Brian Schiff’s Blog
Injury Prevention, Sports Rehab & Performance Training Expert
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Kettlebells are very popular training tools these days. I find them useful in many ways – improving grip strength, core activation, asymmetrical loading, etc. With that said, I also feel with movement flaws and/or improper technique, they carry an inherent injury risk.
It is interesting to note that some people find swings to be very therapeutic and good for their back, while others who are capable of lifting very high loads with traditional lifts find them to be irritating to the spine. So why is this?
If you are like me, knowing the “why” or “cause and effect” behind exercise is very important. I am not one to blindly use an exercise without knowing its intended purpose and then quantifying risk vs. reward and results. So, it was with great interest I read Stuart McGill and Leigh Marshall’s recent article on kettlebell swings, snatches and bottoms-up carries in the NSCA Journal of Strength & Conditioning Research (Jan 2012).
While the sample size is small, I think the article provides some gems in regard to training given no one has really looked at spine loading during various swings and carries. The authors used surface EMG to record muscle activation of the back, hip and core muscles throughout the various exercises – swing, swing with Kime (abdominal pulse at top of the swing), swing to snatch, racked carry and bottoms-up carry.
Without going into all the tiny details, I wanted to share what I consider to be some key takeaways for rehab and training:
- Unlike traditional low back extension exercises such as lifting a bar or squatting exercises, the swing creates a relatively high posterior shear force (namely L4 on L5) in relation to the compressive load – this may explain why some powerlifters have no issues with heavy dead lifts but are bothered by swings
- Both compressive and shear forces were highest at the beginning of the swing
- From a compressive standpoint loads with a 16 kg kettlebell (swing) are less than one-half of that of lifting 27 kg on an Olympic bar and these would seemingly pose a low relative injury risk
- KB swings do appear to require sufficient spine stability in this shear mode to ensure that is is a “safe” exercise selection
- Those with back pain develop movement flaws and the authors report one of the most common is to move the spine under load instead of the hips – so instead of hip hinging, injured clientele are more apt to shift or bend the spine leading to repetitive and harmful forces
- A modified approach to swings with careful cueing and progression is suggested for clinicians
- The bottoms-up carry poses more challenge to the core musculature likely due to requiring more grip strength (thus stiffening the core per McGill in Ultimate Back Fitness & Performance) as well as necessitating more control to carry it, hence making it a good choice for training in terms of activation of these muscles
So, in my mind kettlebell training (like any other form of training) requires proper form, movement assessment and an intimate knowledge of the client’s medical and training history. In addition to that, we must carefully scrutinize execution of the exercise and deliver appropriate feedback and analysis.
While maximal shear occurs at the bottom, I cannot help but wonder about the potential impact of tight iliopsoas muscles given their unique relationship to the lumbar spine and reverse muscle action. It would be interesting to know if those with a greater anterior tilt and tightness are more likely to experience higher shear forces or potential back soreness over time.
This brings the discussion back to quality of movement and movement assessment. In my mind, adequately assessing the hips (flexibility, strength and stability) is also a key variable in determining how best to approach integrating the swings. As Gray would say, the lumbar spine needs stability while the hips require mobility.
A lack of hip mobility is definitely a relative precaution for swings in my mind. On top of that, fundamental hip strength/stability and core strength should be evident. Perhaps even regressing to rudimentary hip thrusts and bridges may be the best place to start for those needing a primer on form and proper movement before moving to a basic swing.
Nonetheless, a big thanks to Stuart McGill and Leigh Marshall for this work and giving us some practical food for thought. I hope this information helps you as much as it did me. May your training be safe and effective!
I think it is safe to say most would agree that deadlifts are great for building maximal lower body strength. Elite Olympic weightlifters are generally able to lift more loads in this lift compared to other free weight exercises. I know personally that I like to use it to develop lumbar extensor strength, as well as in place of the squat if I want to avoid spinal compression from the weight of the bar.
In the past I have heard some strength coaches say they don’t use a hex bar for deadlifts because it is not the same as lifting a straight bar. While not always sure exactly what they mean by that, I found a recent article in the July 2011 Journal of Strength & Conditioning Research very insightful. The researchers looked at the difference between straight and hexagonal bar deadlifts in submax loading situations.
The concern with deadlifting has always been stress on the spine. The study notes:
“For world class athletes lifting extremely heavy loads, lumbar disk compression forces as large as 36,400 N have been reported.”
Lifters have long been encouraged to keep the barbell as close to them as possible to reduce the moment arm. The issue with the straight bar is that it can impinge on the body. Thus, the trap bar or hex bar apparatus was developed. The researchers hypothesized that the hex bar would reduce the joint movements and resistance moment arms. In addition, they hypothesized that larger forces would be produced with the submax loads.
The study use 19 male powerlifters and was conducted 3 months after their most recent competition where most were at the end of a training cycle aimed at matching or exceeding their previous competition performance. The subjects (following their own warm-up) performed HBD and SBD at 10, 20, 30, 40, 50, 60, 70 and 80% of his SBD 1RM. Twelve markers were placed on the body for biomechanical analysis.
