Search

Abstract Prematurity is associated with lower exercise capacity, which relies on the integrity of the cardiovascular, pulmonary, and skeletal muscle systems. Our animal model mimicking prematurity-associated conditions showed altered muscle composition and atrophy in adulthood. This study aimed to compare muscle composition and strength in adults born preterm versus full-term controls. This observational cohort study recruited 55 adults born preterm, ≤ 29 weeks’ of gestation and 53 full-term controls who underwent musculoskeletal ultrasound imaging to assess morphology of the rectus femoris at rest and during a maximal voluntary contraction. Maximal voluntary contraction of the hands and legs were measured by manual dynamometry. In adults born preterm, there was lower muscle strength (handgrip: − 4.8 kg, 95% CI − 9.1, − 0.6; knee extensor: − 44.6 N/m, 95% CI − 63.4, − 25.8) and smaller muscle area (− 130 mm2, 95% CI − 207, − 53), which was more pronounced with a history of bronchopulmonary dysplasia. Muscle stiffness was increased in the preterm versus term group (0.4 m/s, 95% CI 0.04, 0.7). Prematurity is associated with alterations in skeletal muscle composition, area, and function in adulthood. These findings highlight the necessity to implement preventive and/or curative approaches to improve muscle development and function following preterm birth to enhance overall health in this population.

Objectives: To measure the potential effects of an overground exoskeleton-assisted walking programme on upper limb strength and mass, as well as on wheelchair propulsion performances and abilities in individuals with chronic spinal cord injury. Design: Prospective, single-group, pre–post intervention study. Participants: Ten individuals with chronic (≥ 18 months) spinal cord injury who use a wheelchair as their primary mode of locomotion and who had little-to-no motor function in the lower limbs. Methods: Individuals completed a progressive 16-week exoskeleton-assisted walking programme (34 × 1-h sessions, 1–3 sessions/week). Upper limb muscle strength was measured with dynamometers (isokinetic, Jamar). Upper limb lean mass (dual-energy X-ray absorptiometry) was used to calculate relative strength. Field tests (20-m wheelchair propulsion, and slalom test) and the Wheelchair Skills Test Questionnaire determined performances and abilities. Wilcoxon signed-rank tests were used with the following criteria: p 5%. Results: Only natural velocity during the 20-m wheelchair propulsion test (i.e., fundamental wheelchair ability) changed following the intervention (p = 0.01, effect size = 0.82, relative variation = +14.5%). Conclusion: Overall, upper limb muscle function did not significantly and meaningfully change following the exoskeleton-assisted walking programme in this population. Additional research is needed to verify how changes in training volume would affect strength and advanced wheelchair-related abilities and performance, as well as the response in individuals who are deconditioned or novices to wheelchair use (e.g., subacute spinal cord injury).

BackgroundAs many as 60% of individuals use a wheelchair long term after a spinal cord injury (SCI). This mode of locomotion leads to chronic decline in lower-extremity weight-bearing activities and contributes to the development of severe sublesional osteoporosis and high rates of fragility fracture. Overground exoskeleton-assisted walking programs provide a novel opportunity to increase lower-extremity weight bearing, with the potential to improve bone health. ObjectiveThe aim of the study is to measure the potential effects of an exoskeleton-assisted walking program on lower-extremity bone strength and bone remodeling biomarkers in individuals with chronic (≥18 months) SCI who use a wheelchair. MethodsIn total, 10 participants completed a 16-week exoskeleton-assisted walking program (34 individualized 1-hour sessions, progressing from 1 to 3 per week). Bone mineral density and bone strength markers (dual-energy x-ray absorptiometry: total body, left arm, leg, total hip, and femoral neck and peripheral quantitative computed tomography: 25% of left femur and 66% of left tibia) as well as bone remodeling biomarkers (formation=osteocalcin and resorption=C-telopeptide) were measured before and after intervention and compared using nonparametric tests. Changes were considered significant and meaningful if the following criteria were met: P5%. ResultsSignificant and meaningful increases were observed at the femur (femoral neck bone mineral content, bone strength index, and stress-strain index) and tibia (cortical cross-sectional area and polar moment of inertia) after the intervention (all P