EMG interpretation is not easy because there is a lot of overlap of factors, especially in dynamic contractions.
Since there are soooooo many factors that influence the EMG I recommend to check for the time of activation and time of inactivation of the muscle(s) your were looking at. Everything else is very difficult and always depending on the question and the procedure you used.
Интерпретация эмг определяется диапазоном показателей и динамикой показателей между параметрами в состоянии расслабления мышцы и ее напряжения
If you normalize the EMG using MVIC, be aware that you can get >100% activation during dynamic contractions.
To echo what has been said prior. What you take from dynamic EMG is largely related to the aim. Normalization is required if you want to assess a relative activation level in comparison to other muscles (and between days) but caution against using MVIC as it does produce lower EMG levels compared to high velocity actions (particularly triceps surae). Timing of activation and de-activation is a good start that will also allow you to assess co-contraction etc. It really depends on the aim though. In Addition to Professor Hof's paper another good papers to look at is Farina 2006 (http://journals.lww.com/acsm-essr/Abstract/2006/07000/Interpretation_of_the_Surface_Electromyogram_in.6.aspx) but depending on what you particularly want to look at (i.e comparisons of magnitude, co-contraction) there are others.
In my Mphil thesis is used integrated EMG over 30s for each of my dynamic workloads - whilst I hadn't seen this done before (normally iEMG is done over a shorter time or a single contraction) it worked well for me and allowed comparison between intensities.
See FARINA D, MACALUSO A., FERGUSON RA, and DE VITO G. (2004). Effect of power, pedal rate, and force on average muscle fiber conduction velocity during cycling. JOURNAL OF APPLIED PHYSIOLOGY. vol. 97, pp. 2035-2041.
Other good article...Farina, D.(2006). Interpretation of the surface electromyogram in dynamic contractions. Exerc. Sport Sci Rev. 34, 121-127. doi 10.1249/00003677-200607000-00006
I have used integrated EMG for a number of years to quantify things like: bursts of muscle activity during pedaling, dynamic resistance training, and testing the effectiveness of various rehab modalities (usually different arm or leg positions during rehab exercises). I always need to have markers to denote the transition from con to ecc. In addition, since the time of the movements are not fixed unless using isokinetic, you will have varied sample sizes within each burst. therefore you need to standardize the iemg to a fixed sample size to control for variation in movement speed.
to study the EMG in dynamic conditions is a difficult matter and the difficulties grow with increasing dynamics. As a good tool, I would preliminarly suggest Wavelet transform.
First of all, you should clear whether it is isokinetic in nature or not.
The use and interpretation of all EMG data, regardless of whether it is acquired with static or dynamic activity, requires a thorough understanding of the origins of the signal, the factors that influence the quality of the signal, and the factors that change the signal (e.g with movement or over time). There is also the obvious, how do these data allow you to address a research question. Finally, all necessary measures of experimental control (normalization, minimization of altered recording volumes) are needed to allow for even the most basic interpretation of the findings. If all of these things are completed and the findings are presented with sufficient detail and consideration of limitations, any results can be discussed and ultimately left up to the reader to be critical of. Most people who misinterpret EMG do so by over-generalizing the findings.
I believe that all the references posted here are a good start and that timing (onset and termination of activation) is often a great place to start. Try to minimize experimental bias and always conduct visual inspection of your data.
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