Weight-bearing Physical Activity Research Articles

Weight-Bearing Physical Activity, Lower-Limb Muscle Mass, and Risk of Knee Osteoarthritis.

It has been demonstrated that total physical activity is not associated with risk of osteoarthritis. However, the association of different types of physical activity with incident knee osteoarthritis remains unclear. To determine whether weight-bearing recreational physical activities are associated with increased risk of incident knee osteoarthritis. This prospective cohort study used data from the Rotterdam Study (1996 to 2009), including participants with knee x-ray measurements at baseline and follow-up examinations. Participants with knee osteoarthritis at baseline were excluded. Residents aged 45 years and older of the Ommoord district in the city of Rotterdam in The Netherlands were invited to join the Rotterdam Study (78% response rate). Analysis was conducted in June 2023. Total, weight-bearing, and non-weight-bearing recreational physical activities collected by questionnaires at baseline. Incident radiographic knee osteoarthritis measured by knee x-ray was the primary outcome, and incident symptomatic knee osteoarthritis defined by x-ray and knee pain questionnaire was the secondary outcome. The association of different types of recreational physical activity with radiographic knee osteoarthritis was examined using logistic regression within generalized estimating equation framework after adjusting for potential confounders. A prespecified stratification analysis was planned on the basis of lower-limb muscle mass index (LMI) tertiles, measured by dual-energy x-ray absorptiometry. A total of 5003 individuals (2804 women [56.0%]; mean [SD] age, 64.5 [7.9] years) were included. The knee osteoarthritis incident rate was 8.4% (793 of 9483 knees) for a mean (SD) follow-up time of 6.33 (2.46) years. Higher weight-bearing activity was associated with increased odds of incident knee osteoarthritis (odds ratio [OR], 1.22; 95% CI, 1.10-1.35; P < .001), but non-weight-bearing activity was not (OR, 1.04; 95% CI, 0.95-1.15; P = .37). In the analysis stratified by LMI tertiles, the association of weight-bearing activity with incident osteoarthritis was found only among 431 patients in the lowest LMI tertile (OR, 1.53; 95% CI, 1.15-2.04; P = .003), but not among patients in the middle or high LMI tertile. The findings of this study suggest that weight-bearing activity is associated with incident knee osteoarthritis in people with low levels of lower-limb muscle mass, which might be a promising avenue for tailored advice for physical activity.

Semantic representation and comparative analysis of physical activity sensor observations using MOX2-5 sensor in real and synthetic datasets: a proof-of-concept-study

The widespread use of devices like mobile phones and wearables allows for automatic monitoring of human daily activities, generating vast datasets that offer insights into long-term human behavior. A structured and controlled data collection process is essential to unlock the full potential of this information. While wearable sensors for physical activity monitoring have gained significant traction in healthcare, sports science, and fitness applications, securing diverse and comprehensive datasets for research and algorithm development poses a notable challenge. In this proof-of-concept study, we underscore the significance of semantic representation in enhancing data interoperability and facilitating advanced analytics for physical activity sensor observations. Our approach focuses on enhancing the usability of physical activity datasets by employing a medical-grade (CE certified) sensor to generate synthetic datasets. Additionally, we provide insights into ethical considerations related to synthetic datasets. The study conducts a comparative analysis between real and synthetic activity datasets, assessing their effectiveness in mitigating model bias and promoting fairness in predictive analysis. We have created an ontology for semantically representing observations from physical activity sensors and conducted predictive analysis on data collected using MOX2-5 activity sensors. Until now, there has been a lack of publicly available datasets for physical activity collected with MOX2-5 activity monitoring medical grade (CE certified) device. The MOX2-5 captures and transmits high-resolution data, including activity intensity, weight-bearing, sedentary, standing, low, moderate, and vigorous physical activity, as well as steps per minute. Our dataset consists of physical activity data collected from 16 adults (Male: 12; Female: 4) over a period of 30–45 days (approximately 1.5 months), yielding a relatively small volume of 539 records. To address this limitation, we employ various synthetic data generation methods, such as Gaussian Capula (GC), Conditional Tabular General Adversarial Network (CTGAN), and Tabular General Adversarial Network (TABGAN), to augment the dataset with synthetic data. For both the authentic and synthetic datasets, we have developed a Multilayer Perceptron (MLP) classification model for accurately classifying daily physical activity levels. The findings underscore the effectiveness of semantic ontology in semantic search, knowledge representation, data integration, reasoning, and capturing meaningful relationships between data. The analysis supports the hypothesis that the efficiency of predictive models improves as the volume of additional synthetic training data increases. Ontology and Generative AI hold the potential to expedite advancements in behavioral monitoring research. The data presented, encompassing both real MOX2-5 and its synthetic counterpart, serves as a valuable resource for developing robust methods in activity type classification. Furthermore, it opens avenues for exploration into research directions related to synthetic data, including model efficiency, detection of generated data, and considerations regarding data privacy.

