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fpozzi23
02-22-2010, 05:11 AM
Dear colleagues,

We are currently working on a fatigue protocol on the Biodex System
III isokinetic dynamometer. The protocol consists of
concentric/eccentric (CON/ECC) contractions at 120/sec with a range
of motion of 45. Due to the narrow range of motion and the moderately
high speed, the Biodex barely gets up to full speed during the
eccentric contractions. This was confirmed upon inspection of the
speed data in which we noted that during the CON phase the speed ramps
up to 120/sec almost immediately, but during the ECC phase the speed
ramps up slower; often taking ~30-40 of the range to get up to speed.
Occasionally it doesn't even reach 120/sec if the subject is not
'pushing hard enough', which is bound to occur in a fatigue protocol
by definition. We've tried adjusting the ECC torque limit and changing
the "cushion" (from soft to hard), but we are still experiencing the
same problems.

In short, it appears as though ECC contractions are forced by the
software into a very soft "cushion". Since we are primarily concerned
with the ECC phase, this is a significant issue for us.

If anybody has had similar issues with the Biodex and have found a
resolution, any suggestions would be highly appreciated.

Thank you in advance.
Federico Pozzi