So, have you ever experienced pain in the buttock that radiates down into the thigh? Maybe even felt some numbness and tingling? Recently, I was contacted by an experienced marathoner who has been plagued by pain in the buttock and posterior thigh. He self diagnosed himself as having piriformis syndrome after doing some research on the Internet. So. what is piriformis syndrome?
Some experts debate whether it truly exists, but essentially, it involves the piriformis, a small pear shaped muscle in that helps externally rotate (turn out) the hip and the sciatic nerve which runs down the entire back of the leg and is responsible for sensation and motor movement patterns of many of the muscles in the lower leg.
It is suggested that in this syndrome the sciatic nerve essentially becomes compressed or irritated by a tight piriformis muscle. The sciatic nerve travels above, below or even through the piriformis muscle itself based on anatomical studies.
Some have even suggested that prolonged sitting with the hips turned out or sitting on a wallet can contribute to this problem. I even remember being told in PT school that it is more common in truck drivers. With that said, I think I can count on one, if not both hands the number of patients I have seen in 15 years that I truly believe had piriformis syndrome.
Now back to my runner. He began having pain in his left buttock and hamstring in late December after seeing a trigger point specialist who suggested he had a tight piriformis and did some deep tissue work on it. A short time afterward, he began having symptoms. He saw a physical therapist for 2-3 sessions and was given some stretches to do. Meanwhile, he began getting deep tissue massage focused on the area in January and February.
Most adult males are in search of that ever elusive six pack, right? Well, most intelligent trainers and strength coaches are well aware that there is so much more than just crunches to making the core functional.
With that said, I believe abs may be one of the most over trained sets of muscles today. Some people are doing ab work daily. Why? Our abs function daily to stabilize and resist force, as well as activate trunk movements.
In reality, the aesthetics of the midsection have far more to do with nutrition and body fat than the number of crunches one does. My aim today is not to discuss this, but instead to talk about an interesting article in the latest Strength and Conditioning Journal that discusses the effects of over training the rectus abdominis on weightlifting performance.
In this article, Ellyn Robinson discusses the best way to allow athletes to stabilize weight overhead during complex lifts such as snatches, cleans and jerks. She aptly points out that if an athlete cannot stabilize the weight overhead, he/she could miss the lift in front or behind the body.
So, for Labor Day 2010, I decided to take my family to Kings Island. I have always been a fan of thrill rides and it has been well over a decade since I had been to Kings Island. It was also before I have experienced more than one bout of sciatica.
My nieces live nearby and they agrred to watch my sons for a brief time while my wife and I headed off to ride some of the bigger rides. I insisted we ride the Beast – a coaster classic by any standards. It is the world’s longest wood coaster and lots of fun.
What I failed to remember was just how much jarring and abuse the good ol’ Beast could inflict on one’s body in those tiny little cars. After 4 minutes of fun, it all came back to me. For those who don’t know, I have been training for a marathon and admittedly after most 19 plus mile runs (I did one on Sunday) my back is stiff for a day or two.
Perhaps riding the Beast (and the Racers too at my wife’s insistence) the day after a long run was not such a wise move. 🙂 I woke up this morning with what I term “old man back.” Now while that may sound funny, to anyone who has experienced it, you know how unpleasant it is.
I crawled out of bed and managed to teach a boot camp class at 5:30 AM without incident. Beyond the stiffness, my day has been marked by difficulty bending forward and lots of ice. I am not complaining as much as I am telling you that as we get older (unfortunately I mean older than age 30) our shock absorption qualities in the spine begin to decline.
You see, our discs between the vertebrae act as a cushion and help prevent injury. But, as we age, they naturally begin to degenerate in our thirties (degenerative disc disease – bummer). This ultimately means we are more vulnerable to harmful forces and stress on the spine. Ever wonder why those signs warn you not to ride if you have neck or back pain?
It is likely the sudden torque, twists, turns and bumps that may leave you feeling rough then next day. Am I saying not to ride? NO!! I love coasters. I will be back at it again in the near future. What I am saying is know your own personal situation and if you have some past back issues like me, be prepared to endure “old man back” for a few days as you hit the theme parks.
I will be over it in a day or so. As a matter fo fact I ran 4 miles today with no pain. Some keys to spinal fitness are:
- Practice good body mechanics with bending, lifting, sitting, etc.
- Don’t sit too much without standing up. Our bodies need balance, and too much sitting (flexion) is bad for the discs in the back. Be sure to stand up no less than once per hour as your back craves to be in extension an equal amount of time. Standing back bends (sets of 5-10) is a great way to improve spinal fitness if you have a desk job.
- Stretch and strengthen the abdominals, but avoid full sit-ups.
- Strengthen the low back muscles and hips.
- Avoid flexion and rotation moments.
In the end, if you have a flare-up, then use ice and let pain guide your movements. One last tip: stick to the steel coasters for a smoother ride!
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