Running Energy Cost and Spring-Mass Behavior in Young versus Older Trained Athletes.

Purpose: The aim of this study was to compare energy cost of running and lower limb spring-mass characteristics and maximal power between young and older highly trained runners.

Methods: Twenty highly trained male endurance runners were divided into two groups: young and master athletes. Two testing sessions were used to measure and compare (i) lower limb power during three jumping tests (squat jump (SJ), countermovement jump (CMJ), and rebound jump (RJ)) as well as stiffness during the RJ test and running trials (using an OptoJump system (Microgate, Bolzano, Italy) placed on the floor for jumping and on each side of the treadmill belt for running), and (ii) the energy cost of running and oxygen consumption (V˙O2) kinetics (using an Oxycon Pro breath-by-breath gas analyzer (Jaeger, Höchberg, Germany)) at three speeds: 10 km·h, self-selected speed, and speed corresponding to 90% of the second ventilatory threshold (VT2).

Results: Energy cost of running was higher in masters than in young athletes at all speeds (10 km·h, 13.0%; self-selected, 10.8%; 90% VT2, 7.7% on average). Jumping power was lower in masters (SJ, -28.0%; CMJ, -30.5%; RJ, -27.9%) and significantly correlated with energy cost at 10 km·h and at self-selected speed (10 km·h: r = -0.71, -0.70, -0.47; self-selected speed: r = -0.76, -0.74, -0.58, respectively). RJ stiffness was also lower in masters (-27.8%), although stiffness during running showed no difference between groups.

Conclusions: A long-lasting running practice seemed to preserve the bouncing mechanism of master athletes, yet their energy cost was higher when compared with younger runners, which might have been associated with a lower muscle power.