Musculoskeletal Injury Rates in Multiday Marathon Runners Performing Ten Consecutive Marathons on a Repeat Course

Objective: To describe musculoskeletal injury rates in recreational runners completing ten marathons over ten consecutive days to help event organisers plan future injury preventative advice and strategies. Methods: An observational study involving 27 recreational runners (age 45.1 ± 7.47 yrs, mass 74.5 ± 12.39 kg, years running 11.6 ± 9.42 yrs, average weekly mileage 41.9 ± 12.72 miles). Main outcome measures included total and percentage of musculoskeletal injuries, timing of injury occurrence during 10-day event, and daily individual marathon times. Results: Twenty-six runners sustained 108 injuries, averaging 4 injuries per runner (90.13 per 1000hr). 89% of injuries involved the lower extremity; 24.1% foot, 18.5% hip/buttock, 16.7% ankle and 16.7% lower leg. Common injuries were blisters (15.7%), Achilles tendinitis (11.1%), medial tibial stress syndrome (MTSS) (10.2%), iliotibial band syndrome (ITBS) (9.3%) and low back pain (LBP) (9.3%). 64.3% of injuries were sustained to the left limb. Chisquared analysis revealed more injuries in days 1-3 than days 4-6 (p=0.013) and days 7-10 (p=0.001). Repeated measures ANOVA comparing Days 1-3, 4-6 and 7-10 showed a significant main effect (p=0.039). Post hoc analysis revealed Days 1-3 were significantly quicker time than days 7-10 (p=0.037, difference of 0.276 hrs). Conclusion: Blisters, Achilles tendinitis, MTSS and ITBS are the most common lower extremity injuries in multiday marathons runners performing a repeat course over 10 consecutive days.Runners entering these events should perform appropriate injury prevention programmes. Runners should also be more reserved at the beginning of multiday events to avoid high initial injury risk. However, further investigation of injury rates and risk factors using larger sample sizes is required

The effect of running nine marathons in nine days on proprioception and balance

Background: Multi-day running events are becoming increasingly popular with nonprofessional athletes. However, it is unknown how and when this type of event affects injury risk factors such as proprioception and balance. Objective: To evaluate the effect of running one, five consecutive and nine consecutive marathons on joint position sense (JPS) and dynamic balance. Design: Cross-sectional, observational study. Setting: Sports-injury clinic. Participants: 21 athletes completing the event (age 44.8±8.09 yrs, mass 74.4±13.14 kg, years running 10.4±7.39 yrs, average weekly mileage 44.8±12.09 miles) entered the study. Ten athletes completed the JPS testing and five athletes completed the dynamic balance testing. Assessment of Risk Factors: Risk factors were assessed the day before the event (day zero) and then following completion of one (day one), five (day five) and nine (day nine) consecutive marathons. The independent variable was time. Main Outcome Measurements: JPS error into flexion and extension, star-excursion balance test (SEBT) and number of injuries per runner. Results: Friedman's ANOVAs indicated no effects of time on JPS into extension (p=0.94), dominant-leg anterior (p=0.52) or posterior-lateral (p=0.65) SEBT reach. JPS flexion error significantly decreased by 1.3° from day one to five (p=0.032). Non-dominant leg anterior, posterior-medial and posterior-lateral SEBT reaches significantly decreased from day zero to nine by 0.09% (p=0.043), 0.13% (p=0.043) and 0.17% (p=0.043) of leg length respectively. Dominant leg posterior-medial SEBT reach also significantly decreased by 0.12% of leg length (p=0.043) from day zero to nine. There were 4.2 injuries per runner. Conclusions: The results suggest multi-day running events can cause over four lower limb injuries per runner and reduce dynamic balance ability. Nonprofessional athletes completing these events should be aware of this high injury occurrence and prepare appropriately. Injury prevention programmes incorporating dynamic balance may be recommended. However future studies with additional risk factors and larger sample sizes are needed to substantiate these findings

Restricted Unilateral Ankle Dorsiflexion Movement Increases Interlimb Vertical Force Asymmetries in Bilateral Bodyweight Squatting

The purpose of this study was to investigate the effect of unilateral restrictions in ankle-dorsiflexion range of motion (DF-ROM) on interlimb vertical ground reaction force (vGRF) asymmetries. Twenty healthy and physically active volunteers (age 23 ± 3 years; height 1.72 ± 0.1 m; mass 74.9 ± 20.3 kg) performed 3 barefoot bodyweight squats (control condition) and with a 10° custom-built forefoot wedge under the right foot to artificially imitate ankle DF-ROM restriction (wedge condition). Force data were used to calculate the mean asymmetry index score for the upper descent phase, lower descent phase, lower ascent phase, and upper ascent phase during the bilateral squat. Significant differences were found for comparisons for each phase between conditions, with effect sizes ranging between 0.7 and 1.1. Asymmetry index scores indicated that for all phases, the unrestricted limb in the wedge condition produced greater vGRF. Therefore, interlimb differences in ankle DF-ROM can cause interlimb asymmetries in vGRF during bilateral squatting. As such, athletes with asymmetrical squat mechanics should be screened for interlimb differences in ankle DF-ROM to ascertain whether it is a contributing factor

