Figure 4
From: Adding Stiffness to the Foot Modulates Soleus Force-Velocity Behaviour during Human Walking
Slower fascicle shortening speed contributed to enhanced soleus force production.
(a) Soleus peak force was plotted against fascicle velocity at the time of peak force (N = 20, mean ± s.e.m). With added foot stiffness (ΔK), there was a shift towards slower fascicle velocity at the time of peak plantar flexor force. At the greatest stiffness (ΔK = 65.6 N/mm), the soleus fascicle was actually lengthening during peak force production. P-values indicate the main effect of added foot stiffness and significant pair-wise comparisons are denoted by the square brackets. (b) Force per unit activation was quantified as the ratio of integrated soleus force and integrated soleus activation during stance (N = 19, mean ± s.e.m). Added foot stiffness increased the force per unit activation (p = 0.010). The greatest added foot stiffness condition (ΔK = 65.6 N/mm) had greater force per unit activation compared to ΔK = 14.8 N/mm and ΔK = 28.7 N/mm (denoted by the square brackets).
