Drop-jump flight did not show a difference in maturation (early-average P = 1.000; early-late P = 1.000; average P = 1.000). Squat-jump performance did not demonstrate any significance (early-average P = .618; early-late P = 1.000; P = 1.000). Countermovement-jump performance did not show any significance (early-average P = 1.000; early-late P = 1.000; average-late P = .492). Finally, agility performance does not show any significance between maturation levels(early-average maturer P = .450; early-late P = 1.000; average-late P = .830). Agility in young soccer players appears to follow a nonlinear trajectory, with cognitive factors possibly playing a more significant role than previously thought.

Features of the state of bone tissue in children with cerebral palsy. Part 1. Etiological aspects. A literature review

BACKGROUND: The growth of the human body is the most significant period of development of the bone tissue, because it is during this period that the size, shape, and architectonics of bone are formed against the background of increasing body weight and increasing physical exertion. Considering a number of pathological factors of the underlying disease (alimentary, neurological, hormonal, stress, and physical), bone tissue in children with cerebral palsy grows and develops with deviations from the norm. АIM: To present up-to-date generalized information about the features of bone tissue in children with cerebral palsy to orthopedic traumatologists, neurologists, and physical therapy specialists. MATERIALS AND METHODS: Studies on the problem of bone tissue condition in patients with cerebral palsy were analyzed. Data published over the past 20 years were searched in the scientific databases PubMed, Google Scholar, Cochrane Library, Crossref, and eLibrary without language restrictions. RESULTS: In the last 20 years, the number of studies about pediatric osteoporosis has increased. The gold standard for determining the level of bone mineral density is dual-energy X-ray absorptiometry. However, its use in children has presented some difficulties and limitations. In children, the relationship between bone mineral density values and the risk of fractures has not been well studied, which does not allow us to discuss about osteoporosis based on densitometric bone mineral density data alone. In patients with cerebral palsy, a decrease in bone mineral density and bone mass during growth was found. Previous studies showed that the main factors associated with a decrease in bone mineral density in this group of patients include neuroendocrine causes due to growth retardation against the background of CNS damage, alimentary factors, decreased calcium and vitamin D concentrations, systemic use of glucocorticoids, intake of antiepileptic drugs, decreased motor activity, and low muscle mass. Increasing serum vitamin D concentrations does not have a positive effect on bone mass, although increasing serum calcium concentrations is associated with an increase in bone mineral density. CONCLUSIONS: Identifying and correcting factors leading to decreased bone mineral density in children with cerebral palsy can improve bone health in this group of patients. The absence of a relationship between bone mineral density values and the risk of fractures in children with cerebral palsy does not allow us to discuss about osteoporosis based only on bone mineral density densitometric data. There may be more factors leading to an increased risk of bone fractures in children with cerebral palsy that require further study.

The estimation of pubertal growth spurt parameters using the superimposition by translation and rotation model in Korean children and adolescents: a longitudinal cohort study.

Understanding the characteristics of the pubertal growth spurt in Korean children and adolescents can serve as crucial foundational data for researching puberty and growth-related disorders. This study aims to estimate the key parameters of pubertal growth, specifically the age and magnitude of the pubertal growth spurt, utilizing longitudinal data from a cohort of Korean children and adolescents. This study used mixed longitudinal height data from a cohort of Korean elementary, middle, and high school students aged 7-18 years. The Superimposition by Translation and Rotation (SITAR) model, a shape-invariant growth curve model, was utilized to estimate a reference height velocity curve for the entire dataset and individual curves via random effects to evaluate pubertal growth parameters. Altogether, 3,339 height measurements (1,519 for boys and 1,820 for girls) from 270 individuals (123 boys and 147 girls) were analyzed. The average age of growth spurt onset in Korean boys was 10.17 ± 0.61 years (mean ± SE), with peak height velocity occurring at 12.46 ± 0.69 years of age (9.61 ± 1.26 cm/year). Korean girls, contrarily, experience their growth spurt at an earlier age (8.57 ± 0.68 years), with peak height velocity occurring at 10.99 ± 0.74 years of age (8.32 ± 1.09 cm/year). An earlier onset of puberty in both sexes is associated with a shorter growth spurt duration (0.63 years for boys and 0.58 years for girls) and a higher peak height velocity (1.82 cm/year for boys and 1.39 cm/year for girls). These associations were statistically significant for both sexes (all p < 0.0001). This study is the first to use the height velocity curve from the SITAR model to examine the pubertal growth spurt of Korean children and adolescents. The estimated timing and magnitude of the pubertal growth spurt, and their relationships can be useful data for clinicians and researchers.

Higher peak height velocity in early maturing girls depends on insulin rather than fat mass or IGF-I

Abstract Objective Age at pubertal onset has decreased over the recent decades. Early maturing girls have longer puberty duration, and higher peak height velocity (PHV) than late maturing girls. To what extent this is generated by increased insulin-like growth factor-I (IGF-I), fat mass, or fasting insulin levels is currently unknown. Design, setting, participants A population-based study—part of the COPENHAGEN puberty study—longitudinal part. Eighty-one girls evaluated biannually for a median of 10 (2-15) visits for a total of 815 evaluations. Methods Pubertal staging, anthropometric measures, PHV, skin fold thickness (SFT), and IGF-I and fasting insulin levels were measured. Results Early maturing girls achieved similar final height compared to late maturing girls (166.1 vs 167.1 cm, P = .36). Early pubertal onset was associated with significantly greater PHV (8.7 vs 7.4 cm/year, P &amp;lt; .001) and a longer puberty duration (age at onset of breast development to age at PHV [1.8 vs 1.1 years, P &amp;lt; .001]) compared with late maturation. After correcting for age at pubertal onset, neither body mass index, SFT, nor IGF-I levels differed between early vs late maturing girls. By contrast, fasting insulin levels were significantly higher in early compared with late maturing girls 1.5, 2.0, and 3.0 years after pubertal onset (all P = .039). Conclusion Growth velocity was higher and more prolonged in early compared with late maturing girls and associated with higher insulin levels. Thus, the higher insulin levels may compensate for the shorter total growth period by intensifying the pubertal growth period. Clinical trial registration number NCT01411527.