Effect of acute resistance exercise on bone turnover in young adults before and after concurrent resistance and interval training.

Weight-bearing physical activity can stimulate bone adaptation. This investigation explored the effect of an acute bout of resistance exercise before and after resistance+interval training on circulating biomarkers of bone metabolism and muscle-bone crosstalk. Healthy young male and female participants (n = 21 male, 28 ± 4 years; n = 17 female, 27 ± 5 years) performed a 6 × 10 squat test (75% 1RM) before and after a 12-week resistance+interval training program. Before and after completion of the training program, blood samples were collected at rest, immediately postexercise, and 2 h postexercise. Blood samples were analyzed for βCTX, P1NP, sclerostin, osteocalcin, IGF-1, and irisin. Significant effects of acute exercise (main effect of time) were observed as increases in concentrations of IGF-1, irisin, osteocalcin, and P1NP from rest to postexercise. A sex*time interaction indicated a greater decline in βCTX concentration from rest to 2 h postexercise and a greater increase in sclerostin concentration from rest to immediately postexercise in male compared with female participants. Sex differences (main effect of sex) were also observed for irisin and P1NP concentrations. In summary, changes in concentrations of biochemical markers of bone metabolism and muscle-bone crosstalk were observed in males and females after an acute bout of resistance exercise and following 12 weeks of resistance+interval training.

Does the use of i-FACTOR bone graft affect bone healing in those undergoing periacetabular osteotomy (PAO) for hip dysplasia?

Introduction: Developmental Dysplasia of the hip (DDH) is a common cause of hip pain and a leading cause of early-onset hip osteoarthritis. Periacetabular osteotomy (PAO) aims to delay progression of osteoarthritis in those with DDH. As with any surgical procedure there are risks of complications, resulting in long-term pain and reduced function. The most common major surgical complication following PAO is bone non-union. Appropriate bone healing is a major focus of early rehabilitation as it allows full weightbearing capacity and physical activity progression.

Is Regular Weight-Bearing Physical Activity Throughout the Lifecourse Associated with Better Bone Health in Late Adulthood?

We considered how weight-bearing physical activity (WBPA) through the lifecourse related to bone health in late adulthood in the Hertfordshire Cohort Study (HCS), a cohort of community dwelling adults born 1931–9, to identify sex-specific differences and periods critical for optimal bone health. Available questionnaire data from 258 participants (128 men and 130 women) included current reported lifestyle factors (including physical activity) and WBPA, coded as participation in WBPA aged < 18 years; aged 18–29 years; aged 30–49 years and aged ≥ 50 years. Responses were recorded as none/once a month/once a week/> once a week. Hip bone mineral density (BMD) was measured using a Lunar Prodigy DXA scanner. The mean age was 75.4 (SD 2.5) years in men and 75.7 (SD 2.6) years in women. Men reported significantly higher levels of past WBPA aged < 18 years (p = 0.006) and aged 18–29 years than women (p < 0.001). We observed greater BMD at total hip in women who reported regular WBPA at ages 18–29 years (p = 0.02) and 30–49 years (p = 0.02) compared with those who reported no WBPA (p = 0.019), after adjustment for confounders including current activity levels. In this cohort of older adults, recalled regular WBPA around the time of peak bone mass acquisition was less common in women than men, but associated with higher hip BMD in women in late adulthood.

Weight-bearing physical activity in people with diabetes-related foot disease: A systematic review.

