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Latissimus Dorsi Length Test (Muscle Length Test)

Learn how to perform the Latissimus Dorsi Length Test to assess the length of the back and shoulder muscles for physical therapy. Step-by-step instructions and demonstrations included in the video.

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00:04 - 00:07This is Brent of the Brookbush Institute, bringing you another muscle
00:07 - 00:11length test. In this video we're going to do the lat length test.
00:11 - 00:16Now the lat length test we use to determine if the latissimus dorsi is one
00:16 - 00:19of the muscles restricting shoulder flexion. I'm then going to show you some
00:19 - 00:24of the if-then scenarios, that will help you determine whether the lats, the
00:24 - 00:29shorter internal rotators of the shoulder, or both are involved. I'm going
00:29 - 00:36to have my friend Melissa come out, she's gonna help me demonstrate. So what the
00:36 - 00:42lat length test really is, is a shoulder flexion test. It's just a very quick
00:42 - 00:47shoulder flexion test, just like shoulder flexion goniometry. Alright so what I'm
00:47 - 00:50gonna have you do, sorry start here, laying flat. I'm going to have you try to
00:50 - 00:57bring this part of your forearm back to the table in front of you. Alright
00:57 - 01:01there you go, so you guys see. We know that normal shoulder flexion is between
01:01 - 01:05100 and 185 degrees, so she's missing some shoulder flexion right.
01:05 - 01:11The lat length test part comes in and it goes, if you really push it, can you
01:11 - 01:15push it, just go all the way down to the table, go for it. Alright she pushes
01:15 - 01:21her arms down and does this, did you guys see all this lumbar extension. I have to
01:21 - 01:25start thinking to myself all right the muscles that could restrict shoulder
01:25 - 01:31flexion, I got the teres major, subscapularis, the latissimus dorsi
01:31 - 01:37pectoralis major probably not likely in this position. Of those muscles, which one
01:37 - 01:41crosses the lumbar spine, well the lattisimus dorsi crosses the lumbar
01:41 - 01:46spine. Not only does it cross the lumbar spine, but it will cause lumbar extension,
01:46 - 01:52which is exactly what I saw. So when I told Melissa to go ahead and push it, or
01:52 - 01:55I could even add a little overpressure, obviously you wouldn't want to do that to a
01:55 - 01:59painful shoulder. But if you added a little overpressure and it pulled her into
01:59 - 02:04lumbar extension, I know that she ran out of room from her lats, and had to shorten
02:04 - 02:08it somewhere else. So this would be a positive lat length test. I know that the
02:08 - 02:13lats are one of the structures that could be restricting her shoulder
02:13 - 02:15flexion. There's another way to go about this,
02:15 - 02:18we'll start over. This time we'll put her in a hook lying
02:18 - 02:23position. Now hook lying position posteriorly tilts the pelvis a little bit,
02:23 - 02:27flattens up the lumbar spine and it kind of anchors the pelvis
02:27 - 02:32a little bit, so that lumbar extension is not as easy to get in this position. Now
02:32 - 02:37I have her go ahead and pull this way, and usually what you'll have is in that
02:37 - 02:42same individual, somebody will actually look like they're even more restricted
02:42 - 02:47and shoulder flexion. I could test to see how much the lats are contributing to
02:47 - 02:52this by going okay, let's go ahead and bring your legs up, push you into a
02:52 - 02:57posterior tilt, and you guys see how when I pushed her into a posterior tilt her
02:57 - 03:02arms came up a little bit. That's a pretty good sign that her lats are
03:02 - 03:08contributing to the restriction on her shoulders. So that's all the lat length
03:08 - 03:13test does. Is the lat one of the muscles restricting shoulder flexion, the problem
03:13 - 03:18with that is, is it doesn't do all that much for us from a practical application
03:18 - 03:22standpoint. I still don't know if it's subscapularis and teres major
03:22 - 03:28contributing to this. So how would I figure that out? Well I could go back to
03:28 - 03:36my goniometry, if you guys remember shoulder external rotation is done here.
03:36 - 03:42Alright, why shoulder external rotation? Well subscapularis, teres major,
03:42 - 03:47latissimus dorsi are all internal rotators. But if i go and put the arm
03:47 - 03:52back in ninety degrees of shoulder abduction, i just shortened the lats a little