Musculoskeletal injury rates in multiday marathon runners performing a repeat course

Background: Ultramarathon events are increasingly popular amongst non-elite athletes. However, there is little research investigating musculoskeletal injury rates, specifically multiday events using the same racing route. Objective: To describe musculoskeletal injury rates in runners completing ten marathons over ten consecutive days. Design: Observational. Setting: Sports-injury clinic. Participants: 27 athletes entered the study (age 45.1±7.47 yrs, mass 74.5±12.39 kg, years running 11.6±9.42 yrs, average weekly mileage 41.9±12.72 miles). 26 athletes completed all 10 marathons on a repeat, anti-clockwise, circular road course. One athlete withdrew due to serious injury. Main Outcome Measurements: Musculoskeletal injuries were recorded by trained medical staff three times each day. An injury audit questionnaire was used to document injury rate, type and location. Injuries were defined as a specific musculoskeletal abnormality that the runner perceived to effect performance. Results: 26 athletes sustained 108 injuries, averaging 4 injuries per athlete. 89% of injuries involved the lower extremity, 24.1% occurred in the foot, 18.5% the hip/buttock, 16.7% the ankle and 16.7% in the lower leg. The most common injuries were blisters (15.7%), Achilles tendinitis (11.1%), medial tibial stress syndrome (10.2%), iliotibial band syndrome (ITBS) (9.3%) and low back pain (LBP) (9.3%). 64.3% of injuries were sustained to the left limb. Chi-squared analysis revealed more injuries in days 1–3 than days 4–6 (p=0.013) and days 7–10 (p=0.001). Conclusions: Lower extremity injuries are highly likely in multiday marathon running; the most common being blisters, Achilles tendinitis, medial tibial stress syndrome, ITBS and LBP. Athletes entering these events should engage in appropriate injury prevention programmes. The majority of injuries were sustained to the left limb and during the first three days. Multiday marathon event organisers should consider alternating route direction to reduce injury risk; potentially the result of prolonged, altered gait biomechanics. However, further investigation of injury risk factors using larger sample sizes is required

Previous high-intensity activity affects lower limb strength ratios

Lower limb strength ratios are important in assessing muscular imbalances. Typically, these ratios are derived from assessment of explosive, maximum effort activities. Such assessment can be functional or isokinetic. The single-effort nature of these assessments does not provide information on imbalance changes following muscular contractions. Any such change could indicate an increased risk of injury after a period of activity, thus raising questions as to the correct procedure of muscle imbalance assessment. Therefore, the aim of the current study was to assess muscle imbalances over maximum effort repeated cycling sprints. Seventeen healthy, physically active young adults (females: n=4, height 1.62±0.03 m, body mass 68.0±6.5 kg; males: n=13, height 1.80±0.06 m, body mass 80.5±13.8 kg) performed five 6-s sprints with 24-s rest interval on a Lode Excalibur bike with torque and power data recorded for each leg. Average, average maximum (average of maximum from each sprint) and peak torque (TAv, TAvM and TP, respectively) and power (PAv, PAvM and PP, respectively) were obtained for each leg. Ratios of these variables were calculated as (((stronger leg-weaker leg) / (average of two legs))*100). Wilcoxon’s test revealed a significantly stronger leg (P<0.05) for all torque and power variables. Friedman’s test indicated a significant ratio increase between TAv (11.7±6.8%) and TAvM (4.6±3.0%, P=0.001) and TP (4.1±3.5%, P=0.001), as well as between PAv (8.8±5.0%) and PAvM (4.5±2.9%, P=0.003) and PP (4.2±2.6, P=0.003%) but not between TAvM and TP (P=0.421) or PAvM and PP (P=0.981). The results indicate that high-intensity activity increases lower limb strength imbalance, resulting in different ratios. We posit that muscle imbalance assessment activities conducted at rested state may not accurately reflect the true strength difference between limbs, leading to inaccurate training or rehabilitation advice

Immune checkpoints in rheumatoid arthritis: progress and promise

Rheumatoid arthritis (RA) is one of the most prevalent autoimmune inflammatory conditions, and while the mechanisms driving pathogenesis are yet to be completely elucidated, self-reactive T cells and immune checkpoint pathways have a clear role. In this review, we provide an overview of the importance of checkpoint pathways in the T cell response and describe the involvement of these in RA development and progression. We discuss the relationship between immune checkpoint therapy in cancer and autoimmune adverse events, draw parallels with the involvement of immune checkpoints in RA pathobiology, summarise emerging research into some of the lesser-known pathways, and the potential of targeting checkpoint-related pathways in future treatment approaches to RA management