IntroductionWeight‐bearing physical activity is important for people with diabetes‐related foot disease but may also contribute to ulceration or delayed ulcer healing. No overview of weight‐bearing activity of people at different stages of foot disease is available. We aimed to summarise quantitatively measured daily activity levels in people with diabetes‐related foot disease.MethodsWe systematically searched peer‐reviewed literature for studies reporting objectively measured weight‐bearing activity in people with diabetes‐related foot disease. We calculated daily step counts' means (over studies) and weighted means (over participants). International Working Group on the Diabetic Foot (IWGDF) risk strata, different climates, and activity indoors versus outdoors were compared.ResultsFrom 1247 publications, 27 were included. Mean steps/day in people with IWGDF risk 1/2: 6125 (12 studies; 345 participants; weighted mean: 5384). In IWGDF risk 3: 6167 (8 studies; 291 participants; weighted mean: 6239). In those with a foot ulcer: 4248 (6 studies; 186 participants; weighted mean: 4484). People living in temperate oceanic climates are more active compared to those in hotter or more humid climates (mean steps/day for no ulcer: 7712 vs. 5224 [18 studies]; for ulcer: 6819 vs. 2945 [6 studies]). People are more active indoors than outdoors (mean 4047 vs. 2514 [3 studies]).ConclusionLevels of weight‐bearing physical activity are similar between people with diabetes at various risk levels for foot ulceration but lower for those with a foot ulcer. Weight‐bearing activity differs depending on the climatological environment and is higher indoors than outdoors. These findings provide reference for intervention studies or for clinicians aiming to provide mobility advice in this population.

P132 Does weight-bearing physical activity track through the lifecourse? Findings from the Hertfordshire Cohort Study

Abstract Background/Aims Physical activity is known to be beneficial for musculoskeletal health across the lifecourse. We have previously demonstrated that regular participation in weight-bearing physical activity (WBPA) at the time of peak bone mass acquisition is associated with higher hip bone mineral density in late adulthood in women. Understanding how WBPA tracks across the lifecourse may help us develop interventions to promote WBPA for musculoskeletal benefit; we consider these relationships here. Methods The study population consisted of 128 men and 130 women from the Hertfordshire Cohort Study. Questionnaire data on participation in sports and leisure time exercise involving WBPA e.g. running, racquet sports, football, rugby, hockey and dancing, but not walking, cycling or swimming were collected for the following age bands: &amp;lt;18 years; ages 18-29 years; ages 30-49 years; and ≥50 years. Responses were coded as none/ once a month/ once a week/ ≥once a week. Data on current lifestyle and physical activity levels were also collected. Results The mean age of participants was 75.4 (SD 2.5) years in men and 75.7 (SD 2.6) years in women. Men tended to report higher levels of past WBPA throughout the lifecourse, with significant differences in WBPA up to the age of 18 years (p = 0.006) and 18-29 years (p &amp;lt; 0.001). Table 1 shows kappa statistics of relationships between reported WBPA levels at different ages. These decreased over time, and while broadly similar, the tracking was generally stronger in women than men. For example, we observed that participants who were active at 30-49 years were more likely to remain active in late adulthood with kappa in men 0.393 (95%CI: 0.295-0.442) and kappa in women 0.492 (95% CI: 0.400-0.555). Conclusion WBPA decreased with advancing age in both sexes, though was generally higher in men than women in this retrospective cohort study. The correlation between WBPA at different stages of the lifecourse weakened as time between the measurements increased in both sexes. Our results highlight the need for further work to understand the drivers to encourage WBPA at different stages in the lifecourse and to facilitate development of appropriate interventions to promote WBPA for musculoskeletal benefit. Disclosure J. Zhang: None. K. Jameson: None. L. Westbury: None. N. Fuggle: None. K. Ward: None. C. Cooper: None. E. Dennison: None.

Effect of Exercise Volume on Plantar Microcirculation and Tissue Hardness in People With Type 2 Diabetes.

Objective: Exercise has been reported to be beneficial for people with type 2 diabetes (T2DM), but exercise, especially weight-bearing exercise, may increase the risk of diabetic foot ulcers (DFUs). This study aimed to explore the associations between different volumes of weight-bearing physical activities and plantar microcirculation and tissue hardness in people with T2DM. Methods: 130 elderly people with T2DM were enrolled for this cross-sectional study. They were classified into the high exercise volume group and the low exercise volume group based on their weekly energy expenditure (metabolic equivalents per week) in the past year. Weekly energy expenditure was calculated using the International Physical Activity Questionnaire and the Compendium of Physical Activities. The plantar oxygen saturation (SO2) and soft tissue hardness of each participant’s right foot were measured. Results: A total of 80 participants completed the trial. The average exercise energy expenditure of the high exercise volume group and the low exercise volume group were significantly different (p < 0.05). The results showed that the SO2 of the high exercise volume group (67.25 ± 6.12%) was significantly higher than the low exercise volume group (63.75 ± 8.02%, p < 0.05). The plantar tissue hardness of the high exercise volume group was lower than the low exercise volume group in the big toe, midfoot and hindfoot regions (p < 0.05). Conclusion: This study demonstrates that higher volumes of exercise are associated with better plantar microcirculation and lower plantar tissue hardness in people with T2DM. The findings of this study indicate that weight-bearing exercise may not increase risk of developing diabetic foot ulcers.