03:52 - 03:56bit right. It's like halfway through a lat pulldown. So these structures that
03:56 - 04:01are more likely to restrict this range of motion in this position are the
04:01 - 04:09shorter external rotators. So if I had positive lat length tests, and then I did
04:09 - 04:15external rotation and she had full 95 degrees, I might be able to deduce that
04:15 - 04:20it's the lats restricting her shoulder flexion, and
04:20 - 04:27the short internal rotators, teres major and subscapularis. If I had a
04:27 - 04:31positive lat length test and she only had 85 or 80 degrees of shoulder
04:31 - 04:36external rotation, then I know it's probably teres major, subscapularis and
04:36 - 04:43latissimus dorsi. If I had a negative lat length test right, so that's
04:43 - 04:46I did those lat length tests, she had restricted shoulder flexion but
04:46 - 04:51pulling you into a posterior pelvic tilt, or laying your legs flat didn't change
04:51 - 04:55anything. So pulling your legs this way didn't cause your arms to come up, laying
04:55 - 05:01your legs flat didn't cause your lumbar spine to go into extension right, that's
05:01 - 05:05a negative lat length test. But I came over here and she was still restricted
05:05 - 05:11in internal rotation, then I know it's not my latissimus dorsi but my short
05:11 - 05:17internal rotators that are causing a restriction in shoulder flexion. You
05:17 - 05:23guys catch all that. So let me review this a little bit. If I had positive lat
05:23 - 05:29length test, negative shoulder external rotation. So somebody had normal external
05:29 - 05:35rotation, then it's probably just the lats. If I had positive lat length test, and
05:35 - 05:41somebody had reduced shoulder external rotation, they had a limit in external
05:41 - 05:45rotation, then it's probably not only the latissimus dorsi, but the subscapularis
05:45 - 05:51and teres major. If I didn't get a positive lat length test, but I have a
05:51 - 05:56restriction in external rotation, then it's probably the subscapularis and teres
05:56 - 06:02major, and not the lats. Now on a side note, if we take this back to movement
06:02 - 06:06impairment, generally speaking the only time I find
06:06 - 06:13that the lats are tight without the subscapularis and teres major coming along
06:13 - 06:20for the ride, is when latissimus dorsi over activity is not stemming from upper
06:20 - 06:24body dysfunction, but from lumbo-pelvic hip dysfunction.
06:24 - 06:29In other words somebody has an anterior pelvic tilt maybe with some low back
06:29 - 06:37pain, and you notice limited shoulder flexion, however that limited shoulder
06:37 - 06:41flexion is caused from over activity of the latissimus dorsi as a lumbar
06:41 - 06:45extensor, and your intervention, your corrective exercise, your physical
06:45 - 06:50therapy, your therapeutic modalities should be focused on trying to fix an
06:50 - 06:55anterior pelvic tilt, not this. I'm willing to bet that if it's upper-body
06:55 - 07:01dysfunction that's causing the limit in shoulder flexion, but not only will your
07:01 - 07:06lats be tight, but so will your teres major, and your subscapularis along with
07:06 - 07:10potentially your anterior tippers of your scapula. Now if you guys want to
07:10 - 07:14know how to differentiate between lumbo-pelvic hip complex and upper body
07:14 - 07:20dysfunction, go check out the videos on the overhead squat assessment,
07:20 - 07:26particularly the overhead squat assessment sign clusters. You'll see one
07:26 - 07:29for upper body dysfunction, one for lumbo-pelvic hip dysfunction, one for
07:29 - 07:32lower leg dysfunctional, one for asymmetrical weight shift. Go over the
07:32 - 07:37ones for upper body and lumbo-pelvic hip. I think you'll be able to differentiate
07:37 - 07:41those two dysfunctions, go back and start thinking about the lat length test
07:41 - 07:48versus external rotation goniometry, and think about how those play out positive
07:48 - 07:54or a negative lat length test, restricted or normal external rotation. I think
07:54 - 07:59before you know it you'll have a shorter list of muscles that could be
07:59 - 08:03restricting this motion. Which means less release techniques, less lengthening
08:03 - 08:06techniques, and less mobilization techniques that you'll need, which means
08:06 - 08:11a more refined program, a more effective program, a more efficient program and
08:11 - 08:15hopefully better results. I'll talk with you guys soon.
08:21 - 08:23

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