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dkamenetzky77
06-24-2011, 01:52 AM
I would like to ask you please for suggestions about wireless EMG equipment to be used in youth evaluations (sports and clinical patients). Its benefits and problems and also the possibility of each equipment to be integrated with other tools for videography, plantar pressure analysis, etc.
Thank you very much for your help.
Regards,
Daniel

syu71
06-24-2011, 12:45 PM
Hi Daniel,

We just evaluated a couple of wireless EMG systems here at USC. I think I can help a bit if you can provide more details (e.g. activities, muscle groups, amount of channels, etc.) about your application.

The major advantages of wireless EMG systems are easiness to use and promptness in experiment preparation. On the other hand, the major issues are signal interference and loss of flexibility, comparing to a wired EMG system. Most key players in the field have done a pretty good job to tackle the former issue with advanced technology. In return, wireless EMG systems lose some flexibility, well, more or less.

For youth athletes, I think you may need a system with adjustable gain to prevent crosstalk. Do you plan to collect data on the field or in the lab? What's the input format of the system you like to synchronize with? It seems to me that you are collecting some gait and running trials, right?

Best regards,
Sean

dkamenetzky77
06-24-2011, 02:13 PM
Thank you Sean for your answer.
I'm organizing a service to evaluate performance of different sports in the field mainly and in lab if necessary. Also we will evaluate youth with different type of motor disabilities. Gait and running probably will have the main representation in our work, but will not be restricted to it only. The analysis will be oriented to improve motor sports performance and also to solve injuries related to sports technique. The data will be use to make decisions for training and treatment implementation.
My intention is to integrate the EMG data with plantar pressure analysis (mainly with a portable Tekscan) and also with video data that I'm currently collecting with a regular commercial camera that films at 300 frames per second.
I'm looking for good enough data to make clinical decisions at the same time that allows for a "comfortable" (if possible) usage and fast set up (to prevent as much as possible an uncomfortable situation for the youth to be evaluated).
Let me know if the information responds to your questions please.
I would like hopefully brands and prices (if is available the information). Also, technical opinion.
Thanks
Daniel

ecramp48
06-28-2011, 09:53 AM
I'm currently collecting with a regular commercial camera that films at 300 frames per second.

With a frame rate of 300 fps, you're recording a video frame every 3.3ms - so one factor that you will need to take into account is the signal delay introduced by the EMG system that you use.

Many wireless EMG systems using standard telemetry protocols like Zigbee and Bluetooth have signal delays ranging from 16ms to 48ms and higher. If you are recording EMG data from a system with a significant fixed delay then you will require post-processing to get the EMG data and video data back into synchronization.

syu71
06-29-2011, 12:59 PM
Mr. Cramp brought up a very good point. I totally with his opinion that signal delay is also a very important issue, and very common in wireless EMG systems for buffering and D/A conversion. Range of delay for the systems we have examined is from 0ms to 500 ms. Different manufacturer has different concerns and usage regarding the delay. You may need to find a good combination of system delay and gain for your system.