Hi,

These are the primary movements for those two muscles, so your MVCs will need to include knee flexion and knee extension if you want to have meaningful MVCs and normalization values.

Our group has had better results doing the MVCs in a seated position for older patients. This way the participants are more comfortable during the task, but you could also have them prone for knee flexion.

Task specific treatment is, in my opinion the best way. But that always with resistance .

Working with resistance or load ( Toine van de Goolberg is the best method to create an better coordination and muscle power.

The 7 article about the diagonals are full of task specific resistance therapy in combination with differential Motoric Learning.

Example to create more power in stand phase rsistance against the swing leg is enoug to create more power in the stand leg. But with an good resistance ( R.M. 75% and 3 times 10 rehearsal and that 3 times an week !

good luck

jan

I agree with the above comments. Why not just take the peak value from a set of 3-5 trials. Isometric just means it's static, not necessarily for a specified amount of time, and you would get that at the greatest arm moment.

All you need is to work out the seat height in relation the participant.

What is the task you are trying to improve? If it is leg curls you need to practice that. If it is sit- to-stand you need to practice that. We know from triathlon’s that swimming or biking improvements do not carry over into gait. One needs to practice all the skills in the triathlon individually and not expect that the preferred skill will carry over to other skills.

Another muscle that you may want to strengthen for sit to stand in the gluteus maximus. It is important to consider the task and how the muscles coordinate during the typical task and compare it with what the subjects does. You also need to know what the various joints doing during the task. I s the hip being extended too soon before adequate hip flexion? Did the hip flex first before they left the chair? It has been shown that the gluteus maximus or quad muscles are not the first muscles to contract. Hip flexion begins as the trunk moves forward over the knees. The calf muscles and gluteus maximus work with the hips begin to leave the chair.

It is important to consider the task and practice the task as an exercise with the timing that those needed muscles would typically be active.

The intensity of the task, in my experience, should be enough to make the task easier and not too much that the person could not do several practices. If it is so intense that the person can only practice it once or twice, motor learning will not be as significant as it would be if more practices of the task was

Practices more times. I like using neuromuscular or functional electrical stimulation as the timing is controlled by the therapist watching the task and using the remote switch to correct the timing. It is used first at the typical movement when it is needed. The therapist observing can see if it look easier and ask the adult how was it. It may be that you need to start the simulation sooner as the timing was not soon enough. Correct the timing and the muscles chosen though observation and videotaping so that you can see what happened and what was different with NMES than without NMES.

When NMES is used, the subject can feel the stimulation and muscles working and just thinking about doing the task at a whole. As progression is seen it is possible to try ti without turning on the stimulation. Observe what happened and what the subject felt about that. Go back and use the NMES again to the most needed muscles and at times using the lesser needed just as a reminder. That of course if you are using several NMES units and muscles.

I agree with Erik and Chris answer. Simple task with resistance against knee flexion and extension should be enough, probably better with seating position. But are we sure that all elderly can perform maximum contractrion? Do we really need maximum contraction? If we want to compare group of people or different muscles we need to normalize emg signal based on some reference value. For my personal experience for elderly people better results of normalisation we achieved when we have used reference value not for 'unknown' maximum resistance.

For Sit To Stand test condition we take the mean value of 0.1s around time event, which was the time when person just lift of the chair/seat what we marked based on synchronise video recording.

For other test/condition you can imagine that you test knee flexors/extensors with the same load - but not maximum load. The advantage is that all participants are testing in the same load condition.

Good luck

Greg