Etiologic factors associated with Achilles tendinitis in runners

Purpose: The purpose of this study was to determine whether relationships e xist between selected training, anthropometric, isokinetic muscular strengt h, and endurance, ground reaction force, and rearfoot movement variables in runners afflicted with Achilles tendinitis. Methods: Specifically, we exam ined differences in selected measures between a noninjured cohort of runner s (N = 58) and a cohort of injured runners with Achilles tendinitis (N = 31 ). Isokinetic, kinetic. and kinematic measures were collected using a Cybex II+ isokinetic dynamometer (Medway, MA), AMTI force plate (500 Hz), and Mo tion Analysis high-speed videography (200 Hz), respectively. Separate discr iminant function analyses were performed on each of the five sets of variab les to identify the factors that best discriminate between the injured and control groups, Results: Years running, training pace, stretching habits (i njured runners were less likely to incorporate stretching into their traini ng routine), touchdown angle, plantar flexion peak torque at 180 degrees.s( -1), and arch index were found to be significant discriminators. Conclusion : A combined discriminant analysis using the above mentioned significant va riables revealed that plantar flexion peak torque, touchdown angle, and yea rs running were the strongest discriminators between runners afflicted with Achilles tendinitis and runners who had no history of overuse injury.