I only train my core isometrically. Without movement. No sit-ups, no side bends, no toes-to-bars, no Russian twists, none of that. I do this for two reasons: safety and functionality.
Firstly let’s look at the spine. It is made up of a series of bony vertebrae with vertebral disks in between them. Vertebral disks are made of two parts, the outer, solid layer called the Annulus Fibrosis, and the inner, viscous layer called the Nucleus pulposus. A herniation occurs when the inner layer pushes its way out through the outer layer, often (very painfully) impinging a nerve coming off the spinal cord. I don’t need to tell you that as an athlete, you don’t want this. No one does. If you do herniate a disk and it hits a nerve root, you’re looking at a lot of pain, rehab, and potentially months off of your sport.
Core exercises that involve movement of the spine increase your chances of suffering a disk herniation. Research shows that repeated spinal flexion (bending forward) is needed to cause disk herniations . If a researcher wants to herniate a spine specimen, they will put it through thousands of cycles of flexion and extension with moderate compression. That is exactly what you are putting your spine through every time you do a sit-up or a poorly executed back extension on a GHD (compression in this case is caused by your own core muscles, think of each vertebrae as a book stacked on top of another, your muscles squeeze down on the stack of books to keep them from falling over). Why would you put your spine through that? There are several safer, more effective alternatives to train these muscles.
Research also shows that repeated twisting also makes you more vulnerable to a herniation by slowly wearing away at layers of the annulus fibrosis, making it easier for the nucleus pulposus to herniate . Sure, Russian twists are working your obliques, but at what cost?
The human spine is very good at absorbing compressive forces, the vertebrae–disks and vertebral curves all allow for this. The spine is not, however, nearly as good at handling forces like shear. For example NIOSH, a health and safety board recommends a spinal compression force of no higher than 3400N during work tasks, while the limit for shear forces is only 1000N . The exact numbers are not important, but safety experts agree that our spines are about 3.5 times better at handling compression than they are shear. Excessive shear becomes a problem when the spine is fully flexed forward (think sit-ups, toes-to-bars, etc). These exercises definitely do a good job of working your rectus abdominus, but not without introducing potentially dangerous and unnecessary shear forces on your lumbar spine. Exercises that keep the spine in neutral or near neutral are safer because they put the spine in a position to handle forces compressively instead of introducing shear forces.
At this point is when someone would usually say something along the lines of “Well I do exercises X and my back is fine! This can’t be true.” Your back may be fine if you’re doing these exercises now, but it may not be in the future. You may be fine in the future too even if you continue to do these exercises, but you are definitely increasing your risk by continuing to do so. To succeed in any sport, you need to stay healthy. There is no reason to put your spine through potentially dangerous exercises when safer alternatives exist (more on these alternatives later). Also, you should keep in mind that the absence of pain does not mean the absence of injury. Only the outer layers of the annulus fibrosis contain sensory nerve fibers , so during the early stages of a herniation, pain would not be an issue.
Almost every sport I can think of requires a core that is neutral or near neutral (don’t think of neutral as a perfect position, think of it as a certain small range of motion around that position), and a core that is braced isometrically. The only example I can think of where this isn’t true is gymnastics (but gymnasts are freaks of nature, so let’s ignore them) and maybe swimming or rowing. I’m sure there are more, but that doesn’t really matter. Most sports require a neutral, isometrically braced spine.
This is especially true of strength sports. The squat, Snatch, and Clean & Jerk all require a neutral spine that is braced isometrically. Those who bench with an arch won’t have a neutral spine and some deadilfters prefer pulling with their spine in a little bit of flexion, but both of these exercises definitely require the spine to be braced isometrically. If strength athletes always need isometric core strength, the majority of their core training should be isometric as well. Since the spine is capable of moving in three different planes, the core should be trained isometrically resisting motion in all three of these planes. You should select exercises that resist flexion and extension (bending forward and backwards), lateral flexion (bending to either side) and rotation (twisting). Below is a list of exercises that I have had good success with implementing in my training, that challenge the core in all three planes of motion. Assuming you have the basic stability needed to do them, these exercises are a solid foundation.
