Most of our skeletal muscles span across two or three joints. When the muscles contract, they will move the joints and create movement. To train individual muscles, you simply move the joint against resistance. At least this is the principle behind strength training. Want a bigger biceps? Do more bicep curls! We learn this in highschool biology!
Based on this understanding, the classic recipe of getting a solid washboard abs is to do lots of crunches and sit-ups. If you want to have strong backs, do Jefferson Curls.
What Is The Problem
As they say, the devil is ALWAYS in the details. Moving individual joints may be great for individual muscle hypertrophy, but it may not always be great for joint health. Any first year biology undergraduate student can tell you that there is a spectrum of joints in our body based on its mobility and stability. The more mobile the joint, the less stable it is.
Some of these joints are built for power production (i.e. speed and strength combined) while others are built for stability. Some joints are simply stronger in certain position than at other position. The spine has many joints that allows movement. Execute too many movement under load, say sit-ups or Jefferson curls, and you will end up with spine disk herniation. There’s a reason why career powerlifters and olympic weightlifters would not move their spine while lifting weights off the floor.
Your typical undergrad should also be able to explain that there are three types of work that can be done by muscles:
- Concentric. Such as when you curl up in a bicep curl.
- Isometric. Such as when you hold the barbell at 90 0 angle without moving.
- Eccentric. Such as when you lower the barbell in a bicep curl.
And here is where wisdom comes into play. Training all the muscles the same way will simply result in chronic pain. For those of you with low back pain, it is easy for the doctor or physiotherapist to say “you need more core strength”. Its another thing to train your core with proper exercise in proper posture. For those that need to train their core to alleviate their low back discomfort, Back Mechanics is an excellent source. The push up is a good exercise to train your upper body and core as long as you train properly.