Short- and long-term effects of altered point of ground reaction force application on human running energetics

Abstract

The current study investigates the effect of altering the point of force application (PFA) from the rearfoot towards the fore of the foot on the metabolic energy consumption and the influence of transitioning to this technique over a short or a longer timeframe. The participants were randomly assigned into two experimental and one control group: a short-term intervention group (STI, =17; two training sessions), a long-term intervention group (LTI,=10; 14-week gradual transition) and a control group (CG, =11). Data were collected at two running velocities (2.5 and 3.0 m s). The cost coefficient (i.e. energy required per unit of vertical ground reaction force; J N) decreased (<0.001) after both interventions due to a more anterior PFA during running (STI: 12%, LTI: 11%), but led to a higher (<0.001) rate of force generation (STI: 17%, LTI: 15.2%). Dynamic stability of running showed a significant (<0.001) decrease in the STI (2.1%), but no differences (=0.673) in the LTI. The rate of metabolic energy consumption increased in the STI (=0.038), but remained unchanged in the LTI (=0.660). The CG had no changes. These results demonstrate that the cost coefficient was successfully decreased following an alteration in the running technique towards a more anterior PFA. However, the energy consumption remained unchanged because of a simultaneous increase in rate of force generation due to a decreased contact time per step. The increased instability found during the short-term intervention and its neutralization after the long-term intervention indicates a role of motor control errors in the economy of running after acute alterations in habitual running execution.

Effect of habitual foot-strike pattern on the gastrocnemius medialis muscle-tendon interaction and muscle force production during running

“…Recent studies also demonstrate that gait retraining from rearfoot to forefoot strike running did not change running economy when sufficient intervention trainings (≥8) were provided (21,65). As such,…”

Fuzziness of muscle synergies in patients with multiple sclerosis indicates increased robustness of motor control during walking

“…Local dynamic stability assessment. The local dynamic stability represents the ability of the system to respond to small internal perturbations 50 , representing how the system is able to maintain stability and detects neuromuscular control errors in achieving it 51,52 . To assess the local dynamic stability, we adopted the maximum finite-time Lyapunov exponents (MLE) of the human system during walking.…”

Habitual foot strike pattern does not affect simulated Triceps Surae muscle metabolic energy consumption during running

“…Moreover, previous experimental research already demonstrated that differences in whole body metabolic energy consumption between foot strike patterns are small (Ogueta-Alday et al, 2014) or even non-existing (Cunningham et al, 2010; Gruber et al, 2013; Lussiana et al, 2017; Perl et al, 2012). Studies investigating the effect of gait retraining from rearfoot to forefoot strike running do not find an effect on the metabolic energy consumption during running when enough training sessions (?8) were offered (Ekizos et al, 2018; Roper et al, 2017). However, when only two training sessions were provided an initial increase in metabolic cost is reported (Ekizos et al, 2018), indicating the need for habituation.…”

“…Studies investigating the effect of gait retraining from rearfoot to forefoot strike running do not find an effect on the metabolic energy consumption during running when enough training sessions (?8) were offered (Ekizos et al, 2018; Roper et al, 2017). However, when only two training sessions were provided an initial increase in metabolic cost is reported (Ekizos et al, 2018), indicating the need for habituation. Hence, since habituation is necessary when switching foot strike pattern and switching ultimately does not result in a reduced metabolic cost, switching foot strike pattern seems to be ineffective from a performance point of view.…”