Differences and Influence of Emg-Time Quantities in Healthy Subjects and Patients With Achilles Tendinitis

It is assumed that movement patterns of the lower extremities influence the frequency of running-specific complaints. Moreover, these patterns might differ between healthy and injured persons, whereby it is not clear which pattern should be considered physiological. It has been mentioned variously that the natural movement in walking barefoot elicits few complaints. It should thus be possible to demonstrate that movement patterns of patients differ from healthy subjects in shoes, but that the movement behavior of barefoot patients approaches that of healthy individuals. Possible differences in EMG-patterns of the lower extremities were examined in a total of 22 subjects with Achilles tendinitis [AT] and 20 healthy individuals [H]. To characterize the movement behavior, the start [tini], total time [ttot] and time of maximum [tmax] EMG-activity was measured in the Mm. peroneus longus [PM], gastrognemius med. [GM] and lat. [GL] at 12km/h in a treadmill test under randomized conditions (shod, barefoot; ANOVA, Tukey-Kramer's test, α = 0.05). Interpretation of the data was made in relation to the touch down of the foot. The results show a delayed onset of activity of PM in shoes in AT (p < 0.05) with no differences between barefoot and shod conditions in AT and H (p > 0.05). With respect to GM and GL, tini was delayed, tmax was attained later and ttot was lower in AT (p < 0.05). Moreover, the EMG time quantities for GM in AT under barefoot conditions approached those of H, so a difference between AT and H could no longer be determined under barefoot conditions. It is concluded that movement patterns of the lower extremities differ in patients with AT from those of healthy control persons when shoes are worn. If the patients are instructed to walk barefoot, the EMG behavior approaches that of the healthy persons. Optimization of shoes and insoles for patients and in prevention to suit the individual barefoot conditions should be discussed and recommended where appropriate.