Effects of various walking intensities on leg muscle fatigue and plantar pressure distributions

BackgroundPhysical activity may benefit health and reduce risk for chronic complications in normal and people with diabetes and peripheral vascular diseases. However, it is unclear whether leg muscle fatigue after weight-bearing physical activities, such as brisk walking, may increase risk for plantar tissue injury. In the literature, there is no evidence on the effect of muscle fatigue on plantar pressure after various walking intensities. The objectives of this study were to investigate the effects of various walking intensities on leg muscle fatigue and plantar pressure patterns.MethodsA 3 × 2 factorial design, including 3 walking speeds (1.8 (slow and normal walking), 3.6 (brisk walking), and 5.4 (slow running) mph) and 2 walking durations (10 and 20 min) for a total of 6 walking intensities, was tested in 12 healthy participants in 3 consecutive weeks. The median frequency and complexity of electromyographic (EMG) signals of tibialis anterior (TA) and gastrocnemius medialis (GM) were used to quantify muscle fatigue. Fourier transform was used to compute the median frequency and multiscale entropy was used to calculate complexity of EMG signals. Peak plantar pressure (PPP) values at the 4 plantar regions (big toe, first metatarsal head, second metatarsal head, and heel) were calculated.ResultsTwo-way ANOVA showed that the walking speed (at 1.8, 3.6, 5.4 mph) significantly affected leg muscle fatigue, and the duration factor (at 10 and 20 min) did not. The one-way ANOVA showed that there were four significant pairwise differences of the median frequency of TA, including walking speed of 1.8 and 3.6 mph (185.7 ± 6.1 vs. 164.9 ± 3.0 Hz, P = 0.006) and 1.8 and 5.4 mph (185.7 ± 6.1 vs. 164.5 ± 5.5 Hz, P = 0.006) for the 10-min duration; and walking speed of 1.8 and 3.6 mph (180.0 ± 5.9 vs. 163.1 ± 4.4 Hz, P = 0.024) and 1.8 and 5.4 mph (180.0 ± 5.9 vs. 162.8 ± 4.9 Hz, P = 0.023) for the 20-min duration. The complexity of TA showed a similar trend with the median frequency of TA. The median frequency of TA has a significant negative correlation with PPP on the big toe ( r = -0.954, P = 0.003) and the first metatarsal head ( r = -0.896, P = 0.016).ConclusionsThis study demonstrated that brisk walking and slow running speeds (3.6 and 5.4 mph) cause an increase in muscle fatigue of TA compared to slow walking speed (1.8 mph); and the increased muscle fatigue is significantly related to a higher PPP.

Modeling the musculoskeletal loading in bone remodeling at the hip of a child

Background and objectivesThe mechanical load associated with physical activity affects the bone adaptation process. The bone adaptationeffect varies with age, being more effective during childhood and adolescence, particularly during pre-pubertal years. Bone-strengthening physical activity is recommended for children and adolescents. The number of time periods (bouts) per day of vigorous physical activity seems to be more important than the total cumulative time for optimal bone strength. So, the aim of this study was to evaluate the effects of weight-bearing physical activity on bone mineral density (BMD) of the proximal femur through computational simulation considering the intensity, exposure time (bouts) and regionalization of the results. MethodsFor this purpose, a finite element model of a 7 year-old child femur was developed based on computed tomography images. Musculoskeletal loads were obtained from experimental kinematic data of weight-bearing physical activity performed by children of the same age (standing, walking, running, jumping). The effects of physical activity on BMD of several regions of interest of the femur were analyzed using a bone remodeling model. A daily accumulation of 400 min of physical activity (200 min walking and 200 min standing) was considered as reference, against with which the effects of additional 10 min loading bouts were compared: 10 min bouts of vigorous intensity physical activity vs. 10 min bouts of light to moderate intensity physical activity. ResultsThe simulations revealed greater increases in BMD associated with higher intensity and longer duration of physical activity. The largest BMD increases occurs during the first 10 min bout compared to longer durations and in less mineralized central regions compared to regions far from the neutral axis of the bone. ConclusionWeight bearing physical activity is more effective in bone remodeling when the musculoskeletal loading is more intense and of short duration and, under these conditions, less mineralized regions are more positively impacted.

