Bioproject, Chydenius Institute, Finland. 12:45:03 11/5/01
Protocol For Ramp Pilot Study
Equipment: HUR Leg-Extension/Curl Research Line, NORAXON Myosystem 1400.
Test protocol. The time for one subject to complete the tests is estimated to be about 45 - 50 min.
For isometric MVC extension it is important to instruct the subject not to "kick" but to gradually (yet swiftly) increase the force to maximum. The electrodes must be attached at least 5 min in advance of the tests in order for the impedance to reach a stable level.
Step Procedure Duration
1 Marking, skin preparation (cleaning, electrode place abrasion) and fixing the electrodes.
ca 10 min
2 "Standard warm up": squatting, MVC, etc. ca 10 min
3
MVC test.
Isometric MVC extension with 90 degrees joint angle.
MVC extension Resting
MVC extension Resting
MVC extension
4 – 5 s 30 – 60 s 4 – 5 s 30 – 60 s 4 – 5 s
4 Resting 30 – 60 s
5
MVC test.
Isometric MVC flexion with 90 degrees joint angle.
MVC flexion Resting MVC flexion Resting MVC flexion
4 – 5 s 30 – 60 s 4 – 5 s 30 – 60 s 4 – 5 s
6 Resting ca 5 – 10 min
7
Ramp test. Straight extended leg. Increases load at a rate around 5 Nm/s for max 20 seconds.
Ramp test 1 Resting Ramp test 2
ca 20 s ca 5 min ca 20 s
8 Resting ca 5 min
9
MVC test.
Isometric MVC, straight leg.
MVC extension Resting
MVC extension
4 – 5 s ca 5 min 4 – 5 s
rampprot.sdw 1/2
Bioproject, Chydenius Institute, Finland. 12:45:03 11/5/01
Data acquisition and processing. Data is sampled with Myosoft (NORAXON) with sampling rate 2000 S/s, 12 bit resolution, gain set to 1000. Auxiliary input used for force and angle. The raw data is exported in asc-format for further processing and calibration. Before the measurement session the zero levels for the force and angle sensors are measured (with zero force input and the lever arm in downward vertical position). The objective of the study is to (hopefully) confirm the repeatability of the measurements within experimental errors and to assess the variations of the results. The central issue is to check the expected linear relationship between EMG and force. The next step will then be to investigate whether this relationship can e.g. be used for distinguishing effects of hypertrophy versus neural factors.
Optional tests. If time allows one can do some of the following optional tests in addition to the basic protocol above.
Optional Test Description
1. Ramp test at different joint angles Ramp tests with 90 and 135 degree joint angles.
(Ramp test with straight legs – 180 degree joint angle – is already completed with the first pilot test setup.) Do different joint angles dramatically alter the EMG-force relationship?
2. Dynamic test MVC kicks at preset loads.
3. Reversed ramp test As the usual ramp test but in reverse order; that is, starting with maximal load and gradually decrease the load. The question is still open how to practically implement this.
4. Feedback ramp test Isometric setup with a visual feedback of the force level displayed on the computer screen. The subject is instructed to increase the force according to a predetermined force-time trajectory (e.g. with a rate around 5 Nm/s).
Research team:
P Konrad (p.konrad@t-online.de) M Herrala (Mika.Herrala@oulu.fi) F Borg (borgbros@netti.fi)
rampprot.sdw 2/2
