The relationship of gymnastics participation in childhood and adolescence to skeletal development and maintenance

Osteoporosis, through its association with age-related fracture, is a major public health concern worldwide. Although osteoporosis was once considered a disease of the elderly, it is now recognized as a condition that has childhood antecedents. The capacity of bone to adapt is the greatest before puberty because of a higher rate of modeling and remodeling. Therefore, the amount of bone gained during childhood and adolescence has the potential to impact lifetime skeletal health. Children who participate in greater amounts of physical activity have greater bone mineral accrual in adolescence as well as a greater peak bone mass in young adulthood. Structured impact loading during growth also positively influences bone parameters. However, the intensity, duration and frequency of loading that is required to elicit skeletal benefits are not well established. Furthermore, although structured physical activity during growth has been hypothesized to delay or prevent the risk of osteoporosis and related fracture later in life there is no clear evidence of a persisting benefit once the loading stimulus has been removed. Therefore, the objective of this thesis was to investigate low-level impact loading during growth and skeletal development as well as to determine the influence of the withdrawal of the loading stimulus on adult bone parameters. Two studies were necessary to realize this objective. The findings should help to determine whether adolescent and adult bone health benefits from structured physical activity during growth. If this is found to be the case then structured gymnastic activity could be promoted as an effective means to optimize adult bone mass, structure and estimated strength. Study 1: The purpose of study one was to investigate whether the differences previously reported in the skeleton of competitive female gymnasts (high level gymnastics exposure) are also demonstrated in young children with a current or past participation history in recreational or precompetitive gymnastics (low level gymnastics exposure). One hundred and sixty three children (30 gymnasts, 61 ex-gymnasts, and 72 non-gymnasts) between 4 and 6 years of age were recruited and measured annually for four years. Total body (TB), lumbar spine (LS) and femoral neck (FN) bone mineral content (BMC) was measured by dual energy x-ray absorptiometry (DXA) at each measurement occasion. Bone mass, density, structure and estimated strength was determined using peripheral quantitative computed tomography (pQCT) at the radius and tibia during the third measurement occasion. Multilevel random effects models were constructed and used to predict differences in TB, LS and FN BMC between groups while controlling for differences in body size, physical activity and diet. Analysis of covariance (covariates of sex, age and height) was used to investigate differences in bone content, density, area, and estimated strength at the radius and tibia. Gymnasts had 3% more TB and 7% more FN BMC than children participating in other recreational sports at the fourth measurement occasion (

LANDING ASYMMETRY IN BACK TUCKED SALTOS AND THE EFFECT OF TAKEOFF ASYMMETRY

Landing asymmetry is an injury risk factor in gymnastics. This study examined whether takeoff force asymmetry is related to landing asymmetry during back tucked saltos in competitive gymnasts. Each gymnast performed an isometric leg strength test followed by multiple back tucked salto trials with no takeoff instruction, leaning with 60% asymmetry to the right, and 60% asymmetry to the left using a standard asymmetry index. Forces were measured at takeoff and landing. The novel experimental approach successfully produced distinct takeoff asymmetry levels. There was a significant rightward asymmetry in baseline landing peak vertical force, possibly due to right leg strength dominance. Landing asymmetry was also generated in the left and right leaning conditions. Both takeoff and leg strength asymmetries may play a role in landing force asymmetries in back tucked saltos

Do women athletes’ experiences of menstrual function and dysfunction vary across competition levels? A mixed methods exploration

Menstrual dysfunction is a common phenomenon in sport and many women describe that their menstrual cycle can negatively impact their sport participation, performance, and experiences. However, there is little research examining if competition level plays a role in women athletes’ rates and experiences of menstrual function and dysfunction. Therefore, the purpose of this study was to explore and describe rates and experiences of menstrual function and dysfunction among athletes of differing competition levels. An online mixed methods approach was applied. Women athletes (N = 63), between 14 and 39 years of age (M = 24.20, SD = 6.53), competing in a range of sports from the local to international level completed an anonymous interview style survey to generate data. Data analysis for this project was an iterative and integrated process where quantitative and qualitative data were considered together and are represented through reported statistics and generated themes. Although group differences were hypothesized, no differences based on competition level in rates or experiences of menstrual dysfunction were observed. In addition to detailed descriptive statistics, five themes were generated: Normalizing Dysfunction; Menstrual Symptoms; Clothing as a Distraction; Participation Impact; and Regaining Control. In line with previous research, the women in this study experienced a range of menstrual dysfunctions that impacted their sport experiences. However, this study highlights that regardless of competition level or sport type women face challenges in sport regarding menstrual function and due to the normalization of dysfunction in sport women athletes’ health and well-being are not always supported

At what age do normal weight Canadian children become overweight adults? Differences according to sex and metric

Background: The prevalence of overweight and obesity doubles between adolescence and young adulthood. However, the exact age, and appropriate metric to use, to identify when overweight develops is still debated. Aim: To examine the age of onset of overweight by sex and four metrics: body mass index (BMI), fat mass (%FM), waist circumference (WC) and waist-to-height ratio (WHtR). Methods: Between 1991 and 2017, serial measures of body composition, were taken on 237 (108 males) individuals (aged 8 to 40 years of age). Hierarchical random effects models were used to develop growth curves. Curves were compared to BMI, %FM and WC overweight age and sex-specific cut-points. Results: In males the BMI growth curve crossed the cut-point at 22.0 years compared to 23.5 and 26.5 years for WHtR and %FM respectively; WC cut-off were not reached until 36 years. In females the BMI growth curve, crossed the overweight cut-point at 21.5 years compared to 14.2 years for %FM and at 21.9 and 27.5 years for WC and WHtR respectively. Conclusions: Overweight onset occurs during young adulthood with the exception of WC in males. BMI in males and %FM in females were the metric identifying overweight the earliest

