Lifetime sport and leisure activity participation is associated with greater bone size, quality and strength in older men

Introduction: It remains uncertain whether long-term participation in regular weight-bearing exercise confers an advantage to bone structure and strength in old age. The aim of this study was to investigate the relationship between lifetime sport and leisure activity participation on bone material and structural properties at the axial and appendicular skeleton in older men (>50 years).

Methods: We used dual-energy X-ray absorptiometry (DXA) to assess hip, spine and ultradistal (UD) radius areal bone mineral density (aBMD) (n=161), quantitative ultrasound (QUS) to measure heel bone quality (n=161), and quantitative computed tomography (QCT) to assess volumetric BMD, bone geometry and strength at the spine (L₁–L₃) and mid-femur (n=111). Current (>50+ years) and past hours of sport and leisure activity participation during adolescence (13–18 years) and adulthood (19–50 years) were assessed by questionnaire. This information was used to calculate the total time (min) spent participating in sport and leisure activities and an osteogenic index (OI) score for each participant, which provides a measure of participation in weight-bearing activities.

Results: Regression analysis revealed that a greater lifetime (13–50+ years) and mid-adulthood (19–50 years) OI, but not total time (min), was associated with a greater mid-femur total and cortical area, cortical bone mineral content (BMC), and the polar moment of inertia (I _p) and heel VOS (p ranging from <0.05 to <0.01). These results were independent of age, height (or femoral length) and weight (or muscle cross-sectional area). Adolescent OI scores were not found to be significant predictors of bone structure or strength. Furthermore, no significant relationships were detected with areal or volumetric BMD at any site. Subjects were then categorized into either a high (H) or low/non-impact (L) group during adolescence (13–18 years) and adulthood (19–50+ years) according to their OI scores during each of these periods. Three groups were subsequently formed to reflect weight-bearing impact categories during adolescence and then adulthood: LL, HL and HH. Compared to the LL group, mid-femur total and cortical area, cortical BMC and I _p were 6.5–14.2% higher in the HH group. No differences were detected between the LL and HL groups.

Conclusions: In conclusion, these findings indicate that long-term regular participation in sport and leisure activities categorized according to an osteogenic index [but not the total time (min) spent participating in all sport and leisure activities] was an important determinant of bone size, quality and strength, but not BMD, at loaded sites in older men. Furthermore, continued participation in weight-bearing exercise in early to mid-adulthood appears to be important for reducing the risk of low bone strength in old age.

Motivational interviewing in the prevention and management of chronic disease : improving physical activity and exercise in line with choice theory

Discusses the relationship between motivational interviewing and choice theory in working with chronically ill clients/patients.

The effect of insulin and exercise on c-Cbl protein abundance and phosphorylation in insulin-resistant skeletal muscle in lean and obese Zucker rats.

Aims/hypothesis: Recruitment of the protein c-Cbl to the insulin receptor (IR) and its tyrosine phosphorylation via a pathway that is independent from phosphatidylinositol 3prime-kinase is necessary for insulin-stimulated GLUT4 translocation in 3T3-L1 adipocytes. The activation of this pathway by insulin or exercise has yet to be reported in skeletal muscle. Methods: Lean and obese Zucker rats were randomly assigned to one of three treatment groups: (i) control, (ii) insulin-stimulated or (iii) acute, exhaustive exercise. Hind limb skeletal muscle was removed and the phosphorylation state of IR, Akt and c-Cbl measured.  Results:   Insulin receptor phosphorylation was increased 12-fold after insulin stimulation (p<0.0001) in lean rats and threefold in obese rats. Acute exercise had no effect on IR tyrosine phosphorylation. Similar results were found for serine phosphorylation of Akt. Exercise did not alter c-Cbl tyrosine phosphorylation in skeletal muscle of lean or obese rats. However, in contrast to previous studies in adipocytes, c-Cbl tyrosine phosphorylation was reduced after insulin treatment (p<0.001). Conclusions/interpretation: We also found that c-Cbl associating protein expression is relatively low in skeletal muscle of Zucker rats compared to 3T3-L1 adipocytes and this could account for the reduced c-Cbl tyrosine phosphorylation after insulin treatment. Interestingly, basal levels of c-Cbl tyrosine phosphorylation were higher in skeletal muscle from insulin-resistant Zucker rats (p<0.05), but the physiological relevance is not clear. We conclude that the regulation of c-Cbl phosphorylation in skeletal muscle differs from that previously reported in adipocytes.

Evaluation of a brief pilot nutrition and exercise intervention for the prevention of weight gain in general practice patients

Objective To pilot-test a brief written prescription recommending lifestyle changes delivered by general practitioners (GPs) to their patients.

