Evaluating the effects of hormone therapy termination on skeletal muscle and physical independence in postmenopausal women.

OBJECTIVE: In women, the age-related decline in skeletal muscle structure and function is accelerated after menopause, which implicates the role of decreased circulating estrogen levels. Indeed, boosting estrogen, by means of postmenopausal hormone therapy (HT), generally proves beneficial to skeletal muscle. The evidence regarding whether these benefits persist even after cessation of HT is limited, nor is it clear how physical behavior (PB) impacts on benefits. Hence, this exploratory study focused on the interplay between HT administration/cessation, PB and in vivo skeletal muscle structure and function. METHODS: Fifty healthy women (≥60 y) were included; 19 had an HT administration history (≥9 mo, with now ~8-y hiatus in treatment) and 31 no such history. On seven continuous days, PB data were collected using triaxial accelerometry and analyzed using compositional data analysis. Gastrocnemius medialis muscle volume, architecture, and function were determined using ultrasonography, electromyography, dual x-ray absorptiometry, and dynamometry. Current serum estradiol levels were measured using ELISA. RESULTS: Only fascicle length and duration of HT administration were positively associated. With respect to PB levels, we found a pattern suggesting greater vitality (higher physical activity and lower sedentarism) in previous HT users, compared with nonusers, despite the two groups currently no longer exhibiting significantly different levels of circulating estradiol. CONCLUSIONS: After an 8-year hiatus in treatment, HT provides limited advantages in gastrocnemius medialis muscle properties. Interestingly, it perhaps enhances vitality despite prolonged cessation, which in the longer term would facilitate greater physical independence, especially considering the association of sedentary behavior with greater frailty.

Seasonal variations in vitamin D do not change the musculoskeletal health of physically active ambulatory men with cerebral palsy: a longitudinal cross-sectional comparison study.

Increased levels of vitamin D in the summer months from natural seasonal variations in sun exposure have been linked to improvements in musculoskeletal health and function in UK populations; however, studies have shown that differences in lifestyles because of disability can inhibit the natural vitamin D increase in these populations. We hypothesized that men with cerebral palsy (CP) will experience smaller increases in 25-hydroxyvitamin D (25(OH)D) from winter to summer and men with CP will not experience any improvements in musculoskeletal health and function during the summer. A longitudinal observational study in 16 ambulant men with CP aged 21.0 ± 1.3 years and 16 healthy, physical activity matched, typically developed controls aged 25.4 ± 2.6 years, completed assessments of serum 25(OH)D and parathyroid hormone during winter and summer. Neuromuscular outcomes included vastus lateralis size, knee extensor strength, 10-m sprint, vertical jumps, and grip strength. Bone ultrasounds were performed to obtain radius and tibia T and Z scores. Men with CP and typically developed controls showed a 70.5% and 85.7% increase in serum 25(OH)D from winter to summer months, respectively. Neither group showed seasonal effect on neuromuscular outcomes muscle strength, size, vertical jump, or tibia and radius T and Z scores. A seasonal interaction effect was seen in the tibia T and Z scores (P < .05). In conclusion, there were similar seasonal increases in 25(OH)D observed in men with CP and typically developed controls, but serum 25(OH)D levels were still considered insufficient to improve bone or neuromuscular outcomes.

Musculoskeletal Health in Active Ambulatory Men with Cerebral Palsy and the Impact of Vitamin D.

