Training is very much like academics.
This statement especially rings true when it comes to the SAID principle.
The SAID principle = Specific Adaptation to Imposed Demand.
In training, this is often not understood by trainees or even most trainers and as a result, it is generally ignored when exercise and goals are being planned out. This lack of regard for the SAID principle can actually be detrimental to the trainee and the trainees ability to accomplish their goal.
The key word to focus on here is specific. Meaning your body adapts to how it is trained, and as such – can adapt in many more ways than just the loss of fat and the hypertrophying of muscle tissue.
3 factors regarding training modalities and the need for specifcity:
1. A one size fits all approach does not work in fitness, the only cookie cutter factor in fitness is that everybody needs to train.
2. Doing the correct type of training will get you the correct type of adaptation. If you’re training to improve your grip in rock climbing, you aren’t going to be doing laps in a pool.
3. Training intelligently and with a purpose should be your top priority. This doesn’t mean you can’t try new things from time to time as fun, but do understand that every stimulus you impose on your body through exercise will request a response from the body – that adaptive response can very likely cause a counterproductive reaction regarding the specific goal at hand.
There’s many benefits that occur with strength training, such as neural adaptations involving disinhibition of inhibitory mechanisms, as well as intra- and intermuscular coordination improvements.
Disinhibition affects the following mechanisms:
– Golgi tendon organs – sensory receptors, located near the myotendinous junction, that elicit a reflex inhibition of the muscle they supply when it undergoes excessive tension, either by shortening or passive stretching
– Renshaw cells – inhibitory connecting neurons (interneurons) found in the spinal cord, whose role is to dampen the rate of discharge of alpha motor neurons, thus preventing the muscular damage derived from tetanic contraction
– Supraspinal inhibitory signals – conscious or unconscious inhibitory signals that come from the brain
(This is how you improve your body’s ability to function at cellular level).
The components of intramuscular coordination are as follows:
– Synchronization – the capacity to contract motor units simultaneously or with a minimum latency (that is, with a delay less than five milliseconds)
– Recruitment – the capacity to recruit motor units simultaneously
– Rate coding – the capacity to increase firing rate (motor unit discharge rate) in order to express more strength
(This is how you build the ability to perform better at any given physical task).
Now let’s take in to consideration the addition of cardiovascular training (benefits are the specific adaptations to the heart that occur from only cardio):
A study from 1976 in the Journal of Applied Physiology found two times the cortisol at 30min of cardio (75% intensity) compared to 10min of cardio. Excess cardiovascular training can have counterproductive adaptations to physiology when prolonged.
A study from 2011 analyzed the cortisol levels in 304 amateur endurance athletes and the average additional secretion above the control was 42%! This can lead to altered immune function, cognitive decline, damaged reproductive health, bone loss, etc. Excess cortisol can promote fat storage and muscle loss over time. This is mainly due because it inhibits testosterone, and generates a poor testosterone-to-cortisol (T:C) ratio.
Another way cardio or endurance exercise leads to muscle loss, is by causing a shift in fiber type. As illustrated below, endurance training produces a considerable shift from Type-2 (favour testosterone) to Type-1 muscle fibers (favour cortisol) in just 16 weeks. This means you will become weaker.
Other than facilitating testosterone and muscle growth, type-2 muscle fibers promote fat loss. Meaning, the less you have the less you burn. Interestingly, the inactive population has more type-2 fibers than endurance athletes!
Implying that NON-runners have superior testosterone-to-cortisol ratios; and suggesting that the practice of ‘jogging’ may be accelerating the muscle loss, fiber shift, and fat storage that’s normally associated with aging.
Excess cardio when in a caloric deficit can have some detrimental effects to your body composition as well. Research suggests that nearly 40% of weight lost in a caloric deficit is muscle.
At the end of the day, strength training with low rest intervals and in successive form is and will always remain superior in improvements in overall health, strength and body composition related goals.