Does the muscle activation pattern and movement pattern during a handball throw differ between handball players with normal posture and those with abnormal posture

Sakinepoor, A, Degens, H ORCID: https://orcid.org/0000-0001-7399-4841 and Mazidi, M (2025) Does the muscle activation pattern and movement pattern during a handball throw differ between handball players with normal posture and those with abnormal posture. Sport Sciences for Health. ISSN 1824-7490

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Abstract

Purpose: This study compared upper body kinematics and muscle activation during throwing in male handball players with forward head and rounded-shoulder posture (FHRSP) to those without such posture. Methods: Fifteen male handball players with and fifteen without FHRSP performed five standing throws, during which joint kinematics and muscle activity were measured in the following muscles: supraspinatus, erector spinae, upper trapezius, middle trapezius, latissimus dorsi, and pectoralis major. The participants in the healthy group and the head-forward and rounded-shoulder group performed two types of throws (slow-power throw and high-power throw), each of which was measured. The slow-power throw was performed at 50–60% of maximal capacity, whereas the high-power throw was performed at 100% effort. Results: The results showed that the pectoralis major muscle was activated earlier in FHRS in both slow-power throw [FHRS group (ms): P < 0.01, mean ± standard deviation (SD): 354 ± 54; healthy group (ms): 371 ± 43] and high-power throw [FHRS group (ms): P < 0.01, mean ± SD: 245 ± 45; healthy group (ms): 270 ± 40] throws, while deactivation was delayed in the slow-power throw [FHRS group (ms): P < 0.03, mean ± SD: 922 ± 110; healthy group (ms): 862 ± 128] and high-power throw [FHRS group (ms): P < 0.04, mean ± SD: 684 ± 113; healthy group (ms): 637 ± 99] throws. The external shoulder rotation in the slow-power throw (FHRS: P < 0.01, mean ± SD: 12.9 ± 3.4; healthy group: 16.3 ± 3.5) and high-power group (FHRS: P < 0.01, mean ± SD: 16.3 ± 4.5; healthy group: 21.8 ± 5.1) throws showed a decreased range of motion in FHRS. The same applied to the range of motion in shoulder abduction in the slow-power throw position (FHRS: P < 0.01, mean ± SD: 39.9 ± 7.5; healthy group: 46.2 ± 8.5). Conclusions: FHRSP in handball players is accompanied by changes in the muscle activation pattern and movement pattern that can put them at risk of injuries to the upper limb. In addition, these results indicate that muscle imbalance leads to alterations in movement and muscle patterns, which may subsequently result in injury and functional impairment.