PURPOSE: (1) To determine the contribution of diet, time spent outdoors, and habitual physical activity (PA) on vitamin D status in men with cerebral palsy (CP) compared to physical activity matched controls (TDC) without neurological impairment; (2) to determine the role of vitamin D on musculoskeletal health, morphology, and function in men with CP compared to TDC. MATERIALS AND METHODS: A cross-sectional comparison study where 24 active, ambulant men with CP aged 21.0 ± 1.4 years (Gross Motor Function Classification Score (I-II) and 24 healthy TDC aged 25.3 ± 3.1 years completed in vivo assessment of musculoskeletal health, including: vastus lateralis anatomical cross-sectional area (VL ACSA), isometric knee extension maximal voluntary contraction (KE iMVC), 10 m sprint, vertical jumps (VJ), and radius and tibia bone ultrasound (US) Tus and Zus scores. Assessments of vitamin D status through venous samples of serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone, dietary vitamin D intake from food diary, and total sun exposure via questionnaire were also taken. RESULTS: Men with CP had 40.5% weaker KE iMVC, 23.7% smaller VL ACSA, 22.2% lower VJ, 14.6% lower KE iMVC/VL ACSA ratio, 22.4% lower KE iMVC/body mass (BM) ratio, and 25.1% lower KE iMVC/lean body mass (LBM) ratio (all p < 0.05). Radius Tus and Zus scores were 1.75 and 1.57 standard deviations lower than TDC, respectively (p < 0.05), whereas neither tibia Tus nor Zus scores showed any difference compared to TDC (p > 0.05). The 25(OH)D was not different between groups, and 90.9% of men with CP and 91.7% of TDC had low 25(OH)D levels when compared to current UK recommendations. The 25(OH)D was positively associated with KE iMVC/LBM ratio in men with CP (r = 0.500, p = 0.020) but not in TDC (r = 0.281, p = 0.104). CONCLUSION: Musculoskeletal outcomes in men with CP were lower than TDC, and despite there being no difference in levels of 25(OH)D between the groups, 25 (OH)D was associated with strength (KE iMVC/LBM) in the CP group but not TDC. The findings suggest that vitamin D deficiency can accentuate some of the condition-specific impairments to musculoskeletal outcomes.

Correction to: The difference in sleep, sedentary behaviour, and physical activity between older adults with 'healthy' and 'unhealthy' cardiometabolic profiles: a cross-sectional compositional data analysis approach.

[This corrects the article DOI: 10.1186/s11556-019-0231-4.].

The Effects of Displacing Sedentary Behavior With Two Distinct Patterns of Light Activity on Health Outcomes in Older Adults (Implications for COVID-19 Quarantine).

Rationale: The COVID-19 pandemic is limiting outdoor and community-based activities, especially for older adults owing to the requirement for self-isolation, potentially increasing prolonged sedentary behavior (SB). Given a poor tolerance for intense exercise, SB displacement with light intensity physical activity (LIPA) is a promising health enhancing alternative. Therefore, the aims of this study were to investigate the effects of two different types of SB displacement on health outcomes in older adults and any differential impact of associated LIPA pattern. Method: 28 older women (age: 73 ± 5 years, height: 1.60 ± 0.07 m, weight: 67 ± 10 kg, and BMI: 26.1 ± 3.6 kg/m2) underwent overnight fasted dual energy x-ray absorptiometry (DEXA) imaging, blood sampling, and functional assessments before being randomly allocated to one of two groups: (1) single continuous bout of 45-50 min LIPA daily (n = 14); or (2) SB fragmentation (SBF; ~48 min LIPA daily, 2 min LIPA for every 30 min of SB; n = 14). Compliance was systematically monitored using tri-axial accelerometery. All measures were taken at weeks 0 and 8. Results: Physical behavior significantly altered (decreased SB/increased LIPA; p < 0.05) and to a similar extent in both groups. We observed a significant reduction in serum triglycerides [p = 0.045, effect size (ɳp 2) = 0.15; SBF: -0.26 ± 0.77 mmol/L, LIPA: -0.26 ± 0.51 mmol/L], improved 30 s sit-to-stand (STS) count (p = 0.002, ɳp 2 = 0.32, 2 ± 3 STS) and speed (p = 0.009, ɳp 2 = 0.35, -10 ± 33%), as well as increased average handgrip strength (p = 0.001, ɳp 2 = 0.45, 6 ± 12%), and gait speed (p = 0.005, ɳp 2 = 0.27, 0.09 ± 0.16 m/s) in both groups. Interestingly, SBF caused a greater increase in peak handgrip strength (8 ± 14%), compared to LIPA (2 ± 10%; p = 0.04, ɳp 2 = 0.38). Conclusion: SB displacement induced significant improvements in fasting triglycerides, gait speed, as-well as STS endurance/speed in older women. Frequent vs. continuous SB displacement also caused greater increases in handgrip strength. While both SB displacement protocols display promise as efficacious home-based interventions for self-isolating older adults, our results would suggest a physical functioning advantage of the SBF protocol for certain outcomes.

