Daily Pain Severity but Not Vertebral Fractures Is Associated With Lower Physical Activity in Postmenopausal Women With Back Pain.

Back pain lifetime incidence is 60%-70%, while 12%-20% of older women have vertebral fractures (VFs), often with back pain. We aimed to provide objective evidence, currently lacking, regarding whether back pain and VFs affect physical activity (PA). We recruited 69 women with recent back pain (age 74.5 ± 5.4 years). Low- (0.5 < g < 1.0), medium- (1.0 ≤ g < 1.5), and high-impact (g ≥ 1.5) PA and walking time were measured (100 Hz for 7 days, hip-worn accelerometer). Linear mixed-effects models assessed associations between self-reported pain and PA, and group differences (VFs from spine radiographs/no-VF) in PA. Higher daily pain was associated with reduced low (ß = -0.12, 95% confidence interval, [-0.22, -0.03], p = .013) and medium-impact PA (ß = -0.11, 95% confidence interval, [-0.21, -0.01], p = .041), but not high-impact PA or walking time (p > .11). VFs were not associated with PA (all p > .2). Higher daily pain levels but not VFs were associated with reduced low- and medium-impact PA, which could increase sarcopenia and falls risk in older women with back pain.

Associations between childhood and adulthood socioeconomic position and grip strength at age 46 years: findings from the 1970 British Cohort Study.

BACKGROUND: Muscle weakness is a key criterion for important age-related conditions, including sarcopenia and frailty. Research suggests lower childhood socioeconomic position (SEP) may be associated with muscle weakness in later life but there is little evidence on associations in younger adults closer to peak muscle strength. We aimed to examine relationships between indicators of SEP in childhood and adulthood and grip strength at age 46y. METHODS: We examined 7,617 participants from the 1970 British Cohort Study with grip strength measurements at 46y. We used sex-specific linear regression models to test associations between five different indicators of SEP in childhood and adulthood (paternal occupational class and parental education levels at age 5 and own occupational class and education level at age 46) and maximum grip strength. Models were adjusted for birth weight, BMI in childhood and adulthood, adult height, disability in childhood, leisure-time physical activity in childhood and adulthood, sedentary behaviour in childhood and adulthood, occupational activity and smoking at age 46. RESULTS: Among women, lower SEP in childhood and adulthood was associated with weaker grip strength even after adjustments for covariates. For example, in fully-adjusted models, women whose mothers had no qualifications at age five had mean grip strength 0.99 kg (95% CI: -1.65, -0.33) lower than women whose mothers were educated to degree and higher. Among men, lower levels of father's education and both adult SEP indicators were associated with stronger grip. The association between own occupational class and grip strength deviated from linearity; men in skilled-manual occupations (i.e. the middle occupational group) had stronger grip than men in the highest occupational group (Difference in means: 1.33 kg (0.60, 2.06)) whereas there was no difference in grip strength between the highest and lowest occupational groups. Adjustment for occupational activity largely attenuated these associations. CONCLUSION: Findings highlight the need to identify age and sex-specific interventions across life to tackle inequalities in important age-related conditions related to weakness.

Age-related declines in muscle and respiratory function are proportionate to declines in performance in Master Track Cyclists.

PURPOSE: Respiratory and musculoskeletal function decline with age, irrespective of physical activity levels. Previous work has suggested that the age-related rate of decline in function of these two systems might be similar, but it is not known to what extent each system contributes to decreasing performance in ageing master cyclists. Therefore, the purposes of this study are (1) whether the age-related rate of decline in respiratory function, respiratory muscle strength, muscle architecture, muscle function, haemoglobin concentration, haematocrit and performance in master cyclists is uniform and (2) which parameters contribute most to the reduction in performance with age. METHODS: Master cyclists were recruited during the Track Cycling Masters World Championship 2019 in Manchester. Respiratory function and respiratory muscle strength were determined using spirometry and a mouth pressure device, respectively. Muscle architecture was determined using ultrasonography, and muscle function by countermovement jump. RESULTS: Forced expiratory volume in the first second, forced vital capacity, fascicle length, muscle thickness, take-off velocity, jump power, jump power per body mass, handgrip strength, haemoglobin concentration and performance correlated negatively with age (p ≤ 0.043). The age-related rate of decline did not differ significantly between parameters (p = 0.124), but it was slower for haemoglobin concentration (p = 0.041). Take-off velocity was the major determinant of performance in 200, 500 and 2000 m track cycling disciplines (R2adj = 0.675, 0.786 and 0.769, respectively; p < 0.001). CONCLUSION: Age-related decline in respiratory and muscle system is accompanied by a similar rate of decline in performance. The major contribution to the age-related decline of performance is reduced muscle function, specifically take-off velocity.