This list if by no means exhaustive. Get creative and find what works for you.
At the end of the day, you can train your core muscles in whatever way you want to train them. Just be aware of the risks and rewards that come with your choice of exercises and take this information into consideration before your next core workout; it’s probably not worth it. Stay safe!
Toxic is bad. Or is it? New studies of seagrasses reveal that they are surprisingly good at detoxifying themselves when growing in toxic seabed. But if seagrasses are stressed by their environment, they lose the ability and die. All over the world seagrasses are increasingly stressed and one factor contributing to this can be lack of detoxification.
Seagrass meadows grow along most of the world’s coasts where they provide important habitats for a wide variety of life forms. However in many places seagrass meadows have been lost or seriously diminished and in several places, researchers and authorities work hard to understand what is happening and prevent the seagrasses from disappearing.
Now biologists from SDU add another important piece to the understanding of sea grass life.
It has long been known that the toxin sulphide is part of the threat to seagrasses. Sulphide is a naturally occurring toxin found in the seabed where seagrasses grows. The seabed is characterized by lack of oxygen and a smell of rotten eggs from sulphides.
A widely held theory states that seagrasses cannot tolerate sulphide and that increasing amounts of sulphide due to increased pollution have a negative effect on seagrasses.
Sulfide is absorbed by plant tissue
“But our research shows that seagrasses are actually capable of protecting themselves from sulphide. In fact, seagrasses benefits from sulphide”, explains postdoc Harald Hasler-Sheetal who has conducted the research together with Professor Marianne Holmer, both from the Department of Biology, University of Southern Denmark.
against app. two thirds of the sulphide that enters the plant from toxic seabed. The last third is absorbed by the plant’s tissue and here enzymes convert the sulphide into beneficial nutrients.
But the discovery that a seagrass can protect itself from sulfide does not mean that all is good.
"Seagrasses cannot tolerate sulphide under all circumstances. If a seagrass is stressed, the plant’s capacity to detoxify itself will weaken, and the plant will be less capable of protecting itself from sulphide. It’s like when humans are stressed; then we cannot perform optimally. Stressed seagrasses grow slower and may die back – this is what we see in many parts of the world”, explains Harald Hasler-Sheetal.
A character that revolves around the theme of holding back your emotions or feelings. A kind and slightly naive boy who was bullied for uncontrollable and frightening hallucinations, he uses the name Kiz in attempt to reclaim the nickname his bullies used on him.
in death his bitterest regret was not being able to show others what he sees. Understanding deep down that this won’t solve his problem and ashamed of the power he is given to bring his art to life, he only draws nonobjective things, afraid his thoughts can hurt others as they hurt him.
As his works are manifestation of thoughts, they do not have the lifespan of real things. But they are capable of inflicting very real fear and danger, and Kiz views himself a monster unworthy of love, bottling up his feelings until the things he wanted to express leak out of him.
“I’m sure you hear often that there is an invisible thread that connects us, but humans are not stationary objects.
In reality, if the heart were to be represented by a ball of yarn, our constant interactions with the world around us snag and tangle the string of our souls until the spool is empty and we can move no more. That is what we call ‘death’ in the human world.
If you think of it this way, death happens when we have spread ourselves thin through the world, or it happens quickly and abruptly; when the string is severed prematurely. But even then, it is not fair to say everyone’s heart is the same as string on a spool.
Some people lay the faintest of threads in their path, like a spider slowly spinning a web, unnoticed and unknowingly changing the world around them.
Some people trail thick ribbons throughout the world, pulling others closer and bandaging their wounds before the ribbons decay, as all bonds eventually will.
Some people’s souls are like vines, winding their way around the limbs of those nearest to them and slowly choking them to death.
Some people sew holes into history, leaving stitches in time that linger long after death.
But some people’s souls are like anchors, their heavy hearts dragging chains behind them.
Nobody can see the path they lay, nor the paths of others entangled in their wake. Do not underestimate your own significance in this world.”