Using isotemporal substitution to predict the effects of changing physical behaviour on older adults' cardio-metabolic profiles.

BACKGROUND: It has been advocated that older adults should concomitantly spend less time in sedentary behaviour (SB), and engage in sufficient physical activity (PA), to reduce their risk of cardio-metabolic diseases. However, it is not clear what intensity of PA must be done to offset SB engagement. AIM: Model how cardio-metabolic profiles could change if older adults replaced an hour per day (hr·day-1) of a physical behaviour intensity with 1 hr·day-1 of another physical behaviour of a different intensity. METHODS: Older adults (n = 93, 60-89 years old, 55% female) wore a thigh-mounted triaxial accelerometer for seven consecutive free-living days to estimate mean daily hourly engagement in SB, Standing, Light Intensity PA (LIPA), sporadic moderate to vigorous physical activity (sMVPA, bouts <10 continuous minutes), and 10-minute MVPA (10MVPA, bouts ≥10 continuous minutes. Fasting whole blood concentration of plasma glucose, triglyceride, total cholesterol, and glycated haemoglobin (%), along with serum concentration of lipoprotein lipase (LPL), interleukin-6 (IL-6), and procollagen III N-terminal propeptide (PIIINP) were measured. RESULTS: Isotemporal Substitution, with covariate adjustment, suggested that: total cholesterol concentration could theoretically decrease when 1 hr·day-1 of SB is replaced with Standing, when 1 hr.day-1 of LIPA is replaced with Standing, and when 1 hr·day-1 of sMVPA is replaced with Standing. Triglyceride concentration theoretically decreased when 1 hr·day-1 of SB, Standing, LIPA, or sMVPA is replaced with 10MVPA. Triglyceride concentration theoretically increases when 1 hr·day-1 of 10MVPA is replaced with SB, Standing, or LIPA. No associations with time reallocation appears to exist for LPL, HbA1c, IL-6, and PIIINP. CONCLUSION: The type of physical behaviour being replaced could be crucial for total cholesterol maintenance. Engagement in 10MVPA could be necessary to improve triglyceride concentration.

The difference in sleep, sedentary behaviour, and physical activity between older adults with 'healthy' and 'unhealthy' cardiometabolic profiles: a cross-sectional compositional data analysis approach.

BACKGROUND: Studies have seldom used Compositional Data Analysis (CoDA) to map the effects of sleep, sedentary behaviour, and physical activity on older adults' cardio-metabolic profiles. This study therefore aimed to illustrate how sleep, sedentary behaviour, and physical activity profiles differ between older adult groups (60-89 years), with 'low' compared to those with 'high' concentrations of endocrine cardio-metabolic disease risk markers, using CoDA. METHOD: Ninety-three participants (55% female) wore a thigh-mounted triaxial accelerometer for seven consecutive free-living days. Accelerometer estimates of daily average hours of engagement in sedentary behaviour (SB), standing, light-intensity physical activity (LIPA), sporadic moderate-vigorous physical activity (sMVPA, accumulated with bouts between 1 and 10 min), 10-min moderate-vigorous physical activity (10MVPA, accumulated with bouts ≥10 min), in addition to self-reported sleeping hours were reported. Fasted whole blood concentrations of total cholesterol, triglyceride, glucose, and glycated haemoglobin, and serum lipoprotein lipase (LPL), interleukin-6 (IL-6), and procollagen III N-terminal propeptide were determined. RESULTS: Triglyceride concentration appeared to be highly dependent on 10MVPA engagement as the 'low' and 'high' concentration groups engaged in 48% more and 32% less 10MVPA, respectively, relative to the geometric mean of the entire study sample. Time-use composition of the 'low' LPL group's engagement in 10MVPA was 26% less, while the 'high' LPL group was 7.9% more, than the entire study sample. Time-use composition of the 'high' glucose and glycated haemoglobin groups appeared to be similar as both engaged in more Sleep and SB, and less 10MVPA compared to the study sample. Participants with a 'low' IL-6 concentration engaged in 4.8% more Sleep and 2.7% less 10MVPA than the entire study sample. Time-use composition of the Total Cholesterol groups was mixed with the 'low' concentration group engaging in more Standing and 10MVPA but less Sleep, SB, LIPA, and sMVPA than the entire study sample. CONCLUSION: Older adults should aim to increase 10MVPA engagement to improve lipid profile and decrease SB engagement to improve glucose profile.

