**3.2. Order of muscle participation**

From the GEAV signal, the order of participation of each muscle can be seen. This order remained constant in all three conditions: tibialis anterior, hamstrings, gastrocnemius, and quadriceps. The AT muscle was the first one to be activated during the stride; it was activated before the flight of the ipsilateral foot, in the last part of unipodal support. The BF and ST were activated after the TA, but in the swing phase, i.e., when the contralateral leg was resting on the floor. The GN was activated in the final flight. Vastus medialis and RF were also activated in the final flight, but after the GN.

Comparison by EMG of Running Barefoot and Running Shod 81

**Left leg muscles RF VM GN TA BF ST** 

**Right leg muscles RF VM GN TA BF ST** 

**Barefoot** 8 6 8 96 90 98 **Standard shoes** 8 6 10 94 90 84 **Athletic shoes** 8 6 8 94 88 84

**Barefoot** 6 6 8 94 88 94 **Standard shoes** 6 8 10 94 90 88 **Athletic shoes** 10 6 10 94 90 90 **Table 4.** Time of occurrence (in % of the jogging cycle) of the GEAV peak in each of the three different

**Figure 4** shows the maximum activity displayed during the entire cycle by each of the twelve muscles. In all three conditions the muscles that had the highest amplitude were the

The maximum amplitude of homologous muscles was of the same order of magnitude for

There is no statistically significant difference between the three conditions with respect to

**Figure 6a** shows the maximum activity during the support phase produced after the impact of the heel. The TA, GN, and BF muscles in both legs increased their activity with both types

The evolution of electrical activity in buffer muscles (RF and VM) during the loading phase

**Figure 7** shows the increase (not normalized, in mV) of EMG activity with respect to the barefoot condition. When subjects wore standard shoes with hard soles, the RF of the left leg increased its maximum amplitude after impact, and the left VM decreased their activity.

When subjects wore their own shoes, the RF of the left leg decreased its peak amplitude

When the shoe was harder, the left RF increased its activity and the VM of both legs decreased. When the shoe was softer, the RF of both legs and the VM of the left leg

after impact. The left VM decreased its activity; and the one of the right, increased.

decreased its activity, and the right VM slightly increased its activity.

VM, GN and TA. The muscles that showed less activity were the BF, ST and RF.

*3.4.2. Maximum amplitude during the support phase after impact* 

was not the same in both legs, neither with both types of shoes.

of shoes. The behaviour of RF, VM, and ST varied positively and negatively.

**Locomotion condition** 

**Locomotion condition** 

locomotion conditions.

both legs, as shown in **Figure 5**.

the value of the amplitude peak.

*3.4.1. Maximum amplitude along the entire cycle* 
