Re: preserving knees and shoulders....
The main flag I see in your story is the bench press. I don't like it at all as an exercise. To start with, you rarely push anything heavy horizontal to your body in real life. A push up is about the most you'll ever do pushing in that direction. When standing, it simply doesn't work, as it only takes a few pounds of force to tip you over backwards. When you push something heavy, you have to lean way over - you end up configuring your body into what is basically an overhead push.
By putting a bench behind your back, you are making an artificial movement pattern into a heavy exercise. Worse, unlike an overhead press or a push up, the bench acts as a crutch in stabilizing the scapulae, allowing a whole bunch of shoulder girdle stabilizers to get a free ride. They can eventually become weak in relation to the strength of muscles stressed built by the bench press, and you can end up with serious imbalance in the shoulder - an injury waiting to happen. Many people find ways to balance this out somewhat with other exercises in their routine, but I would rather just avoid exercises that are not inherently sound altogether.
As far as the heaviness of squats, the topic here is how to keep your knees and shoulders healthy for Aikido. Squatting with the addition of double your body weight is a bit overkill for this purpose. I doubt most people would even need to lift with the addition of their bodyweight - somewhere in the half to full bodyweight range is probably fine.
The rep range determines what body systems you are training, and which energy systems get worked. The spectrum is roughly divided into named categories. Low reps (~1-6) work strength and short term energy systems, higher reps (~7-12) work strength-endurance and medium term energy sytems. Above about 15 reps, it starts to become aerobic endurance training.. Very low reps train the shortest-term energy system and heavily stress the nervous system. Heavy 1RM compound lifts can take over a week to fully recover from, neurologically. Pushing a 5RM set to concentric failure, or beyond, using assisted reps, partials, negatives, etc...can have a similar effect. This is the main reason so many people have overtraining problems with weights, and end up stagnating or getting chronic problems. Overtraining, and the chance of acute injury during the lift itself are the main reasons most people probably shouldn't mess with this stuff. For general conditioning, it's not necessary.
Last edited by Kevin Wilbanks : 08-19-2007 at 03:33 PM.