What is Strength Really?

Let us first correct that basic definition that strength is the ability of the body to produce maximum force. It is not! Strength is the ability of the body (muscles) to produce force; the ability of the body to produce maximum force is maximum strength. Even then, this implies that strength is some sort of general property of human capability, which totally ignores the fact that strength depends on the way in which it is produced or measured. After all, we frequently are exposed to arguments about who is the strongest type of person – the weightlifter, the powerlifter, the wrestler, the footballer, the manual labourer, the Highland Games contestant, a world Strongman competitor….?

 

 

So what does one generally do when a client approaches you to develop sport specific”strength”, “functional strength”, “core strength” or rotator cuff strength? Well, you design a programme based upon your personal education and experience, often almost reflexively choosing to use Olympic lifting methods, circuit training, machine training, HIT (“High Intensity Training”), plyometrics and so forth, depending more often on personal bias than a thorough, objective analysis of what is involved.

 

 

Your client might be an experienced athlete like a gymnast, boxer or martial artist who challenges you with the very real point that most of the best performers in their sports never use weights, so how can doing a power clean, balancing on a ball or using a resistance machine really improve their sport specific strength? Anecdotes about all the results you have achieved may be to no avail because your client might detect that you do not fully understand the nature of the specific forms of strength (and power) required. This is yet another reason why it is vital to understand the whole spectrum of what strength really is.

 

 

DEFINING STRENGTH

 

 

“maximal strength” is the ability of a particular group of muscles to produce a maximal voluntary contraction in response to optimal motivation against an external load. This strength is usually produced in competition and may also be referred to as the “competitive maximum strength.” It is not the same as “absolute strength” which usually is associated with the greatest force which can be produced by a given muscle group under involuntary muscle stimulation by, for example, electrical stimulation of the nerves – supplying the muscles or recruitment of a powerful stretch reflex by sudden extremes of loading.  This is roughly equivalent to maximal eccentric strength- but this is difficult to measure because there are feedback mechanisms in the body which would prevent our body from continuing to produce enough force to the point of mechanical and structural failure- basically an injury!!

 

 

Gil also got us to recognise the role of creating force internally to create bracing forces and effectively achieve Posture , as well as applying external forces against an object to create movement.

 

 

 To prevent confusion, we also need to note that the term “absolute strength” sometimes is used to define the maximum strength which can be produced irrespective of one’s body mass.

 

 

It is also useful to recognise that one may define isometric, concentric and eccentric strength maxima, since every sport requires distinct levels of each one of these types of maximum. As a matter of interest, these maxima given in order of magnitude are: eccentric, isometric, concentric, which most of us already know from training experience – we can always handle between 25-40 percent more load during the eccentric phase of most movements.

 

 

STRENGTH AND FITNESS

 

 

Now that we have dissected strength in greater depth we can define “fitness” (“the ability to cope effectively with a given stress”) in more detail. Fitness comprises a series of interrelated structural and functional factors, which conveniently may be referred to as the basic S-factors of fitness (Siff, “Supertraining”): Strength, Speed, Stamina (general endurance or local muscular endurance), Suppleness (flexibility), Skill (neuromuscular efficiency), Structure (somatotype, size, shape) and Spirit (psychological preparedness). Within the scope of skill, there is also a fitness quality known as Style, the individual manner of expressing a particular skill.

 

 

We can now construct a comprehensive model of physical fitness from the functional motor elements of fitness, as shown in Figure 1.

 

 

Gil showed us this diagram and made the case that there are very few exercises that can adequately train all these components fully, but perhaps an Olympic Weightlifting clean or snatch could be that exercise??!!

 

 

 

 

Figure 1. Pyramid Model showing the major components of musculoskeletal fitness

 

 

The diagram illustrates that strength, endurance and flexibility may be produced statically or dynamically, unlike speed, which changes along a continuum from the static to the dynamic state.

 

 

The quality of flexibility has been placed at the centre of the base of the pyramid, because the ability to exhibit any of the other qualities generally depends on existence of some range of movement (ROM). It should be noted that static or dynamic flexibility refers to the maximum ROM that may be attained under static or dynamic conditions, respectively. The line joining all adjacent pairs of primary fitness factors depicts a variety of different fitness factors between each of the two extremes. The model thus allows us to identify an extended list of fitness factors.

 

 

Complex fitness factors should be viewed as convenient descriptors of qualities which are involved in different proportions in a particular physical activity. Nevertheless, this pyramidal model enables us to understand sport specific fitness and training far more effectively than with a simplistic model based only on the primary functional fitness factors of strength, endurance, speed and flexibility.

 

 

One may also consider the concept of “relative strength” (e.g., how much you lift divided by your bodyweight), especially since a client may grow stronger in terms of absolute strength, but her bodymass may also increase, so that in relative terms, she has grown weaker. The improvement in other fitness factors relative to bodymass may also be highly relevant. For instant, “relative power” (power per unit bodymass) is very important in cases where the athlete has to increase power without increasing bodymass (e.g. a weightlifter or boxer in a specific bodymass division). In sports which require the athlete to increase muscle endurance without increasing bodymass, “relative endurance” needs to be enhanced. In this case, one might even distinguish between “relative static endurance” and “relative dynamic endurance”. Depending on the sport, improvement of “relative speed-strength endurance” (or relative strength endurance) under repeated cyclic or acyclic conditions, may also be relevant.

