Mechanical loading of the Achilles tendon during different rehabilitation exercises: A cross sectional observational study

Abstract Background Achilles tendon injuries are common in active populations and heel raising exercises are commonly used in tendon rehabilitation programmes. This study compared characteristics of force occurring within the healthy Achilles tendon during two different types of exercise conditions that can be used in Achilles tendon rehabilitation. Method A cross-sectional, observational study was conducted to compare force fluctuations occurring within the Achilles tendon during two different types of heel raising exercise. All subjects performed firstly, a set of traditional eccentric heel drops (HD) and secondly an adapted walking drill (WD), and results were compared. 13 Healthy subjects were recruited from staff and post graduate students as a sample of convenience from the biomechanics department at the University of Bath. Tendon forces were calculated using a combination of data collected from force plate, motion analysis and real time ultrasound. Results Fluctuations in force were seen in all subjects in both exercise conditions. The HD condition produced a statistically significant increase in force fluctuations compared to the WD condition (p<0.001). Conclusion This study shows that force fluctuations can be stimulated at different levels during functional movement patterns and exercise conditions. Therefore, exercise routines can be tailored to meet individual needs and the stage of the pathology. These findings may have implications for exercise progressions in the rehabilitation of Achilles tendon disorders. Future research is needed determine if differences in tendon force fluctuations correlate with pathology. Summary Statement This study is of interest to clinicians, exercise professionals and researchers with an interest in the study of Achilles tendon biomechanics and the management of tendon injuries.