Author(s): CELEBI, E., GUREL, M., OZCADIRCI, A., BOZGEYIK-BAGDATLI, S., BAZANCIR-APAYDIN, Z., APAYDIN, H., COSKUN, G., Institution: HACETTEPE UNIVERSITY GRADUATE SCHOOL OF HEALTH SCIENCES, Country: TURKEY, Abstract-ID: 2087

INTRODUCTION:
Ultra-trail running is characterized by prolonged duration, repeated downhill sections, and substantial cumulative eccentric loading on the knee extensor complex and surrounding connective tissues (1). Although physiological and performance responses to ultra-endurance running have been widely investigated, mechanical adaptations of knee muscles and connective tissues remain unclear. The aim of this study was to compare the mechanical properties of Quadriceps, knee exstensor and flexor muscle strength, and dynamic balance between ultra-trail runners and age- and sex-matched healthy controls.
METHODS:
A total of 36 participants (3 Female and 15 Male for each group) were included in this cross-sectional study, consisting of 18 ultra-trail runners (mean age 42.00±7.03 years; mean BMI 24.26±2.06 kg/m²) and 18 age- and sex-matched controls (mean age 42.33±6.93 years; mean BMI 25.59±3.85 kg/m²). Among the ultra-trail runners, the mean longest completed race distance was 76.61±30.96 km.The mechanical properties (tone (F), stiffness (S) and creep (C)) of the quadriceps muscle were assessed using a MyotonPRO device. Measurements were obtained from the rectus femoris, vastus lateralis, and vastus medialis obliquus components of the quadriceps muscle, as well as the iliotibial band and the patellar tendon. Knee extensor and flexor muscle strength were evaluated with a handheld dynamometer. Dynamic balance was assessed using the Y Balance Test, and a composite score was calculated from anterior, posterolateral, and posteromedial reach distances.All measurements were performed both the dominant and non-dominant lower extremity.
RESULTS:
Significant between-group differences were observed in the dominant lower extremity for vastus medialis F (p=0.038) and C (p=0.006), as well as for iliotibial band S (p=0.019) and C (p = 0.021). However, no significant differences were found in the rectus femoris, vastus lateralis, or patellar tendon in the dominant limb (all p>0.05). Furthermore, no significant between-group differences were observed in the non-dominant limb for F, S, or C values of the rectus femoris, vastus lateralis, vastus medialis, iliotibial band, or patellar tendon (all p>0.05). Significant between-group differences were observed in the Y Balance composite scores for both the dominant (p=0.004) and non-dominant limbs (p=0.001). Knee extensor muscle strength demonstrated significant between-group differences in both the dominant and non-dominant limbs, favoring the ultra-trail group (both p<0.001). Likewise, knee flexor muscle strength was significantly greater in the ultra-trail group in the dominant (p<0.001) and non-dominant limbs (p=0.001).
CONCLUSION:
The findings indicate that chronic exposure to ultra-trail running may induce side-specific mechanical adaptations in periarticular soft tissues, accompanied by enhanced strength and dynamic balance capacity, potentially reflecting sport-specific neuromuscular conditioning.