Terminal Syme Amputation of the Great Toe in the Pediatric Population.

In the pediatric population, chronic ingrown toenails (onychocryptosis) can cause infection (paronychia), debilitating pain, and may be unresponsive to conservative treatments. Following multiple failed interventions, a terminal Syme amputation is one option for definitive treatment of chronic onychocryptosis. This procedure involves amputation of the distal aspect of the distal phalanx of the great toe with complete removal of the nail bed and germinal center, preventing further nail growth and recurrence. A retrospective review was performed to determine outcomes of a terminal Syme amputation in the pediatric population. Inclusion criteria included treatment of onychocryptosis involving terminal Syme amputation with a minimum follow-up of 1 year. The medical record was reviewed to assess previous failed treatment efforts, perioperative complications, radiographic outcomes, and the need for additional procedures. From 1984 to 2017, 11 patients (13 halluces) with onychocryptosis were treated with a terminal Syme amputation. There were no intraoperative complications. One hallux had a postoperative infection requiring antibiotics as well as partial nail regrowth following the terminal Syme procedure that required subsequent removal of the residual nail. Following partial nail ablation, the patient had no further nail growth. An additional patient also developed a postoperative infection requiring oral antibiotic treatment. All patients returned to full weight-bearing physical activities within 6 weeks of surgery. Terminal Syme amputation was successful in treating pediatric patients who have recalcitrant onychocryptosis and paronychia. There was little functional consequence following terminal Syme amputation of the great toe in this patient population, making it an effective salvage procedure. Level IV-retrospective comparative study.

The effects of different accumulated pressure-time integral stimuli on plantar blood flow in people with diabetes mellitus

BackgroundExercise, especially weight-bearing exercise (e.g. walking), may affect plantar tissue viability due to prolonged repetitive high vertical and high shear pressure stimulus on the plantar tissue, and further induce development of diabetic foot ulcers (DFUs). This study aimed to investigate the effects of different accumulated pressure-time integral (APTI) stimuli induced by walking on plantar skin blood flow (SBF) responses in people with diabetes mellitus (DM).MethodsA repeated measures design was used in this study. Two walking protocols (low APTI (73,000 kPa·s) and high APTI (73,000 × 1.5 kPa·s)) were randomly assigned to ten people with DM and twenty people without DM. The ratio of SBF measured by laser Doppler flowmetry after walking to that before (normalized SBF) was used to express the SBF responses.ResultsAfter low APTI, plantar SBF of people with DM showed a similar response to people without DM (P = 0.91). However, after high APTI, people with DM had a significantly lower plantar SBF compared to people without DM (P < 0.05). In people with DM, plantar SBF in the first 2 min after both APTI stimuli significantly decreased compared to plantar SBF before walking (P < 0.05).ConclusionsPeople with DM had a normal SBF response after low APTI walking but had an impaired SBF response after high APTI walking, which suggests that they should avoid weight-bearing physical activity with intensity more than 73,000 kPa·s and should rest for more than 2 min after weight-bearing physical activity to allow a full vasodilatory response to reduce risk of DFUs.

Incident Type 2 Diabetes and Risk of Fracture: A Comparative Cohort Analysis Using U.K. Primary Care Records.

