Abstract Athletes participating in sports characterized by specific loading modalities have exhibited different levels of augmentation of bone properties; however, the extent to which these loading ...environments affect bone micro-architecture and estimated bone strength (i.e. bone quality) remains unclear. Furthermore, the relative role of impact loading versus loading due to muscle forces in determining bone properties is confounded. The objectives of this study were 1) to examine the role of impact loading on bone quality of the distal radius and distal tibia in elite athletes, as determined by high resolution peripheral quantitative computed tomography (HR-pQCT) and finite element analysis (FEA), and 2) to investigate the relationship between bone quality and muscle strength in elite athletes. Ninety-five females (n = 59) and males (n = 36) between the ages of 16–30 years participated in the study. Participants included alpine skiers (high-impact), soccer players (moderate impact), swimmers (low-impact), and non-athletic controls. All group comparisons were made after accounting for age, height, and body mass. As expected, minimal differences in HR-pQCT parameters across groups were observed at the non weight-bearing distal radius. At the weight-bearing distal tibia, female alpine skiers and soccer players had significantly higher bone density, cortical thickness, and failure load (i.e. bone strength (N) in compression estimated by FEA) than swimmers (p < 0.05). Female alpine skiers also had lower trabecular separation than swimmers and controls. Male alpine skiers had 20% higher trabecular bone mineral density than swimmers, and male soccer players exhibited 22% higher trabecular number than swimmers at the distal tibia (p < 0.05). Male alpine skiers and soccer players had 28–38% higher failure load at the distal tibia than swimmers. No differences in bone parameters were observed between swimmers and controls for either sex at either site. Both muscle strength and sporting activity were predictors of failure load at the distal tibia in the female cohort. Sporting activity, but not muscle strength, was a significant predictor of failure load in the male cohort at both the radius and tibia. This data suggests that impact loading in sporting activity is highly associated with bone quality. Longitudinal and interventional studies are required to further clarify the muscle–bone interaction.
To determine the dose-response relationship between ambulatory load magnitude during a walking stress test and load-induced changes in serum concentration of cartilage oligomeric matrix protein ...(sCOMP) in healthy subjects.
Design: sCOMP was assessed before and after a 30-min walking stress test performed on three test days by 24 healthy volunteers. In each walking stress test, one of three ambulatory loads was applied in a block randomized crossover design: normal body weight (BW) (100%BW = normal load); reduced BW (80%BW = reduced load); increased BW (120%BW = increased load). Knee kinematics and ground reaction force (GRF) were measured using an inertial sensor gait analysis system and a pressure plate embedded in the treadmill.
Load-induced increases in sCOMP rose with increasing ambulatory load magnitude. Mean sCOMP levels increased immediately after the walking stress test by 26.8 ± 12.8%, 28.0 ± 13.3% and 37.3 ± 18.3% for the reduced, normal or increased load condition, respectively. Lower extremity kinematics did not differ between conditions.
The results of this study provide important evidence of a dose-response relationship between ambulatory load magnitude and load-induced changes in sCOMP. Our data suggests that in normal weight persons sCOMP levels are more sensitive to increased than to reduced load. The experimental framework presented here may form the basis for studying the relevance of the dose-response relationship between ambulatory load magnitude and load-induced changes in biomarkers involved in metabolism of healthy articular cartilage and after injury.
Summary Objective To test the hypotheses that 1) 14-days of immobilization of young healthy subjects using a 6°-“head-down-tilt-bed-rest”-model (6°-HDT) would reduce cartilage thickness in the knee ...and serum Cartilage oligometric matrix protein (COMP) concentration and 2) isolated whole body vibration training would counteract the bed rest effects. Method The study was performed and designed in compliance with the Declaration of Helsinki and is registered as trial DRKS00000140 in the German Clinical Trial Register (register.germanctr.de). Eight male healthy subjects (78.0 ± 9.5 kg; 179 ± 0.96 cm, 26 ± 5 years) performed 14 days of 6°-HDT. The study was designed as a cross-over-design with two study phases: a training and a control intervention. During the training intervention, subjects underwent 2 × 5-min whole body vibration training/day (Frequency: 20 Hz; amplitude: 2–4 mm). Magnetic resonance (MR) images (slice thickness: 2 mm; in-plane resolution: 0.35 × 0.35 mm; pixels: 448 × 512) were taken before and after the 6°-HDT periods. Average cartilage thicknesses were calculated for the load bearing regions on the medial and lateral articulating surfaces in the femur and tibia. Results While the control intervention resulted in an overall loss in average cartilage thickness of −8% (pre: 3.08 mm ± 0.6 mm post: 2.82 mm ± 0.6 mm) in the weight-bearing regions of the tibia, average cartilage thickness increased by 21.9% (pre: 2.66 mm ± 0.45 mm post: 3.24 mm ± 0.63 mm) with the vibration intervention. No significant differences were found in the weight-bearing regions of the femur. During both interventions, reduced serum COMP concentrations were observed (control intervention: −13.6 ± 8.4%; vibration intervention: −9.9 ± 3.3%). Conclusion The results of this study suggest that articular cartilage thickness is sensitive to unloading and that vibration training may be a potent countermeasure against these effects. The sensitivity of cartilage to physical training is of high relevance for training methods in space flight, elite and sport and rehabilitation after illness or injury.