Design The Active Nutrition Script (ANS) included five nutrition messages and personalised exercise advice for a healthy lifestyle and/or the prevention of weight gain. GPs were asked to administer 10 scripts over 4 weeks to 10 adult patients with a body mass index (BMI) of between 23 and 30 kg m− 2. Information recorded on the script consisted of patients' weight, height, waist circumference, gender and date of birth, type and frequency of physical activity prescribed, and the selected nutrition messages. GPs also recorded reasons for administering the script. Interviews recorded GPs views on using the script.

Setting General practices located across greater Melbourne.

Subjects and results Nineteen GPs (63% female) provided a median of nine scripts over 4 weeks. Scripts were administered to 145 patients (mean age: 54 ± 13.2 years, mean BMI: 31.7 ± 6.3 kg m− 2; 57% female), 52% of whom were classified as obese (BMI >30 kg m− 2). GPs cited ‘weight reduction’ as a reason for writing the script for 78% of patients. All interviewed GPs (90%, n = 17) indicated that the messages were clear and simple to deliver.

Conclusions GPs found the ANS provided clear nutrition messages that were simple to deliver. However, GPs administered the script to obese patients for weight loss rather than to prevent weight gain among the target group. This has important implications for future health promotion interventions designed for general practice.

PGC-1α and exercise: important partners in combating insulin resistance

Diabetes and obesity are characterised by an impairment in mitochondrial function resulting in a decrease in glucose and fatty acid oxidation, respiration and an increase in intramuscular triglycerides (IMTG's) and insulin resistance. Peroxisome proliferator-activated receptor (PPAR)-ggr coactivator 1agr (PGC-1agr) is a nuclear transcriptional coactivator which regulates several important metabolic processes including, mitochondrial biogenesis, adaptive thermogenesis, respiration, insulin secretion and gluconeogenesis. In addition, PGC-1agr has been shown to increase the percentage of oxidative type I muscle fibres, with the latter responsible for the majority of insulin stimulated glucose uptake. PGC-1agr also co-activates PPAR's agr, bgr/dgr and ggr which are important transcription factors of genes regulating lipid and glucose metabolism. Exercise causes mitochondrial biogenesis, improves skeletal muscle fatty acid oxidation capacity and insulin sensitivity, therefore making it an important intervention for the treatment of insulin resistance. The expression of PGC-1agr mRNA is reduced in diabetic subjects, however, it is rapidly induced in response to interventions which signal alterations in metabolic requirements, such as exercise. Because of the important role of PGC-1agr in the control of energy metabolism and insulin sensitivity, it is seen as a candidate factor in the etiology of type 2 diabetes and a drug target for its therapeutic treatment.

Are unilateral and bilateral patellar tendinopathy distinguished by differences in anthropometry, body composition, or muscle strength in elite female basketball players?

Background: Overuse injury to the patellar tendon (patellar tendinopathy) is a major reason for interrupted training and competition for elite athletes. In both sexes, the prevalence of unilateral and bilateral tendinopathy has been shown to differ. It has been proposed that bilateral pathology may have a different aetiology from unilateral pathology. Investigation of risk factors that may be unique to unilateral and bilateral patellar tendinopathy in female athletes may reveal insights into the aetiology of this condition.
Objectives: To examine whether anthropometry, body composition, or muscle strength distinguished elite female basketball players with unilateral or bilateral patellar tendinopathy.
Methods: Body composition, anthropometry, and muscle strength were compared in elite female basketball players with unilateral (n = 8), bilateral (n = 7), or no (n = 24) patellar tendinopathy. Body composition was analysed using a dual energy x ray absorptiometer. Anthropometric measures were assessed using standard techniques. Knee extensor strength was measured at 180°/s using an isokinetic dynamometer. z scores were calculated for the unilateral and bilateral groups (using the no tendinopathy group as controls). z scores were tested against zero.
Results: The tibia length to stature ratio was approximately 1.3 (1.3) SDs above zero in both the affected and non-affected legs in the unilateral group (p<0.05). The waist to hip ratio was 0.66 (0.78) SD above zero in the unilateral group (p<0.05). In the unilateral group, leg lean to total lean ratio was 0.42 (0.55) SD above zero (p<0.07), the trunk lean to total lean ratio was 0.63 (0.68) SD below zero (p<0.05), and leg fat relative to total fat was 0.47 (0.65) SD below zero (p<0.09). In the unilateral group, the leg with pathology was 0.78 (1.03) SD weaker during eccentric contractions (p<0.07).
Conclusions: Unilateral patellar tendinopathy has identifiable risk factors whereas bilateral patellar tendinopathy may not. This suggests that the aetiology of these conditions may be different. However, interpretation must respect the limitation of small subject numbers.

