Mareike Schmitt1, Lutz Vogt1, Jan Wilke1, Daniel Niederer2. 1. Department of Sports Medicine and Exercise Physiology, Goethe University Frankfurt am Main, Ginnheimer Landstraße 39, D-60487, Frankfurt am Main, Germany. 2. Department of Sports Medicine and Exercise Physiology, Goethe University Frankfurt am Main, Ginnheimer Landstraße 39, D-60487, Frankfurt am Main, Germany. niederer@sport.uni-frankfurt.de.
Abstract
BACKGROUND: Excessive unilateral joint loads may lead to overuse disorders. Bilateral training in archery is only performed as a supportive coordination training and as a variation of typical exercise. However, a series of studies demonstrated a crossover transfer of training-induced motor skills to the contralateral side, especially in case of mainly unilateral skills. We compared the cervical spine and shoulder kinematics of unilateral and bilateral training archers. METHODS: In this cross-sectional study, 25 (5 females, 48 ± 14 years) bilaterally training and 50 age-, sex- and level-matched (1:2; 47.3 ± 13.9 years) unilaterally training competitive archers were included. Cervical range of motion (RoM, all planes) and glenohumeral rotation were assessed with an ultrasound-based 3D motion analysis system. Upward rotation of the scapula during abduction and elevation of the arm were measured by means of a digital inclinometer and active shoulder mobility by means of an electronic caliper. All outcomes were compared between groups (unilaterally vs. bilaterally) and sides (pull-hand- vs. bow-hand-side). RESULTS: Unilateral and bilateral archers showed no between group and no side-to-side-differences in either of the movement direction of the cervical spine. The unilateral archers had higher pull-arm-side total glenohumeral rotation than the bilateral archers (mean, 95% CI), (148°, 144-152° vs. 140°, 135°-145°). In particular, internal rotation (61°, 58-65° vs. 56°, 51-61°) and more upward rotation of the scapula at 45 degrees (12°, 11-14° vs. 8°, 6-10°), 90 degrees (34°, 31-36° vs. 28°, 24-32°), 135 degrees (56°, 53-59° vs. 49°, 46-53°), and maximal (68°, 65-70° vs. 62°, 59-65°) arm abduction differed. The bow- and pull-arm of the unilateral, but not of the bilateral archers, differed in the active mobility of the shoulder (22 cm, 20-24 cm vs. 18 cm, 16-20 cm). CONCLUSIONS: Unilaterally training archers display no unphysiologic movement behaviour of the cervical spine, but show distinct shoulder asymmetris in the bow- and pull-arm-side when compared to bilateral archers in glenohumeral rotation, scapula rotation during arm abduction, and active mobility of the shoulder. These asymmetries in may exceed physiological performance-enhancing degrees. Bilateral training may seems appropriate in archery to prevent asymmetries.
BACKGROUND: Excessive unilateral joint loads may lead to overuse disorders. Bilateral training in archery is only performed as a supportive coordination training and as a variation of typical exercise. However, a series of studies demonstrated a crossover transfer of training-induced motor skills to the contralateral side, especially in case of mainly unilateral skills. We compared the cervical spine and shoulder kinematics of unilateral and bilateral training archers. METHODS: In this cross-sectional study, 25 (5 females, 48 ± 14 years) bilaterally training and 50 age-, sex- and level-matched (1:2; 47.3 ± 13.9 years) unilaterally training competitive archers were included. Cervical range of motion (RoM, all planes) and glenohumeral rotation were assessed with an ultrasound-based 3D motion analysis system. Upward rotation of the scapula during abduction and elevation of the arm were measured by means of a digital inclinometer and active shoulder mobility by means of an electronic caliper. All outcomes were compared between groups (unilaterally vs. bilaterally) and sides (pull-hand- vs. bow-hand-side). RESULTS: Unilateral and bilateral archers showed no between group and no side-to-side-differences in either of the movement direction of the cervical spine. The unilateral archers had higher pull-arm-side total glenohumeral rotation than the bilateral archers (mean, 95% CI), (148°, 144-152° vs. 140°, 135°-145°). In particular, internal rotation (61°, 58-65° vs. 56°, 51-61°) and more upward rotation of the scapula at 45 degrees (12°, 11-14° vs. 8°, 6-10°), 90 degrees (34°, 31-36° vs. 28°, 24-32°), 135 degrees (56°, 53-59° vs. 49°, 46-53°), and maximal (68°, 65-70° vs. 62°, 59-65°) arm abduction differed. The bow- and pull-arm of the unilateral, but not of the bilateral archers, differed in the active mobility of the shoulder (22 cm, 20-24 cm vs. 18 cm, 16-20 cm). CONCLUSIONS: Unilaterally training archers display no unphysiologic movement behaviour of the cervical spine, but show distinct shoulder asymmetris in the bow- and pull-arm-side when compared to bilateral archers in glenohumeral rotation, scapula rotation during arm abduction, and active mobility of the shoulder. These asymmetries in may exceed physiological performance-enhancing degrees. Bilateral training may seems appropriate in archery to prevent asymmetries.
Entities:
Keywords:
Archery, kinematics; Arrow; Bow; Movement behaviour
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