Biomechanical Analysis of the Kinetic Chain in Individuals with Shoulder Pain in Comparison to Asymptomatic Individuals.
Musculoskeletal system. Physical functional performance. Physical
examination. Range of motion. Postural balance.
BACKGROUND: The kinetic chain concept proposes a view of the body through a series of
interdependent links responsible for the sequential transmission of energy through the
musculoskeletal and fascial systems. Alterations in the components of the kinetic chain can
impair this energy transmission and overload adjacent body structures, which may be related to
the risk of shoulder pain and injuries. Biomechanical impairments in different body segments
have already been investigated in athletes with shoulder pain. However, the association between
factors related to the kinetic chain and shoulder pain in individuals not engaged in sports is not
established. Furthermore, the synthesis of the biomechanical characteristics of this population
has not yet been presented in the literature.
OBJECTIVES: To verify the association between biomechanical factors related to the kinetic
chain and the presence of shoulder pain and to summarize the literature that investigated
changes in components of the kinetic chain in non-athletes with shoulder pain compared to
asymptomatic individuals.
METHODS: These are two studies: a cross-sectional survey and a systematic review. The first
study investigated lumbopelvic stability, active range of motion, and peak isometric muscle
strength in individuals with and without shoulder pain. A multivariate binary logistic regression
was carried out in IBM® SPSS® 25 software to analyze the odds of each being part of one of
the groups (with or without shoulder pain). The second study brought together the findings of
observational studies indexed until December 2022 in the MEDLINE, CINAHL, Web of
Science, EMBASE, and SCOPUS databases. The Joanna Briggs Institute Critical Appraisal
Tool for Cross-Sectional Analytical Studies assessed the risk of bias and the Grading of
Recommendations, Assessment, Development, and Evaluation (GRADE) defined the quality
of evidence.
RESULTS: On the cross-sectional study, 40 individuals were assessed: 19 with shoulder pain
and 21 asymptomatic. Only the isometric strength of the trunk extensor muscles presented a
statistically significant contribution to the regression model (p = 0.03 | odds ratio = 0.99), with
no significant associations between the other outcomes and the presence of shoulder pain. In
the review, four cross-sectional studies with low risk of bias were included (n = 358, 179
individuals with shoulder pain). Very low-quality evidence indicated that individuals with
shoulder pain may present a reduced range of motion and muscular endurance in the
thoracolumbar region and hips and decreased neuromuscular control of the lower extremities
compared to asymptomatic individuals. Findings related to thoracic spine posture were
conflicting.
CONCLUSION: Isometric strength of the trunk extensor muscles may be associated with the
presence of shoulder pain and observational studies indicate that individuals with shoulder pain
may present alterations in mobility, muscular endurance, and/or neuromuscular control in the
thoracolumbar region and in the lower extremities compared to asymptomatic individuals.
These findings suggest that physical assessments considering non-local biomechanical factors
may be relevant in the population with shoulder pain.