ACE2 expression in adipose tissue is associated with cardio-metabolic risk factors and cell type composition-implications for COVID-19

Background COVID-19 severity varies widely. Although some demographic and cardio-metabolic factors, including age and obesity, are associated with increasing risk of severe illness, the underlying mechanism(s) are uncertain. Subjects/methods In a meta-analysis of three independent studies of 1471 participants in total, we investigated phenotypic and genetic factors associated with subcutaneous adipose tissue expression of Angiotensin I Converting Enzyme 2 (ACE2), measured by RNA-Seq, which acts as a receptor for SARS-CoV-2 cellular entry. Results Lower adipose tissue ACE2 expression was associated with multiple adverse cardio-metabolic health indices, including type 2 diabetes (T2D) (P = 9.14 x 10(-6)), obesity status (P = 4.81 x 10(-5)), higher serum fasting insulin (P = 5.32 x 10(-4)), BMI (P = 3.94 x 10(-4)), and lower serum HDL levels (P = 1.92 x 10(-7)). ACE2 expression was also associated with estimated proportions of cell types in adipose tissue: lower expression was associated with a lower proportion of microvascular endothelial cells (P = 4.25 x 10(-4)) and higher proportion of macrophages (P = 2.74 x 10(-5)). Despite an estimated heritability of 32%, we did not identify any proximal or distal expression quantitative trait loci (eQTLs) associated with adipose tissue ACE2 expression. Conclusions Our results demonstrate that individuals with cardio-metabolic features known to increase risk of severe COVID-19 have lower background ACE2 levels in this highly relevant tissue. Reduced adipose tissue ACE2 expression may contribute to the pathophysiology of cardio-metabolic diseases, as well as the associated increased risk of severe COVID-19.Peer reviewe

Towards a System Level Understanding of Non-Model Organisms Sampled from the Environment: A Network Biology Approach

The acquisition and analysis of datasets including multi-level omics and physiology from non-model species, sampled from field populations, is a formidable challenge, which so far has prevented the application of systems biology approaches. If successful, these could contribute enormously to improving our understanding of how populations of living organisms adapt to environmental stressors relating to, for example, pollution and climate. Here we describe the first application of a network inference approach integrating transcriptional, metabolic and phenotypic information representative of wild populations of the European flounder fish, sampled at seven estuarine locations in northern Europe with different degrees and profiles of chemical contaminants. We identified network modules, whose activity was predictive of environmental exposure and represented a link between molecular and morphometric indices. These sub-networks represented both known and candidate novel adverse outcome pathways representative of several aspects of human liver pathophysiology such as liver hyperplasia, fibrosis, and hepatocellular carcinoma. At the molecular level these pathways were linked to TNF alpha, TGF beta, PDGF, AGT and VEGF signalling. More generally, this pioneering study has important implications as it can be applied to model molecular mechanisms of compensatory adaptation to a wide range of scenarios in wild populations

Cardiomyocyte and vascular smooth muscle independent 11β-hydroxysteroid dehydrogenase 1 amplifies infarct expansion, hypertrophy and the development of heart failure following myocardial infarction in male mice

Global deficiency of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), an enzyme that regenerates glucocorticoids within cells, promotes angiogenesis, and reduces acute infarct expansion after myocardial infarction (MI), suggesting that 11β-HSD1 activity has an adverse influence on wound healing in the heart after MI. The present study investigated whether 11β-HSD1 deficiency could prevent the development of heart failure after MI and examined whether 11β-HSD1 deficiency in cardiomyocytes and vascular smooth muscle cells confers this protection. Male mice with global deficiency in 11β-HSD1, or with Hsd11b1 disruption in cardiac and vascular smooth muscle (via SM22α-Cre recombinase), underwent coronary artery ligation for induction of MI. Acute injury was equivalent in all groups. However, by 8 weeks after induction of MI, relative to C57Bl/6 wild type, globally 11β-HSD1-deficient mice had reduced infarct size (34.7 ± 2.1% left ventricle [LV] vs 44.0 ± 3.3% LV, P = .02), improved function (ejection fraction, 33.5 ± 2.5% vs 24.7 ± 2.5%, P = .03) and reduced ventricular dilation (LV end-diastolic volume, 0.17 ± 0.01 vs 0.21 ± 0.01 mL, P = .01). This was accompanied by a reduction in hypertrophy, pulmonary edema, and in the expression of genes encoding atrial natriuretic peptide and β-myosin heavy chain. None of these outcomes, nor promotion of periinfarct angiogenesis during infarct repair, were recapitulated when 11β-HSD1 deficiency was restricted to cardiac and vascular smooth muscle. 11β-HSD1 expressed in cells other than cardiomyocytes or vascular smooth muscle limits angiogenesis and promotes infarct expansion with adverse ventricular remodeling after MI. Early pharmacological inhibition of 11β-HSD1 may offer a new therapeutic approach to prevent heart failure associated with ischemic heart disease