The toughest part about posts covering the science behind what goes on in the gym is finding interesting topics that can covered in less than 600 words! How our muscles work is one such topic. Personally, I had no clue until I got my CSCS. It is incredibly interesting and complex stuff and with that certification, and having completed my first graduate level class in Anatomy & Physiology, I can safely say that I know enough to at least blog about it 🙂 Still though, it’s a huge topic and can easily take an entire chapter of a college level textbook, or even an entire book if we’re talking about the entire musculoskeletal system. Lets focus this post just on contraction though. I’m going to cheat a little bit and leave you with a great YouTube video (below) that covers it in detail. Here are a few things to keep in mind as you watch the video:

• Skeletal muscle is what we’re concerned with at the gym.
• Muscles never push, they only pull. Seems odd at first but even with something like bench press where you’d swear your muscles are pushing, your triceps are pulling your arms to straighten them out and your pecs are pulling your shoulders in towards the body. The combination of these two pulling motions effectively pushes the resistance upwards.
• Near the beginning of the video they show the neuron, neuromuscular junction, etc. A very interesting point here has to do with how our nervous system coordinates the firing of these neurons. Which motor units are fired and in what sequence is critical for the efficient contraction of the muscle. When we first learn a new exercise and feel clumsy or weak, its because our neuromuscular system hasn’t yet learned which units to fire and in what order to complete the movement optimally.This is all part of neuromuscular adaptations, another incredibly interesting topic. If you’ve been lifting for a while and try something brand new, you can actually see and feel this happening just after a few sets of doing something new. Don’t believe me, try doing Renegade Rows for the first time with Kettle Bells!
• There are a lot of theories on what exactly cases soreness (no its not lactic acid) but the leading theory is that it’s the result of damage that you’ve done while working out, and the subsequent repair process. That damage is in the form of small tears to the filaments in the video, Myosin and Actin (well, there’s a little more to it than just that but for summary sake that close enough). So when you are watching these guys in action during the video imagine them working so hard that some of them are actually damaged!

Happy Lifting!