DOES A WHEELCHAIR BADMINTON SMASH MOTION AFFECT SHOULDER JOINT AND TRUNK MOVEMENTS AND SWING SPEED?

Y. Tamura¹, N. Maeda¹, M. Komiya¹, K. Fukui², M. Yoshimi¹, K. Tsuchida¹, T. Abekura¹, Y. Urabe¹

¹Hiroshima University, Department of Sports Rehabilitation, Graduate School of Biomedical and Health Sciences, Hiroshima, Japan, ²Japan Para Badminton Federation, Edogawa-ku, Japan

Background: Para badminton players are classified into standing and wheelchair classes according to their disability level. Smash motion in the standing position (ST) is performed by a rotational movement followed by lower limbs, pelvis, trunk, and upper limbs in that order (Sekiguchi et al., 2017). In the wheelchair sitting position (WC), however, lower limbs and pelvis are fixed to the wheelchair, which restricts their rotational movements and is also expected to affect trunk and upper limbs movements. Although upper limbs, especially shoulder joint, and trunk movements may also affect performance such as swing speed, the effects of difference in postures during smash motion on movements and performance have not been investigated.

Purpose: To compare shoulder joint and trunk movements during smash motion in the ST and the WC and to investigate whether differences in these movements affect swing speed.

Methods: The participants were 13 healthy males with at least 3 years of badminton experience. All participants were right-handed. The task movement was free swing motion assuming a smash in the ST and the WC. Shoulder joint and trunk movements during that measured by using LIBERTY (Polhemus), a magnetic 3-dimensional position measuring device. The amount of change in shoulder joint internal rotation angle from the maximum external rotation (MER) to impact and the trunk right rotation angle at takeback were calculated. Swing speed was measured by using the Multi Speed Tester II (SSK). Outcomes were confirmed using paired t-test to compare the ST and the WC for each measure. Statistical significance was set at 5%.

Results: The amount of change in shoulder joint internal rotation angle in the WC was significantly smaller than in the ST (p<0.01) (ST: 66.2±34.7°, WC: 41.7±23.2°). Angle of the trunk right rotation in the WC was significantly smaller than in the ST (p<0.01) (ST: 23.3±4.7°, WC: 13.5±4.5°). Furthermore, swing speed in the WC was significantly lower than in the ST (p<0.01) (ST: 150.7±14.0 km/h, WC: 122.4±8.7 km/h).

Conclusions: The results of this study showed that a smash motion in the WC limited shoulder joint and trunk movements compared to those in the ST. These are thought to be caused by difference in spinal alignment, such as a decrease in lumbar curvature due to sitting and by the physical obstacle of the wheelchair, which limits swing motion. Also, it has been reported that the internal rotation angle of shoulder joint at impact and the angle of trunk rotation in the direction of the dominant hand at takeback are positively correlated with swing speed (King et al., 2020). In this study, those movements in the WC were smaller than in the ST, which may have contributed to the decrease in swing speed.

Implications: The results of this study indicate that wheelchair badminton players have restricted shoulder joint and trunk movements during the smash motion compared to standing players, which affects the decrease in swing speed.

Funding acknowledgements: We have no funding acknowledgement in this study.

Keywords:
Para badminton
Smash motion
Motion analysis

Topics:
Sport & sports injuries
Musculoskeletal: upper limb
Musculoskeletal

Did this work require ethics approval? Yes

Institution: Hiroshima University

Committee: The Ethical Committee for Epidemiology of Hiroshima University

Ethics number: E-2690