 

 

STRENGTH FACTORS IN ACTION

 

 

So far, we have discussed different types of strength or strength qualities as components of fitness, but it is also very informative to analyse strength at the level of individual actions. This is best done by studying the curve of how the force changes with respect to time for any given movement, such as the idealised and simplified graph in Figure 2

 

 

Gil showed us the diagram below WITHOUT the answers filled in and asked us to come up with the 7 missing qualities of strength.  As a group we were about 50% or so on the money so clearly a few days with Mr Siff and Supertraining for a refresher are required!!!

 

 

Figure 2 A typical force-time curve describing the lifting of a free weight from a given position and returning it to rest. Movement occurs only when the force exceeds the weight of the object, namely over the shaded portion of the curve.

 

 

Analysis of this curve reveals several characteristics associated with the production of strength, some of which we have not discussed yet, namely:

 

 

1. Starting Strength

 

2. Acceleration-Strength

 

3. Rate of Force Development (RFD)

 

4. Explosive Strength (Maximum RFD)

 

5. Maximum Strength

 

6. Strength-Endurance

 

7. Deceleration Strength

 

 

So to answer one of my questions which was, ‘ what is starting strength,’ below is the definition.  Remember also that a typical Force-Velocity curve is a Concentric representation of forces over time so technically the starting strength component (like the acceleration strength component) occurs up and to the left of the curve just behind maximal strength (it’s isometric)!! So it wouldn’t actually have a place on the typical curve like the one I have included below!!

 

 

 

 

Here, “starting-strength” refers to the ability of the muscles to develop force at the beginning of the working contraction before external movement occurs and is always produced under conditions of isometric muscle action. This fact alone has important consequences for strength training, because it dispels the opinion that the once-popular method of isometric training should be completely abandoned in modern training. On the contrary, the ability to generate starting strength rapidly can exert a profound effect on the dynamics of an entire movement, not only in terms of the magnitude of the impulse, but also regarding the psychological sensation of “lightness” that it creates during the crucial initial stage of a highly resisted movement. “Acceleration-strength”, describes the ability to quickly achieve maximal external muscle force once dynamic movement has begun.

 

 

“Explosive Strength” characterizes the ability to produce maximal force in a minimal time. It is most commonly displayed in athletic movements when the contraction of the working muscles in the fundamental phases of the exercise is preceded by mechanical stretching (such as any plyometric, throwing, kicking, striking or rebounding action in many sports). In this instance, the switch from stretching to active contraction uses the elastic energy of the stretch to increase the power of the subsequent contraction. Mathematically, it is given by the maximum value of the slope of the force-time curve (where this slope is called the Rate of Force Development, RFD).

 

 

“Strength-Endurance” characterizes the ability to effectively maintain muscular activity under work conditions of long duration. In sport this refers to the ability to produce a certain minimum driving force for a prolonged period. (Examples: any longer sprint events in running, cycling, swimming for dynamic strength-endurance, and any prolonged grappling in wrestling and scrumming in rugby for static or quasi-isometric strength-endurance).

 

 

“Deceleration-Strength” refers to the ability to slow down any movement whenever necessary, especially as a joint is reaching its end of range of movement. It occurs under eccentric conditions and frequently is called into play by reflexes, which are activated to prevent injury to the joints. It is vital that this quality be adequately developed in anyone who takes part in any rapid, ballistic or powerful sports, as well as in “plyometric” or rebound training, because many injuries can result from inefficiency in slowing down or halting a forceful movement.

 

 

If the load is near maximal, then the initial slope of the Force-Time curve is small and the time taken to produce movement is prolonged. This requires the exhibition of the motor quality of “static strength-endurance”, (Examples: wrestling or rugby scrumming) as opposed to “dynamic strength-endurance”, which refers to the muscle endurance required to maintain movement over a given interval (Examples: gymnastics, track running, longer sprint swimming ). This quality may be involved in carrying out a set of repetitions with a load or by maintaining cyclic work of various intensities

 

 

Suppose that we now wish to use this information to compare the performances of two different athletes in executing the same exercise. Athlete A may not be able to produce the same maximum force as athlete B, but he can produce his maximum faster than A, so that if they are to compete against one another in a contact sport, A may well defeat B in very short duration, explosive encounters. In general, if the sport concerned requires rapid Rate of Force Development, then athlete A will often have the advantage. This quality is essential in any sports that involve jumping, hitting or throwing, such as basketball, martial arts, American football and track-and-field. In this case, any training aimed at increasing B’s maximal strength or bulk will be misdirected, because he needs to concentrate more on explosive strength (RFD) training. If the sport requires a high maximal force or a large amount of momentum to be exerted irrespective of time (Examples: as in powerlifting or prolonged scrummaging or strongman contests), then athlete B will prove to be superior. In such a situation, athlete A will not improve unless he trains to increase maximal strength.

 

 

Incidently here is a Force-Time curve that Gil also showed us.  If you take the same definitions above you can start to see that an Olympic Lift develops nearly all the qualities of strength due to the nature of the lift.  Qualities 1 to 2 above are achieved from the initiation of 1st pull.  The quality of Reactive strength (not in Mel Siff definition) is achieved during the double knee bend or unweighting phase where there is an eccentric stretch of the quadriceps. This is followed by the qualities of 3, 4 and 5 to the end of the 2nd pull.  Then finally as you drop under the bar to catch it there is a massive requirement of 7 to decelerate the bar!!!! What an exercise!!!