To estimate risk of fracture in men and women with recent diagnosis of type 2 diabetes compared with individuals without diabetes. In this cohort study, we used routinely collected U.K. primary care data from The Health Improvement Network. In adults (>35 years) diagnosed with type 2 diabetes between 2004 and 2013, fractures sustained until 2019 were identified and compared with fractures sustained in individuals without diabetes. Multivariable models estimated time to first fracture following diagnosis of diabetes. Annual prevalence rates included at least one fracture in a given year. Among 174,244 individuals with incident type 2 diabetes and 747,290 without diabetes, there was no increased risk of fracture among males with diabetes (adjusted hazard ratio [aHR] 0.97 [95% CI 0.94, 1.00]) and a small reduced risk among females (aHR 0.94 [95% CI 0.92, 0.96]). In those aged ≥85 years, those in the diabetes cohort were at significantly lower risk of incident fracture (males: aHR 0.85 [95% CI 0.71, 1.00]; females: aHR 0.85 [95% CI 0.78, 0.94]). For those in the most deprived areas, aHRs were 0.90 (95% CI 0.83, 0.98) for males and 0.91 (95% CI 0.85, 0.97) for females. Annual fracture prevalence rates, by sex, were similar for those with and without type 2 diabetes. We found no evidence to suggest a higher risk of fracture following diagnosis of type 2 diabetes. After a diagnosis of type 2 diabetes, individuals should be encouraged to make positive lifestyle changes, including undertaking weight-bearing physical activities that improve bone health.

Using Elastographic Ultrasound to Assess Plantar Tissue Stiffness after Walking at Different Speeds and Durations

Exercise has been demonstrated to improve health in people with diabetes. However, exercise may increase risk for foot ulcers because of increased plantar pressure during most weight-bearing physical activities. To date, there is no study investigating the effect of various walking speeds and durations (i.e., the most common form of exercise in daily living) on the plantar foot. The objective of this study was to investigate the effect of various walking intensities on plantar tissue stiffness. A 3 × 2 factorial design, including three walking speeds (1.8, 3.6 and 5.4 mph) and two durations (10 and 20 min), was tested in 12 healthy participants. B-mode and elastographic ultrasound images were measured from the first metatarsal head to quantify plantar tissue stiffness after walking. Two-way ANOVA was used to examine the results. Our results showed that the walking speed factor caused a significant main effect of planar stiffness of the superficial layers (p = 0.007 and 0.003, respectively). However, the walking duration factor did not significantly affect the plantar stiffness. There was no interaction between the speed and duration factors on plantar tissue stiffness. Regarding the walking speed effect, there was a significant difference in the plantar stiffness between 1.8 and 3.6 mph (56.8 ± 0.8% vs. 53.6 ± 0.9%, p = 0.017) under 20 min walking duration. This finding is significant because moderate-to-fast walking speed (3.6 mph) can decrease plantar stiffness compared to slow walking speed (1.8 mph). This study suggests people at risk for foot ulcers walk at a preferred or fast speed (3.6 mph) rather than walk slowly (1.8 mph).

Bone mineral density in male weight-classified athletes is higher than that in male endurance-athletes and non-athletes

Weight-bearing physical activity and intense mechanical stimuli affect the bone through the endocrine system; hence, bone-loading sports affect bone mineral density. We hypothesized that weight-classified athletes, such as those practicing wrestling and judo, have relatively high bone mineral density because these activities have a higher impact on the entire body during daily training compared to low- or non-impact activities. We aimed to investigate the bone mineral density of weight-classified athletes (participating in wrestling and judo) to compare the parameters with those of endurance-athletes and non-athletes. Thirty-three college athletes (aged 18-22 years) were divided into three groups, wrestlers, judoka, and endurance-athletes, according to their sports history. Eight non-athletes participated as controls. Bone mineral density was determined by whole-body dual-energy X-ray absorptiometry. Mean whole-body bone mineral density of wrestlers and judoka was higher than that of endurance-athletes and non-athletes (P<0.01). The bone mineral density of athletes competing in wrestling and judo was higher than that of non-athletes when adjusted for body mass. The present study demonstrated that weight-classified athletes have significantly higher bone mineral density compared to endurance- and non-athletes, despite rapid weight loss before competitions.

Altered forefoot function following a military training activity

BackgroundInjury rates are high in populations that regularly undertake weight-bearing physical activity, particularly military populations. Military training activities, that often include load carriage, have been associated with lower limb injury occurrence, specifically stress fractures. Research questionRecent work identified plantar loading variables as risk factors for lower limb stress fractures in Royal Marines recruits that were assessed during barefoot running. This study aimed to quantify how those plantar loading variables changed in Royal Marines recruits following a prolonged military load carriage activity, to further understand potential mechanisms for lower limb stress fractures. MethodsBilateral, synchronised plantar pressure and lower limb kinematic data were recorded during barefoot running at 3.6 m s−1 (±5%) pre- and post- a 12.8-km training activity (∼150 min). The training activity was completed with an average speed typical of walking (1.4 m.s-1), and 35.5 kg of additional load was carried throughout. Data were collected from 32 male Royal Marines recruits who completed the training activity in week-21 of the 32-week training programme. Plantar pressure variables and ankle dorsiflexion were compared between pre- and post-activity. ResultsPost-activity there was reduced loading under the forefoot and increased loading under the rearfoot and midfoot. There was no change in dorsiflexion touchdown angle, but an increase in peak dorsiflexion and range of motion post-activity. SignificanceThe increased rearfoot loading, reduced forefoot loading and increased ankle dorsiflexion following a prolonged military load carriage activity suggest a reduced transfer of loading from the rearfoot to the forefoot during stance, which may have implications for the development of stress fractures, particularly of the metatarsals.

