Evidence that ageing does not influence the uniformity of the muscle–tendon unit adaptation in master sprinters

Differences in the adaptation processes between muscle and tendon response to mechanical loading can lead non-uniform properties within muscle–tendon unit (MTU), potentially increasing injury risk. The current study analysed of triceps surae (TS) MTU 10 young (YS; 22 ± 3 yrs) older (OS; age 65 8 yrs; i.e. master) (inter)national level sprinters 11 recreationally active adults (YC; 23 detect possible non-uniformities due habitual ageing. Triceps strength, stiffness maximal strain were assessed both legs during voluntary isometric plantarflexion contractions via dynamometry ultrasonography. Irrespective leg, OS YC comparison YS demonstrated significantly (P < 0.05) lower TS strength stiffness, with no differences YC. Furthermore, group detected (average legs: 3.7 0.8%, 4.4 0.8% 4.3 0.9%) as well inter-limb symmetry indexes (range across groups: –5.8 4.9%; negative value reflects higher for non-preferred leg). Thus, findings provide clear evidence a disruption uniformity master sprinters, demonstrating that ageing tendons maintain their integrity meet increased functional demand elite sports.