The Laws of Motion and the Roles They Play in Strength Training

​If you are anything like me, you may feel eclipsed by the amount of theoretical and practical knowledge that you want to learn and apply constantly in a continued effort to develop in your professional world.

One of the areas of focus for me right now is to understand and best apply the science of training when I am training and educating my athletes. I constantly self-analyse and ask myself “how can I be better” – the answer, knowledge is king!
 
In this blog I shall dive deeper into outlining the application of forces and helping you to understand Newton’s Laws of Motion when applying them in strength training.

Newton’s First Law: the Law of Inertia

“Every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force”.

​​Or simply put – every object will remain at a state of uniform motion and stay in that state of motion until an external force is applied to it.

The key point to take away from this is that if there is no change in external forces acting on an object then the object will maintain a constant velocity.
 
We can observe the Law of Inertia in the very basic exercises we perform in the gym environment. When your athlete(s) are squatting, there are multiple changes of the external forces.

During the eccentric phase (descent) of the movement there is an evidential change in the external force that acts upon the barbell and the person in order to alter the velocity of the movement at the bottom. This is observed when your athlete stops and absorbs (isometric phase) the weight then reverses the direction of the movement, during the concentric phase (ascent).  In order to change the direction of a movement at a certain speed, we must be able to efficiently absorb the load through the deceleration phase, change direction and then accelerate. An example of this would be efficiently side stepping a defender when in attack.

When programming for your athlete(s), I would recommend the inclusion of Triphasic Training. I have found by incorporating a Triphasic phase, especially during pre-season, is very effective. I often incorporate a Triphasic phase once my athletes have conducted a 3-4 week ‘shock’ phase (others may call this a General Preparation Phase (GPP)). A Triphasic phase can be extremely taxing on the central nervous system; this is why I place my Triphasic phase after my ‘shock’ phase.
 
My ‘shock’ phase (or GPP) focuses on improving general strength and hypertrophy. This enables my athletes to become more resilient. The areas of focus are on the general movement patterns such as the Squat, Deadlift (and other hinge movements), Linear and Lateral movements plus upper body Push/Pull movements. Also incorporating various single leg variations.
I will cover Triphasic Training in greater detail in another blog.

Newton’s Second Law: the Law of Force and Acceleration

“Force is equal to the change in momentum (mV) per change in time. For a constant mass, force equals mass times acceleration: F=ma.”

​Or simply put – the relationship between an object’s mass (m), its acceleration (a) and the applied force (F) is F= ma. The key point to take away from this is Force is King.
 
In the most simplistic way I can understand and rationalise quantitative results in elite sport is; the difference between winning and losing (or coming 1st or 2nd place) is largely due to the difference in the athletes' ability to produce force. The ability to produce maximal force in both cyclic and acyclic sports is one of the key performance variables that we as S&C coaches need to look to exploit and encourage.
 
I have the term; Force is King in the forefront of my mind more often than not when training athlete(s), whether they are a beginner (amateur) or elite (professional). I aim to achieve maximal force production through varying methods of strength training.

For the beginner, I would use Modified Maximal Effort (MME) Training and for the elite, I would use Maximal Effort (ME) Training. The biggest differentiation between the two forms of training is that for the beginner by following a MME programme, they would increase their duration under load by looking to complete 3-5reps of their max (3RM). This would lead to an increase in strength and neural efficiency. However, by spending more time (reps) under the barbell, their confidence and efficiency for that lift will also be increased.

​For the elite athlete(s), following a ME programme whereby I will look at their 1RM (rather than their 3RM) will indicate that their competency, efficiency and strength has already been demonstrated for that lift.

Newton’s Third Law:  the Action - Reaction Law

“For every action, there is an equal and opposite reaction.”

​The key point to take away from this is that the reaction is equal and opposite. Forces always occur in pairs. When one body pushes or pulls against another the second body pushes or pulls back. 

Referencing from one of the many great articles on the Elitefts website, Newton’s third law can be explained further when relating to the force velocity curve. We already understand that every force has an equal and opposite reaction. Therefore if your athlete(s) are now stronger by moving left-right on the force velocity curve (Fig 1) following a periodized training programme, they will then have the ability to produce a greater amount of force that will propel their bodies or opponents’ bodies further.
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Fig 1

Wrapping up

​In summary, this blog has been challenging for me to put across, as I myself have learnt a lot from researching, understanding and producing the information in my own words on this topic. After all, I’m not the sharpest tool in the box when it comes to physics. Newton’s three laws of motion are very much apparent and can be reflected in every aspect of strength training.
 
The Law of Inertia states that if there is no change in external forces acting on an object then the object will maintain a constant velocity. By varying the muscular contractions involved in your athlete(s) training, this will hep to improve their; Maximal, Explosive, Starting and Accelerating strength. 
 
The Law of Force and Acceleration ultimately states that Force is King. By varying your methods of strength training and strength testing (ME & MME), you can achieve significant strength gains with your athlete(s) no matter what level they are at.

The Law of Action-Reaction states that for every action there is an equal and opposite reaction. By following the force velocity curve under a periodized training programme, your athlete(s) will improve in strength and in their ability to produce greater amounts of force.
 
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You're probably already going through some ideas in your head, right? Tell me how you can apply any of the Laws of Motion in you or your athletes’ training programme. I'd love to help out!