45 & Thrive: Contraction action – Key movement terms at the core of strength training programs

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When one is new to fitness training, or returning after a significant period of time, then considering possible programs, meeting with personal trainers, or even Googling various training protocols can seem daunting – especially when one is trying to keep track of some of the key terminology.  It’s not that the fundamental ideas behind fitness training are particularly challenging, but an early barrier to comfort with these programs can be as simple as understanding the basic terms and ‘lingo’ used regularly within this world.

So today, a little primer on a few key training terms particularly focused on the action and movement of muscles while doing functional strength training. By the way, functional strength training, the type of training at the core of 45 & Thrive, involves the performing of exercises against resistance (weights, machines, body weight) in such a manner that the improvements in strength and fitness are directly related to the movements and activities of an individual’s daily life. Put another way, we train in the gym to make the tasks, chores, work, fun, play, and life outside the gym easier.

Okay, let’s get started. An initial concept important to the understanding of human movement is that of Anatomical Position – This is the reference position for all body parts in relation to each other as standardized in the fields or medicine, anatomy, kinesiology, and personal training. In short, it is a map, or layout for the human body; standing upright, face and palms forward, feet approximately a shoulder-width apart, and arms hanging naturally at the side. From this standardized posture, body movements and indeed many of the names of body parts, are derived.

Flexion — Movement at a joint, or involving multiple joints where the joint angle decreases and the body part moves away from anatomical position. Example: When we perform a bicep curl with a dumbbell, the action from start of the exercise to the point where we have ‘curled’ it as far as possible, is a flexion.

Extension – Movement at a joint, or involving multiple joints where the joint angle increases and the body part returns to anatomical position. Example: When we perform a bicep curl with a dumbbell, the action from the end of the ‘curl’ portion, back to the starting (anatomical) position, is an extension.

Hyperextension – Movement at a joint, or involving multiple joints, where the body part moves from extension beyond anatomical position. Example: Tilting the head/neck back beyond anatomical position like when we look up at the stars, or when we arch our backs beyond anatomical position. Hyper, meaning beyond or excessive, may also used with the terms flexion and extension to describe a movement which goes beyond anatomical position to an unstable or injury prone position. We try to avoid that.

Concentric Muscle Contraction – The muscle(s) shorten as body segment moves through flexion. Example: When we perform a bicep curl with a dumbbell, during the flexion phase (first half of the overall exercise) the biceps muscle undergoes concentric contraction; the muscle fibres shorten as they add force to the resistance and movement occurs.

Eccentric Muscle Contraction – The muscle lengthens, under tension, as it returns to anatomical position. The muscle lengthens due to the resistance being greater than the force the muscle is producing. This happens as we either consciously ‘turn off’ some of our muscle fibres to allow the return motion to take place, or, when we are fatigued to the point where we can no longer produce enough force to hold the concentrically contracted position. Example: The controlled lowering phase of the bicep dumbbell curl results in this type of contraction of the biceps muscle. So, the biceps muscle does not only work as we curl the dumbbell upwards, but is also engaged as we lower the weight to the starting position. During this second phase of the exercise, this additional and complementary contraction occurs, which further works the muscle, and does so in a way different than a concentric flexion.

Isotonic Contractions A collective term which refers to the action of a muscle undergoing both concentric and eccentric contractions during exercise. Example: A complete bicep curl exercise, single repetition, from start to finish would be considered isotonic, as its fibres changed length while contracting throughout the exercise.

Isometric Contractions – A muscular contraction where the length of the muscle does not change. The muscle fires or activates with force/tension, but there is no movement at the joint. The joint remains static. This might sound counter-intuitive, but we have all contracted muscles, yet no movement has occurred. Simply standing upright and holding that posture requires muscles to contract and help hold that position, from our core, through to our legs and feet. In the gym, when we do ‘plank’ exercises, or hold a steady position performing a ‘wall sit,’ we are doing isometric exercise.

So, there you have it. Some key terms related to strength training and, in particular, how we both describe and understand body movements centred around muscle contraction through joints. Hopefully when these terms arise, either in discussion with a personal trainer, watching YouTube videos on new exercises or technique, or while reading about new training programs, an increased familiarity with these terms enhances understanding, focus, and performance of your training routines.

Next time, I look forward to discussing how, through 45 & Thrive, we apply an understanding of the mechanics and physiology of the various types of muscle contractions to our method of functional training in order to optimize gains, minimize time spent in the gym, and be prepared to enjoy life to its fullest through robust longevity.

Until next time…

Michael Patterson, M.Ed.
Lift long and Prosper

Michael Patterson M.Ed, has spent 30+ years as a fitness and health professional. He holds degrees in Physical and Health Education, Psychology, and Education. Find out more about Michael and follow him on his website at www.45andthrive.com, and on Instagram @45andthrive. Questions and comments can be sent to mpatterson@kos.net.


*Disclaimer: The information provided and discussed in this column is based on my personal experience, studies of physical and health education and my expertise as a lifelong fitness and health professional.  Any recommendations made about fitness, training, nutrition, supplements or lifestyle, or information provided through this column, should be discussed with your physician or other health-care professional.

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