in this section I want to talk about how we use the dynamometer to measure GP and pinch in our uh clinical practice um as you can see there are many uh different brands of dynamometers that that are available on the market but um uh the most popular ones are jmar uh for the grip um Pinch at a grip and pinch um you will see jmar jar is actually the brand of the Dem not the dynamometer so uh don't be surprised that people just say jmar and um to measure uh the grip strength um if you want um to refer to the norm that you need to follow the standardized position and the standardized position uh for using jmar um is you we put the bar right uh this bar at the second Groove um no matter uh the size of the hand so that says for children for um uh teens or older adults we all use this uh the same uh uh position of the bar and secondly we want to position our uh client to um to be tested and the the the posture for the test is we have the shoulder in adduction elbow in 90° of FL action and form in neutral and then we slide in um the Jr uh into our participants hand okay and typically we ask them to um to squeeze as hard as possible and try not to hold their breath especially for those who had um hard surgery because uh it's uh a big no for them to hold their breath okay so our instructions matters so we will tell them um to squeeze as hard as possible and at the same time don't hold your breath so I typically just um tell them like when they start squeeze squeeze squeeze stop and then they will relax and then I would read the number uh you have to uh be careful which number you you read it can be kilogram or can be in pounds so uh but be consistent and uh clinically we take three uh t test and then we average it and then we record the average one same thing for the uh pinch gauge um the same position for the shoulder in uh adduction elbow in 90° of fraction from in neutral it is uh the therapist to slide in uh the pinch gauge whether we want to do Palmer pinch L pinch or tip pinch again the position never change what changes is um the way that we position the gauge okay and again we take three um tests and then we average and then we document the average one so these are U quite Universal in a way um if um to some reason you cannot uh assume in the standardized position then you have to document in what position that you U measure and um so that when we want to monitor the Improvement of over time we have to follow the same posture that we measure in the very beginning and then we can document how much they have been improved since day one okay that being said since we are deviating from the standardized position we cannot use the number and revert it to the norm because the norm is built based on the standardized position okay so here's how we um use the nor Norm or when we cannot use the norm how can we interpret the results so first of all let's talk about uh the norm um so this is the norm that I basically uh copy from the text block these two Norms um say I gave an example um here oh so the norm we are taking the method we call two standard deviation method what that means is um um once standard deviation is um how far away U the deviation is from the mean which is the average score when its two standard deviation away U so basically the two standard deviation cover 90% of the population when is beyond the two standard deviation that means it's just the 5% that is not within um the two standard deviation and we call it um abnormal however you may argue with within that 5% um 2.5 of them are above and 2.5 of them are below right yes when it's above two standard Dev uh deviation they are Superman we don't we don't worry about you know do we need to tr them because they are really strong they're above average per person what we need to worry about is when the number is below the two standard deviation so uh the example here that I um show is so we have a 45 year old male um his uh right grip is 50 lbs and then we want to determine if this number is within uh normal so we uh refer to the grip strength Norm here and it's male um so we refer to the men um and then his uh right grip and then within his uh age so with 45 right hand the average or the mean should be 110 right and two standard deviation we just need to take that standard deviation and times two so for the r for the age of 45 the standard deviation for the right arm is 20 uh 23 so 2 * 23 is uh 46 so we are looking for uh two standard deviation below the means right so we will M uh we will take the mean score and then minus the two standard deviation which is 64 so any number below or lesser than uh 64 we would uh documented as abnormal so now let's look at this person he has 50 pounds in his right grip it is below the 64 so therefore we um have the conclusion that uh this person's grip strength is abnormal or below normal so in in the situation that we cannot refer um the norm we can compare the right arm to the left arm so and then we call it 10 percentage method typically if this person are uh is a right hand dominant um um uh the grip strength is 10% greater than the left uh arm then that person's left arm if this person's left hand um dominant uh typically uh right and left are pretty much equal Bator so now we have um one example here uh we have a 40 year old male whose uh uh right hand grip is uh 50 pounds and left grip is uh 100 pounds so in a typical healthy uh sorry in a in a typical um situation um since this person is uh right dominant then we would expect the right uh grip should be 110 right um and then um so you can see that we can compare the number um to um the actual U measurement and then we can calculate uh the percentage um so that uh basically we're comparing this person's right hand to the left or the left to the right and over time we're comparing this person within themsel and again um it really depends on the availability of the Norms so some in some situation that the norm may not be accurate for example uh if the norm is built for uh a regular um healthy um subjects it's not applicable for for um uh people with stroke or for people with uh medium nerve injury for example right so a lot of time we would have to compare the number uh from right side to the left side or the left side to the right side I mean to himself so these two methods are um um used quite often so you have to know how to uh first of all uh measure in a standardized way if not we have to document what position that we did and then second of all you will have to know how to interpret the results