First up is a ground breaking study by Dr. Stuart McGill, the foremost researcher on back/core biomechanics in the world at the University of Waterloo. If you want to know the best way to train your core and keep a healthy back (or fix one), go out and read anything you can find by this guy.
This study (23(4)/1148-1161) is a comparison of different strongman events on trunk muscle activation and lumbar spine motion, load, and stiffness. They wired some elite strongman competitors with EMG monitors to precisely measure which muscles were working hardest, when, and what kind of stress was put on the spine.
The six events were farmer's walk, yoke walk, Atlas stone lift, suitcase carry, keg walk, tire flip, and log lift.
Condensing the results for you here it's apparent that picking up a heavy object with a rounded back (Atlas stone) places a ton of stress on the low back (why we deadlift with a straight back), but also shows why hip extensors MUST fire before the back extensors in order to prevent injury.
The yoke carry (carrying a loaded bar across one's back) placed the highest stress on the spine due to bar position (also why I don't favor back squats) and insufficient strength in hips to deal with the load. So carrying something on your back causes massive torso muscle cocontraction, so if core weakness is an issue this is most likely the position to cause injury.
The farmer's carry (carrying a heavy weight in each hand at one's side)and other carrying events placed unique stresses on the core and hip musculature, and in ways different than any lifting event which leads Dr. McGill to conclude that carrying weights would enhance any strength program.
*note* Strength coach Dan John, among others, have for years advocated carrying weights for distance or time as a part of any program.
Guess what my clients will continue to do?!
The second study was a joint project between The University of Memphis, Washington University School of Medicine, and Sports Biomechanics Lab at the University of Alberta.
This study (Journal of Strength and Conditioning Research 23(4)1211-1216) looked at the effects of unstable surface training (standing on bosu balls, airex pads, half rollers etc...) on measures of balance in older healthy adults.
Quoting the results:
Five weeks of unstable surface training does not seem to increase balance capabilities in older persons with normal balance. Thus far, the widespread use of such programs seems questionable in those who do not have balance difficulty.
Go to just about any gym and you'll see trainers putting just about everybody on some sort of rubber ball or pad and having them squat, press, or just stand there.
So folks, unless you are rehabbing some sort of lower body injury or neurologicial impairment getting on one of these pieces of equipment is a total waste of time and energy, not to mention money. The reason lifting something while standing on a bosu ball feels harder is because the unstable surface makes it harder to fully stabilize your torso, thus making you able to apply less force.
When your muscles can't apply as much force you will be weaker, thus allowing you to lift less weight. This means that if your goal is to look better, get stronger, lose weight, or gain muscle you are doing yourself, or your clients, a disservice and won't get the results you are after.
So get off the damn rubber balls, pick up something heavy and carry it around. Lift it over your head and squat with it, then walk around some more with it and leave the circus tricks to the clowns.
No more of this