Summary
Bone quality is affected by muscle forces and external forces. We investigated how micro-architecture is influenced in elite alpine skiers who have received high loading levels throughout ...their adolescent bone development. Bone strength was higher in skiers, likely due to external forces, but muscle forces may also be a significant contributor.
Introduction
Impact loading and muscle forces affect bone quality, but little is known about how they influence 3 dimensional aspects of bone structure. This study investigated bone quality in female and male elite alpine skiers using high-resolution peripheral quantitative computed tomography (HR-pQCT).
Methods
HR-pQCT at the distal radius and tibia, whole-body lean mass, and muscle strength were assessed in 10 female (22.7 ± 3.9 years) and 12 male (25.5 ± 3.3 years) Canadian national alpine team athletes and compared to recreationally active female (
N
= 10, 23.8 ± 3.2 years) and male (
N
= 12; 23.7 ± 3.6 years) control subjects. HR-pQCT standard parameters and customized cortical and finite element (FE) analyses were performed and analyzed using one-way ANOVA and Pearson’s correlation.
Results
Male and female skiers had stronger bones than controls at radius (38–49 %,
p
< 0.001) and tibia (24–28 %,
p
< 0.001). This result was not consistently reflected by total bone mineral density (BMD) because higher trabecular BMD occurred in parallel with lower cortical BMD, which was due to a redistribution of mineral leading to a shift of the endocortical margin toward a thicker cortex. The endocortical regional adaptation was likely responsible for the greater strength of the athletes’ bones. Lean mass and muscle strength was 29 to 90 % greater (
p
< 0.001) in athletes compared to controls. Good associations between muscle strength and FE-estimated bone strength were found (
r
= 0.63 to 0.80;
p
< 0.001), although micro-architecture was more strongly associated with muscle outcomes in females than males.
Conclusions
Higher bone strength in elite alpine skiers is achieved through micro-architectural adaptation that is not apparent by BMD measurements alone. The improved micro-architecture at radius and tibia suggests that muscle forces may play an important role in bone adaptation.
Muscle activity has previously been suggested to minimize soft-tissue resonance which occurs at heel-strike during walking and running. If this concept were true then the greatest vibration damping ...would occur when the input force was closest to the resonant frequency of the soft-tissues at heel-strike. However, this idea has not been tested. The purpose of this study was to test whether muscle activity in the lower extremity is used to damp soft-tissue resonance which occurs at heel-strike during walking. Hard and soft shoe conditions were tested in a randomized block design. Ground reaction forces, soft-tissue accelerations and myoelectric activity were measured during walking for 40 subjects. Soft-tissue mass was estimated from anthropologic measurements, allowing inertial forces in the soft-tissues to be calculated. The force transfer from the ground to the tissues was compared with changes in the muscle activity. The soft condition resulted in relative frequencies (input/tissue) to be closer to resonance for the main soft-tissue groups. However, no increase in force transmission was observed. Therefore, the vibration damping in the tissues must have increased. This increase concurred with increases in the muscle activity for the biceps femoris and lateral gastrocnemius. The evidence supports the proposal that muscle activity damps soft-tissue resonance at heel-strike. Muscles generate forces which act across the joints and, therefore, shoe design may be used to modify muscle activity and thus joint loading during walking and running.
Summary
Whole-body vibration training may improve bone quality through structural adaptation. We tested if 12 months of training affects bone structure in osteopenic postmenopausal women by using ...advanced 3-dimensional high-resolution imaging techniques. We found that whole-body vibration training did not improve bone structure compared to inactive controls.
Introduction
Whole-body vibration training (WBVT) has been suggested as a preventive measure against bone loss. Contradicting results of previous studies may be confounded by insufficiently sensitive bone density measures to detect relevant bone changes. WBVT may improve bone quality through structural adaptations, without increasing bone mineral density (BMD). We hypothesized that 12 months of WBVT will improve or maintain bone microarchitecture and bone strength in osteopenic postmenopausal women.
Methods
Twenty-two women received WBVT for 2–3 sessions/week and were compared with 20 controls. Bone outcomes were measured by high-resolution peripheral quantitative CT (HR-pQCT, XtremeCT, Scanco Medical) and finite element estimated bone strength. Balance and jump performance and maximum voluntary contraction (MVC) of knee flexor and extensor muscles were recorded. All measurements were taken at baseline, 4, 8, and 12 months and a reduced data set at 4 and 8 months follow-up and compared using a mixed model repeated measures ANOVA.
