The spring-mass model and the energy cost of treadmill running

Abstract

During running, the behaviour of the support leg was studied by modelling the runner using an oscillating system composed of a spring (the leg) and of a mass (the body mass). This model was applied to eight middle-distance runners running on a level treadmill at a velocity corresponding to 90% of their maximal aerobic velocity [mean 5.10 (SD 0.33) m x s(-1)]. Their energy cost of running (Cr). was determined from the measurement of O2 consumption. The work, the stiffness and the resonant frequency of both legs were computed from measurements performed with a kinematic arm. The Cr was significantly related to the stiffness (P < 0.05, r=-0.80) and the absolute difference between the resonant frequency and the step frequency (P < 0.05, r=0.79) computed for the leg producing the highest positive work. Neither of these significant relationships were obtained when analysing data from the other leg probably because of the work asymmetry observed between legs. It was concluded that the spring-mass model is a good approach further to understand mechanisms underlying the interindividual differences in Cr.

Difference in Mechanical and Energy Cost between Highly, Well, and Nontrained Runners

“…According to the training status, the variation in C pe is not associated with the variation in C. Similarly, the kinetic mechanical cost (C ke ) or the mechanical cost of the movements of the segments around the centre of mass (C int ) were not correlated with C ( figure 4). These results agree with numerous studies which have demonstrated that the relationships between C and the mechanical cost are both weak and inconsistent (11,28,37). The mechanical cost reflects a global and indirect expression of the muscular effort which explains why a low correlation is observed between C and the mechanical cost.…”

“…Indeed, it has been shown that less economical runners possess a more compliant running style during ground contact (11,24).…”

Effects of Resistance Training on Running Economy and Cross-country Performance

“…This is a reasonable assertion since both HRT and PRT groups performed the same endurance training outside of their respective resistance training programs. In further support, running economy improved in accord with many of the neuromuscular measures (Table 3 and Table 4) which also coheres well with previous studies (10,33,36,42,43,46) reporting the importance of the neuromuscular characteristics in determining running economy and running performance following combined resistance and endurance training in runners.…”

“…One of the most important roles of the muscle during running is to modulate leg stiffness and storage-recoil of energy. The conversion of energy to motion involves recoil of some elastic energy in muscle and tendon, thus a "stiffer" muscle or tendon would be better at transferring energy economically or without the need for additional oxygen consumption (7,10,43). Indeed, previous evidence has shown a negative correlation between leg stiffness and cost of running (1,2).…”

Lower Limb Mechanical Properties: Significant References Omitted

“…several hours [22,23]) is undergoing unprecedented popularity. Additionally, the potential link with the energy cost of running [24,25] is a crucial factor of human running performance [26]; for moderate intensity Heise and Martin found an inverse relationship between aerobic demand and stiffness [25]. For severe intensity, Dalleau et al [24], Slawinski et al [20], and Rabita et al [19], confirmed that, during a constant-velocity, time-to-exhaustion run on track or treadmill, the same inverse relationship was observed.…”