Etiologic factors associated with Achilles tendinitis in runners

PURPOSE

The purpose of this study was to determine whether relationships exist between selected training, anthropometric, isokinetic muscular strength, and endurance, ground reaction force, and rearfoot movement variables in runners afflicted with Achilles tendinitis.

METHODS

Specifically, we examined differences in selected measures between a noninjured cohort of runners (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 Motion Analysis high-speed videography (200 Hz), respectively. Separate discriminant function analyses were performed on each of the five sets of variables to identify the factors that best discriminate between the injured and control groups.

RESULTS

Years running, training pace, stretching habits (injured runners were less likely to incorporate stretching into their training routine), touchdown angle, plantar flexion peak torque at 180 degrees x s(-1) and arch index were found to be significant discriminators.

CONCLUSION

A combined discriminant analysis using the above mentioned significant variables revealed that plantar flexion peak torque, touchdown angle, and years running were the strongest discriminators between runners afflicted with Achilles tendinitis and runners who had no history of overuse injury.

Etiology of iliotibial band friction syndrome in distance runners

The objectives of our study were: 1) to examine differences between a noninjured cohort of runners (N = 70) and runners afflicted with iliotibial band friction syndrome (ITBFS) (N = 56) according to selected anthropometric, biomechanical, muscular strength, and training measures; 2) to explore multivariate relationships among these measures in both the well and injured groups; and 3) to develop specific hypotheses concerning risk factors for injury that will later be tested in a prospective observational study. High speed videography (200 fps), a force platform (500 Hz), and a Cybex II+ isokinetic dynamometer were used to assess rearfoot motion, ground reaction forces, and knee muscular strength and endurance, respectively. A linear discriminant function analysis of the training data revealed weekly mileage, training pace, number of months using current training protocol, % time spent swimming, and % time spent running on a track to be significant (P < 0.10). Height was a significant anthropometric discriminator, while seven isokinetic strength and endurance measures were found to discriminate significantly between the groups. Calcaneal to vertical touchdown angle, and maximum supination velocity were significant rearfoot movement discriminators. Maximum braking force was the only significant kinetic discriminator. A combined discriminant analysis using those variables found to be significant in the previous analyses revealed weekly mileage, and maximum normalized braking force to be the best discriminators (model P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)