0:04 This is Brent of the Brookbush Institute, bringing you another muscle 0:07 length test. In this video we're going to do the lat length test. 0:11 Now the lat length test we use to determine if the latissimus dorsi is one 0:16 of the muscles restricting shoulder flexion. I'm then going to show you some 0:19 of the if-then scenarios, that will help you determine whether the lats, the 0:24 shorter internal rotators of the shoulder, or both are involved. I'm going 0:29 to have my friend Melissa come out, she's gonna help me demonstrate. So what the 0:36 lat length test really is, is a shoulder flexion test. It's just a very quick 0:42 shoulder flexion test, just like shoulder flexion goniometry. Alright so what I'm 0:47 gonna have you do, sorry start here, laying flat. I'm going to have you try to 0:50 bring this part of your forearm back to the table in front of you. Alright 0:57 there you go, so you guys see. We know that normal shoulder flexion is between 1:01 100 and 185 degrees, so she's missing some shoulder flexion right. 1:05 The lat length test part comes in and it goes, if you really push it, can you 1:11 push it, just go all the way down to the table, go for it. Alright she pushes 1:15 her arms down and does this, did you guys see all this lumbar extension. I have to 1:21 start thinking to myself all right the muscles that could restrict shoulder 1:25 flexion, I got the teres major, subscapularis, the latissimus dorsi 1:31 pectoralis major probably not likely in this position. Of those muscles, which one 1:37 crosses the lumbar spine, well the lattisimus dorsi crosses the lumbar 1:41 spine. Not only does it cross the lumbar spine, but it will cause lumbar extension, 1:46 which is exactly what I saw. So when I told Melissa to go ahead and push it, or 1:52 I could even add a little overpressure, obviously you wouldn't want to do that to a 1:55 painful shoulder. But if you added a little overpressure and it pulled her into 1:59 lumbar extension, I know that she ran out of room from her lats, and had to shorten 2:04 it somewhere else. So this would be a positive lat length test. I know that the 2:08 lats are one of the structures that could be restricting her shoulder 2:13 flexion. There's another way to go about this, 2:15 we'll start over. This time we'll put her in a hook lying 2:18 position. Now hook lying position posteriorly tilts the pelvis a little bit, 2:23 flattens up the lumbar spine and it kind of anchors the pelvis 2:27 a little bit, so that lumbar extension is not as easy to get in this position. Now 2:32 I have her go ahead and pull this way, and usually what you'll have is in that 2:37 same individual, somebody will actually look like they're even more restricted 2:42 and shoulder flexion. I could test to see how much the lats are contributing to 2:47 this by going okay, let's go ahead and bring your legs up, push you into a 2:52 posterior tilt, and you guys see how when I pushed her into a posterior tilt her 2:57 arms came up a little bit. That's a pretty good sign that her lats are 3:02 contributing to the restriction on her shoulders. So that's all the lat length 3:08 test does. Is the lat one of the muscles restricting shoulder flexion, the problem 3:13 with that is, is it doesn't do all that much for us from a practical application 3:18 standpoint. I still don't know if it's subscapularis and teres major 3:22 contributing to this. So how would I figure that out? Well I could go back to 3:28 my goniometry, if you guys remember shoulder external rotation is done here. 3:36 Alright, why shoulder external rotation? Well subscapularis, teres major, 3:42 latissimus dorsi are all internal rotators. But if i go and put the arm 3:47 back in ninety degrees of shoulder abduction, i just shortened the lats a little 3:52 bit right. It's like halfway through a lat pulldown. So these structures that 3:56 are more likely to restrict this range of motion in this position are the 4:01 shorter external rotators. So if I had positive lat length tests, and then I did 4:09 external rotation and she had full 95 degrees, I might be able to deduce that 4:15 it's the lats restricting her shoulder flexion, and 4:20 the short internal rotators, teres major and subscapularis. If I had a 4:27 positive lat length test and she only had 85 or 80 degrees of shoulder 4:31 external rotation, then I know it's probably teres major, subscapularis and 4:36 latissimus dorsi. If I had a negative lat length test right, so that's 4:43 I did those lat length tests, she had restricted shoulder flexion but 4:46 pulling you into a posterior pelvic tilt, or laying your legs flat didn't change 4:51 anything. So pulling your legs this way didn't cause your arms to come up, laying 4:55 your legs flat didn't cause your lumbar spine to go into extension right, that's 5:01 a negative lat length test. But I came over here and she was still restricted 5:05 in internal rotation, then I know it's not my latissimus dorsi but my short 5:11 internal rotators that are causing a restriction in shoulder flexion. You 5:17 guys catch all that. So let me review this a little bit. If I had positive lat 5:23 length test, negative shoulder external rotation. So somebody had normal external 5:29 rotation, then it's probably just the lats. If I had positive lat length test, and 5:35 somebody had reduced shoulder external rotation, they had a limit in external 5:41 rotation, then it's probably not only the latissimus dorsi, but the subscapularis 5:45 and teres major. If I didn't get a positive lat length test, but I have a 5:51 restriction in external rotation, then it's probably the subscapularis and teres 5:56 major, and not the lats. Now on a side note, if we take this back to movement 6:02 impairment, generally speaking the only time I find 6:06 that the lats are tight without the subscapularis and teres major coming along 6:13 for the ride, is when latissimus dorsi over activity is not stemming from upper 6:20 body dysfunction, but from lumbo-pelvic hip dysfunction. 6:24 In other words somebody has an anterior pelvic tilt maybe with some low back 6:29 pain, and you notice limited shoulder flexion, however that limited shoulder 6:37 flexion is caused from over activity of the latissimus dorsi as a lumbar 6:41 extensor, and your intervention, your corrective exercise, your physical 6:45 therapy, your therapeutic modalities should be focused on trying to fix an 6:50 anterior pelvic tilt, not this. I'm willing to bet that if it's upper-body 6:55 dysfunction that's causing the limit in shoulder flexion, but not only will your 7:01 lats be tight, but so will your teres major, and your subscapularis along with 7:06 potentially your anterior tippers of your scapula. Now if you guys want to 7:10 know how to differentiate between lumbo-pelvic hip complex and upper body 7:14 dysfunction, go check out the videos on the overhead squat assessment, 7:20 particularly the overhead squat assessment sign clusters. You'll see one 7:26 for upper body dysfunction, one for lumbo-pelvic hip dysfunction, one for 7:29 lower leg dysfunctional, one for asymmetrical weight shift. Go over the 7:32 ones for upper body and lumbo-pelvic hip. I think you'll be able to differentiate 7:37 those two dysfunctions, go back and start thinking about the lat length test 7:41 versus external rotation goniometry, and think about how those play out positive 7:48 or a negative lat length test, restricted or normal external rotation. I think 7:54 before you know it you'll have a shorter list of muscles that could be 7:59 restricting this motion. Which means less release techniques, less lengthening 8:03 techniques, and less mobilization techniques that you'll need, which means 8:06 a more refined program, a more effective program, a more efficient program and 8:11 hopefully better results. I'll talk with you guys soon. 8:21
