Hi Wanda,

I never heard about EMG recording during a  endurance running in order to assess the fatigue, but alsways after the running. Usually fatigue is investigated during static condition with a force cell in order to separate central from peripheral fatigue.

Here an article that talks about that

http://link.springer.com/article/10.1007/s004210050426

If you want to investigate the fatigue in dynamic condition the only reasonable thing to do is to calculate the emg activation of the interested muscles for each gait cycle.If fatigue influence your kinematics, it might be that the EMG pattern of activation also change. You can calculate this activation pattern for each muscle by identifying the timing of activation for each gait cycle and the integral of this activation.

There is a nice work of Laquaniti and Ivanenko where they assess the locomotion program during walking by using EMG.

http://jn.physiology.org/content/95/6/3426.short

Take a look.

Good luck!

Ivan

Hello,

Based on our studies on muscle fatigue in the past (see Roots et al, 20XX, J Appl Physiol and Vawda et al, 19XX, JMRCM), I just want to say that muscle fatigue is a complex problem / question. If you are interested in the basic processes / reasons, muscle force or work measurements are relevant, and it might be worth being aware of differences in fatigue depending on whether muscles operate at constant length (isometric) or with shortening. Basically, it might be worth reading the background findings, as listed in the above.

Hope this is useful,

KW

You might be able to get some idea from the FFT of the EMG. During fatiguing muscle units tend to fire more synchronised, leading to a larger, sharper peak in the frequency spectrum of your EMG.

The analysis of muscle fatigue is fraught with difficulty as previously mentioned. The use of amplitude is rather ambiguous because you can get both an increase and decrease with fatigue. Using FFT to analyse frequency is perhaps a better approach but this requires a static contraction. We are looking at the feasibility of using the point of isometric contraction during the SSC and using this from each cycle contiguously to give a record that can then be analysed by FFT. This is only only done after the data has been collected.