Weight-Bearing Physical Activity Influences the Effect of Vitamin D on Bone Turnover Markers in Patients with Intellectual Disability.

Individuals with intellectual disabilities (IDs) are at increased risk for low bone mass and fragility fractures, and those who are nonambulatory may be at even higher risk. Patients with IDs often are vitamin D deficient, but there is little information concerning how vitamin D treatment of patients with IDs affects markers of bone formation and resorption. We performed a retrospective analysis of 23 institutionalized individuals with IDs who were the subject of a performance improvement continuing medical education project designed to reduce risk for fracture by optimizing serum vitamin D levels. Patients were divided into those with normal weight-bearing (NWB) physical activity (15 patients: 14 men, 1 woman) and those with low weight-bearing (LWB) physical activity (8 patients: 7 men, 1 woman). All of the subjects received 50,000 IU of vitamin D3 weekly for 4 to 8 weeks, followed by a maintenance dose of 50,000 IU monthly for 3 to 6 months. Bone turnover markers (type 1 cross-linked C-telopeptide [CTX], type 1 N-terminal propeptide [P1NP], and parathyroid hormone [PTH]) and 25(OH)-vitamin D levels were measured before and after vitamin D supplementation. At baseline, there were no significant differences in the serum levels of 25OH-D, PTH, P1NP, or CTX between the two groups (NWB and LWB). Vitamin D levels were increased to a higher value in LWB subjects than in NWB subjects (61 ± 4.1 vs 48.4 ± 2.2 ng/mL, P < 0.001). Vitamin D treatment suppressed PTH (20.5% ± 14.3% vs 31.4% ± 7.7%, P = not significant) and P1NP (33.0% ± 6.2% vs 29.4% ± 6.9%, P = not significant) similarly in both groups. Although CTX levels declined by 26.4% ± 5.3% (P = 0.0002) in NWB individuals (as anticipated), vitamin D supplementation resulted in an unexpected 25.8% ± 8% increase (P = 0.01) in CTX in LWB individuals, suggesting osteoclast activation. Although high-dose vitamin D appeared to suppress osteoclast activity in NWB adults with IDs, the increase in serum CTX levels in those with LWB activity implies activation of osteoclasts that could exacerbate their unique low bone mass and increase fracture risk. The results support the use of a lower-dose vitamin D regimen in this patient group with LWB.

Effects of a Home‐Based Physical Rehabilitation Program on Tibial Bone Structure, Density, and Strength After Hip Fracture: A Secondary Analysis of a Randomized Controlled Trial

Weight‐bearing physical activity may decrease or prevent bone deterioration after hip fracture. This study investigated the effects of a home‐based physical rehabilitation program on tibial bone traits in older hip fracture patients. A population‐based clinical sample of men and women operated for hip fracture (mean age 80 years, 78% women) was randomly assigned into an intervention (n = 40) and a standard care control group (n = 41) on average 10 weeks postfracture. The intervention group participated in a 12‐month home‐based rehabilitation intervention, including evaluation and modification of environmental hazards, guidance for safe walking, nonpharmacological pain management, motivational physical activity counseling, and a progressive, weight‐bearing home exercise program comprising strengthening exercises for the lower legs, balance training, functional exercises, and stretching. All participants received standard care. Distal tibia (5% proximal to the distal end plate) compressive bone strength index (BSI; g2/cm4), total volumetric BMD (vBMDTOT; mg/cm3), and total area (CSATOT; mm2), as well as midtibia (55%) strength–strain index (SSI; mm3), cortical vBMD (vBMDCO; mg/cm3), and ratio of cortical to total area (CSACO/CSATOT) were assessed in both legs by pQCT at baseline and at 3, 6, and 12 months. The intervention had no effect (group × time) on either the distal or midtibial bone traits. At the distal site, BSI of both legs, vBMDTOT of the fractured side, and CSATOT of the nonfractured side decreased significantly over time in both groups 0.7% to 3.1% (12 months, p < 0.05). At the midshaft site, CSACO/CSATOT and SSI of both legs, and vBMDCO of the fractured leg, decreased significantly over time in both groups 1.1% to 1.9% (12 months, p < 0.05). Trabecular and cortical bone traits of the tibia on the fractured and the nonfractured side deteriorated throughout follow‐up. The home‐based physical rehabilitation intervention aimed at promoting mobility recovery was unable to prevent bone deterioration in older people after hip fracture. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Sports participation and fracture in older Australian men.

