The Relationship Between Running Biomechanics and Running Economy: A Systematic Review and Meta-Analysis of Observational Studies.

BACKGROUND: Running biomechanics is considered an important determinant of running economy (RE). However, studies examining associations between running biomechanics and RE report inconsistent findings. OBJECTIVE: The aim of this systematic review was to determine associations between running biomechanics and RE and explore potential causes of inconsistency. METHODS: Three databases were searched and monitored up to April 2023. Observational studies were included if they (i) examined associations between running biomechanics and RE, or (ii) compared running biomechanics between groups differing in RE, or (iii) compared RE between groups differing in running biomechanics during level, constant-speed, and submaximal running in healthy humans (18-65 years). Risk of bias was assessed using a modified tool for observational studies and considered in the results interpretation using GRADE. Meta-analyses were performed when two or more studies reported on the same outcome. Meta-regressions were used to explore heterogeneity with speed, coefficient of variation of height, mass, and age as continuous outcomes, and standardization of running shoes, oxygen versus energetic cost, and correction for resting oxygen or energy cost as categorical outcomes. RESULTS: Fifty-one studies (n = 1115 participants) were included. Most spatiotemporal outcomes showed trivial and non-significant associations with RE: contact time r = - 0.02 (95% confidence interval [CI] - 0.15 to 0.12); flight time r = 0.11 (- 0.09 to 0.32); stride time r = 0.01 (- 0.8 to 0.50); duty factor r = - 0.06 (- 0.18 to 0.06); stride length r = 0.12 (- 0.15 to 0.38), and swing time r = 0.12 (- 0.13 to 0.36). A higher cadence showed a small significant association with a lower oxygen/energy cost (r = - 0.20 [- 0.35 to - 0.05]). A smaller vertical displacement and higher vertical and leg stiffness showed significant moderate associations with lower oxygen/energy cost (r = 0.35, - 0.31, - 0.28, respectively). Ankle, knee, and hip angles at initial contact, midstance or toe-off as well as their range of motion, peak vertical ground reaction force, mechanical work variables, and electromyographic activation were not significantly associated with RE, although potentially relevant trends were observed for some outcomes. CONCLUSIONS: Running biomechanics can explain 4-12% of the between-individual variation in RE when considered in isolation, with this magnitude potentially increasing when combining different variables. Implications for athletes, coaches, wearable technology, and researchers are discussed in the review. PROTOCOL REGISTRATION: https://doi.org/10.17605/OSF.IO/293 ND (OpenScience Framework).

Occupational risk factors for shoulder chronic tendinous pathology in the Spanish automotive manufacturing sector: a case-control study.

BACKGROUND: Musculoskeletal Diseases (MSDs) are among the most prevalent health problems encountered in the workforce in Europe. Multiple risk factors contribute to their onset. In the present study, different individual risk factors for chronic tendinous pathology affecting the shoulder were analysed in a sample of workers from the automotive manufacturing sector. METHODS: An observational retrospective study was conducted with 73 cases of officially recognised and compensated occupational diseases and 94 aleatory cases of healthy workers from the same car assembly company. The experimental group comprised individuals with tendinous chronic pathology of the rotator cuff. Multiple variables that identified the risks present in the job were assessed along with participants clinical evaluation. Furthermore, two standardised guidelines for risk factors assessment were also used: the Spanish National Institute of Social Security (INSS) and the American Occupational Information Network (O*Net). Both descriptive statistical analysis and Odds ratios calculations considering the occupational disease as a dependent variable were performed. RESULTS: The use of hand tools, exposure to mechanical pressure in the upper limbs and awkward postures were the most prevalent risk factors. Pressure on the palm of the hand and the hand tool impacting the hand were also important risk factors. Some psychosocial factors such as lack of autonomy and mental workload were also associated shoulder tendinous diseases. The association of age, load handling, and awkward postures were the core risk factors responsible for most of the tendinous chronic injuries of the shoulder in this sample of car assembly workers. CONCLUSIONS: Both ergonomic and psychosocial factors were present and increased the risk of developing occupational chronic tendinopathies at the shoulder in this sample of workers. Aging, load handling, and awkward postures showed the strongest predictive values. Greater knowledge of how risk factors interact would facilitate the design of better preventive workplace strategies.