Muscular Activity Of Athletes With Unilateral Lower Limb Tendinopathy In Running

Abstract

Altered muscular activity of the lower limb is seen as one possible risk factor for achilles or patellar tendinopathy in athletes. In addition, the characteristics of the neuromuscular control in patients and necessary consequences on the choice of treatment options are also under discussion. However it is unclear, if valid differences in muscular activity between healthy subjects and patients could be quantified. PURPOSE: To determine muscular activity during running in athletes suffering from unilateral achilles or patellar tendinopathy. METHODS: 35 athletes with achilles tendinopathy (40 ± 7 yrs; training units/week: 4.8 ± 2), 16 athletes with patellar tendinopathy (37 ± 9 yrs; training units/week: 5.6 ± 2) and 33 healthy athletes (29 ± 9 yrs; training units/week: 5.3 ± 3), matched by overall training load, were analysed on the treadmill (velocity: 3.3m/s). Muscular activity (EMG) of Mm. tib. anter., pero. long., gastro. med., vast. med., rec. fem. and bic. fem. were measured. Mean normalized amplitude quantities were assessed during the gait cycle phases (in % of total gait cycle). Group comparisons were analysed using mean, 95% CI and one way ANOVA (a = 0.05). RESULTS: EMG amplitude of patients during weight acceptance (Awa) and maximum amplitude (Amax) were statistically significant reduced in Mm. tib. anter.(Awa: -19.2%; Amax: -40.0%), gastro. med..(Awa: -36.4%; Amax: -38.2%) and vast. med..(Awa: -27.1%; Amax: -48.8%) compared to healthy subjects (P < 0.05). In contrast, no differences between groups were observed in preactivation phase and for Mm. pero. long., rec. fem., bic. fem.. In addition, no differences were assessed between the injured and the uninjured leg and due to pathology (achilles vs. patellar tendinopathy). CONCLUSIONS: Muscular activity in running is reduced bilaterally in unilateral lower limb tendinopathy. Therefore, interventions focusing on the improvement of sensorimotor control seem to be a promising treatment option in athletes with achilles or patellar tendinopathy.