The magnitude and character of resistance-training-induced increase in tendon stiffness at old age is gender specific.

Human tendon mechanical properties are modified with loading. Moreover, there are indications that the training response in the tendon is gender specific. The aim of the current study was to examine whether in vivo patella tendon stiffness (K) differentially alters with training in older males compared with females. We also aimed to identify which endocrine pathway underlies the responses. Maximal knee extensor forces were also monitored to determine the training effect on muscle function. Fourteen healthy, habitually active older persons (seven males aged 74.0 ± 1.2 years (mean±SEM) and seven females aged 76.7 ± 1.2 years) were tested at baseline and after 12 weeks of weekly, progressive resistance training. With training, percentage increase in quadriceps maximum voluntary isometric force (MVC) was similar in males (2,469.6 ± 168.0 to 3,097.3 ± 261.9 N; +25.3 ± 6.1% (p < 0.01)) and females (1,728.8 ± 136.3 to 2,166.5 ± 135.8 N; +30.4 ± 15.1% (p < 0.05)), respectively. K increased more in males (338.0 ± 26.6 to 616.9 ± 58.7 N/mm; 79.8 ± 4.2% (p < 0.001)) compared to females (338.9 ± 31.0 to 373.2 ± 25.8 N/mm; +13.0 ± 3.7% (p < 0.001)). Interestingly, a pattern was found whereby below ~40% MVC, the females showed their greatest degree of K changes, whereas the males showed their greatest degree of K change above this relative force level. This gender contrast was also true at a standardised force level (1,200 N), with 5.8 ± 0.4% vs. 82.5 ± 1.8% increments in the females (i.e. value change from 380.3 ± 14.1 to 402.4 ± 13.3 N/mm) and the males (i.e. value change from 317.8 ± 13.8 to 580.2 ± 30.9 N/mm), respectively (p < 0.001). While circulating levels of both IGF-I and IL-6 did not alter with training, IGFBP-3 showed a significant training effect (19.1 ± 4.8%, p < 0.001) and only in the male sub-group (p = 0.038). We show here that with training, in vivo older females' tendon is less dramatically modulated than that of males'. We also show that the relative forces, at which the greatest adaptations are exhibited, differ by gender, with a suggestion of endocrine adaptations in males only. We thus propose that both training and rehabilitation regimens should consider gender-specific tendon responsiveness, at least in older persons.

Influences of carbohydrate plus amino acid supplementation on differing exercise intensity adaptations in older persons: skeletal muscle and endocrine responses.