Anthropometry, physical performance, and ultrasound patellar tendon abnormality in elite junior basketball players: a cross-sectional study

Objective: Patellar tendinopathy has been reported to be associated with many intrinsic risk factors. Few have been fully investigated. This cross-sectional study examined the anthropometric and physical performance results of elite junior basketball players with normal or abnormal patellar tendons to see if any measures were associated with changes in tendon morphology.

Methods: Agility, leg strength, endurance, and flexibility were measured in 71 male and 64 female players. A blinded radiologist ultrasonographically examined their patellar tendons and athletes were grouped as having normal or abnormal tendons. One-way ANOVA was used to test for differences in anthropometric and physical performance data for athletes whose tendons were normal or abnormal (unilateral or bilateral tendinopathy) on ultrasound.

Results: Results show that females with abnormalities in their tendons had a significantly better vertical jump (50.9±6.8 cm) than those with normal tendons (46.1±5.4 cm) (p = 0.02). This was not found in males. In males, the mean sit and reach in those with normal tendons (13.2±6.7 cm) was greater (p<0.03) than in unilateral tendinopathy (10.3±6.2 cm) or in bilateral tendinopathy (7.8±8.3 cm). In females, those with normal tendons (13.3±4.8 cm) and bilateral tendinopathy (15.8±6.2 cm) were distinctly different from those with unilateral tendinopathy (7.9±6.6 cm).

Conclusion: Flexibility and vertical jump ability are associated with patellar tendinopathy and the findings warrant consideration when managing young, jumping athletes.

Vascularity and pain in the patellar tendon of adult jumping athletes : a 5 month longitudinal study

Background: This study investigated changes in tendon vascularity in 102 (67 men and 35 women) volleyball players over a 6 month competitive season.

Methods: Athletes were examined with both grey scale ultrasound and standardised colour Doppler settings. Vessel length and pain were measured each month on five separate occasions. Vascular tendons were divided into (i) those that were vascular on all occasions (persistent vascularity) and (ii) those that were vascular on more than two but less than five occasions (intermittent vascularity).

Results: A total of 41 of the 133 abnormal tendons were vascular on two or more occasions. Of these, 16 had persistent vascularity and 25 had intermittent vascularity. There was no significant difference in the prevalence of vascularity between men and women. None of the tendons had a pattern of vascularity over the season that could be clearly interpreted as the onset or resolution of vascularity. Subjects with changes in both tendons were more likely to have persistent vascularity (p = 0.045). Vessels were longer in tendons with persistent vascularity (p<0.000) and pain was significantly greater (p = 0.043) than in tendons with intermittent vascularity. Tendons with intermittent vascularity had similar pain scores on all days, whether or not they had detectable blood flow.

Where is all the pressure coming from? Messages from mothers and teachers about preschool children's appearance, diet and exercise

This study used interviews and qualitative analyses to investigate the nature of the messages that preschool children receive from mothers and teachers about their bodies, general appearance, exercise and eating practices. Participants were 10 female teachers and 53 mothers. The behaviours of the 53 children (24 boys, 29 girls) were also observed to determine the nature of their eating and exercise behaviours. The results demonstrated that both mothers and teachers expressed concerns about their own bodies. Mothers also communicated messages to their daughters about losing weight and messages to their sons about increasing their muscles. Both girls and boys were concerned about their appearance, particularly their clothes and hair. Girls also demonstrated some concerns about losing weight, and boys with increasing muscles. Implications of these results are discussed in terms of designing education programs for mothers, teachers and children to prevent the development of body image concerns and disordered eating among children. Copyright © 2006 John Wiley & Sons, Ltd and Eating Disorders Association.

Prospective study of change in patellar tendon abnormality on imaging and pain over volleyball season

Objective: Patellar tendon injury, defined by tendon abnormality (TA) on imaging and by pain, is common among volleyball players, but little is known about change in this injury over a volleyball season. Increased activity in the season compared with the off season may result in the development of TA and/or pain. This study investigated the behaviour of TA and pain over a competitive volleyball season.

Methods: Tendon abnormality and pain were measured in 101 volleyball players at the beginning and end of a season. Pain was measured with the single leg decline squat test, which loads the patellar tendon, and TA was detected with ultrasound imaging. Hours of weekly activity were measured and compared during the season and the off season. The proportion of tendons that underwent development and resolution in TA and/or pain over the season was investigated.

Results: Hours of weekly activity was greater during the season than in the off season. Most of the tendons investigated (66.3%) did not undergo a change in TA or pain over the season. Tendon abnormality and/or pain developed in 16.6% of tendons and resolved in 11.2%.

Conclusions: The tendons of volleyball players respond variably to the increased load over the season. Change in TA and pain does not appear to be entirely dependent upon load.