From passion to profit: the growth of Mambokadzi Bath and Body

Learning outcomes By the end of the lesson, students should be able to identify and think critically about common business problems and come up with possible solutions, explain how a business owner’s attributes can influence the business decisions they make, use available information to assess the viability and sustainability of a business model/strategy, determine the strengths and weaknesses of a particular marketing strategy and suggest ways to improve it and use the information provided to evaluate the risks and benefits of business growth strategies and determine their appropriateness for specified circumstances. Case overview/synopsis Mambokadzi is a small business with considerable potential in Zimbabwe’s beauty and personal care industry. The case study spans several years, highlighting Sharon Chingwaro’s journey as she navigates the difficulties of starting and growing a business with limited resources. The case study delves into various aspects of running a small business, such as production, marketing, distribution, human resources and intellectual property. It also discusses the value of resilience and endurance, as well as the need for resourcefulness when starting and growing a business under difficult circumstances. This case study is intended to teach entrepreneurship and marketing strategies to both under- and postgraduate students, with a particular emphasis on the difficulties of starting and growing a business in a limited-resource environment. It has applications in a variety of fields, including entrepreneurship, strategic management and marketing. Complexity academic level This case study is suitable for undergraduate and postgraduate students. Supplementary materials Teaching notes are available for educators only. Subject code CSS 3: Entrepreneurship.

“Who’s Got Talent?” Change of Direction, Anthropometric Characteristics and Maturity Offset Differences Between Elite and Sub-Elite Young Soccer Player

ABSTRACT Agility, anthropometrics and maturity-offset have been considered fundamental for talent identification in soccer. The aim of this study is to compare 83 young soccer players (U12) from elite (28) and sub-elite (55) teams, to investigate the influences of anthropometric characteristics and maturation on Change-of-Direction (CoD) with the ball (dribbling) and without the ball. ANCOVA was run to investigate potential differences in Agility T-Test and Shuttle Dribble Test between categories while simultaneously controlling for the effects of anthropometric variables such as Peak Height Velocity (PHV), Weight, and Height. Agility T-Test performance does not significantly differ between the two categories (F-value = 0.537, p > .05). However, the Weight significantly influences the results (F-value = 18.425, p < .001, Eta-Squared = 0.172) and also PHV has a significant impact on them (F-value = 10.099, p < .01, Eta-Squared = 0.094). The Shuttle Dribble Test performance significantly varies between two groups (F-value = 5.207, p < .05, Eta-Squared = 0.057). Only Weight significantly influences this test (F-value = 4.324, p < .05, Eta-Squared = 0.048). Our findings indicate that during the U-12 age period, technical skills emerge as a crucial discriminant factor between elite and sub-elite young soccer players, contrarily to the athletic performance without the ball. In addition, the maturity stage specifically influences the Agility T-Test and Weight is significantly related to lower time to complete both in Agility T-Test and SDT.

Poly-methionine/graphitic carbon nitride modified screen-printed electrodes: A metal-free, bio-interface for tryptophan sensing

Tryptophan (TRP) is an essential amino acid needed for the growth and proper functioning of the human body. A balanced intake of TRP-rich food products is essential to meet the daily requirements. As both low and high levels of TRP are associated with clinical disorders, an optimum amount of TRP intake is critical. Hence, developing a method to efficiently detect TRP in food and nutritional supplements is essential. Accordingly, this study reports the electrochemical detection of TRP using poly-methionine/graphitic carbon nitride modified screen-printed electrode (gCN.Meth|SPE). To our knowledge, this study is the first attempt to decipher the electrodeposition of gCN.Meth on a conducting substrate through a systematic analysis of the electro-functionalized gCN.Meth surface using XRD, FT-IR, HR-SEM, EDX, and AFM. The synergistic benefits of both the gCN and conducting poly(methionine) resulted in augmented electrochemical performance exhibiting a pronounced TRP oxidation peak in both cyclic voltammetry (CV) and square wave voltammetry (SWV). The improved electrochemical response can be ascribed to the specific interactions between the TRP and gCN through π- π interactions and hydrogen bonding and electrostatic interaction between TRP and methionine. This facilitated interaction resulted in the electro-catalytic oxidation of TRP with a negative potential shift of 0.126 V and a 16.6-fold increase in the current response compared to unmodified SPE. The gCN.Meth|SPE exhibited a 25.12 times higher sensitivity compared to bare SPE, with a linear response in the concentration ranges of 1.0–300.0 μM and a low detection limit of 29.9 nM. The interference study further indicated that gCN.Meth-modified SPEs is highly effective for the precise and reliable detection of tryptophan in real samples.