I have a question for you.  What is strength?  How do you know that someone is “strong” when watching him/her in a sport or compared to someone else?  What criteria as you thinking about when you think of a strong person?  A football player, perhaps?  Or maybe those crazy guys and gals on ESPN’s “World’s Strongest Man and Woman” competitions.  Well, believe it or not, there are actually many sub-categories of strength and having a better understanding of each will make your efforts in the gym pay off when you are training for your sport.

Limit Strength

The first classification of strength we’ll look at is limit strength.  You most likely have never seen limit strength demonstrated in person, but you may have heard the familiar story of the mother lifting the car off her injured child to save him.  Well folks, that is limit strength!  Limit strength usually only appears as a survival response and is the peak force your nervous system is capable of exerting in a single, maximum contraction.  This is an involuntary strength, meaning you can’t consciously head out to your car and just lift it up no matter how psyched you are!  Hypnosis can also produce limit strength in those individuals susceptible to it, but that would be a rather odd request of your hypnotherapist!

Maximum Strength

Maximum strength the peak force your nervous system is capable of producing in a single voluntary contraction without any consideration of time.  The time factor is important, as we’ll see when we defined some other strength qualities.  Maximum strength is best demonstrated by powerlifters competing in a meet.  These folks are trying to lift the most weight they can, and it doesn’t matter if it takes 2 seconds or 5.  For the recreational weight trainer, this is representative of your 1 repetition maximum in an exercise. 

There are three true levels of maximum strength: your concentric, isometric, and eccentric.  Your concentric maximum is the most weight you can lift against gravity.  For example, in the bench press, the concentric maximum would be the most weight you can push off your chest to lock-out.  This is actually your weakest strength.

Your isometric strength is the most weight you can hold in a certain position.  The amount you can hold depends on the joint angles of the exercise you are referring to, but generally this strength is about 10-15% stronger than your concentric strength.  An example of this strength would be the amount of weight you could hold at lock-out of the bench press.

Finally, your eccentric strength is the maximum amount of weight you can lower under control during an exercise.  Under control is the key word, since a falling weight does not demonstrate your eccentric strength.  In general, eccentric strength is about 30-100% stronger than concentric strength on any given exercise.  This is an important strength quality, especially for those seeking maximum strength performance.

Speed-Strength

Speed-strength is a primary quality of most sports and highly coveted for that reason.  When you think of a “powerful” player, you are most likely thinking of speed-strength.  Speed-strength is the ability of the nervous system to produce the greatest force possible in the shortest time possible.  Here comes the time factor!  If you lift 200 pounds in the bench press in 5 seconds, and your buddy lifts the same 200 pounds in the bench in 2 seconds, your buddy is more powerful than you are.  This is one reason why “powerlifting” as a sport is technically mis-named, since there is no time component for the lifters to concern themselves with.  A running back hitting the hole hard and an Olympic weightlifter performing the clean and jerk and snatch are two great examples of speed-strength.  Sprinters are another excellent example.  But this strength quality is broken down into three sub-categories as well:

a.       Starting strength: this is the capacity to generate force at the beginning of a muscular contraction and initiate movement.  This is the key component when the resistance the athlete must overcome is light (e.g. baseball pitchers) or non-existent (e.g. boxers throwing a punch).

b.      Explosive strength: the capacity to develop force quickly once movement has been initiated, or the rate at which one can develop maximal force.  This strength quality is important in sports where the resistance to overcome is fairly heavy, such as a shot-putter or wrestler. 

c.       Reactive strength: the ability to switch from an eccentric contraction to a concentric contraction.  This quality is referred to as the stretch-shortening cycle by sports researchers.  This is an important strength in sports where jumping and ballistic movements are common, such as basketball and volleyball.

Absolute Strength

Absolute strength is the maximum force a person can generate, irrespective of bodyweight and time of force development.  Offensive linemen are strong and big.  So are sumo wrestlers.  Neither athlete is usually concerned with gaining a little extra mass, whether that is muscle or fat, since the extra weight will assist them with their sport.

Relative Strength

This is the maximum force a person can produce per unit of bodyweight, irrespective of time of force development.  This usually affects athletes in weight-class sports, such as boxing, wrestling and judo.  These athletes want to be as strong as they can be and usually as light as they can be.  In fact, many team sport athletes should be concerned with their relative strength development.  A basketball player that gains 50 pounds on his squat, but also gains 20 pounds of bodyweight may or may not be a better player (depending on whether or not the athlete needed the extra bodyweight). 

Optimal Strength

This is the optimal level of maximal strength needed for a particular sport, in that and further increase in strength would NOT improve performance.  This seems somewhat contradictory at first, since many folks erroneously believe that an athlete can never be too strong.  In actuality, some sports abilities would be hampered by dramatic strength increases.  As an example, a tennis player would benefit from a strength-training program tremendously.  But, if that same player focuses on developing his maximal strength to the fullest, he may become a poorer tennis player.  Maximal strength is not correlated to performance in a sport like tennis.

Strength Endurance

The last strength quality we’ll look at refers to the athlete’s ability to resist fatigue in strength performances of long duration.  This is an important quality in elite level rowers and cyclists.  The resistance that must be overcome for long durations may vary, from relatively heavy (e.g. wrestlers in 3 minute round matches) or relatively light (e.g. table tennis).  Different training regimes are needed in each scenario.

There you have it—a primer on the different strength qualities.  You never knew that such a straight-forward topic was actually more complex.  The training parameters for each strength quality vary as well and we can look at that more in future articles.

Note: Much of the material for this article was adapted from the Poliquin Performance International Certification Program Theory Level 1 Manual.