Are associations between physical activity and bone mineral density in adults sex- and age-dependent? An analysis of the UK Biobank study.

Although physical activity (PA) is recognized as a key bone mass determinant across life, athlete studies suggest that it may be less effective in women and older individuals. This has not been explored within the general population. We aimed to address this knowledge gap using data from the UK Biobank Study, a large population-based study of middle-aged and older adults. Free-living PA data collected at 100 Hz for 7 d using wrist-worn accelerometers were classified as sedentary behavior (0-29 milligravities [mg]), light (30-124 mg), or moderate-to-vigorous PA (125 + mg). LS and FN-BMD were assessed using DXA. The associations between PA and BMD were assessed using linear regression models, with formal assessments of sex and age interactions undertaken and adjustments made for accelerometer wear time, height, body mass index, education, ethnicity, disability, and (in women only) menopausal status. In total, 15 133 UK Biobank participants (52% women) had complete PA, bone, and covariate data. In this sample, greater overall and moderate-to-vigorous PA was associated with higher LS BMD. In women, these associations were typically weaker in older individuals, for example, regression coefficients in women aged 70 yr or older were ~50% lower than at 45-54 yr (age-by-PA interactions P < .01 in all models). Similar associations were observed in basic but not full models for FN BMD. Greater sedentary time was associated with lower LS BMD in men only, and greater light PA and sedentary time were associated with higher and lower FN BMD, respectively, in both sexes. These results suggest that associations between PA and bone health at clinically-relevant sites are weaker in older than younger women. That positive associations are evident between overall and moderate-vigorous PA and FN BMD even in women ≥70 yr suggests that PA for bone health should still be promoted in older women.

A 12-month continuous and intermittent high-impact exercise intervention and its effects on bone mineral density in early postmenopausal women: a feasibility randomized controlled trial.

BACKGROUND: Intermittent mechanical loading generates greater bone adaptations than continuous mechanical loading in rodents but has never been evaluated in humans. This study aimed to evaluate the feasibility of a continuous and intermittent countermovement jump (CMJ) intervention for attenuating early postmenopausal BMD loss. METHODS: 41 healthy early postmenopausal women (age=54.6±3.4 years) were randomly assigned to a continuous countermovement jumping group, an intermittent countermovement jumping group or a control group for 12 months. Adherence and dropout rates were recorded along with bone mineral density (BMD) at lumbar spine, femoral neck and trochanter sites at baseline, 6 months and 12 months. RESULTS: 28 participants completed the study. Dropout rate during the intervention (from the initiation of exercise) was 36% from continuous and 38% from intermittent countermovement jumping groups. For the participants that completed the intervention, adherence was 60.0±46.8% for continuous and 68.5±32.3% for intermittent countermovement jumping. The control group lost significant lumbar spine BMD (% difference=-2.7 [95%CI: -3.9 to -1.4]) and femoral neck BMD (% difference=-3.0% [95%CI: -5.1 to -0.8]). There was no statistically significant change in BMD for either countermovement jumping group. There was no statistically significant difference in BMD change between continuous or intermittent countermovement jumping groups when compared with the control group. CONCLUSIONS: Adherence and dropout rates were in line with previous similar interventions. To evaluate the effect of continuous and intermittent exercise on BMD, future studies should focus on maintaining participant engagement and adherence to the exercise intervention.

Determinants of Performance in the Timed Up-and-Go and Six-Minute Walk Tests in Young and Old Healthy Adults.

The aim of this study was to assess associations between performance in the timed up-and-go (TUG) and six-minute walk distance (6MWD) with physiological characteristics in young and old healthy adults. Thereto, we determined TUG, 6MWD, normalised jump power, centre of pressure displacement during 1-leg standing, forced expiratory volume in 1 s, percentage of age-predicted maximal heart rate (HR%) and height in 419 healthy young (men: 23.5 ± 2.8 years, women: 23.2 ± 2.9 years) and old (men: 74.6 ± 3.2 years, women: 74.1 ± 3.2 years) adults. Normalised jump power explained 8% and 19% of TUG in young (p = 0.025) and older men (p < 0.001), respectively. When fat mass percentage and age were added to normalised jump power, 30% of TUG was explained in older men (R2adj = 0.30, p < 0.001 to 0.106). Appendicular lean muscle mass percentage (ALM%) and age were the best determinants of TUG for older women (R2adj = 0.16, p < 0.001 to 0.01). HR% explained 17-39% of 6MWD across all groups (R2adj = 0.17 to 39, p < 0.001). In conclusion, in men, jump power was a key determinant for TUG, while in old women only it was the ALM%. As HR% was the most important determinant of 6MWD, motivational bias needs to be considered in the interpretation of this test.