Losses in physiological function in healthy ageing occur partly as a consequence of reduced protein intake and partly as a consequence of less than 30-min/day of moderate to vigorous physical activity. The current study aimed to compare the effects of two different intensities of resistance training in healthy older adults, whose habitual dietary intake was supplemented with carbohydrate and amino acid preparations. We hypothesised that although intensive exercise with appropriate carbohydrate and amino acid supplementation would result in the most profound impact on in vivo markers of healthy physiologic and endocrine functions in previously sedentary older individuals, the effectiveness of the less intense exercise prescription with supplementation would also result in beneficial adaptations over and above findings of previous studies on low intensity exercise alone. Twenty-nine older adults (out of 32) completed the study after being randomly assigned to low (SUP_LowR, i.e., approximately 40% 1RM; n = 16) versus high resistance training (SUP_HighR, i.e., approximately 80% 1RM; n = 13) for 12 weeks. A carbohydrate supplement was ingested immediately before and during every exercise session and an amino acid cocktail was ingested post-exercise. Neither intervention significantly impacted upon body composition assessed using: Body mass index, waist/hip ratio and bioelectric impedance. Muscle strength increased similarly in the two groups with the SUP_HighR protocol showing 46 +/- 8%, 10.8 +/- 4.4% and 26.9 +/- 4.9% (P < 0.01) improvements in 1-RM strength, unilateral and bilateral knee extension torque, respectively, compared with 39 +/- 2%, 9.4 +/- 3.7% and 29.5 +/- 8.2% (P < 0.01) increments in the same measures in the SUP_LowR group. Lean muscle thickness however, showed a greater benefit of the SUP_LowR protocol (8.7 +/- 3.9% increase, P < 0.05) compared with the SUP_HighR protocol, which elicited no significant change. In terms of functional abilities, only the standing-from-lying (SFL) test exhibited an improvement in rate in the SUP_HighR group (-11.4%, P < 0.05). The SUP_LowR group, on the other hand, showed significant improvements in the get-up-and-go (-8.7 +/- 3.6%, P < 0.05), the SFL (-4.7% change, P = 0.05) and the 6-min walk (7.2 +/- 2.2% increase in distance covered, P < 0.01) tests. Following overnight fasting, serum levels of glucose changed significantly (-13 +/- 4.7% decrease, P < 0.01) in SUP_LowR. Serum levels of insulin (-25 +/- 5.3% decrease, P = 0.05), neuropeptide Y (-24 +/- 15.3% decrease, P = 0.02), and IGFBP-3 (-11 +/- 6.6% decrease, P = 0.03), changed significantly in SUP_HighR. Circulating levels of interleukin-6, tumour necrosis factor-alpha and insulin-like growth factor 1 did not alter significantly in either intervention group. These data suggest that whilst both interventions were beneficial in older persons, the end targets as well as metabolic and hormonal adaptations are different. The supplementation plus low exercise regimen tended to impact on muscle hypertrophy combined with increased habitual function. Supplementation plus high-intensity exercise regimen improved markers of strength, but not to a significantly greater extent than supplementation plus low intensity exercise.

Influence of exercise intensity in older persons with unchanged habitual nutritional intake: skeletal muscle and endocrine adaptations.

Long-term adherence to training programmes is difficult to attain. Yet, the benefits of exercise to general health and well-being are undeniable. Any measure to demonstrate the minimum required exercise for maximal benefit to a person is a promising avenue towards increasing the uptake and adherence to physical activity for the general public. The purpose of this study was to compare the effects of two different intensities of resistance training in healthy older adults. We hypothesised that compared to high-intensity resistance exercise, relatively low training intensity could also improve in vivo markers of healthy physiologic and endocrine functions in previously sedentary older individuals. Thirty (out of a possible 34 recruited) older adults were randomly assigned to low (LowR, i.e. approximately 40% one repetition maximum (1RM)) versus high-resistance training (HighR, i.e. approximately 80% 1RM) for 12 weeks. Neither intervention significantly impacted upon body composition markers including: body mass index (BMI), waist/hip ratio and bioelectric impedance. Muscle strength data showed an advantage for the HighR protocol with 51 +/- 4% and 22.4 +/- 10.2% (P < 0.05) improvements in 1RM strength and bilateral knee extension torque, respectively, compared with 17 +/- 1% and 10.3 +/- 4.7% (P < 0.05) increments in 1RM strength and bilateral torque in the LowR group. Unilateral torque did not change significantly in either group. Quadriceps muscle thickness data also showed a significantly greater benefit of the HighR protocol (5.8 +/- 2.6% increase) compared with the LowR protocol (no change). Functional ability tests, including Get-up-and-go (GUG), Standing from lying and the 6-min walk, showed changes of -11.6 +/- 4.8%, -15.6% and 8.5 +/- 1.7% (P < 0.05), respectively, in HighR compared with only one significant improvement in the LowR, namely a -10.8 +/- 3% (P < 0.05) improvement in the GUG test. Overnight fasting serum levels of IGFBP-3 increased, NPY decreased and TNF-alpha decreased significantly in the LowR group. Serum levels of glucose increased and NPY decreased significantly in HighR. Circulating levels of I, IL-6 and IGF-1 did not change with either intervention. In vivo physiologic changes show functional advantages for older persons carrying out high-resistance training. At the endocrine level, such an advantage is not clear. In fact, in terms of changes in sera levels of fasting glucose, IGFBP-3 and TNF-alpha, there appears to be an advantage to carrying out the lower intensity exercises for the aged populations where endocrine adaptations are key.