Bilateral Musculoskeletal Asymmetry and Injury Characteristics Among Competitive Track-and-Field Athletes: A Cross-Sectional Analysis

Abstract

Background: Musculoskeletal asymmetry of the body bilaterally is commonly used in studies involving athletes where asymmetries in flexibility and range of motion of joints and functional movements can indicate movement restrictions and can possibly affect injury outcomes. Nevertheless, there could be discrepancies in asymmetry between tests and athletic populations. In the present study, bilateral asymmetry was examined with selected musculoskeletal and functional assessments and injury patterns in track-and-field athletes.
Methods: A cross-sectional study was conducted on 100 competitive track-and-field athletes (58 males, 42 females; mean age 20.22 ± 2.93 years). Anthropometric characteristics such as height, body mass and body mass index (BMI) were measured. Bilateral assessments consisted of the Active Knee Extension (AKE) test, the Active Dynamic Leg Length/ADLT assessment, the Thomas test, hip external rotation (Hip ER), hip internal rotation (Hip IR) and the Lower Quarter Y-Balance Test (LQYBT). Bilateral asymmetry was quantified as an asymmetry index based on the absolute right–left difference relative to the larger absolute side value. Descriptive and comparative statistical analyzes were also performed on injury status, anatomical location, onset, mechanism, severity, diagnosis, training/competition context and time lost.
Results: The athletes' mean values for height, body mass and BMI were 171.17 ± 8.19 cm, 68.35 ± 16.07 kg, and 23.13 ± 4.12 kg/m², respectively. The greatest bilateral asymmetry mean values in the athletes were found in ADLT (13.50 ± 11.63%), the Thomas test (12.00 ± 15.47%), hip external rotation (7.93 ± 11.66%), hip internal rotation (6.93 ± 10.02%), LQYBT (3.98 ± 3.44%), and AKE (1.65 ± 3.18%), respectively. Injured athletes accounted for 68%. In the injured group, the most frequently involved anatomic areas were knee (16.2%), lower leg (14.7%), hip/groin (13.2%), and shoulder (13.2%). Acute injuries constituted 33 cases (48.5%) and overuse injuries 30 cases (44.1%), while 63 of 68 injured athletes had non-contact injuries. The most common diagnoses were muscle injuries (33.8%), tendons (19.1%) and ligaments (16.2%). The mean number of days lost after injury was 50.21 ± 76.15 days, with the median value being 21 days. Comparing results between groups, AKE asymmetry was significantly greater in injured than non-injured athletes (2.07% vs. 0.74%, p = 0.011), while hip external rotation asymmetry was significantly lower (5.09% vs. 13.98%, p = 0.003).
Conclusion: Track-and-field competitors have been found to possess significant variation in their levels of bilateral asymmetry in the various musculoskeletal and functional tests, with ADLT and Thomas test possessing highest levels of asymmetry on an average. High incidence of injuries was noted, with majority of injuries being non-contact injuries and significant variations in time loss. Differences in the levels of bilateral asymmetry between injured and non-injured individuals show that bilateral asymmetry cannot be used as an universal indicator of injury risk.