The leg press machine I use is such that the legs are perpendicular to the spine, so there is no pressure on the spine along the body axis. The pressure is almost entirely on the heap joint and the pelvis (although it is along a non-natural direction, a point that was not discussed and might be of some significance).
I don't understand how this can be the case. There is rarely no pressure on your spine. Unless you hang upside down or lay on your back with your knees bent, there's pretty much always pressure. You get 3x the compression on your lower back just by sitting down.
Again, though, what's the problem with pressure on the spine? Why is it a bad thing, unless it's applied wrongly, of course.
The thing is you have to weigh the rare need for car pushing against the risk of not being able to even push even your chair due to a serious back problem... And anyway, that's what AAA is for... :-)
This makes the implication that those who use free weights will be prone to serious back problems when, actually, just the general population, in fact the majority, are almost certain to develop back problems. I would also question the notion that by choosing to lift heavy things via free weights that i'm "rolling a dice" with my health.
Also, the majority of "back injuries" occur when bending over, picking up low load items such as a pen or newspaper. Not lifting heavy things. The notion that lifting heavy weights = serious back problems just has no basis, in itself.
What's a serious back problem, anyway? Plenty of people get back to lifting heavy things and being pain free after spine fractures, bulges and herniations. More importantly and again, plenty of people who have zero symptoms are lifting or being athletic or physical with herniations and bulges yet have no idea. So I question the relevance that serious back problems have to squats, free weights, or lifting heavy things in general.
With regards to the AA/car comment - One of my clients, a 58 year old female who, up until 2 years ago had back pain for about 15 years, has requested to try and push and pull a car for some fun strongman style conditioning this summer (she knows another trainer and I go out the back during summer and pull cars/vans).
Getting stronger is empowering.
With that being said, the car comment was flippant, really. "functional" is like "toning", it means different things to different people and no one is really right or wrong.
no, it is exactly what physics says: If the power is given, the speed and force are inversely proportional (power being the multiplication of them).
I'm definitely not a physics pro so, i'm open to being criticised here but, I just don't get what you're saying. Doesn't force = mass x acceleration?
As far as I understand, the only way a slow bar speed can generate maximum force is if the load is really high (so the intent on lifting fast is still there). If you try and lift a heavy weight slowly, it will not move. However, a heavy weight will move slowly. What i'm criticising is light weights moving slowly and the claim that this some how generates maximum force.
Say your squat weight (including body weight) is 500 pounds, when jumping you will only push downwards 300 or so (just a number I picked) at the max. But in jumping you don't care about the force, you care about power summed over duration (i.e. energy that will translate to height).
I would say if it's a high enough box, it's going to end in disaster if you push with 300lbs of worth of your max. If you want to jump at a maximum height you better give it everything, as if 500lbs is on your back.... The same principle gets applied to speed/dynamic work. Light weights lifted with maximum force.
Training slow is a great way to, well, become slow, or slower. If we go back to our general population clients, and factor in that power is one of the first things to diminish with age, then i would be even more inclined to train the ability to move fast, to be explosive.
I'm enjoying the food for thought, though.
It's definitely interesting. Whilst I don't have a the majority of my clients do heavy BB back squats, it's not for the same reason. However most of my clients came to me with some kind of pain or injury, or history of pain or injury, or post pain or injury. It's became a niche of mine. I don't deal directly with pain, I have a good physio I work with, but I deal with lots of people in pain in conjunction with the physio. Therefore, I have a different perspective than what's being discussed here. Actually, the opposite end of the spectrum. Strength training and free weights are almost the basis for what I do with clients - if strength training is the basis, then movement is the "base". Movement as in, our primitive, instinctive, intuitive capacity to move efficiently that mother nature provided us with and modern lifestyle sucks out of us. I help people get that back and, when they get it back, I "cement" the ability with strength. When they get this, then the prospect of pushing a car sounds like fun rather than daunting :P
No one has ever been injured during any session with me and i've dealt and deal with some very physically delicate people*. I do a lot of (relatively) heavy lifting. Therefore, I take exception to the notion that i'm putting people at risk buy taking this approach as opposed to making it all machine based. My approach is nothing new, either, and is just my interpretation of borrowed principles and information from many great minds and pioneers in various fields.
*physically delicate people. There's 2 common things I see in the most frail of clients I work with. Poor movement and lack of strength. Movement is always first, though. I think the forest is being missed for the trees. Or the messenger is being shot instead of the culprit (the messenger being free weights/ back squats).