Regular weight-bearing physical activity can reduce fracture risk through an increase in bone strength, as well as reducing falls risk by improving muscle strength and balance. In this study, we aimed to determine whether a specific type of physical activity, sports participation, reduces fracture risk in older Australian men. Participation in sporting activities was documented for men aged 60years and over enrolled in the Geelong Osteoporosis Study situated in south-eastern Australia. Fractures at any skeletal site (excluding skull, face, fingers and toes) and major osteoporotic fracture sites (MOF; wrist, proximal humerus, spine and hip) were ascertained through examination of radiological reports (median follow-up 6.63years, IQR 5.58-7.29). Multivariable logistic regression was used to investigate the association between sports participation (either binary or continuous) and any fracture or MOF. Other clinical measures and lifestyle variables (such as comorbidity, falls and mobility) were included as potential confounders. During follow-up, 82 of 656 men (12.5%) sustained at least one fracture at any site and 58 sustained at least one MOF (8.8%). Of those who did and did not fracture (any site), 17 (20.7%) and 204 (35.5%) participated in at least one sporting activity. For MOF, the values were 11 (19.0%) and 210 (35.1%), respectively. Participation in any sporting activity was associated with a reduction in the likelihood of any fracture during follow-up (unadjusted: OR 0.47, 95%CI 0.27-0.83), which persisted after adjusting for other factors (adjusted: OR 0.52, 95%CI 0.29-0.91). The results for MOF were similar (unadjusted: OR 0.43, 0.22-0.85; adjusted 0.48, 0.24-0.95). When considering sports participation as a continuous variable, a trend was observed (adjusted: p = 0.051 and p = 0.059 for any and MOF, respectively). A sensitivity analysis showed similar results when excluding men who reported using a walking aid. In this group of older men, participation in sporting activity was associated with a reduced risk of fracture during the subsequent follow-up period.

Changes in eating behavior and plasma leptin in children with obesity participating in a family-centered lifestyle intervention

The goal of childhood obesity lifestyle interventions are to positively change body composition, however it is unknown if interventions also modulate factors that are related to energy intake. This study aimed to examine changes in eating behaviors and plasma leptin concentrations in overweight and obese children participating in a 1-year family-centered lifestyle intervention. Interventions were based on Canadian diet and physical activity (PA) guidelines. Children were randomized to 1 of 3 groups: Control (Ctrl; no intervention), Standard treatment (StnTx: 2 servings milk and alternatives/day (d), 3x/wk weight-bearing PA), or Modified treatment (ModTx: 4 servings milk and alternatives/day; daily weight-bearing PA). Study visits occurred every 3-months for 1-y; interventions were held once a month for 6-months with one follow-up visit at 8-months. Ctrl received counselling after 1-y. Caregivers completed the Children's Eating Behavior Questionnaire (CEBQ) and reported on diet and activity. Plasma leptin were measured from morning fasted blood samples. Seventy-eight children (mean age 7.8 ± 0.8 y; mean BMI 24.4 ± 3.3 kg/m2) participated; 94% completed the study. Compared to baseline, at 6-months StnTx reduced Emotional Overeating and Desire to Drink scores (p < 0.05) while Food Responsiveness scores were reduced in both StnTx and ModTx (p < 0.05). At 1-year, scores for Desire to Drink in StnTx remained reduced compared to baseline (p < 0.05). Plasma leptin concentrations were significantly lower in ModTx at 6-months compared to baseline (p < 0.05). This study resulted in intervention groups favorably changing eating behaviors, supporting the use family-centered lifestyle interventions using Canadian diet and PA recommendations for children with obesity.