Preterm birth and adolescent bone mineral content

The purpose of this study was to determine the influence of preterm low birth weight on bone mineral content in adolescence. In 2007 to 2008, data on adolescents were obtained for study, including 16 females and 25 males who were born preterm (37 weeks' gestation) between October 1, 1989, and December 31, 1995, with a birth weight of less than 1850 g. Preterm low-birth-weight individuals were age- and sex-matched to full-term (>37 weeks) normal-birth-weight (>2500 g) controls. Total body, hip, and spine bone mineral content (BMC) was assessed using dual energy X-ray absorptiometry. Male preterm individuals had less BMC at the proximal femur in adolescence compared with controls (p < 0.05). However, once adjusted for age, maturity, height, weight, physical activity, and diet, there were no differences between groups (p < 0.05) in any bone parameters. These findings suggest that preterm birth and low birth weight did not influence bone accrual in these individuals at adolescence

Assessing the sensibility and utility of a short-form version of the HIV Disability Questionnaire in clinical practice settings in Canada, Ireland and the USA: a mixed methods study

Objectives The Short-Form HIV Disability Questionnaire (SF-HDQ) was developed to measure the presence, severity and episodic nature of health challenges across six domains. Our aim was to assess the sensibility, utility and implementation of the SF-HDQ in clinical practice. Design Mixed methods study design involving semistructured interviews and questionnaire administration. Participants We recruited adults living with HIV and HIV clinicians in Canada, Ireland and the USA. Methods We electronically administered the SF-HDQ followed by a Sensibility Questionnaire (face and content validity, ease of usage, format) and conducted semistructured interviews to explore the utility and implementation of the SF-HDQ in clinical practice. The threshold for sensibility was a median score of >5/7 (adults living with HIV) and>4/7 (HIV clinicians) for ≥80% of items. Qualitative interview data were analysed using directed content analysis. Results Median sensibility scores were >5 (adults living with HIV; n=29) and >4 (HIV clinicians; n=16) for 18/19 (95%) items. Interview data indicated that the SF-HDQ represents the health-related challenges of living with HIV and other concurrent health conditions; captures the daily episodic nature of HIV; and is easy to use. Clinical utility included measuring health challenges and change over time, guiding referral to specialists and services, setting goals, facilitating communication and fostering a multidisciplinary approach to care. Considerations for implementation included flexible, person-centred approaches to administration, and communicating scores based on personal preferences. Conclusions The SF-HDQ possesses sensibility and utility for use in clinical settings with adults living with HIV and HIV clinicians in three countries

The effects of a gymnastics program on early childhood body composition development

The dramatic rise in health care and economic costs as well as increases in morbidity and mortality related to lifestyle behaviors and non-communicable diseases have resulted in an increasing emphasis on research and intervention initiatives aimed at primary prevention. As there is growing evidence that the antecedents of adult diseases such as obesity and osteoporosis have roots in early childhood, physical activity interventions in early childhood (4 to 6 years of age), which has been identified as a critical period, may influence the development of fat and bone mass at this young age and have a potential impact on adolescent and young adult health status and thus improve population health. The intent of this study was to investigate the effects of structured physical activity, specifically early involvement in gymnastics, on early childhood body composition development.Sixty three (25 male and 38 female) 4 to 6 year old children participating in gymnastics programs were compared to 95 control (49 male and 46 female) children. Anthropometric measurements included height, weight, BMI, waist circumference, and skinfold thickness. Dual energy x-ray absorptiometry (DXA) was used to measure whole body bone density and fat mass. Physical activity, physical inactivity, dietary intake, and birth weight of the participants as well as parental heights and weights were also obtained. No significant differences were found, at any age, between the groups in height, weight, BMI, waist circumference, skinfold thickness, physical activity, physical inactivity, dietary intakes, and birth weight or in parental heights and weights (p>0.05). Additionally, there were no significant differences in fat and bone parameters once the confounders of age and size were controlled (p>0.05). This investigation found that young children entering a gymnastics program did not differ in either bone mass or fat mass compared to controls. This was surprising as differences in these parameters have been found in adolescent gymnasts. Thus my results indicate that the potential effects of gymnastics training may have not yet manifested themselves. To answer this question longitudinal measures are required to ascertain whether the body composition differences observed in adolescent gymnasts are due to prolonged exposure to gymnastics involvement

Structural Strength Development at the Proximal Femur in 4- to 10-Year-Old Precompetitive Gymnasts: A 4-Year Longitudinal Hip Structural Analysis Study

Y avait-il une vie politique dans les cités de l’Empire romain ? Poser la question, déjà, risque de paraître absurde, puisque les cités, au moins dans les provinces orientales, étaient des poleis, et par elles-mêmes le cadre naturel de la vie politique. Faire de la politique a dû être le sine qua non des cités, même pendant une époque d’absolutisme comme celle de la domination des empereurs romains. Bien sûr, depuis le début de l’époque hellénistique, les cités ont perdu peu à peu leur libert..