Results
Thirty-one women completed the study with 90 % compliance (WBVT:
n
= 17, control
n
= 14). Total BMD (
p <
0.001), cortical area*(
p =
0.004), cortical thickness (
p
= 0.011), and cortical porosity (
p
= 0.024) all significantly decreased over time in both groups; WBVT did not affect the response. All other bone outcomes were not affected by WBVT or time. No difference in measures of balance, jump height, and MVC due to WBVT were detected.
Conclusion
In our cohort, WBVT did not lead to improved bone quality in postmenopausal osteopenic women after 12 months of training compared to controls, and there were no detected benefits related to balance and muscle strength outcomes.
Arthritis induces bone loss by inflammation-mediated disturbance of bone homeostasis. On the other hand, pain and impaired locomotion are highly prevalent in arthritis and result in reduced general ...physical activity and less pronounced mechanical loading. Bone is affected by mechanical loading, directly through impact with the ground during movement and indirectly through muscular activity. Mechanical loading in its physiological range is essential for maintaining bone mass, whereas disuse leads to bone loss. The aim of this study was to investigate the impact of mechanical loading on periarticular bone as well as inflammation during arthritis. Mechanical loading was either blocked by botulinum neurotoxin A (Botox) injections before induction of arthritis, or enhanced by cyclic compressive loading, three times per week during arthritis induction. Arthritis was verified and evaluated histologically. Trabecular and cortical bone mass were investigated using micro-computed tomography (μCT), subchondral osteoclastogenesis and bone turnover was assessed by standard methods. Inhibition of mechanical loading enhanced arthritis-induced bone loss while it did not affect inflammation. In contrast, enhanced mechanical loading mitigated arthritis-induced bone loss. Furthermore, the increase in bone resorption markers by arthritis was partly blocked by mechanical loading. In conclusion, enhanced arthritic bone loss after abrogation of mechanical loading suggests that muscle forces play an essential role in preventing arthritic bone loss. In accordance, mechanical loading of the arthritic joints inhibited bone loss, emphasizing that weight bearing activities may have the potential to counteract arthritis-mediated bone loss.
Based on the European Space Agency (ESA) Science in Space Environment (SciSpacE) community White Paper "Human Physiology - Musculoskeletal system", this perspective highlights unmet needs and ...suggests new avenues for future studies in musculoskeletal research to enable crewed exploration missions. The musculoskeletal system is essential for sustaining physical function and energy metabolism, and the maintenance of health during exploration missions, and consequently mission success, will be tightly linked to musculoskeletal function. Data collection from current space missions from pre-, during-, and post-flight periods would provide important information to understand and ultimately offset musculoskeletal alterations during long-term spaceflight. In addition, understanding the kinetics of the different components of the musculoskeletal system in parallel with a detailed description of the molecular mechanisms driving these alterations appears to be the best approach to address potential musculoskeletal problems that future exploratory-mission crew will face. These research efforts should be accompanied by technical advances in molecular and phenotypic monitoring tools to provide in-flight real-time feedback.
BackgroundFunctional properties of bone in rheumatoid arthritis (RA) are still not well characterised.ObjectivesThis study aimed to define the impact of anti-citrullinated antibodies (ACPA) on ...biomechanical properties in RA.MethodsBased on on high-resolution peripheral quantitative computed tomography (HR-pQCT) data from the distal radius of ACPA-positive RA (RA+), ACPA-negative RA (RA-) and healthy controls (HC) micro-finite element analysis (µFEA) was carried out to measure failure load and stiffness of bone.(1 Comparisons of µFEA parameters between groups was calculated and multivariate models were used to determine the role of demographic, disease-specific and structural data of bone strength.ResultsA total of 276 subjects (96 RA+, 84 RA- and 96 HC) were analysed. Age and sex distributions were not significantly different between the three groups. In RA +but not in RA- failure load and stiffness were significantly decreased compared to HC (both p<0.001). Lower bone strength affected both female and male RA +patients and was related to longer disease duration. Impaired bone strength was correlated with altered bone density and microstructural parameters, which were all decreased in RA+. Multivariate models showed that ACPA status (p=0.007) and sex (p<0.001) were independently associated with reduced biomechanical properties of bone in RA.ConclusionsIn summary, µFEA showed that bone strength is significantly decreased in RA +but not in RA- disease.Reference1 Macneil JA, Boyd SK. Bone strength at the distal radius can be estimated from high-resolution peripheral quantitative computed tomography and the finite element method. Bone2008;42(6):1203–13.Disclosure of InterestNone declared
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