RESUMO
BACKGROUND: Chronic neck pain (CNP) is a prevalent musculoskeletal condition including notable impairments in respiratory function. The diaphragm, serving dual roles in respiration and spinal stability, is intricately linked to the cervical spine through fascial, neurophysiological, and biomechanical connections. However, to date, none has investigated the diaphragm function in patients with CNP. OBJECTIVES: To investigate the diaphragm function, respiratory muscle strength, and pulmonary function in patients with CNP. In addition, their associations were also examined. DESIGN: A case-control study. METHODS: A total of 54 participants were recruited including 25 patients with CNP (CNP group) and 29 healthy adults (CON group). Pulmonary function including forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), and respiratory muscle strength represented by maximal inspiratory (MIP) and maximal expiratory pressure (MEP), as well as diaphragm function including ultrasonographic measures of mobility and thickness changes during maximal inspiration and expiration were assessed in all participants. Additionally, the intensity of pain and disability were evaluated using a Visual Analog Scale and Neck Disability Index only in patients with CNP. RESULTS: Significant reductions of the FVC, FEV1, MIP, and MEP were found in the CNP group compared to the CON group (p < 0.05). The diaphragm mobility and thickness changes were also significantly decreased in the CNP group than the CON group with medium effect sizes (p < 0.05). Only diaphragm thickness change was positively correlated with FVC, FEV1, and MEP in patients with CNP. Furthermore, MEP showed the strongest contribution to diaphragm thickness change based on the regression analysis. CONCLUSIONS: Impaired diaphragm function, respiratory muscle strength, and pulmonary function were observed in patients with CNP. Patients with smaller diaphragm thickness change had poorer pulmonary function and reduced maximal expiratory muscle strength. Diaphragm assessment and intervention may be considered in CNP management.
RESUMO
BACKGROUND: Badminton is a sport demanding both high aerobic and anaerobic fitness levels, and fatigue can significantly impact game performance. However, relevant studies are limited, and none have employed a wearable inertial measurement unit (IMU) to investigate the effects of fatigue on athletic performance in the field. HYPOTHESIS: Overall performance and body acceleration in both time and frequency domains during the fundamental badminton skills of vertical jumping and changes of direction will be affected by fatigue. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 38 young badminton players competing at the Division I level participated. Body accelerations while performing vertical jump and agility-T tests before and immediately after undergoing a fatigue protocol were measured by an IMU, positioned at the L4 to L5 level. RESULTS: Jumping height decreased significantly by 4 cm (P < 0.01) after fatigue with greater downward acceleration (1.03 m/s2, P < 0.05) during the squatting subphase. Finishing time increased significantly by 50 ms only during the 10-m side-shuffling of the agility-T test (P = 0.02) after fatigue with greater peak and mean accelerations (3.83 m/s2, P = 0.04; 0.43 m/s2, P < 0.01), and higher median and mean frequency (0.38 Hz, P = 0.04, 0.11 Hz, P = 0.01). CONCLUSION: This study using a wearable IMU demonstrates the effects of fatigue on body acceleration in badminton players. The frequency-domain analysis further indicated that fatigue might lead to loss of voluntary control of active muscles and increased impacts on the passive elastic elements. CLINICAL RELEVANCE: The findings imply that fatigue can lead to diminished athletic performance and highlight the potential for an increased risk of sports injuries. Consequently, maintaining precision in monitoring fatigue is crucial for elite young badminton players.