Article

Circuit resistance training (CRT) should promote favorable kinematics
(scapular posterior tilt, upward rotation, glenohumeral or scapular external
rotation) to protect the shoulder from mechanical impingement following
paraplegia. Understanding kinematics during CRT may provide a biomechanical
rationale for exercise positions and exercise selection promoting healthy
shoulders. The purposes of this study were: (1) to determine whether
altering hand position during CRT favorably modifies glenohumeral and scapular
kinematics and (2) to compare 3-dimensional glenohumeral and scapular kinematics
during CRT exercises. HYPOTHESES: The hypotheses that were tested were: (1)
modified versus traditional hand positions during exercises improve kinematics
over comparable humerothoracic elevation angles, and (2) the downward press
demonstrates the least favorable kinematics. DESIGN: This was a cross-sectional
observational study. METHODS: The participants were 18 individuals (14 men, 4
women; 25-76 years of age) with paraplegia. An electromagnetic tracking system
acquired 3-dimensional position and orientation data from the trunk, scapula, and
humerus during overhead press, chest press, overhead pulldown, row, and downward
press exercises. Participants performed exercises in traditional and modified
hand positions. Descriptive statistics and 2-way repeated-measures analysis of
variance were used to evaluate the effect of modifications and exercises on
kinematics. RESULTS: The modified position improved kinematics for downward press
(glenohumeral external rotation increased 4.5 degrees [P=.016; 95% CI=0.7, 8.3]
and scapular external rotation increased 4.4 degrees [P<.001; 95% CI=2.5, 6.3]),
row (scapular upward rotation increased 4.6 degrees [P<.001; 95% CI=2.3, 6.9]),
and overhead pulldown (glenohumeral external rotation increased 18.2 degrees
[P<.001, 95% CI=16, 21.4]). The traditional position improved kinematics for
overhead press (glenohumeral external rotation increased 9.1 degrees [P=.001; 95%
CI=4.1, 14.1], and scapular external rotation increased 5.5 degrees [P=.004; 95%
CI=1.8, 9.2]). No difference existed between chest press positions. Downward
press (traditional or modified) demonstrated the least favorable kinematics.
LIMITATIONS: It is unknown whether faulty kinematics causes impingement or
whether pre-existing impingement causes altered kinematics. Three-dimensional
modeling is needed to verify whether "favorable" kinematics increase the
subacromial space. CONCLUSIONS: Hand position alters kinematics during CRT and
should be selected to emphasize healthy shoulder mechanics.
CI - (c) 2016 American Physical Therapy Association.

Langue : ANGLAIS