Muscular strength is directly related to force production. Not only in sports but it is related to our each and every movement. Movement of our body parts is possible due to strength be it flexing a finger or getting up from the bed.
Paralysed people cannot move their body parts because they have lost the capacity to produce strength.
A new born baby cannot stand up and walk because they has less strength. So, we can say that for every movement of body part or for moving body from one position to another position, strength is required.
Whenever we think about sports performance, the first thing which comes into our mind is the muscular strength. Normally we use the term strength instead of muscular strength. If we ask someone a question, do you have the strength to do this physical work? He or she will knowingly or unknowingly flex his or her muscle and say I have the strength to do this. This shows in itself that somewhere strength is associated with muscles.
Strength is normally understood as the ability of the muscle or group of muscles of an individual to exert force against the resistance. If we are talking about exerting force then the question which comes in our mind is, why do we want to exert force? For this we have to look into the nature of the sports activities. We try to act against the resistance. Now the resistance can be of two types. It can be internal resistance like your own body weight or it can be external resistance like opponent’s body weight. In some of the cases we act against the resistance which we cannot conquer and in some of the cases we act to overcome that resistance. In both the cases we exert force with the help of our muscles.
Muscular strength is thus, ‘the ability of the muscle or muscle groups of an individual to exert force on the resistance to overcome it or to act against it as per the demand of the sports activity’.
Moving further, we look at how the muscular strength ability is used according to the nature of sports. We find that sometimes we need to apply force against the maximum resistance, but it is for shorter duration and sometimes we need to apply the force for longer duration.
Taking into account the nature of sports as far as strength abilities are concerned, we can divide the strength abilities into three parts—
(a) Maximum Strength: The name itself reflects that we are talking about something to its maximum limit. So, we can say that when our muscle or muscles group is able to generate the force with 100 per cent effort by which we are able to tackle the maximum resistance in a single contraction, it is called maximum strength of an individual. It is the ability which is of great use in the sports like weight lifting, throw events in athletics, etc.
(b) Explosive Strength: In some of the books, you may find this with the name of elastic strength. This is the ability where both strength and speed comes into play. When the muscle or group of muscles contract with high speed to overcome or to act against the resistance with 70 per cent to 80 per cent effort, then it is called the explosive strength. There are several examples where the explosive strength is required such as jumping, sprinting in athletics, boxing, etc.
(c) Strength Endurance: As it reflects from the name itself that it is related to the work which is done for longer duration. It is both strength as well as endurance which comes into play. In simple words, we can say that when our muscle or a group of muscles act against the resistance with 50 per cent to 60 per cent effort or try to overcome the resistance for longer duration in spite of having fatigue, then it is called that the individual is having strength endurance. There are many sports where we can easily see the use of this ability such as hill running in cross country race, cycling, swimming, etc.
As we know that strength depends upon the contraction of muscles and several other factors. So let us have a look on the factors which play major role in the liberation of force by the muscles.
These are as follows—
1. Neural Control: How much force the muscle will generate largely depends upon three major factors.
Number of motor units involved in the contraction — If the greater number of motor units are recruited then more amount of force will be generated.
Size of the motor units involved in the contraction — If the size of the motor units is greater, then also, the amount of force generated will be higher.
Intensity of nerve impulse — If the intensity of nerve impulse is faster, then also, the force generated by the muscle will be higher.
2. Muscle Cross-section: It is well known to everyone that liberation of force largely depends upon the size of the muscles. The more the size, the more force it will generate.
3. Muscle fibre: Muscles are made up of two types of fibres, one is fast twitch fibre (white) and another is called slow twitch fibre (red). Both the fibres are present in the muscles. The quality of the muscle depends upon the proportion of the fibres in the particular muscle. If the fast twitch fibres are more in ratio, then the muscle will contract faster and generate more force. This type of muscle has anaerobic capacity. Whereas, the muscle having slow twitch fibre will generate less force in comparison to the muscle with fast twitch fibres.
4. Energy supply: Muscles get their energy by the breakdown of ATP (Adenosine Triphosphate) and CP (Creatine Phosphate) which is stored in the body. The amount of ATP and CP store is very essential for the muscular activities as it provides the energy to the muscles.
5. Psychological factors: In many of the situations, the psychological factors contribute a lot in getting more forceful muscular contraction. The factors such as anger, aggression, motivation, etc., play a very crucial role in pushing their mind to develop very strong nerve impulse which can lead to activate more number of motor units.
