Low back pain and asymmetry.

Do oarsmen have asymmetries in the strength of their back and leg muscles?
IF these oarsmen were more symmetrical would they not be in pain?

From the study below:
"Patterns of asymmetry of muscle activity were observed between the left and right erector spinae muscles during extension, which was significantly related to rowing side (P < 0.01). These observations could be related to the high incidence of low back pain in oarsmen."

Here we have a supported study of asymmetry and injury/pain. This is what we have been saying (asymmetry matters) in the last few days with our posts on asymmetry. This study eludes to a finding that strength can test normal and symmetrical, but EMG activity can show patterns of asymmetry that can result in problems/pain.

Have you ever rowed? I mean truly rowed, in a shell, on the water, not on land or on a Concept 2 rower? It is just not the same, especially if you have an unilateral asymmetrical loading arc, like an oarsman pulling from port or starboard. I have rowed on the water just like this, briefly, one summer in a camp for young teens. I rowed on my home town course, on the World famous Royal Canadian Henley Regatta. I was the 2nd seat, starboard, in an 8 man shell. 8 oars in the water, 8+1 guys, one oar a piece, alternating port and starboard. I was behind the stroke. I hated it. Perhaps the hardest thing I had ever done sport wise to that point, largely because this dude setting the pace was jacked on caffeine, or something else, I think. No one works harder than rowers if you ask me, they are some of the fittest athletes in the world. Why? because it is a whole body effort.
Ok, enough of the fluff.

Now imagine rowing like this for many years in high school, college and/or competitively. Forcefully pulling on one oar, across an arc of pull out one side of the boat, thousands of times a day for many years. If that isn't something that will develop asymmetry I do not know what might. Oarsman are under near constant high end effort pushing and pulling loads (push with the legs, pull with the arms). There are few, if any, sports with such high end constant effort than rowing.

From the Parkin et al study:
"The aim of this study was to establish whether asymmetry of the strength of the leg and trunk musculature is more prominent in rowers than in controls. Nineteen oarsmen and 20 male controls matched for age, height and body mass performed a series of isokinetic and isometric strength tests on an isokinetic dynamometer. These strength tests focused on the trunk and leg muscles. Comparisons of strength were made between and within groups for right and left symmetry patterns, hamstring: quadriceps ratios, and trunk flexor and extensor ratios. The results revealed no left and right asymmetries in either the knee extensor or flexor strength parameters (including both isometric and isokinetic measures). Knee extensor strength was significantly greater in the rowing population, but knee flexor strength was similar between the two groups. No difference was seen between the groups for the hamstring: quadriceps strength ratio. In the rowing population, stroke side had no influence on leg strength. No differences were observed in the isometric strength of the trunk flexors and extensors between groups, although EMG activity was significantly higher in the rowing population. Patterns of asymmetry of muscle activity were observed between the left and right erector spinae muscles during extension, which was significantly related to rowing side (P < 0.01). These observations could be related to the high incidence of low back pain in oarsmen."- Parkin et al.

Extra sauce:
I "caught a crab" many times when a novice oarsman and was nearly vaulted out of the boat on one fatal event. A crab is the term rowers use when the oar blade gets “caught” in the water. It is caused by a momentary flaw in oar technique and the paddle end of the oar is pulled into the depths instead of skimming just below the surface. Catching a crab has happened to anyone who has ever rowed. A crab may be minor, allowing the rower to quickly recover, or it may be so forceful that the rower is ejected from the boat as the handle end catches the oarsman under the arms lifting them out of the boat.

J Sports Sci. 2001 Jul;19(7):521-6.
Do oarsmen have asymmetries in the strength of their back and leg muscles? Parkin S1, Nowicky AV, Rutherford OM, McGregor AH.