by Mr A.E. Hoosen
Strength is the ability of our muscles to overcome resistance. As you may be aware of your experience or from the experiences of others around you, strength can be gained and lost. This is as a result of a phenomenon described by the SAID (Specific Adaptations to Imposed Demands) principle. We take advantage of this by maintaining or improving our strength by performing some form of resistance training. Most perceive resistance training exclusive for the herculean fellows who frequent gyms, but as you shall hopefully read further on it is important for us all.
How do we gain strength?
We gain strength by repeatedly exposing our body to some form of resistance. There are three movement patterns which can be employed; isometric, isotonic and isokinetic movements.
Isometric movement is when one applies a force to an object, the object does not move and area of effect in the muscle occurs at one specific angle in the joint’s range of movement (ROM). An example of this would be when one tries to open a bottle and the lid does not budge.
Isotonic movements are movements where one applies a force to an object, the object moves as a result and the demand on the muscle occurs in a wider range within the joint’s ROM. This is the most common form of activity that people perform e.g. running and shall be discussed in further detail later.
Isokinetic movements occur when one moves a resistance provided by a dynamometer, at a specified speed and the demand of the muscle occurs at a specified range of the joint’s ROM. Isokinetic machines used to provide isokinetic training are limited in their use due to lack of proliferation of these machines due to the great expense of this equipment. Its value is that we are able to measure the strength of muscle groups that provide a specific movement and is useful to researchers, athletes and individuals who require some form of injury rehabilitation.
As mentioned above isotonic movements can be used to describe nearly all forms of activity; swimming, walking, lifting the groceries from the boot, brushing your teeth to training in a gym. For this discussion, what is important for you to know is there are two phases in isotonic movements. The first phase is the action phase or where you exert yourself to move against resistance, like standing up from a chair. The second phase is the relaxation phase, this is when you allow the resistance to overcome you and you return to your original position, from the standing position to the seated position. Most people just “plonk” in their chairs, but if you sit in a controlled manner using your legs and bum to slow your body down as opposed to using your arms to slow you down, the benefit of this will be seen in your legs.
Power, speed and muscle endurance can be trained depending on the level of resistance and the number of repetitions. Higher levels of resistance (75-90% of your maximum ability) performed with fewer repetitions (1-7 repetitions); tend to favour muscle power and speed. Lower levels of resistance (50-75% of your maximum ability) performed with higher repetitions (8-15 repetitions); favours muscle speed and endurance.
When one starts with training, one notices that within two to three weeks, one is able to perform against a higher resistance. This is due to improvements not specifically in the muscles but in the nerves that control muscle contraction. These nerves recruit muscle in a more efficient manner by increasing the proportion of the muscle fibres contracting at the same time and this result is seen in improved strength and enhanced muscle tone. Strength gains made after this are generally seen when the muscle increases in size (hypertrophy). This increase in size can be attributed to the gradual increase in resistance to the exercise or by increasing the speed of their action movement and by slow controlled movement in the relaxation phase
Why do we lose strength?
Our muscles are in a state of flux where protein components of muscle are constantly being added and removed. When we stop exercising or being active, we lose the speed at which we add protein to muscles. This has the effect of decreasing muscle size. Apart from decreasing muscle size, we dont use the neural pathways that connect to the muscle and the nerve component becomes inefficient and as a result a smaller proportion of the muscle fibres contract exerting less force and is displayed as weakness.
The Benefits of strength training.
Athletes benefit from strength training in the improvement of speed, power and endurance. Non-athletes also gain this benefit however this is generally not why they remain active in training. Increases in muscle tone and size are the aesthetic benefits of training. The increases in muscle mass, enhances metabolism, aiding those in weight loss programmes and can be a means of improving blood sugar control for diabetics.
Joint stability is enhanced, muscles that surround the joint become stronger and it allows for better joint mechanics which is beneficial for injury prevention. Enhanced joint mechanics coupled with better nerve efficiency results in improvements in overall balance.
Tendons which are the muscular attachments to bone also strengthen due to the repeated tension applied by contracting muscle. This is beneficial to those who have osteoporosis. Due to the tension applied to the bone, via the tendon and the muscle working against a resistance, bone density can improve if the appropriate stimulus is applied. The enhancement of balance means that the chances of a fall occurring are less likely. This is most favourable to the person who wants to prevent the progression of osteoporosis.
As we age, our muscle composition and strength decreases. This is a natural process; however it can be slowed down to a degree allowing us to maintain strength, power and muscular endurance. Children can also benefit from strength training however children should approach with caution and must be supervised by a professional like a biokineticist. Body weight resistance exercises are appropriate for children, however with the ever increasing demands of high school sport, more youth are turning to weight training. In order for these individuals to train safely and avoid injury to their growth centres in their bones they should avoid heavy weights. Youth should focus on correct form and technique first using low intensity resistances, before progressing to a moderate intensity resistance.
Well thats it for all the theory - we look forward to seeing you in ACTION!
